U.S. patent application number 16/103643 was filed with the patent office on 2019-02-21 for unmanned aerial vehicle system for inspecting railroad assets.
The applicant listed for this patent is BNSF Railway Company. Invention is credited to Todd Graetz, Gary Grissum, Michael Mischke.
Application Number | 20190054937 16/103643 |
Document ID | / |
Family ID | 65360188 |
Filed Date | 2019-02-21 |
View All Diagrams
United States Patent
Application |
20190054937 |
Kind Code |
A1 |
Graetz; Todd ; et
al. |
February 21, 2019 |
UNMANNED AERIAL VEHICLE SYSTEM FOR INSPECTING RAILROAD ASSETS
Abstract
An aerial system control network, an unmanned aerial vehicle
(UAV) system, and a method provide for inspecting railroad assets
using a UAV. The aerial system control network includes a plurality
of towers and a ground control system connected to the plurality of
towers. The ground control system transmits, via a plurality of
communication towers, a flight plan including a rail system and a
flight path; receives, via the plurality of communication towers,
data while the UAV is in monitoring the rail system; detects an
interference along the flight path based on the received data, and
adjusts the flight plan based on the interference.
Inventors: |
Graetz; Todd; (Keller,
TX) ; Grissum; Gary; (Fort Worth, TX) ;
Mischke; Michael; (Fort Worth, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BNSF Railway Company |
Fort Worth |
TX |
US |
|
|
Family ID: |
65360188 |
Appl. No.: |
16/103643 |
Filed: |
August 14, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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62545946 |
Aug 15, 2017 |
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62548636 |
Aug 22, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B61L 23/044 20130101;
G06T 2207/10016 20130101; G08G 5/0013 20130101; B64C 39/024
20130101; B61L 23/047 20130101; B61L 23/04 20130101; G06T
2207/10032 20130101; G08G 5/0069 20130101; G08G 5/0039 20130101;
G06T 7/001 20130101; B61L 23/041 20130101; B61L 23/048 20130101;
G06T 2207/30184 20130101; G08G 5/0034 20130101; G06T 2207/30108
20130101; B64C 2201/123 20130101 |
International
Class: |
B61L 23/04 20060101
B61L023/04; G08G 5/00 20060101 G08G005/00; G06T 7/00 20060101
G06T007/00; B64C 39/02 20060101 B64C039/02 |
Claims
1. An aerial system control network for an unmanned aerial vehicle
(UAV) for inspecting railroad assets comprising: a plurality of
towers; and a ground control system connected to the plurality of
towers, the ground control system configured to: transmit, via a
plurality of communication towers, a flight plan including a rail
system and a flight path, receive, via the plurality of
communication towers, data while the UAV is monitoring the rail
system, detect an interference along the flight path based on the
received data, and adjust the flight plan based on the
interference.
2. The aerial system control network of claim 1, wherein the
received data includes current air traffic data, obstruction data,
geographic information data, and aviation voice data.
3. The aerial system control network of claim 1, wherein: the
plurality of communication towers include an aviation band radio
configured to communicate data with other aerial vehicles, and the
flight plan is adjusted based on the communicated data.
4. The aerial system control network of claim 1, wherein: the UAV
includes at least one camera configured to capture images of the
rail system, and the received data includes a plurality of images
captured from the at least one camera mounted on the UAV.
5. The aerial system control network of claim 4, wherein the ground
control system is further configured to: monitor the plurality of
images for a deviation from the flight plan; adjust the flight plan
to maintain the rail system in the plurality of images.
6. The aerial system control network of claim 1, wherein the ground
control system is further configured to: monitor the plurality of
images for a faulty condition of the rail system.
7. The aerial system control network of claim 6, wherein the faulty
condition is identified from: a difference in an first image and a
second image taken in succession along the flight path; and a
difference in the first image and a stored image from a previous
flight of the UAV captured of the same location.
8. An unmanned aerial vehicle (UAV) system for monitoring a rail
system, the UAV system comprising: a UAV; and an aerial system
control network comprising: a plurality of communication towers;
and a ground control system connected to the plurality of towers,
the ground control system configured to: transmit, via the
plurality of communication towers, a flight plan including a rail
system and a flight path, receive, via the plurality of
communication towers, data while the UAV is monitoring the rail
system, detect an interference along the flight path based on the
received data, and adjust the flight plan based on the
interference.
9. The UAV system of claim 8, wherein the received data includes
current air traffic data, obstruction data, geographic information
data, and aviation voice data.
10. The UAV system of claim 8, wherein: the plurality of
communication towers include an aviation band radio configured to
communicate data with other aerial vehicles, and the flight plan is
adjusted based on the communicated data.
11. The UAV system of claim 8, wherein: the received data includes
a plurality of images captured from at least one camera mounted on
the UAV.
12. The UAV system of claim 11, wherein the ground control system
is further configured to: monitor the plurality of images for a
deviation from the flight plan; adjust the flight plan to maintain
the rail system in the plurality of images.
13. The UAV system of claim 11, wherein the ground control system
is further configured to: monitor the plurality of images for a
faulty condition of the rail system.
14. The UAV system of claim 13, wherein the faulty condition is
identified from: a difference in an first image and a second image
taken in succession along the flight path; and a difference in the
first image and a stored image from a previous flight of the UAV
captured of the same location.
15. A method for an aerial system control network of an unmanned
aerial vehicle (UAV) for inspecting railroad assets, the method
comprising: transmitting, via a plurality of communication towers,
a flight plan including a rail system and a flight path; receiving,
via the plurality of communication towers, data while the UAV is
monitoring the rail system; detecting an interference along the
flight path based on the received data; and adjusting the flight
plan based on the interference.
16. The method of claim 15, wherein the received data includes
current air traffic data, obstruction data, geographic information
data, and aviation voice data.
17. The method of claim 15, further comprising: communicating, via
an aviation band radio in the plurality of communication towers,
data with other aerial vehicles, wherein the flight plan is
adjusted based on the communicated data.
18. The method of claim 15, wherein: the received data includes a
plurality of images captured from at least one camera mounted on
the UAV.
19. The method of claim 18, further comprising: monitoring the
plurality of images for a deviation from the flight plan; adjusting
the flight plan to maintain the rail system in the plurality of
images.
20. The method of claim 18, further comprising: monitoring the
plurality of images for a faulty condition of the rail system,
wherein the faulty condition is identified from: a difference in an
first image and a second image taken in succession along the flight
path; and a difference in the first image and a stored image from a
previous flight of the UAV captured of the same location.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY
[0001] This application claims priority under 35 U.S.C. .sctn.
119(e) to U.S. Provisional Patent Application No. 62/545,946 filed
on Aug. 15, 2017 titled "AN UNMANNED AERIAL VEHICLE SYSTEM FOR
INSPECTING RAILROAD ASSETS." This application also claims priority
under 35 U.S.C. .sctn. 119(e) to U.S. Provisional Patent
Application No. 62/548,636 filed on Aug. 22, 2017 titled "AN
UNMANNED AERIAL VEHICLE SYSTEM FOR INSPECTING RAILROAD ASSETS." The
above-identified provisional patent application is hereby
incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates in general to railroad asset
management and in particular to an unmanned aerial vehicle system
for inspecting railroad assets.
BACKGROUND
[0003] The safety and efficiency of railroad operations is heavily
dependent upon constant analysis of trains, right-of-way, rail
track and other assets/facilities. There are a wide variety of
factors that can affect track conditions and impact train movement,
including criminal activity, and extreme weather events that can
lead to track flooding and rail bed erosion or overheating (track
can buckle or distort in high heat). Earthquakes, landslides, and
abandoned vehicles and other objects at grade crossings can block
track.
[0004] Vigilance is always the best defense against these hazards.
As a result, pursuant to Federal Railway Administration (FRA)
regulations and company policies, track/right of way and bridge
maintenance employees routinely inspect the tracks and the
underlying infrastructure, such as bridges, tunnels, support
structures, and signals. At present, this work is done primarily by
company personnel in motor vehicles, on foot, in specialized rail
equipment, or in rail-mounted hi-rail vehicles. This is often a
labor-intensive and sometimes arduous job. While a railroad may do
all it can to make human inspections as safe and accurate as
possible, there is an irreducible element of risk involved whenever
employees are required to go out on track and rail structures.
Employees may need to climb over or onto track structures, which
can be slippery, rough, and/or exposed to the elements. Some
structures, such as bridges, are high above the ground. Trains
moving through inspection zones can increase risk as well,
especially in high-traffic areas.
SUMMARY
[0005] Embodiments of the present disclosure provide an aerial
system control network, an unmanned aerial vehicle (UAV) system,
and a method for inspecting railroad assets using an unmanned
aerial vehicle.
[0006] In one example embodiment, an aerial system control network
provides for inspecting railroad assets using an unmanned aerial
vehicle. The aerial system control network includes a plurality of
towers and a ground control system connected to the plurality of
towers. The ground control system transmits, via a plurality of
communication towers, a flight plan including a rail system and a
flight path; receives, via the plurality of communication towers,
data while the UAV is in monitoring the rail system; detects an
interference along the flight path based on the received data, and
adjusts the flight plan based on the interference.
[0007] In another example embodiment, an unmanned aerial vehicle
(UAV) system provides for inspecting railroad assets using an
unmanned aerial vehicle. The unmanned aerial vehicle (UAV) system
includes a UAV and an aerial system control network. The aerial
system control network includes a plurality of towers and a ground
control system connected to the plurality of towers. The ground
control system transmits, via a plurality of communication towers,
a flight plan including a rail system and a flight path; receives,
via the plurality of communication towers, data while the UAV is in
monitoring the rail system; detects an interference along the
flight path based on the received data, and adjusts the flight plan
based on the interference.
[0008] In another example embodiment, a method provides for
inspecting railroad assets using an unmanned aerial vehicle. The
method includes transmitting, via a plurality of communication
towers, a flight plan including a rail system and a flight path;
receiving, via the plurality of communication towers, data while
the UAV is in monitoring the rail system; detecting an interference
along the flight path based on the received data, and adjusting the
flight plan based on the interference.
[0009] Other technical features may be readily apparent to one
skilled in the art from the following figures, descriptions, and
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] For a more complete understanding of the present disclosure
and its advantages, reference is now made to the following
description taken in conjunction with the accompanying drawings, in
which like reference numerals represent like parts:
[0011] FIG. 1 illustrates an exemplary railway network according to
the various embodiments of the present disclosure;
[0012] FIG. 2 illustrates an exemplary unmanned aircraft systems
(UAS) operations flight control center according to the various
embodiments of the present disclosure;
[0013] FIGS. 3A and 3B illustrate exemplary UASs according to the
various embodiments of the present disclosure;
[0014] FIG. 4 illustrates an exemplary command center (CC) user
interface (UI) according to the various embodiments of the present
disclosure;
[0015] FIG. 5 illustrates an exemplary ground control system (GCS)
facility according to the various embodiments of the present
disclosure;
[0016] FIGS. 6A and 6B illustrate an exemplary telecommunications
tower according to the various embodiments of the present
disclosure;
[0017] FIG. 7 illustrates an exemplary radio frequency (rf)
coverage analysis according to the various embodiments of the
present disclosure;
[0018] FIG. 8 illustrates an exemplary overall system schematic
according to the various embodiments of the present disclosure;
[0019] FIG. 9 illustrates an overview of an exemplary air traffic
awareness system according to the various embodiments of the
present disclosure;
[0020] FIG. 10 illustrates an overview of an exemplary air traffic
awareness system 1000 according to the various embodiments of the
present disclosure;
[0021] FIG. 11 illustrates an exemplary user interface display of
air traffic according to the various embodiments of the present
disclosure;
[0022] FIG. 12 illustrates an exemplary unmitigated near mid-air
collision risk according to the various embodiments of the present
disclosure;
[0023] FIG. 13 illustrates an exemplary pedestrian risk zone
according to the various embodiments of the present disclosure;
[0024] FIG. 14 illustrates an exemplary safe corridor airspace
(SCA) interface according to the various embodiments of the present
disclosure;
[0025] FIGS. 15A, 15B, and 15C illustrate exemplary faulty rail
conditions according to the various embodiments of the present
disclosure;
[0026] FIG. 16 illustrates an exemplary concept of operations
according to the various embodiments of the present disclosure;
[0027] FIG. 17 illustrates an exemplary UAS ecosystem according to
the various embodiments of the present disclosure;
[0028] FIG. 18 illustrates an exemplary UAS system components
according to the various embodiments of the present disclosure;
[0029] FIGS. 19A, 19B, and 19C illustrate exemplary UASs according
to the various embodiments of the present disclosure
[0030] FIG. 20 illustrates an exemplary optical sensor according to
the various embodiments of the present disclosure;
[0031] FIGS. 21A and 21B illustrate an exemplary UAS safety
boundaries according to the various embodiments of the present
disclosure;
[0032] FIGS. 22A and 22B illustrate exemplary track integrity
sensor images according to the various embodiments of the present
disclosure;
[0033] FIGS. 23A, 23B, 23C, and 23D illustrate an exemplary UAS
potential rail head defect according to the various embodiments of
the present disclosure;
[0034] FIG. 24 illustrates an exemplary block diagram of control
network according to the various embodiments of the present
disclosure;
[0035] FIG. 25 illustrates an exemplary right of way/aerial system
control network according to the various embodiments of the present
disclosure; and
[0036] FIG. 26 illustrates an example process for inspecting
railroad assets using an unmanned aerial vehicle in accordance with
various embodiments of the present disclosure.
DETAILED DESCRIPTION
[0037] FIGS. 1 through 26, discussed below, and the various
embodiments used to describe the principles of the present
disclosure in this patent document are by way of illustration only
and should not be construed in any way to limit the scope of the
present disclosure. Those skilled in the art can understand that
the principles of the present disclosure may be implemented in any
type of suitably-arranged device or system.
[0038] Preferred embodiments of the principles of the present
invention are based on an unmanned aerial vehicle (aircraft)
capable of vertical takeoff and landing. Among other things, the
aircraft includes an autopilot system that interfaces with the
system command and control infrastructure. The aircraft also
processes navigation information generated from geographic
information systems, and supports various onboard sensors providing
location information. The aircraft and overall right of way systems
also feature equipment that are capable of transmitting to, and
receiving information from, an onboard navigation beacon (ADSB)
and/or a mode C transponder or its equivalent.
[0039] Embodiments of the aircraft have sufficient onboard
electrical power generation capability to provide reliable power to
all of the other various aircraft systems, such as the sensor,
communications, and control subsystems. In addition, the aircraft
preferably has sufficient liquid fuel capacity to support flight
durations in excess of 8 hours. The aircraft also has the payload
capability needed to support multiple sensors for gathering
information and the communications and control subsystems need to
pass that information in real time to a flight operations center.
The aircraft preferably also includes onboard information storage
media for local storage of gathered information. In addition, the
system includes both onboard and external subsystems for
facilitating emergency maneuvering and landing of the aircraft on
the flight corridor.
[0040] In general, the onboard sensors take high resolution precise
location photos no less than two times a second and 1/4 foot or
greater resolution from the operating altitude. Preferably, the
sensor system also has built-in local computational capability, its
own navigation system, and independent communication capability for
communicating with other onboard subsystems including the
autopilot. The sensors may include a photo sensor, a video camera,
a thermal imager, and/or a multispectral sensor. In particular, the
sensor system includes a real time day and night video camera for
pilot situational awareness, which includes at least some limited
real time protection capability.
[0041] The system also includes software focused on rail detection
and analysis of right of way conditions, which advantageously
support the inspection of linear assets, such as track, bridges,
and the like. Among other things, the system software, both onboard
and remote, includes machine vision software trained to understand
and recognize critical conditions within an area with at least two
linear borders. The system software is also capable of validating
normal functional conditions on the linear area.
[0042] More specifically, the onboard software runs on the aircraft
in a line between the sensors and the ground based communications
systems. The onboard software processes data collected by sensors,
which is then loaded onto ground based computational systems that
in turn output quantitative and qualitative data about what the
sensors have seen. The software system processes bulk data, creates
another set of geo-located data, and then creates a third set of
data. The system software creates several reports that are
associated with the data of interest, creates a geo-location file
that can allow the users to easily map the location of selected
conditions of interest. Preferably, the bulk data remains
unprocessed and the receivers receive only useable data that they
truly need with bulk data stored for future data mining and
use.
[0043] The system software also includes field information
software, which could be used separately of this system or even
with multiple aircraft. The field information software embodies an
algorithm that maps functionality and determines what order the
software should perform operations, which advantageously eliminates
human error. In particular, the field information software receives
media generated by the sensor system, transfers those data into a
laptop or other processing system, and then starts the local
software. The local software automatically codes, labels and
transfers the data to a drive and files and appropriately transmits
those data to whoever requires them (e.g., different departments in
an organization). The field information software may be used for
any gathered data related to a field location. The field
information software is preferably based on a networked system,
including a server or set of hardware devices. In some embodiments,
the field information software runs after conclusion of a flight by
the aircraft (i.e., performs post-flight data processing). Data may
be distributed among the networked resources, which perform further
analysis and ensure that the data are properly coded and stored.
This helps maintain a chain of custody and minimizes data
errors.
[0044] Right of way, corridors, and towers are important factors in
an aerial railroad inspection system. The present system accesses
the 900 MHz channels used for the automatic train control system
(ATCS) implemented through the AAR, although the actual spectrum in
use is not a strict requirement for practicing the present
principles--other secured and licensed spectrum can be purposed.
The hardware and software of the present system are optimized to
use the low bandwidth AAR channel in a highly functional manner.
For systems using the preferred AAR channels, the user normally
requires a license, and redundant Ethernet controls including
appropriate channels to communicate with the aircraft. These can be
implemented with railroad telecommunications assets.
[0045] The aircraft is preferably a vertical takeoff and landing
aircraft and operates (including landings) anywhere along a
railroad asset network. Once the aircraft is in the air, the pilot
commands the autopilot to start the flight. The flight commences
and the aircraft flies according to a route programmed by
geographical information systems to an actual railroad right of way
and follows that right of way. In other words, when the pilot
actuates the autopilot, the system software takes over and flies
the aircraft as close as possible once over track. The software
system also automatically enables the sensors to start taking two
pictures per second of the track. At the same time, the sensor and
software systems control the pitch, yaw, and roll of aircraft and
sensors such that the appropriate sensor or sensors remain focused
and placed over the track to ensure the required resolution and
overlapping imagery. If analytics software determines after the
flight that there was not enough overlap, or if sections of track
were missed due to right of way occupancy, then the route is
quickly re-flown and the sensor takes more images.
[0046] While the autopilot is on and the sensor are taking photos,
the aircraft control system is leveraging space-based GPS, and
where available, ground based GPS error correction, to keep the
aircraft positioned over the row and maintain operating altitude
and linear flight path compliance, which both guarantees sensor
resolution and compliance with regulatory requirements regarding
heights and width of flight path.
[0047] Again, preferably the aircraft and sensor have independent
navigation systems. Advantageously, when both the aircraft and
sensor(s) have independent navigational systems, computational
power is preserved for critical items tasked to each component. For
example, the sensor system may include sensor stabilization
software and hardware and the sensor is also capable of disabling
image gathering when not over private property.
[0048] Preferably, the aircraft broadcasts its location, speed,
altitude and heading via the existing FAA surveillance network
(SBS) and also to other aircraft equipped to receive these signals.
In addition, the railroad's infrastructure may support
supplementing the FAA SBS system using supplemental
ADSB/transponder receivers, radar and other elements placed along
the right of way. While the aircraft is in flight, its operating
condition, location and overall health are transmitted to the pilot
via the command and control link. During all phases of the flight,
the aircraft has access to multiple command and control transceiver
locations assuring a level of redundancy of command and
control.
[0049] If the aircraft loses connection to the command and control
system, after a period of time as determined by the operator and/or
FAA rules, the aircraft can initiate its "lost link profile" and
either return to launch via pre-determined pathways or in a loss of
communication and power, auto descend and set itself down along the
railroad right of way. The pilot can be aware of lost link
condition and based on the last transmission form the aircraft
would notify users on the row and dispatchers of the aircraft
eminent landing. The sensors secondary communications and
navigation systems may also assist with locating the aircraft.
[0050] If during flight there are other critical systems failures,
the aircraft either automatically initiates one of several
pre-determined flight termination procedures returns to its
launching location or other location of safety as programmed.
During the course of flight, the pilot has the option of utilizing
a second sensor for real time imagery of the row. This secondary
sensor can also be used for some condition analysis, but is
primarily for pilot awareness. If during the course of flight a
critical condition is identified, the aircraft's sensor can utilize
a secondary communications channel not connected to the primary to
send immediate notification to the pilots.
[0051] At the end of a specified mission, the pilot engages the
landing procedures, the aircraft leverages all of the
aforementioned systems to arrive at the landing site, and engages
the landing procedures for vertical landing. The landing procedure
includes the enablement of an air to ground laser providing the
aircraft with precision landing information. In final stages of
fight before landing, the pilot uses the aircraft command and
control system to assure a safe landing. The aircraft has multiple
support systems on board to assure a safe landing. If anything is
present on the ground or area of landing that would preclude a safe
landing, the landing abort procedure is initiated and alternate
landing site is used. After a safe landing, the pilot removes the
sensor data storage drives and plugs them into a server. The server
systems then commence an automated process of analytics and data
delivery that results in delivery of customized reports and
actionable data sets.
[0052] FIG. 1 illustrates an exemplary railway network 100
according to the various embodiments of the present disclosure.
While a railway network is shown in FIG. 1, the principles of the
present disclosure are equally applicable to other types of
networks. The embodiment of railway network 100 shown in FIG. 1 is
for illustration only. Other embodiments of the railway network
could be used without departing from the scope of this
disclosure.
[0053] The freight railway network, shown in FIG. 1, is roughly
32,500 miles of railroad track in mostly rural areas of the western
United States. To safeguard this critical transportation
infrastructure and the communities nearby, routine inspections are
currently performed using a variety of on-track vehicles and
equipment. To enhance those inspections while also improving
occupational safety for railroad personnel, aerial surveillance of
its railroad infrastructure can be performed using unmanned
aircraft systems (UAS). These operations can be beyond visual
line-of-sight (BVLOS) during day and night in visual meteorological
conditions.
[0054] The tracks, comprising the freight railway network and the
area around them ("the property") and the assets on the property
are accurately surveyed using GPS (global positioning system) and
other technologies, such as LIDAR (light detection and ranging). An
enterprise-level geographical information system (GIS) contains
this data and this information is used to plan and conduct flights
directly over its property.
[0055] The unmanned aircraft (UA) is capable of vertical takeoff
and landing (VTOL) and has 10 hours endurance flying at a cruise
speed of approximately 40 kts with a sprint speed in excess of 60
kts. Navigation is via a GPS waypoint-based flight plan. The route
of flight is directly above railroad tracks at above ground level
(AGL) altitudes of 400 ft. and below. The cruise altitude is
typically 380 ft. AGL. The autopilot can hold this altitude to
within +/-10 feet in calm wind conditions and can correct when wind
or environmental factors push the aircraft up or down. The
navigation performance of the system can allow the UA to remain
within a lateral corridor that is approximately +/-100 ft. of the
centerline of the main railroad track. This lateral corridor
corresponds to the bounds of the property. Most avoidance maneuvers
or loiter orbits, when necessary to maintain safety, can be
completed within +/-1,500 ft. of the main track centerline. Sensors
carried onboard the UA are designed to have a narrow field of view
so that data and images collected are of the track area only.
[0056] The rail network is organized into divisions and
subdivisions. Each subdivision contains a length of track 50-300
miles in length. Subdivisions interconnect. Near each terminus of a
rail subdivision is a yard facility covering many acres. These
yards facilities can be staffed and equipped to support UAS
operations. An operator can operate a UAS across the majority of
its network by launching from a yard, flying along a subdivision,
and landing at the next yard where the UA can be inspected,
maintained, refueled, and relaunched. The operator can fly two
missions per day on up to 100 subdivisions.
[0057] To monitor and control its UAS, the operator can leverage
its experience with developing and deploying PTC (positive train
control). The operator uses its existing telecommunications
infrastructure, including privately-owned secured tower facilities
and terrestrial backhaul network, for command and control (C2) of
the UAS fleet, to implement voice communications over VHF aviation
radios, and to provide the flight crews with weather information
from a series of stations located along the tracks.
[0058] The telecommunications network is designed to be robust and
redundant. The telecommunications network reaches back to a network
operations center (NOC) at its headquarters. From the NOC, a train
positioned on any subdivision in the network can be dispatched. The
switches and signals along its route are controlled and crew
coordination over voice radio is conducted entirely from this
central location. Similarly, each UAS can be controlled from its
ground control station (GCS) at a regional flight control center by
one pilot-in-command (PIC) and one co-pilot from either a regional
flight control center or from a central location. It is possible
for the aircraft to be controlled from multiple locations during
the duration of the flight. For example, a regional flight control
center may initiate the flight and then `hand-off` the aircraft to
another flight control center without landing. Command and control
can be accomplished using variations of CNPC (command non-payload
control) or C2 (command and control) radios on dedicated spectrum.
Voice communications are accomplished via remotely controlled
aviation VHF transceivers mounted on towers along the row. UAS
operations also leverage an existing network of local track-side
weather stations.
[0059] The telecommunications infrastructure also is used to
support an air traffic situation awareness system. This system is
capable of displaying the position of both cooperative and
non-cooperative air traffic to the pilot of the UAS. The UA itself
is a cooperative aircraft. The UA can be equipped with a mode S
transponder with ADS-B out.
[0060] UAS operations flight control centers are built at yard
facilities, which can make conduct of inspection missions more
efficient and cost effective. The flight crew plans safety
inspection missions for an area as required. From a dedicated UAS
maintenance and data processing facility at an operations flight
control center, a ground crew can prepare a UA for its mission and
supervises launch and recovery operations. Flying the UA from its
GCS, the flight crew can take advantage of the range and endurance
of the UA to fly over one or more subdivisions per the flight plan.
Some data is streamed live during the flight operation, while the
remaining data is post-processed back at the flight control center.
All relevant data is transferred to cloud data storage for timely
dissemination to appropriate end-users such as track inspectors,
engineering personnel, and maintenance planners.
[0061] FIG. 2 illustrates an exemplary unmanned aircraft systems
(UAS) operations flight control center 200 according to the various
embodiments of the present disclosure. The embodiment of UAS
operations flight control center 200 shown in FIG. 2 is for
illustration only. Other embodiments of the UAS operations flight
control center could be used without departing from the scope of
this disclosure.
[0062] FIG. 2 illustrates the flight control center concept. At the
rail yard, five subdivisions connect. Significant portions of four
other sub-divisions are within 175 miles. Across this region are
numerous flash flood locations, segments of tracks prone to heat
induced buckling, territories without signal feedback for
monitoring of critical assets, and several critical bridges. These
connected subdivisions can benefit from aerial safety inspection
and the timely detection of issues this technology provides.
[0063] A typical rail subdivision 205 starts in a rail yard on the
outskirts of a populated area, extends into more rural areas, and
terminates in another yard near a populated area. Along the way,
the tracks 210 can be in proximity to primary and secondary roads,
can pass through or near small towns or villages, and can pass near
airports. However, since the UA can fly directly over property that
is privately owned, the UAS may not fly directly over
non-participants, except for very short durations (on the order of
seconds) at road crossings. The UAS can feature several safety
protocols designed to keep the UA over or on private property in
the event of an emergency.
[0064] Because yards or sections of subdivisions may lie within
airspace boundaries at the surface, the UAS is regulated when
flying in Class G, Class E, Class D, Class C, and Class B airspace
at or below 400 ft. AGL. The UAS functions to not require taking
off or landing from towered airports. Procedures (described in
paragraphs [0102]-[0128]) are used to operate in controlled
airspace, in the vicinity of airports, and in locations with known
aviation activity. Along with technology, numerous operational and
procedural safety mitigations can be implemented, all with the
intent of maintaining situation awareness of and coordinating with
manned air traffic. Note that the UA is transponder equipped and
the flight crew can have two-way voice communication. The position
of the UA relative to airports and detected air traffic is
monitored at the GCS using moving map displays with VFR sectional
chart overlays. In this way, the BVLOS UAS operation is similar to
manned aircraft operations, especially in Class B, C, and D
airspace. Regarding 14 CFR 91.113, the position of other
cooperative air traffic is known using an air traffic situation
awareness system. For awareness of non-cooperative traffic,
additional sensors like primary radars are used on a
non-interference basis. For further redundancy, visual observers
could be positioned at select locations during flights.
[0065] FIGS. 3A and 3B illustrate exemplary UASs 300, 301 according
to the various embodiments of the present disclosure. The
embodiments of UAS 300 shown in FIG. 3A and UAS 301 shown in FIG.
3B are for illustration only. Other embodiments of the UAS could be
used without departing from the scope of this disclosure.
[0066] The UAS uses hybrid quad-rotor technology, which combines a
fixed-wing aircraft for long duration forward flight with a
quad-rotor system for vertical takeoff and landing. The hybrid
quad-rotor technology enables launching and recovering the UA from
small areas near the tracks or in a yard, while still having the
ability to fly hundreds of miles to inspect entire
subdivisions.
[0067] For BVLOS operations, examples of UAS include both the
HQ-40, HQ-60B and HQ-60C hybrid quad-rotor aircraft. The HQ-40 is a
small UAS with a wing span of 10 ft. and maximum gross weight of 45
lbs. The HQ-60B and C is a larger UAS with wing span of 15 ft. and
a maximum gross weight of 115 lbs. The HQ-60B has more range,
endurance and payload capacity than the HQ-40. These aircraft share
the same flight computer and flight control software as well as
many of the same sub-systems. Both aircraft can be piloted from the
same GCS. Below is a brief description of both aircraft.
[0068] The HQ-40 consists of a single fuselage, single wing, two
booms, two vertical stabilizers, and a single horizontal
stabilizer. The forward flight engine is installed behind the
fuselage. The quad-rotor system motors are installed in the booms.
The aircraft uses two struts on the forward sections of the booms
and the bottom of the vertical stabilizers as landing struts. The
aircraft controls attitude with ailerons on the outboard sections
of the wings and elevators on the horizontal stabilizer. The
aircraft is equipped with a strobe and position lights. It also
features a high visibility paint scheme. FIG. 3A below shows the
HQ-40 airframe. Table 1 and 2 list its physical measurements and
performance characteristics.
TABLE-US-00001 TABLE 1 HQ-40 Aircraft Measurements Aircraft
Measurements Wingspan 110 inches Length 67 inches Body Diameter 7.5
inches Weight Empty 33 lbs. Max Takeoff Gross 45 lbs.
TABLE-US-00002 TABLE 2 Performance Characteristics of HQ-40
Performance Characteristics Endurance 5 hours (GX-35), 2 hours
(B29i) Max Rang 190 NM Max Operating Altitudes 14,000 ft MSL Max
Climb/Descent Rate 1000 fpm Emergency Descent Rate 2000 fpm Max
Speed 80 kts Max Turn Rate 25 deg/sec Max Bank Angle 45 deg Cruise
Speed 28 kts Limitations Headwind 25 kts Crosswind Turbulence 20
kts Mild to Moderate Visibility VMC conditions OAT Max/Min 110 deg
F./-2 deg F. Launch Type/Procedure Vertical Recovery Type/Procedure
Vertical
[0069] The HQ-60B consists of a single fuselage, single wing, two
booms, two vertical stabilizers, and a single horizontal
stabilizer. The forward flight engine is installed behind the
fuselage. The quad-rotor system motors are installed in the booms.
The aircraft uses structures located on the lower center section of
the fuselage and on the bottom of the vertical stabilizers as
landing struts. The aircraft controls attitude with ailerons on the
outboard sections of the wings, elevators on the horizontal
stabilizer, and a rudder on each vertical stabilizer. Each flight
control surface is redundant and is independently controlled and
actuated. The aircraft is equipped with a strobe and position
lights. It also features a high visibility paint scheme. FIG. 3B
below shows the HQ-60B airframe and Tables 3 and 4 list its
physical measurements and performance characteristics.
TABLE-US-00003 TABLE 3 HQ-40 Aircraft Measurements Aircraft
Measurements Wingspan 150 inches Length 96 inches Fuselage Length
47.35 inches Body Diameter 10 inches Weight Empty 53 lbs. Max
Takeoff Gross 115 lbs.
TABLE-US-00004 TABLE 4 Performance Characteristics of HQ-40
Performance Characteristics Endurance 15 hours Max Rang 750 NM Max
Operating Altitudes 14,000 ft MSL Max Climb/Descent Rate 500 fpm
Emergency Descent Rate 1000 fpm Max Speed 80 kts Max Turn Rate 20
deg/sec Max Bank Angle 20 deg Cruise Speed 50 kts Limitations
Headwind 30 kts Crosswind Turbulence 25 kts Mild to Moderate
Visibility VMC conditions OAT Max/Min 110 deg F./-2 deg F. Launch
Type/Procedure Vertical Recovery Type/Procedure Vertical
[0070] HQ-series UAS (HQ-40 and HQ-60B) have been issued Special
Airworthiness Certificates in the Experimental Category and have
accumulated more than 360 hours of VLOS/EVLOS operations and more
than 880 hours in BVLOS operations, with 18 hours of night BVLOS.
This yields a total of 1,258 flight hours as of August 2017.
[0071] FIG. 4 illustrates an exemplary command center (CC) user
interface (UI) 400 according to the various embodiments of the
present disclosure. The embodiment of CC UI 400 shown in FIG. 4 is
for illustration only. Other embodiments of the CC UI could be used
without departing from the scope of this disclosure.
[0072] A GCS facility is outfit with equipment to support multiple
individual flight crews, each flight crew can operate a single UAS
on multiple subdivisions. Each GCS, shown in FIG. 5, can include
the following: ground station laptop: PC computer running GCS
software specific to the UA; ground station device containing
communication radios for telemetry links and management of wireless
links and bridges between aircraft and operator interfaces; ground
station communications antenna(s); and ground station GPS
antenna(s).
[0073] In addition to these components, the GCS can also include
devices for connectivity with the telecommunications network,
equipment and interfaces for use of rail and aviation voice radios,
equipment and interfaces for communication with the flight control
center, software for monitoring the locations of trains, and
equipment and displays for the air traffic situation awareness
system. The ground control station can also include electronics
tools and a backup power system capable of supporting normal
operations for the duration of a flight.
[0074] The HQ-60B uses the UAS autopilot (onboard the aircraft) and
ground control system (GCS). This unit has seen well over 250,000
hours on DoD programs with great success. Autopilot software
features easy-to-define mission parameters and restrictions,
waypoint insertion, context menus for common functions, route copy
between aircraft, easy route planning, high-performance smooth-zoom
2D and 3D terrain mapping, terrain database integration with web
mapping servers for elevation and imagery, intuitive primary flight
displays, and the ability to change airspeed, altitude, and heading
commands at the displays. Displayed data can be configured per user
requirements. A status bar provides a high-level alert
interface.
[0075] The pilot can determine the attitude of the aircraft using
the primary flight display (PFD) on the operator interface and the
aircraft position using the geo referenced imagery in the center of
the default display. The aircraft's position is overlaid on this
imagery. The PFD and the aircraft position are updated at a maximum
rate of 25 Hz.
[0076] Any commands that could be detrimental to the normal
operation of the UA are safeguarded with a confirmation window.
Inputs that could produce an undesirable outcome are guarded and
require multiple steps to activate.
[0077] FIG. 5 illustrates an exemplary ground control system (GCS)
facility 500 according to the various embodiments of the present
disclosure. The embodiment of GCS facility 500 shown in FIG. 5 is
for illustration only. Other embodiments of the GCS facility 500
could be used without departing from the scope of this
disclosure.
[0078] Each flight control center can include a UAS launch and
recovery station (LRS), where a ground crew prepares and maintains
the UA and supervises launch and recovery operations. The HQ-60B
system requires the following equipment for pre-flight preparation
and post-flight activities: shore power supply: 30 V DC power
supply; lithium polymer (LiPo) battery safe storage; LiPo charging
stations: used to charge avionics and VTOL batteries; bulk fuel
supply and transfer equipment; aircraft scale; tool and spares kit:
includes tools required for maintenance and spares for wear items;
launch abort system: enables the ground crew to abort a launch for
safety reasons; webcam/VoIP equipment for communications with
flight crew at GCS; local C2 (command and control) radio for launch
and recovery.
[0079] Ground crews and flight crews can receive training on crew
roles and responsibilities and on crew resource management.
Specific duties of the ground crew are highlighted in paragraphs
[0102]-[0128].
[0080] FIGS. 6A and 6B illustrate an exemplary telecommunications
tower 600 according to the various embodiments of the present
disclosure. The embodiment of the telecommunications tower 600
shown in FIGS. 6A and 6B is for illustration only. Other embodiment
of the telecommunications tower 600 could be used without departing
from the scope of this disclosure. FIG. 7 illustrates an exemplary
radio frequency (if) coverage analysis 700 according to the various
embodiments of the present disclosure. The embodiment of the rf
coverage analysis 700 shown in FIG. 7 is for illustration only.
Other embodiments of the rf coverage analysis 700 could be used
without departing from the scope of this disclosure.
[0081] Command and control of the UA can be accomplished using a
radio network. This does not involve a series of GCS instances
conducting hand-off procedures. Rather, there is one GCS connected
to a network of ground-based radios placed along the flight path of
the UA at regular intervals to maintain persistent
communications.
[0082] To maintain the C2 link between the UA and the GCS, the UA
must be within line-of-sight (LOS) of one or more antennas in this
network. The antenna placement on the network is designed for
overlapping coverage, meaning that the UA can be within LOS of two
radios at all times during flight along a subdivision. The radio
network is connected to the GCS over a network designed for latency
on the order of 50 milliseconds.
[0083] FIGS. 6A and 6B show a telecom tower. This tower is
approximately 300 ft. tall and is located on high ground
approximately 1.6 NM from the tracks. Towers of this type are
positioned along the tracks at intervals of approximately 15 to 30
NM. FIG. 7 shows the RF coverage analysis for a C2 radio network
using towers along a subdivision. Use of seven towers provides
overlapping coverage at track elevation for the length of the
subdivision. Existing towers can be used to install radio networks
along other subdivisions. RF analysis and can conduct appropriate
performance tests are conducted prior to conducting routine BVLOS
UAS operations on those networks.
[0084] The autopilot used in the UA features a built-in
C2/telemetry link on the ISM (industrial, scientific, and medical)
band (2.4 GHz and 900 MHz). Integration of the CNPC/C2 radio adds a
second C2 link to the aircraft. The requirements to perform a
normal VTOL launch and recovery require a higher bandwidth
telemetry link than does cruise flight. During launch, recovery,
and local operations, the C2 link can be the 2.4 GHz radio. When
the aircraft is flown away from the launch and recovery zone, the
communications link is switched to over to the CNPC/C2 radio
network by the flight crew.
[0085] FIG. 8 illustrates an exemplary overall system schematic 800
according to the various embodiments of the present disclosure. The
embodiment of the system schematic 800 shown in FIG. 8 is for
illustration only. Other embodiments of the system schematic 800
could be used without departing from the scope of this
disclosure.
[0086] FIG. 8 is a diagram of communications flow. Command,
control, and telemetry data are transmitted locally on the 2.4 GHz
ISM band during launch and recovery. Once the aircraft is
established in a cruise configuration, the UAS can be ingressed to
the CNPC/C2 network through the closest CNPC/C2 tower. The pilot
makes this change using a custom software application that runs on
the ground station computer. This software also provides feedback
to the pilot on the health and status of the CNPC/C2 system. If for
any reason the link health of the CNPC network is not sufficient,
the UA can be recovered at the flight control center over the local
2.4 GHz ISM link. If for any reason there is an issue with local C2
health, the flight may be postponed until issues are resolved. The
health of all of the radios on the CNPC network can be monitored by
the pilot. If during cruise flight, the link health of a radio is
insufficient for continued flight, the pilot can alter the flight
plan or perform an emergency vertical landing near the tracks.
[0087] FIG. 9 illustrates an overview of an exemplary air traffic
awareness system 900 according to the various embodiments of the
present disclosure. FIG. 10 illustrates an overview of an exemplary
automatic dependent surveillance-broadcast (ADS-B) site locations
1000 according to the various embodiments of the present
disclosure. FIG. 11 illustrates an exemplary user interface display
1100 of air traffic according to the various embodiments of the
present disclosure. The embodiments of the air traffic awareness
system 900 shown in FIG. 9, the ADS-B site locations 1000 shown in
FIG. 10, and the user interface display 1100 shown in FIG. 11 are
for illustration only. Other embodiments of the air traffic
awareness system 900, the ADS-B site locations 1000, and the user
interface display 1100 could be used without departing from the
scope of this disclosure.
[0088] The ability to "see and avoid" other air traffic in
accordance with 14 CFR 91.113 is a critical. The air traffic
situation awareness system can monitor cooperative and
non-cooperative air traffic. Components of this system can include
local sensors and dispatch system and range system software
tools.
[0089] As shown in FIG. 9, the dispatch system is linked to the FAA
air traffic management system (Surveillance Broadcast System) and
can also be linked to networks of local sensors. local network of
ADS-B Xtend receivers can be installed along each subdivision to
augment ADS-B coverage below 500 feet AGL. An example of this is
presented in FIG. 10. RF analysis led to installation of six
additional receivers on the towers along the subdivision to provide
ADS-B coverage to the ground (50 ft. AGL). Note that local sensor
data may not be integrated into the SBS data feed.
[0090] Range system software is an air traffic display designed to
provide situation awareness to the UAS pilot. This aids the pilot
in avoiding nearby manned air traffic, which is unlikely to make
visual contact with the UA. Using the dispatch system, data from
FAA radars and from ADS-B, ADS-R, TIS-B, and FIS-B is fused with
detections from local sensors to present the track of each air
traffic target to the UA PIC on a range system. Various symbols and
alerting features present a representation of both the UA and any
air traffic targets as shown in FIG. 11.
[0091] One example of a local sensor for detection of
non-cooperative traffic is radar which has been tested as part of
this air traffic awareness system. This radar detects personnel,
land vehicles, marine vessels, avian targets, and low-flying
aircraft. With the radar configured to detect and generate tracks
for GA aircraft sized targets, GA aircraft were tracked at a range
of 5.4 NM (10 km) with a median range error of 20 feet (.about.6
meters). Track durations were approximately 70 to 110 seconds. Note
that elevation data is not available, so radar tracks from this
sensor are displayed in two dimensions only. Without any additional
coordination, pilots must assume that targets are co-altitude and
must act appropriately to avoid those targets.
[0092] For the test configuration and environment, the air traffic
awareness system allowed the UA PIC to recognize GA air traffic
(cooperative and non-cooperative) at a range of at least 3 NM. On
average, there was at least 60 seconds between that initial
recognition and the closest point of approach between the
"Intruder" GA aircraft and the UA. In one study to model human
visual acquisition of air traffic, the probability of visual
acquisition of a Piper Archer (a typically sized GA aircraft) by
two pilots actively scanning for air traffic was presented. The
probability of visual detection was shown to be only 10% at a range
of 3 NM (the probability was shown to be 100% at less than 0.5 NM).
Results from another test indicated that recognition of intruders
by the UA PIC using the range system occurred approximately 17
seconds in advance of recognition by ground-based visual observers.
Test results indicate that the use of the air traffic situation
awareness system provides a capability to detect air traffic that
is equivalent to or better than ground-based or airborne visual
observers.
[0093] The deployment of local sensors for non-cooperative traffic
can be based on the following: (1) ADS-B coverage to the ground
along the length of a subdivision for detection of cooperative air
traffic. (2) At locations known to have a high concentration of
non-cooperative air traffic. This knowledge may be the result of
outreach efforts. Depending on the nature of the activity, this may
lead to seasonal rather than year-round deployment of sensors
(radar). (3) Risk assessments specific to the flight corridor over
the tracks. The deployment initially can be based on actual air
traffic data or based on modeling validated by that data. Sensors,
or other mitigations (visual observers), can be placed in locations
where the risk of mid-air collision exceeds that of locations that
have been deemed to have acceptable unmitigated risk of mid-air
collision (relative unmitigated risk).
[0094] Additional air traffic avoidance technologies can be
utilized as they become accepted for operational use. Examples of
such technology include alternative radars and on-board collision
avoidance.
[0095] Two-way voice communications on aviation frequencies is an
important safety mitigation. It allows pilots, who may not see each
other's aircraft, to announce their intentions and coordinate their
actions in a safe manner. The telecom infrastructure can be used to
host CTAF, tower, and approach frequencies local to each
subdivision using IP radio gateway/bridging systems. Such systems
provide push-to-talk capability from tower mounted VHF
transceivers. This is analogous to having a network of aviation
ground station radios such as those used at airports for
UNICOM/CTAF. In certain embodiments, the ground stations are
facilitating air-to-air communications since voice radios are not
carried aboard the UA.
[0096] This usage of aviation VHF transceivers is subject to
FAA/FCC approvals. While this usage is an atypical deployment of
such radios, the usage allows the UAS to operate BVLOS in the NAS
in a manner consistent with manned aviation and has proven to be a
critical element of safe integration of the UA into the NAS.
[0097] Guidelines and procedures in the AIM (aeronautical
information manual) for flight under VFR are followed. The
following is an overview of the procedures for a typical
flight.
[0098] Flight planning can be conducted in the same manner as in
manned aviation. The pilot in command (PIC) is familiar with all
information applicable to the flight. Flight crews can use existing
aviation tools and information sources along with software designed
for the purpose of UAS flight planning over rail infrastructure.
This software uses information collected from the GIS database,
from site surveys, from publicly available data, and from approved
navigation databases to aid in development of flight plans. Flight
plans can take into consideration the following: mission objectives
(subdivision, type of safety inspection, sensor), the local
terrain, the local weather at the launch and recovery sites as well
as along the route of flight, population along the route of flight,
vertical obstructions, launch and recovery climb and descent paths,
local airspace and air traffic considerations, and gatherings of
people or special events near tracks. The intended flight time
drives the fuel requirements for the flight(s). Takeoff time and
total time aloft can be determined so that notifications to other
NAS users (DoD, Ag, GA) can be delivered if necessary, and a NOTAM
(Notice to Airmen) can be filed if one is required.
[0099] The outputs of the planning process are as follows: a set of
GPS coordinates defining the launch and recovery locations; a set
of GPS coordinates defining the landing pattern to the landing
location; a set of GPS waypoints defining the flight route for
normal operations; a set of GPS waypoints defining the flight route
for operation under loss of C2 link; a set of GPS coordinates
defining the airspace boundary (geo-fence) that is designed to
prevent an excursion away from privately owned property; a
description of suitable emergency landing areas (or areas to avoid)
within and immediately beyond the geo-fence; map overlays of
aviation charts, terrain, and demographics for use on moving map
displays in the GCS; information and procedures for transitioning
through any airspace or near any airports along the route of
flight; schedule for issuing notifications and NOTAMs; and
payload/sensor installation and fuel load plan for the ground
crew.
[0100] If during any part of the flight planning process the UAS
PIC believes that the flight cannot be conducted safely, the flight
operation may be postponed until changes can be incorporated or
adequate mitigations can be implemented. Examples include: special
events where a large gathering people may be in close proximity to
the tracks, a seasonal and highly localized crop spraying operation
in close proximity to the tracks, or installation of a new vertical
obstruction in a location where loitering may be required.
[0101] Both the flight crew and ground crew are responsible for
pre-flight actions. At the GCS, the flight crew can configure all
software and displays according to pre-flight checklists. UA
configuration files can be verified, flight plan waypoints can be
loaded into the autopilot interface, maps and map overlays can be
loaded into the autopilot interface and into the air traffic
situation awareness system. Commonly used radio frequencies can be
pre-set. Any sensor interfaces can also be configured.
Communications can be established with the ground crew at the
launch and recovery station (LRS). At the LRS, the ground crew can
perform pre-flight inspection of the UA, can install and configure
the sensor(s) and fuel the UA in accordance with the flight plan.
The ground crew proceeds to power on the systems of the UA in
coordination with the flight crew after configuration of the
software and displays.
[0102] The flight and ground crew each complete final GCS and UA
pre-flight checks such as transfer of flight plans and boundaries
to the autopilot, center of gravity calculation and verification,
C2 and payload link checks, battery voltage checks, fuel quantity
verification, flight control surface calibration checks, IMU
checks, VTOL system checks, and pusher engine start and run-up
checks. With these tasks completed, the flight and ground crew can
coordinate to complete pre-takeoff checks including visual clearing
of the launch area at the flight control center. A ground crew
member mans the launch abort control. At the GCS, the flight crew
can conduct any necessary pre-takeoff radio communication with ATC
or make announcements over CTAF. A final go or no-go decision can
be made by the PIC.
[0103] Vertical launch and transition to forward flight is executed
through an autopilot mode. It involves a series of maneuvers that
occur without manual manipulation of controls by the PIC. With a
`go` decision, the launch can be commanded from the GCS. During the
launch and transition, the ground crew can abort the launch for any
safety reason.
[0104] The vertical climb profile can take the UA to an altitude of
approximately 60 ft. AGL. From there, the UA transitions to forward
flight under power of the forward propulsion motor. Once the UA has
transitioned to forward flight, the PIC at the GCs can verify the
CNPC link health and can ingress the UA to the CNPC network. The
PIC can then activate the flight plan and the UA proceeds to fly
the preprogrammed route.
[0105] During the cruise flight phase, the vehicle follows the
flight plan along the tracks to the specific areas of interest and
can collect the necessary data. During the flight, flight crew can
communicate with ATC and other NAS users and can monitor displays
for the position of other air traffic. Weather, UA flight states,
and health systems such as engine RPM, fuel level, battery life,
GPS signal, and C2 link can also be continuously monitored. The
telemetered position of the UA on the moving map can be used to
ensure the aircraft is executing the flight plan properly. The PIC
can take control at any time to alter the flight plan, or the
course, speed, and altitude of the UA.
[0106] Critical for safe operation of the UA in controlled airspace
are procedures designed to allow the BVLOS inspection mission to
proceed safely and with minimal impact to manned aircraft
operations. For operations in Class B, C, and D airspace, although
the UA is cooperative, it may not be detected by FAA radar given
the low cruise altitude. For routes impacted by this issue,
reporting and loiter points can be established at the intersection
of the tracks and the airspace boundary, and at locations between
1.5 and 3 nautical miles on either side of the intersection of
tracks and the approach to any runways. These can be specified and
named (Point Q (latitude/longitude), etc.) in a Letter of Agreement
(LOA) with the controlling facility. Or, these points can be
referenced by distances and association with landmarks (`1.5 NM
from intersection of rail track and Runway 36`). The UA PIC can
call ATC on aviation voice radio at each reporting point with the
direction of flight. In Class D, ATC acknowledgement of
transmission constitutes approval to proceed to the next reporting
point unless directed to hold. In Class B and C, acknowledgement of
transmission and clearance to proceed must be given. If requested
to hold at a reporting and loiter point, the UAS can fly in an
orbit designed to avoid people and structures on the ground. The UA
can continue on course when traffic is clear and ATC provides
instructions to proceed to the next point.
[0107] Operations in Class E and Class G near airports are similar.
The UA PIC can monitor CTAF and can make position reports. Based on
the voice radio position reports and the movement of air traffic on
the air traffic situation awareness displays, the PIC can
coordinate with manned air traffic using reporting and loiter
points. If necessary, the PIC can loiter well away from the runway
centerline and wait for a manned aircraft to complete an instrument
approach or landing pattern.
[0108] Note that unplanned loitering or turning maneuvers can cause
an excursion of -1,500 ft. laterally from the +/-100 ft. corridor
over rail operator property. Executing such maneuvers in a safe
manner requires knowledge of the vertical obstructions in the area
and the local terrain. This information can be displayed to the
pilot on the GCS moving map to aid situation awareness. Since the
cruise altitude of the UA is -350 ft., the flight path is above
most uncharted vertical obstacles (those less than <200 ft.
tall). The pilot must descend or land next to or on the tracks if
lateral maneuvering may impose a risk of impacting an
obstruction.
[0109] As the end of the mission is reached, the ground crew at the
LRS can be alerted to prepare the recovery site. As the UA nears
the flight control center, the PIC can switch the C2 link from the
CNPC C2 network to the local C2 network. The ground crew can clear
and secure the landing area. In coordination with the ground crew,
the PIC can then initiate the pre-defined landing pattern and
approach. Upon reaching an altitude of approximately 60 ft. within
a specified distance of the touchdown point, the aircraft can
transition to vertical flight and can begin a vertical descent to
the landing point. After reaching the landing point and touching
down, the aircraft can spin down its motors, completing the
recovery phase.
[0110] Following landing, the ground crew can conduct post-flight
inspection of the UA per procedures using checklists. They can
complete logs of UA flight time, VTOL and pusher motor run time,
aircraft power on time, etc. Maintenance logs can be in accordance
with 14 CFR 91.417. The UAS can be hangered and secured. Data can
be transferred from on-board storage. At the GCS, the flight crew
can log PIC/SIC flight times.
[0111] Engine Start: The autopilot features an engine kill/armed
switch for both the pusher and VTOL motors. Both are set to kill at
the GCS before pre-flight. A switch located on the side of the
fuselage is set to `off` and the arming plugs to the VTOL motors
are removed by the ground crew. Pusher engine startup occurs at the
end of the pre-flight checks. First, the pusher engine is enabled.
Next, the switch is set to `on`. The pusher engine is then started
by a ground crew member using an electric starter. Once the pusher
engine has passed its pre-flight checks, the plugs for the VTOL
engines are inserted. VTOL engines are then enabled at the GCS. At
that point, the ground crew can vacate the area in the vicinity of
the aircraft.
[0112] Launch Abort: The launch phase of flight can be aborted for
any reason. This can be accomplished from the GCS by the PIC, or
from the launch abort control at the LRS. The launch abort control
is a special device which can be connected to the GCS via the
telecommunications network.
[0113] Lost Link Plan and Geo-fence Updates: Lost link flight plans
and airspace boundaries (geo-fence) can be updated as required
during long duration flights to ensure that up-to-date information
is taken into account.
[0114] Weather: The UA is unable to operate in visible moisture or
in high winds per its limitations. Local weather stations, aviation
weather forecasts and reports, including weather radar, can be
continuously monitored by the flight crew. In the event of unsafe
weather conditions, the mission can be aborted and the UA can be
landed on or near the tracks. The nearest ground crew can be
dispatched to recover the UA.
[0115] Pilot in Command (PIC): The PIC is responsible for safe
operation of the aircraft. The PIC can make sure all checklist
items pertaining to the operation of the aircraft are followed
during normal, abnormal and emergency situations. Preflight of the
GCS and all phases of flight from "engine start" to "Shut Down" can
be the pilot's responsibility. It can be the PIC's final authority
as to a go, no go decision and any decisions pertaining to safety
of flight. This includes decisions and actions related to
maneuvering the UA to avoid air traffic based on information
displayed on the air traffic situation awareness system.
[0116] Second in Command (SIC): The SIC can be responsible for
aiding the PIC in providing traffic alerts and weather information.
The SIC can also make position reports and handle any air-to-air,
ATC or emergency communications. The SIC can communicate with ATC,
when appropriate. If needed, the SIC can also communicate with
entities to coordinate aircraft positioning and use.
[0117] Both the PIC and SIC can hold FAA Private Pilot certificates
and 3rd class medical certificates.
[0118] Ground Crew A (GCA): The GCA can be responsible for
preflight of the physical aircraft and ensuring that the logbook
items relating to the physical aircraft components are filled out.
The GCA can be required to make sure any aircraft maintenance
required is completed before flight in accordance with any
applicable Latitude maintenance manuals. The GCA can have the final
authority in deciding if the aircraft is worthy of flight. During
launch, it can be the GCA's responsibility to "abort" liftoff of
the aircraft if anything abnormal or dangerous is observed. During
landing, the GCA can be responsible for calling "abort" should the
need arise. Upon recovery, the GCA can conduct a thorough post
flight walk-around and document any damage, abnormality, or other
issues that occurred with the aircraft.
[0119] Ground Crew B (GCB): The GCB can be responsible for site
access and safety and can assist the GCA as needed. The GCB can
ensure that the launch and recovery area are clear of personnel,
objects, and equipment for departure and approach. In the case of a
malfunction or injury to the GCA, the GCB can be responsible for
disabling the engine ignition switch while the GCA is starting the
engine. After launch and recovery, it can be the GCB's
responsibility to ensure all equipment pertaining to the operation
are collected and cleared from the site.
[0120] Ground crew can launch and recover the UA at night. As such,
they can be trained to recognize and overcome visual illusions
caused by darkness, and to understand physiological conditions
which may degrade night vision.
[0121] Ground Crew can hold FAA A&P Mechanic certificates.
[0122] A UAS specific training program can be conducted under the
direction of a qualified instructor. Ground instruction can be
provide to flight crews on operation of all systems required for
BVLOS operations--UA autopilot interface, C2 network control and
health monitoring interface, Air Traffic Situation Awareness
software, and the Aviation Radio software interface. Through ground
instruction, both flight crew and ground crew can be trained on UA
preflight, UA preventative maintenance, and launch and recovery
operations. Through flight instruction, flight crews can gain
proficiency in normal and emergency procedures.
[0123] Personnel may not perform flight duties in a position for
which a documented training program has not been completed.
Recurrent training can include a combination of ground and flight
training.
[0124] Lost Voice Communications: Voice communication among crew
members is important for safety. The PIC and SIC can occupy the GCS
and can communicate directly with each other. The PIC and SIC can
have voice communications with the Ground Crew members at the
remote launch/recovery site via VoIP (voice over internet protocol)
and IP camera equipment. If voice communications cannot be
established or maintained, the operation can be postponed until
communications are established.
[0125] Voice communication is an important operational safety
mitigation for BVLOS operations. The UA may not enter Class B, C,
or D airspace, nor can it launch from within Class B, C, or D
airspace without two-way voice communication with ATC. A loss of
voice communication with ATC in Class B, C, or D controlled
airspace can result in an immediate VTOL recovery of the UA on
property at its present location. The UA may not enter Class E
airspace, nor can it launch from within Class E airspace, without
two-way voice communication over local CTAF. The UA may not fly
within 2 miles of the approach to any airport without two-way voice
communications over CTAF.
[0126] Lost Link: If a loss of C2 link occurs, warnings appear on
the GCS and are accompanied by repeated audio warnings. This is
triggered based on a timeout defined by the PIC and is typically 30
seconds. The autopilot handles a lost link event with a set of
parameters that the PIC defines for the given flight mission,
including a flight timer which defines the maximum amount of time
the aircraft can fly. The flight timer is typically based on loaded
fuel quantity or mission requirements. Also defined is a safe lost
link location (latitude, longitude, altitude) where the aircraft
can fly to via a prescribed set of waypoints called the `Lost Link
Flight Plan`. Once at the lost link location, the aircraft can fly
in an orbit at a defined orbit radius. This location can be within
the boundaries of the flight area and away from persons or
structures. For most situations, it can be over or immediately next
to railroad tracks. Attempts can be made to reestablish
communications with the aircraft. If this is unsuccessful, several
flight termination techniques can be used.
[0127] If lost link occurs during the launch, the aircraft can
continue to its takeoff plan, then follow the lost link procedure.
During climb, cruise, and descent, that aircraft can follow the
lost link procedure. During landing, the aircraft can continue to
follow the preprogrammed landing plan. Should the flight time
expire (timer length set by PIC prior to operations) the aircraft
can direct itself to a preprogrammed auto-land waypoint. The
aircraft can perform a VTOL landing at the auto-land waypoint.
[0128] Lost GPS: In the event of a GPS failure, the aircraft
reverts to an inertial navigation system (INS). Attitude and
heading are maintained. The heading is determined using a
magnetometer. The aircraft position estimate is propagated, thus
the aircrafts position can drift with error in heading measurement
and wind estimate. If the loss of GPS is transient, the autopilot
can switch back to GPS guidance upon regaining a GPS signal. If the
loss of GPS is sustained, flight termination may be executed.
[0129] Flyaway: Airspace boundaries, or geo-fences, can be
established. For any situation where the autopilot is still
functioning onboard the aircraft, but the aircraft is flying away
from its planned course and not responding to commands to return to
course (most likely the result of human error in flight planning,
human error in lost communication flight planning, etc.), flight
termination on airspace boundary violation can lead to a VTOL
landing within 20 meters of the boundary.
[0130] Aircraft System Failure: A major system failure on the UA is
likely to result in a controlled or uncontrolled crash of the
aircraft. A VTOL motor failure can typically result in an
uncontrolled landing. A failure of the forward flight motor can
result in a forced, controlled landing as the HQ system has the
ability to automatically transition to hovering flight and land in
the event of pusher engine failure. Failure of a single flight
control can result in a forced, controlled landing. Failure of
multiple flight controls can likely result in an uncontrolled
landing.
[0131] GCS Failure: In the event of a GCS failure, the aircraft can
continue on its programmed flight plan. However, loss of control
station functionality can eventually result in loss of command and
control link. The aircraft can execute its loss link procedure
until communications can be reestablished.
[0132] Flight Termination: The flight termination mode can be
entered based on any of the following criteria: GPS fail (time
out); GPS and C2 Link (time out); airspace violation (based on
geofence boundary); min/max altitude violation (limits to prevent
excursion above 400 ft. AGL);
[0133] In addition to the criteria list above, purposeful flight
termination can be performed by the PIC at any time. Upon entering
the flight termination mode, the aircraft can automatically perform
an emergency VTOL recovery.
[0134] Any incident, accident, or any flight operation that
transgresses the lateral or vertical boundaries of a flight area or
any restricted airspace or warning area as defined by the
applicable COA must be reported to the UAS integration office.
Accidents and Incidents must be reported to the National
Transportation Safety Board (NTSB) in accordance with 49 CFR
section 830.5 per instructions contained on the NTSB Web site.
[0135] Quarterly after-action reports can document the operations
conducted and future planned activities as well as any lessons
learned from flight activities, including but not limited to
anomalies encountered and effects on airspace and other users (if
any). This information can be supplied to the FAA in support of
future rulemaking.
[0136] To summarize, the following conditions apply to the BVLOS
aerial inspection operation: (1) day and night VMC only; (2) launch
and recovery: From private property only and not from airports; (3)
flight route: cruise at and below 400 ft. above ground level (AGL),
typically 350 ft. AGL; directly over privately-owned property only
(within a +/-100 ft. lateral boundary from the main track
centerline); In Class B, C, D, E and G airspace, but not over
airport property; In remote, rural, suburban, and urban areas;
bounded by `geofence`; (4) UAS: hybrid fixed-wing configuration,
capable of vertical takeoff and landing (VTOL); 15 hours endurance,
750 NM range; operational history of +475 hours and continuing with
an experimental category (SAC-EC) airworthiness certificate; uses
autopilot with DoD pedigree, +250,000 hours and continuing;
equipped with mode S transponder and ADS-B out (TSO unit can be
used if available); equipped with strobe and position lights, high
visibility paint scheme; flight termination mode is emergency
vertical landing; (5) 91.113: air traffic situation awareness
system with fusion of FAA SBS feed and local sensors, moving map
display of targets similar to other traffic display systems; (6)
Two-way voice communications: enables coordination between pilots
and with ATC.
[0137] The following hazards could result from this operation: UAS
has a Near Mid-Air Collision (NMAC) with manned aircraft; and UAS
impacts a person on the ground.
[0138] The risk to non-participating persons on the ground exists
when a loss of control of the aircraft leads to a landing beyond
property. This is mitigated by procedures, visibility enhancement
(so that people on the ground might see an object approach them),
and several safety features of the UAS including geofence and the
flight termination mode, which is designed to execute an emergency
vertical landing on private property (the railroad tracks) under a
variety of circumstances.
[0139] The risk of collision with manned aircraft exists inherently
in the National Airspace System. For this assessment, a
conservative approach can be taken. The risk of near mid-air
collision (NMAC) can be addressed rather than the risk of mid-air
collision (MAC). This risk of NMAC increases if the UA makes an
excursion from the planned flight route and cruise altitude, or if
a manned aircraft is encountered in an unexpected manner (not
detected by the air traffic situation awareness system, does not
respond to request for coordination via two-way voice
communications, maneuvers in erratic or unpredictable ways making
the less maneuverable UA unable to avoid). These situations are
mitigated by flying at or below 400 ft. AGL where there is less air
traffic density. Other mitigations include the air traffic
situation awareness system, filing of NOTAMs (and notification and
coordination with DoD and other NAS users), and visibility
enhancements (so that pilots of manned aircraft might see the UA in
flight).
[0140] The following describes the safety mitigations used in these
BVLOS operations and the model used for assessing the impact of
failures of the mitigations to prevent the hazards.
[0141] For this risk assessment, a key assumption is that each
individual safety mitigation is 100% effective in preventing a
hazard under normal operations. If none of these mitigations fail,
then no hazards occur. This is a simplifying assumption, used to
avoid more complicated modeling of the relative effectiveness of
the mitigations and their possible interactions.
[0142] Efficacy of CONOPS and crew: The BVLOS CONOPS and crew
training have been developed by experienced aviation professionals
and the efficacy of these continue to be evaluated under an R&D
flight test program. For this risk assessment, it is assumed that
the efficacy of the panning behind these operations and the highly
trained humans who can execute these plans can fail to prevent a
hazard 5% of the time in all airspace classes.
[0143] Two-way voice communications: voice communication is an
important operational safety mitigation for BVLOS operations. This
allows pilots of aircraft to coordinate their activities, even if
they do not have visual contact with one another. However, human
error is unavoidable. As shown in Table 5, it is assumed that this
mitigation may fail at a rate of 25% in all airspace classes. It is
also assumed that this mitigation has no effect on the risk of the
UAS impacting a person on the ground. Falling debris due to a
mid-air collision is not considered.
[0144] Air traffic situation awareness system: The ability to "see
and avoid" other air traffic in accordance with 14 CFR 91.113 is a
critical. The air traffic situation awareness system is not a
certified ground-based detect and avoid (GBDSAA) system. It can
monitor and display the position and track of cooperative and
non-cooperative air traffic. This enables the pilot of the UA to
avoid nearby manned air traffic. This capability is important in
non-controlled airspace. The rates in Table 5 are estimated under
the assumption that this system is more likely to fail to prevent
an NMAC in environments where there is likely to be more
non-cooperative, low altitude air traffic. Failure rates range from
5% in Class B, C, and D airspace to 20% in Class E and Class G
airspace. It is assumed that this mitigation as no effect on the
risk of striking a person on the ground.
[0145] UAS Mode S transponder with ADS-B: This equipment makes the
UA a cooperative aircraft and (along with two-way radio
communication) allows the UAS to enter Class B and C airspace per
existing regulations. The rates in Table 5 are estimated under the
assumption that this system is more likely to fail to prevent an
NMAC in environments where there is likely to be more
non-cooperative, low altitude air traffic. Failure rates range from
1% in Class B and Class C airspace and 10% in Class D airspace, to
20% in Class E and Class G airspace. It is assumed that this
mitigation as no effect on the risk of striking a person on the
ground.
[0146] Airport loiter points: procedures have been established to
enhance safety for locations in proximity to airports. These
procedures call for the UA to hold/loiter at locations away from
the extended runway centerline and the approach path to runways
when manned air traffic is in the pattern or on an instrument
approach. These locations are planned and are known to be clear of
vertical obstructions. The rates Table 5 are estimated under the
assumption that this system is more likely to fail to prevent an
NMAC in environments where there is likely to be more
non-cooperative, low altitude air traffic. Failure rates range from
10% in Class B, Class C, and Class D airspace to 20% in Class E and
Class G airspace. It is assumed that this mitigation as no effect
on the risk of striking a person on the ground. Falling debris due
to a mid-air collision is not considered.
[0147] Airspace class specific procedures: procedures have been
developed for operations in various classes of airspace. These
include hold/loiter points prior to entering/exiting controlled
airspace and use of emergency procedures and lost link flight plans
tailored to specific locations to account for avoidance of ground
population, vertical obstructions, and airport property. Failure
rates Table 5 range from 5% in Class B and Class C to 10% in Class
D, Class E, and Class G airspace. It is assumed that this
mitigation as no effect on the risk of striking a person on the
ground. Falling debris due to a mid-air collision is not
considered.
[0148] Pre-flight checklists: proper execution of pre-flight checks
ensures that the system is operating normally, as designed. A fully
functioning system is most likely to be effective at preventing
both an NMAC and at preventing injury to people on the ground. As
shown in Table 5, it is estimated that this mitigation can fail to
prevent an NMAC and prevent impact of persons on the ground at a
rate of 25% in all airspace classes. Again, this is analogous to
assuming that the pilot community is comprised of C students, which
is conservative.
[0149] Strobe and high visibility paint: The UAS is smaller than a
manned aircraft. High visibility paint, strobe, and position lights
increase the likelihood that the UAS can be seen by other aviators
and by people on the ground, especially at night. For this risk
assessment, it is assumed that if visibility enhancements of the UA
were to fail, NMAC would not be prevented at a rate of 10% and
impact of people on the ground would not be prevented at a rate of
90%. This implies that people on the ground are more likely to see
the lighting and paint scheme and take action than are pilots of
manned aircraft.
[0150] NOTAM: A notice to airmen informs other NAS users of the UA
flight activity. This is most likely to prevent an NMAC if the
NOTAM is issued in a timely manner and is read and interpreted
correctly by other NAS users. For this risk assessment, it is
assumed that failure to issue, read, comprehend, and comply or
properly use information in a NOTAM is subject to human error and
thus can fail to prevent a hazard 25% of the time.
[0151] Table 5 below lists the safety mitigations presented above
with estimates of the likelihood that a failure of that mitigation
will fail to prevent a hazardous outcome.
TABLE-US-00005 TABLE 5 Likelihood that Failure of a Safety
Mitigation leads to Hazard Air Traffic Procedures Two-way Situation
UAS Mode S Airport Procedures for Class C Voice awarnesses
Transponder Loiter for Class B and Class D System state Event Comms
System with ADSB Pixots Airports airports Class B NMAC 25% 5% 1%
10% 5% na Pedestrian na na na na na na Injured Class C NMAC 25% 5%
1% 10% na 5% Pedestrian na na na na na na Injured Class D NMAC 25%
5% 10% 10% na 10% Pedestrian na na na na na na Injured Class E or G
NMAC 25% 20% 25% 20% na na Airport Pedestrian na na na na na na
Injured Class G NMAC 25% 50% 25% 20% na na Pedestrian na na na na
na na Injured Procedures Stroke and for Class E High Pilot/ and
Class G Pro-flight Visibility Conops System state Event airports
Checklists Paint NOTAM Efficacy Class B NMAC na 25% 10% 25% 5%
Pedestrian na 25% 90% na 5% Injured Class C NMAC na 25% 10% 25% 5%
Pedestrian na 25% 90% na 5% Injured Class D NMAC na 25% 10% 25% 5%
Pedestrian na 25% 90% na 5% Injured Class E or G NMAC 10% 25% 10%
25% 5% Airport Pedestrian na 25% 90% na 5% Injured Class G NMAC 10%
25% 10% 25% 5% Pedestrian na 25% 90% na 5% Injured
[0152] System failures that lead to a loss of control causing the
UA to deviate from its planned course are more likely to result in
the hazards listed above. These failures and events were developed
using knowledge of UAS sub-systems, how they fail, and what occurs
when they fail. Failure conditions are listed below along with the
resulting deviation from planned course over private property.
[0153] For this risk assessment, two key assumptions about system
failures are: A single system failure has a 0.01 (1%) chance of
occurring; multiple failures have a 0.0001 (0.01%) chance of
occurring; Failure rates are per hour.
[0154] Flyaway: for any situation where the autopilot is still
functioning onboard the aircraft, but the aircraft is flying away
from its planned course and not responding to commands to return to
course (most likely the result of human error in flight planning,
human error in lost communication flight planning, etc.), flight
termination on airspace boundary violation can lead to a VTOL
landing within 20 meters of the boundary. The maximum deviation is
166 ft.
[0155] Ground control system (GCS) Failure: in the event of a GCS
failure, the aircraft can continue on its programmed flight plan.
However, loss of control station functionality can eventually
result in loss of command and control link. The aircraft can
execute its loss link procedure that can eventually result in a
controlled landing on the rail operator's property. For example, a
landing zone is 66 ft. in diameter, which is within the +/-100 ft.
corridor of private property.
[0156] Lost GPS: In the event of a GPS failure, the aircraft
reverts to an inertial navigation system (INS). Attitude and
heading are maintained. The heading is determined using a
magnetometer. The aircraft position estimate is propagated, thus
the aircraft's position can drift with error in heading measurement
and wind estimate. If the loss of GPS is transient, the autopilot
can switch back to GPS guidance upon regaining a GPS signal. If the
loss of GPS is sustained, flight termination may be executed and
the deviation is 66 ft.
[0157] Lost link: If a loss of the command and control (C2) link
occurs, warnings appear on the GCS and are accompanied by repeated
audio warnings. This is triggered based on a timeout defined by the
pilot and is typically 30 seconds. The autopilot handles a lost
link event with a set of parameters that the pilot defines for the
given flight mission, including a flight timer which defines the
maximum amount of time the aircraft can fly. The flight timer is
typically based on loaded fuel quantity or mission requirements.
Also defined is a safe lost link location (latitude, longitude,
altitude) where the aircraft can fly to via a prescribed set of
waypoints called the `Lost Link Flight Plan`. Once at the lost link
location, the aircraft can fly in an orbit at a defined orbit
radius until the expiration of the flight timer. If lost link
occurs during the launch, the aircraft can continue to its takeoff
plan, then follow the lost link procedure. During climb, cruise,
and descent, that aircraft can follow the lost link procedure.
During landing, the aircraft can continue to follow the
preprogrammed landing plan. Should the flight time expire (timer
length set by PIC prior to operations) the aircraft can direct
itself to a preprogrammed auto-land waypoint. The aircraft can then
perform a VTOL landing. The landing zone is 66 ft. in diameter and
this is within the +/-100 ft. corridor of private property.
[0158] Lost voice communications: voice communication is an
important operational safety mitigation for BVLOS operations. The
UA cannot enter Class D or C airspace, nor can it launch from
within Class D or C airspace without two-way voice communication
with ATC. A loss of voice communication with ATC in Class D or C
controlled airspace can result in an immediate VTOL recovery of the
UA on property at its present location. The UA cannot enter Class E
airspace, nor can it launch from within Class E airspace, without
two-way voice communication over local CTAF. The UA cannot fly
within 2 miles of the approach to any airport without two-way voice
communications over CTAF. The landing zone is 66 ft. in diameter
and this is within the +/-100 ft. corridor of private property.
[0159] Electrical power system distribution failure: There is only
one electrical power distribution system, unlike larger transport
aircraft that possess redundant electrical power distribution
systems. The battery backup precludes some electrical power loss
scenarios. Connector and cabling issues that could lead to loss of
power distribution should be identified prior to flight via
pre-flight and regular maintenance inspections. A total loss of
electrical power can cause the autopilot to fail and can kill
ignition to the pusher engine. Without power from the forward
flight engine and without the ability to receive control inputs,
the aircraft, which is statically stable, can glide along a
trajectory dictated by the last control surface positions prior to
the failure. In the worst case, at a glide ratio of approximately
8:1, the aircraft would continue flight straight ahead for an
approximately 3200 linear ft. and then impact the ground.
[0160] Inflight computer failure: there is only one flight
computer/autopilot. If this computer fails, the forward flight
engine would be shut off automatically by what is called the
deadman circuit on the power distribution board. This is a safety
feature of the autopilot that is connected to the forward flight
engine ignition. In the event that the deadman circuit loses a
hardware signal from the autopilot, the engine is killed. Without
power from the forward flight engine and without the ability to
receive control inputs, the aircraft, which is statically stable,
can glide along a trajectory dictated by the last control surface
positions prior to the failure. In the worst case, at a glide ratio
of approximately 8:1, the aircraft would continue flight straight
ahead for approximately 3200 linear feet and then impact the
ground.
[0161] The assumption for this failure scenario is that the
inflight computer experiences a "hard" failure where no autopilot
function is available. Note that killing the engine prevents a true
flyway condition.
[0162] A worse-case scenario is one in which some function
combination of functions within the flight computer fail in a
manner that allows the UA to fly in a controlled manner without
being responsive to pilot commands. Here, the UA could fly until
fuel is exhausted. The UA has a range of at least 450 NM
(27,337,750 feet). The developers of the autopilot are unaware of
any occurrence of this failure in the operational history of the
unit.
[0163] IMU sensor failure: The aircraft has only one IMU and no
redundant sensors (gyros, accelerometers). A failure which provides
erroneous data can likely result in uncontrolled flight. Emergency
VTOL landing may not be possible. System status is monitored during
flight. If a sensor failure leads to erratic flight behavior, the
pilot can initiate flight termination leading to a crash landing on
or near property, though results can vary depending on the sensor
failure. For this failure, the deviation is assumed to be 600
ft.
[0164] Air data system failure: loss of the air data system can
result in inaccurate altitude and airspeed readings. While the
aircraft may climb or descend (depending on the failure), it can
still remain on its flight path. The aircraft could experience
aerodynamic stall due to an erroneously high airspeed reading. In
this case, the aircraft can stall and crash near its current
location. The alternative is that the airspeed is erroneously low
and the aircraft dives for airspeed, colliding with the ground. In
either case, lateral navigation is maintained. Loss of air data for
any prolonged period can result in an uncontrolled aircraft.
[0165] There is a check prior to flight to confirm air speed sensor
function to assure availability of this system. Air data system
status is monitored during flight. If an air data system anomaly is
quickly identified during flight, the aircraft can be landed on
rail operator property. The landing zone is 66 ft. in diameter and
this is within the +/-100 ft. corridor of private property.
[0166] Air traffic situation awareness system failure: loss of the
SBS data feed and/or loss of the local sensor network, or a local
sensor failure that corrupts the data fusion function can lead to
inaccurate display of air traffic which could result in a mid-air
collision. The flight crew can monitor the health of the system.
This includes monitoring the system indicators, the progression of
tracks of cooperative and non-cooperative targets, and the time
sync with the system server. If an anomaly is quickly identified
during flight, the aircraft can be landed on property. The landing
zone is 66 ft. in diameter and this is within the +/-100 ft.
corridor of private property.
[0167] Propulsion failure: a propulsion system failure with the
autopilot still functioning allows the pilot to control the
landing. By turning with 20 degrees bank angle, the UA can descend
with a turn radius of 665 ft.
[0168] Table 6 below summarizes the amount of deviation from the
flight path corridor most likely to occur if a single failure
happens (the diagonal of the table) and if two failures occur. This
information can be used to develop the probabilities in Table 7
below which can be used in Section 6 for determining the risk of
the UAS impacting/striking people on the ground.
[0169] Using the information developed above, the rate of
occurrence of three different magnitudes of deviation incidents are
estimated. The first is a deviation of 166 ft, the second is a
deviation of 3200 ft, and the third is a longer deviation in which
the UAS is considered to be rogue or uncontrolled (flyaway
scenario). Any deviation less than a 100 ft. deviation from course
is considered to be a normal part of UAS operations.
[0170] Table 7 shows the percentages for the occurrences of
different deviations based on this analysis. Note that the most
likely occurrence, in total, is up to 3200 ft, but greater than 166
ft. However, under a single failure, the UAS is most likely not to
experience a deviation at all.
TABLE-US-00006 TABLE 7 Deviation event percentages based on
reliability analysis Total Single Failure Multiple Failure
Occurrence Occurrence Occurrence Deviation Incident Percent Percent
Percent No deviation (<100 ft) 33.3% 72.7% 25.5% 100-166 ft
12.1% 9.1% 12.7% 167-3200 ft 53.0% 18.2% 60.0% >3200 ft 1.5% 0%
1.8%
[0171] As noted above, it is assumed that a single failure has a
0.01 chance of occurring and that multiple failures have a 0.0001
chance of occurring (that is 1% and 0.01% respectively) per flight
hour. Thus, combining these assumptions with the estimates in Table
7, we can estimate the probability of deviating from the prescribed
path for the different magnitudes of deviation. These are listed in
Table 8.
TABLE-US-00007 TABLE 8 Probability of deviating front the
prescribed path for different magnitudes of deviation. Probability
of Deviation Incident, Deviation Incident P.sub.DI 100-166 ft 9.22
.times. 10.sup.-4 167-3200 ft 1.88 .times. 10.sup.-3 >3200 ft
1.82 .times. 10.sup.-6
[0172] Based on this analysis, and because of the design of this
UAS, shorter deviations are much more likely to occur than larger
rogue deviations. Because the probability of a rogue deviation
failure is magnitudes below that of the other two, it is ignored it
for now. The probability of deviation incident is therefore,
P.sub.DI=9.22.times.10.sup.-4+1.88.times.10.sup.-3=2.80.times.10.sup.-3.
[0173] The following section describes the assumptions used in the
analysis of near mid-air collision as well as a discussion of the
methods for calculating the associated risk.
[0174] Key assumptions in this analysis are as follows: (1) Air
traffic density is correlated with class of airspace--Class B has
the most traffic, then Class C, D, E. Class G has the lowest
traffic density. (2) Air traffic density is lower below 400 ft.
AGL. (3) Air traffic below 400 ft. is uniformly disturbed within a
given class of airspace. (4) Deviation incidents are not accounted
for in determining risk of NMAC.
[0175] A near midair collision (NMAC) as defined by the AIM (7-6-3)
is "an incident associated with the operation of an aircraft in
which a possibility of collision occurs as a result of proximity of
less than 500 feet to another aircraft, or a report is received
from a pilot or a flight crew member stating that a collision
hazard existed between two or more aircraft."
[0176] For this risk assessment, an NMAC volume is modeled as a
sphere around the aircraft. An NMAC occurs if the spheres
surrounding two aircraft intersect. The NMAC volume for the UA is a
sphere with a 500 ft. radius. Since the UA has a wing span of -15
ft., this sphere encapsulates the UA itself and includes a 500 ft.
buffer. The NMAC volume for manned aircraft is a sphere with a 700
ft. radius. Since the wing span of commercial airliners is
approximately 200 ft., this encapsulates the largest of manned
aircraft and also includes the 500 ft. buffer.
[0177] For this risk assessment, it is assumed that air traffic is
uniformly disturbed within a given class of airspace. This allows
for calculation of the likelihood of collision using a basic
geometric (spatial) model. Under this assumption, the airspace is
modeled as a collection of grid cells. Within each cell, air
traffic is approximated as having a constant density.
[0178] It is also assumed that, except for the airspace immediately
surrounding airports, the air traffic density is lower for
altitudes below traffic pattern altitude (.about.800 ft. AGL) and
even lower at and below 400 ft. AGL due to 14 CFR 91.119.
[0179] In reality, there are areas with higher concentrations of
aircraft. Aircraft are more likely to follow certain routes (victor
airways, IR and VR routes, and direct courses between airports).
There is typically higher density near airports, particularly those
near more populous areas and those warranting Class C and B
airspace designations. However, this variation in the environment
can only be accounted for with location specific data which is not
readily available and use of more complex modeling.
[0180] Table 9 provides estimated frequency of air traffic in
different class of airspace in units of aircraft per cubic mile per
hour. These values can be used to calculate risk exposure for near
mid-air collisions in different class of airspace.
TABLE-US-00008 TABLE 9 Air traffic frequency below 800 ft AGL by
airspace class `Near Ground` Frequency (nm{circumflex over (
)}3/hr) Airspace Class (<800 ft AGL) Class B 50 Class C 30 Class
D 15 Class E 10 Class G 5 US Average 0.68.sup.1
[0181] FIG. 12 illustrates an exemplary unmitigated near mid-air
collision risk 1200 according to the various embodiments of the
present disclosure. The embodiment of the unmitigated near mid-air
collision risk 1200 shown in FIG. 12 is for illustration only.
Other embodiments of the unmitigated near mid-air collision risk
could be used without departing from the scope of this
disclosure.
[0182] The frequency of air traffic within a one cubic nautical
mile (per hour) is applied to a cell that is 1 nm by 1 nm by 800
ft. This area reduction makes the air traffic density values
conservative. Near mid-air collisions occur when either aircraft
violates the NMAC volume of the other. To estimate this
probability, a Monte Carlo simulation was performed in which one
billion pairs of random points were selected within an airspace
cell as shown in FIG. 12. The rate at which the distance between
these pairs of points was less than 700 ft. was calculated. The
criteria founded for NMAC was met at a rate of 39%. This value,
3.9.times.10.sup.-1 can be referred to as the geometric risk for
NMAC. This represents the unmitigated risk of near mid-air
collision for all classes of airspace.
[0183] It should be noted that this is a very conservative
estimate. It is assumed that an NMAC event can occur at all
instances less than 1,200 ft. (less than 500 ft. is a dual NMAC
event). However, in reality, aircraft positions follow
trajectories, so any value below 1,200 ft. would have already
triggered an NMAC event for the manned aircraft. This is an
artifact of Monte Carlo simulation.
[0184] Again, a key assumption of this risk assessment is that the
safety mitigations employed for these operations are completely
effective. If none of them fail, then an NMAC does not occur. A
worst-case scenario is one in which all of the possible mitigation
system failures occur under the assumptions in Table 5. Table 10
below presents the probability of NMAC for different
classifications of airspaces using the values and exposure
assumptions from above.
TABLE-US-00009 TABLE 10 Probability of NMAC for Airspace
Classifications Airspace Class P.sub.NMAC Class B 3.81 .times.
10.sup.-9 Class C 2.29 .times. 10.sup.-9 Class D 2.29 .times.
10.sup.-8 Class E 3.05 .times. 10.sup.-7 Class G 3.81 .times.
10.sup.-7
[0185] FIG. 13 illustrates an exemplary pedestrian risk zone 1300
according to the various embodiments of the present disclosure. The
embodiment of the pedestrian risk zone 1300 shown in FIG. 13 is for
illustration only. Other embodiments of the pedestrian risk zone
could be used without departing from the scope of this
disclosure.
[0186] The following section describes the assumptions used in the
analysis of impacting persons of the ground as well as a discussion
of the methods for calculating the associated risk.
[0187] Key assumptions in this analysis are as follows: (1) all
people on the ground are unsheltered. (2) Ground population is
correlated to class of airspace--Class B lies in metro areas, Class
C lies in urban areas, Class D in suburban areas, Class E and G are
in rural areas. (3) Ground population is uniformly disturbed within
a given class of airspace. (4) Any individual who is on the rail
road tracks is an active participant in the operation. Trespassers
are not treated as a special case--they are engaged in unlawful
activity and have accepted associated risks. (5) Humans at road
crossings are assumed to be unsheltered and are accounted for in
the uniform distribution of population density. This is
conservative. (6) Course deviation incidents are accounted for in
determining risk to persons on the ground.
[0188] For this risk assessment, it is assumed that population is
uniformly disturbed within a given class of airspace. This allows
for calculation of the likelihood of collision using a basic
geometric (spatial) model. Given the flight path of the UAS
operation, a ground risk zone is modeled on either side of the path
as shown in FIG. 13. The length of each zone segment is 1 mile and
the width is determined by the gliding capabilities of the UAS. In
certain embodiments, the UA can glide 3,200 ft. from a starting
altitude of 400 ft. AGL. The geometric risk to a pedestrian per
mile is the ratio of the area of a typical human to the area of the
segment in question. For the calculation, the area of a human (as
seen from above) is assumed to be 2.25 square feet. The resulting
geometric risk value is 6.66.times.10.sup.-8 per segment.
[0189] Given a flight route, population densities along the route
can be estimated in the area directly adjacent to the path. For
this risk assessment, the population density associated with
different classes of airspace has been estimated based on example
census data for representative areas. Table 11 lists these
population estimates.
TABLE-US-00010 TABLE 11 Assumed population per segment by airspace
classification Airspace Class Population Per Segment Class B 10,000
Class C 1,000 Class D 100 Class E 10 Class G 1
[0190] Considering the worst-case scenario where all mitigation
systems fail, the calculated probability of striking a human for
different airspace classes with assumed populations per segment,
for the values of assumed population, is given in Table 12. These
values are the population density of a segment is applied to the
geometric risk and reflect the magnitude of the unmitigated risk of
striking a human. A more accurate analysis would use portions of
census block data (or data from another source such as a land scan)
collected along a specific flight path.
TABLE-US-00011 TABLE 12 Geometric Risk to Persons on the Ground for
Airspace Classifications Airspace Class Unmitigted Risk to
Pedestrians Class B 6.66 .times. 10.sup.-4 Class C 6.66 .times.
10.sup.-5 Class D 6.66 .times. 10.sup.-6 Class E 6.66 .times.
10.sup.-7 Class G 6.66 .times. 10.sup.-8
[0191] A key assumption of this risk assessment is that the safety
mitigations employed for these operations are completely effective.
If none of them fail, then a NMAC does not occur. A worst-case
scenario is one in which all of the possible mitigation system
failures occur under the assumptions in Table 5. Table 13 below
presents the probability of striking a person on the ground for
different classifications of airspaces using the values and
assumptions from above.
TABLE-US-00012 TABLE 13 Mitigated Risk to Persons on the Ground by
Airspace Classification Airspace Class P.sub.SH/DI Class B 7.49
.times. 10.sup.-6 Class C 7.49 .times. 10.sup.-7 Class D 7.49
.times. 10.sup.-8 Class E 7.49 .times. 10.sup.-9 Class G .sup. 7.49
.times. 10.sup.-10
[0192] It is assumed that the probability of striking a human on
the ground is also dependent also on an incident occurring. The UAS
may not strike a non-participating human unless it deviates from
its course. Thus, methods of assessing the reliability of the UAS,
beyond the discussed mitigation systems, must be developed. In
general, this is a difficult task because either there is very
limited data, or no data exists, to make an accurate assessment of
UAS component reliability. As such, estimates must be made.
[0193] Thus, we can now calculate P.sub.SH=P.sub.SH|DI P.sub.DI,
where P.sub.DI was defined above in paragraphs [0177]-[0178], and
present Table 14 to include the probability of deviation
incident.
TABLE-US-00013 TABLE 14 Probability of striking a human by airspace
classification given a deviation incident Airspace Class P.sub.SH
Class B 4.19 .times. 10.sup.-9 Class C 4.19 .times. 10.sup.-10
Class D 4.19 .times. 10.sup.-11 Class E 4.19 .times. 10.sup.-12
Class G 4.19 .times. 10.sup.-13
[0194] Some estimates suggest that the inherent risk of NMAC for
General Aviation VFR flight in the NAS is approximately
1.33.times.10.sup.-7 per hour. This risk assessment, which has used
conservative assumptions, indicates that the proposed BVLOS
operation is on the order of the existing level of risk and may not
substantially increase risk in the NAS.
[0195] Estimates of risk of death by being hit by any falling
object are approximately 1.44.times.10.sup.-9 per hour
(3.times.10.sup.-6 per year). This risk assessment, which has used
conservative assumptions, indicates that the proposed BVLOS
operation may not substantially increase risk to persons on the
ground. Table 15 provides a summary of the operational risk
analysis.
TABLE-US-00014 TABLE 15 Summary of Operational Risk Analysis
Probability of NMAC Probability of the UAS between UAS and Manned
Impacting Humans on Airspace Class Aircraft (per hour) the Ground
(per hour) Class B 3.81 .times. 10.sup.-9 4.19 .times. 10.sup.-9
Class C 2.29 .times. 10.sup.-9 4.19 .times. 10.sup.-10 Class D 2.29
.times. 10.sup.-8 4.19 .times. 10.sup.-11 Class E 3.05 .times.
10.sup.-7 4.19 .times. 10.sup.-12 Class G 3.81 .times. 10.sup.-7
4.19 .times. 10.sup.-13
[0196] FIG. 14 illustrates an exemplary safe corridor airspace
(SCA) interface 1400 according to the various embodiments of the
present disclosure. The embodiment of the SCA interface 1400 shown
in FIG. 14 is for illustration only. Other embodiments of the SCA
interface 1400 could be used without departing from the scope of
this disclosure.
[0197] FIGS. 15A, 15B, and 15C illustrate exemplary faulty rail
conditions 1500, 1501, and 1502 according to the various
embodiments of the present disclosure. The embodiments of the
faulty rail conditions 1500, 1501, and 1502 shown in FIG. 15 are
for illustration only. Other embodiments of the faulty rail
conditions 1500, 1501, and 1502 could be used without departing
from the scope of this disclosure.
[0198] Faulty condition 1500 is called a broken rail or rail gap.
Faulty condition 1500 is caused by rapid cooling is an area that
pulls the rail apart.
[0199] Faulty condition 1501 is called a fouled ballast. Faulty
condition 1501 is caused by mud buildup on rail ties. The fouled
ballast causes erosion of the base of the rails and ties. Because
the ballast takes the force of the train from the rail, the mud
buildup causes the ballast to provide less forgiveness of the rail.
The lack of forgiveness causes stress to components of the rail,
such as rail ties, and potentially could loosen or come off the
rail. The fouled ballast can be determined when a prevalence of new
non-ballast appears in the image or that the ties are covered.
[0200] Faulty condition 1502 is called a curved rail, wavy rail, or
misaligned rail. Faulty condition 1502 is caused by sever movement
of the rail due to rapid heating. The rail expands an amount due to
heat that causes the rail to push out. The expansion of the rails
causes deviations in measurements between the rails.
[0201] The faulty conditions 1500, 1501, and 1502 can be detected
by comparing the image to an image of the previous rail and also by
comparing the image to an image or series of images of the rail
taken previously.
[0202] All of the faulty conditions 1502 are analyzed for changes
in pixel coloring, pixel density, and amount of pixels between
components indicating a distance, etc. A changed is identified when
one of the changes occurs between successive images in a single
flight and also identified when one of the changes occurs in images
of the same rail from different UAV flights.
[0203] The faulty conditions can also be detected based on specific
measurements. For example, one standard for rail width is 1435 mm
(4 ft 8.5 in). In this embodiments, when the image taken shows that
the rail deviates from 1435 mm, a curved rail faulty condition 1502
is detected.
[0204] In order to avoid false detects or non-substantial
detections, a threshold can be assigned for each faulty condition
1500, 1501, and 1502. For example, one standard for a gap between
successive rails is 14.30 mm. For the purposes of including
tolerance, a gap threshold could be 14.50 mm. When a gap is
detected less than the 14.50 mm, the system would not identify a
gap.
[0205] Also, the system could identify a length of each rail and
use that to validate different gaps. For example, one standard rail
length is 39 ft. For this length rail, the system can use the gap
threshold in a range that would correspond to each rail. In the
embodiment of the 39 ft. rail, the system could use the gap
threshold to account for gaps between rails, but use a much smaller
gap threshold between the ranges. For example, the system would use
5 mm as a gap threshold for a distance from an end of the rail
greater than 1 ft. and use a 15 mm gap threshold for a distance for
an end of the rail equal to or less than 1 ft.
[0206] The system also makes determination or fault based on the
criticality of the fault. Certain faults can be deemed as critical
or cautionary. Critical faults are faults that could potential
derail or damage a train or significantly impede the train's
movement. Cautionary faults are faults that require maintenance,
but do not pose a risk for derailment, damage or significant
impediment of the train.
[0207] FIG. 16 illustrates an exemplary concept of operations 1600
according to the various embodiments of the present disclosure. The
embodiment of the concept of operations 1600 shown in FIG. 16 is
for illustration only. Other embodiments of the concept of
operations 1600 could be used without departing from the scope of
this disclosure.
[0208] Different concepts of operations 1600 includes, but are not
limited to, supplemental tunnel and bridge inspection 1605,
continuous overflight of assets 1610, supplemental track inspection
1615, and supplement track integrity flights 1620.
[0209] FIG. 17 illustrates an exemplary UAS ecosystem 1700
according to the various embodiments of the present disclosure. The
embodiment of the UAS ecosystem 1700 shown in FIG. 17 is for
illustration only. Other embodiments of the UAS ecosystem 1700
could be used without departing from the scope of this
disclosure.
[0210] The UAS ecosystem includes satellites 1705, GPS modules
1710, propeller 1715, flight control 1720, motor controller 1730,
motor 140, frame 1745, LED positioning lighting 1750, RC receiver
155, remote controller 1760, camera mount 1765, camera 1770, live
image broadcasting 1775, virtual reality goggle 1780,
lithium-polymer battery 1785, etc.
[0211] Satellites 1705 allow communication between the UAS and
flight control center.
[0212] A GPS module 1710 is a device capable of receiving location
information from a GPS satellite. The GPS module is used for both
tracking of the UAS and for the UAS to follow the programmed flight
plan.
[0213] A propeller 1715 is rotably coupled to the UAS and provides
the lift to the UAS. The propellers are used for takeoff and
landing purposes. The UAS can include a plurality of
propellers.
[0214] A flight control 1720 includes the programming for the
flight plan for the takeoff and landing of the UAV. The flight
control 1720 is installed in the UAS. The flight control 1720
controls the propellers according to the flight plan.
[0215] A motor controller 1730 is included in the UAS. The motor
controller 1730 controls the motor 140 for
[0216] A motor 140 provides forward thrust for the UAS. The UAS can
include more than one motor 140.
[0217] A frame 1745 of the UAS provides the support and protection
for the components of the UAS. The frame 1745 is structured in a
manner that the UAS can continue to glide upon failure of the
thrust or lift components or systems.
[0218] LED positioning lighting 1750 is installed on the UAS. The
LED positioning lighting 1750 provide indication of the UAS to
other aircrafts and identify the location of the UAS. The LED
positioning lighting is also beneficial for low visibility
environments, such as tunnels, fog, nighttime, etc.
[0219] An RC receiver 1755 is a wireless receiver built into the
UAS. The RC receiver can communicate with towers or other
satellites to receive signals. The command center transmits signals
to the UAS through the RC receiver 1755.
[0220] A remote controller 1760 is installed in the frame 1745 of
the UAS or communicates through the RC receiver 1755. The remote
controller 1760 can be loaded with the flight plan before the
flight occurs, or can receive an updated flight plan or be
controller through the RC receiver 1755.
[0221] Camera mount 1765 is used to mount camera 1770. The camera
mount 1765 provides support for the camera 1770. The camera mount
1765 can be attached to the base of the frame 1745.
[0222] Camera 1770 is used to capture image and video data in the
rail system. More than one camera and different types of cameras
can be attached to the UAS.
[0223] The camera 1770 is used to identify networks of rail roads
for monitoring. The images of the railroads can also be used to
regulate the flight plan. In other words, if the images do not
confirm the location of the UAV from the flight plan, the flight
plan can be adjusted. The UAV could also send a discrepancy
indication to the command center indicating the difference in
determined location from the flight plan or sensors versus the
determined location from the image.
[0224] The camera 1770 is also used to identify faults in the rail
system. The camera 1770 can detect an obstruction of the rail, such
as a car stalled or parked on the tracks, trash or other debris,
etc. In detecting the faults, the camera 1770 can be used to
capture images of the rail that are analyzed for broken rail/rail
gap 1500, fouled ballast 1501, curved rail 1502, etc.
[0225] Live image broadcasting 1775 is performed using the camera
1770 and the RC receiver 1755. The images/frame captured by the
camera 1770 can be broadcast, such as to the command center. The
live image broadcast can provide real-time image or video for a
user to further analyze a fault situation.
[0226] Virtual reality goggle 1780 can be used by an operator on
the ground or at the command center. The virtual reality goggles
can display the live image broadcasting 1775 from the camera
1770.
[0227] Lithium-polymer battery 1785 is built into the frame 1745 of
the UAS. The battery 1785 can be used to power the different
components of the UAS.
[0228] FIG. 18 illustrates an exemplary UAS system components 1800
according to the various embodiments of the present disclosure. The
embodiment of the UAS system components 1800 shown in FIG. 18 is
for illustration only. Other embodiments of the UAS system
components 1800 could be used without departing from the scope of
this disclosure.
[0229] The UAS system components 1800 include, but are not limited
to, software 1805, UAS 1810, tracker control module 1815, autopilot
1820, laser altimeter above ground sensor 1825, rack mount ground
control station 1830, etc.
[0230] Software 1805 can be installed in the UAS and at the command
center. The software 1805 can perform any of the described
functions in this application.
[0231] UAS 1810 is the unmanned aerial system. The UAS flies over
the rail system to monitor the health of the tracks. The UAS also
monitors the rail for obstructions.
[0232] Tracker control module 1815 tracks the UAS during the
operation. The tracker control module 1815 can include the flight
plan and detect when the UAS is deterring from the flight plan. The
tracker control module 1815 can update the flight plan, determine
an issue with the UAS itself, or indicate an alarm to a user at the
command center.
[0233] Autopilot 1820 controls the UAS 1810. The autopilot 1820 can
be installed in the UAS or on the ground and transmit the
instructions through the RC receiver.
[0234] Laser altimeter above ground sensor 1825 determines the
altitude of the UAS 1810. The laser altimeter 1825 is in
communication with the command center.
[0235] Rack mount ground control station 1830 The rack mount ground
control station 1830 provides for a command center for the UAS
1810. The control station 1830 can control the flight plan of the
UAS and monitor the UAS while performing the flight plan.
[0236] FIGS. 19A, 19B, and 19C illustrate exemplary UASs 1900,
1905, 1910 according to the various embodiments of the present
disclosure. The embodiment of the UASs 1900, 1905, 1910 shown in
FIG. 19 is for illustration only. Other embodiments of the UASs
could be used without departing from the scope of this
disclosure.
[0237] FIG. 20 illustrates an exemplary optical sensor 2000
according to the various embodiments of the present disclosure. The
embodiment of the optical sensor 2000 shown in FIG. 20 is for
illustration only. Other embodiments of the optical sensor 2000
could be used without departing from the scope of this
disclosure.
[0238] FIGS. 21A and 21B illustrate exemplary UAS safety boundaries
2100 and 2101 according to the various embodiments of the present
disclosure. The embodiment of the UAS safety boundaries 2100 and
2101 shown in FIGS. 21A and 21B are for illustration only. Other
embodiments of the UAS safety boundaries could be used without
departing from the scope of this disclosure.
[0239] FIGS. 22A and 22B illustrate exemplary track integrity
sensor images 2200, 2201 according to the various embodiments of
the present disclosure. The embodiment of the track integrity
sensor images 2200, 2201 shown in FIGS. 22A and 22B are for
illustration only. Other embodiments of the track integrity sensor
images could be used without departing from the scope of this
disclosure.
[0240] In images 2200 and 2201, UAS is monitoring the rails 2205.
The UAS inspects each joint 2210 for possible failures.
[0241] FIGS. 23A, 23B, 23C, and 23D illustrate an exemplary
potential rail head defect 2300 according to the various
embodiments of the present disclosure. The embodiment of the
potential rail head defect 2300 shown in FIG. 23 is for
illustration only. Other embodiments of the potential rail head
defect could be used without departing from the scope of this
disclosure.
[0242] Images 2300, 2305, 2310, and 2315 illustrate a UAS detecting
a fault in the rail. In the first image 2300, the UAS system
detects a possible fault. The UAS system zooms in on the rail to
capture image 2305. The UAS system repeats the zooming for image
2315 and 2320 until a fault condition or non-fault condition is
identified and confirmed. A non-fault condition is when the rail is
determined to not require repair.
[0243] FIG. 24 illustrates an exemplary block diagram of control
network 2400 according to the various embodiments of the present
disclosure. The embodiment of the control network 2400 shown in
FIG. 24 is for illustration only. Other embodiments of the control
network could be used without departing from the scope of this
disclosure.
[0244] The control network 2400 includes, but is not limited to,
fixed operator location 2405, field operator location 2410,
autopilot 2415, UAS 2420, wired network 2425, tower 2430, aviation
band radio 2435, etc. The control network 2400 is used to monitor a
rail system for faults or obstructions. The aviation band radio
2435 communicates with another aerial vehicle 2440, which could be
manned or unmanned.
[0245] A fixed operator location 2405 is a command center that is
permanently located. The fixed operator location 2405 can be wired
or wirelessly connected to a tower 2430 for communication with the
UAV.
[0246] A field operator location 2410 is a command center that is
temporarily located. In other words, the field operator location
2410 can be remote from the command center and monitor the UAS in
the field. The field operator location 2405 is wirelessly connected
to a tower 2430 for communication with the UAS 2420. The field
operator location 2410 can also communicate or control the UAS
directly, without use of a tower. The field operator location 2410
can also communicate with the fixed operator location 2405
[0247] An autopilot 2415, while illustrated as located with the
field operator location 2410, could also be located at the fixed
operator location 2405. The autopilot 2415 is used for controlling
the UAS 2420.
[0248] The UAS 2420 flies over the rail system monitoring for
faults or obstructions. The UAS 2420 can also include an autopilot
2415. The UAS 2420 can communicate directly with the autopilot 2415
(if located at the field operator location 2410) or the systems of
the field operator location 2410 or towers 2430.
[0249] The UAS 2420 can be programmed to remain in communication
with a plurality of towers, for example, two towers at a minimum.
This would mean that a transfer to a third tower would be required
before dropping one of the two connected towers. The UAS 2420 (or
the autopilot 2415, systems at the fixed operator location 2410 or
the field operator location 2405) could determine the number of
towers or which towers to connect based on a signal strength, a
quality of the signal, etc.
[0250] Wired network 2425 connects the operator fixed location with
the plurality of tower 2430. The towers 2430 are each individually
connected to the other towers through the wired network 2425.
Because the towers 2430 are connected with the wired network 2425,
the field operator location 2410 can remain in communication with
the UAS 2420 after the UAS has flown out of range of the wireless
signal of the field operator location 2410.
[0251] Tower 2430 transmit and receive wireless signals with the
UAS, the other towers 2430, and the systems of the field operator
location 2410. The towers 2430 are also connected to the wired
network 2425 for communication with the fixed operator location
2405 and the other towers 2430.
[0252] FIG. 25 illustrates an exemplary right of way/aerial system
control network 2500 according to the various embodiments of the
present disclosure. The embodiment of the right of way/aerial
system control network 2500 shown in FIG. 25 is for illustration
only. Other embodiments of the right of way/aerial system control
network could be used without departing from the scope of this
disclosure.
[0253] The right of way/aerial system control network 2500
includes, but is not limited to, UAS 2505, a primary tower 2510, a
secondary tower 2515, ground control system 2520, an autopilot
2530, an RTK 2545, a tower wireless transceiver 2550, a UAV
wireless transceiver 2555, and an autopilot 2560, etc.
[0254] Long range UAS deployments have been focused on military
operations in either military airspace or within the theatre of
foreign combat where rules pertaining to commercial aviation are
not as prevalent. Aircraft location precision, terrain avoidance,
communication/command and control latency and aircraft payload
considerations are radically different and in many cases not
applicable to commercial, low altitude, domestic use.
[0255] In developing the ways/means to pursue long range flight
operations, a solution of systems was created that had several key
features:
[0256] First, control network 2500 provides the ability to ingest
FAA air traffic data (where available) and merge the data with
additional air traffic and obstruction data gathered from
proprietary geographical information data and supplemental aviation
voice/data receivers mounted on the various tower sites along the
right of way.
[0257] Second, navigational assurance for both the aircraft and the
various data gathering sensors--at below 500 ft. AGL, the control
network 2500 assembled in FIG. 25 provides mission planners and
pilots with navigational assurance that assists with terrain
avoidance, navigational precision, sensor/payload focus and
location precision and altitude above ground validation. The sum of
the parts of RTK 2545, UAS 2505, PCC 2530, tower wireless
transceiver 2550, UAV wireless transceiver 2555, ground control
system 2520, primary tower 2510 and secondary tower 2515 provide
this awareness for remote plots to have perspective on the
aircraft's performance, the surroundings, accuracy of flight,
sensor performance and adherence to FAA aviation regulations and
our flight requirements. Lastly, if an emergency situation or
malfunction arises, the sum of the systems will allow the pilot to
safely land the plane on the right of way.
[0258] Third, in addition to the network used to transmit/receive
data from tower wireless receiver 2550 and UAV wireless receiver
2555 as well as autopilot 2560 and ground control 2520, an aviation
band radio 2435 is mounted near every airport within proximity to
2510 and 2515 which provides the pilot with the ability to
communicate with other planes in proximity of the airport and
therefore avoid low altitude interactions near rural/un-towered
airports--a critical safety feature and quite unique to this
deployment.
[0259] FIG. 26 illustrates an example process for inspecting
railroad assets using an unmanned aerial vehicle in accordance with
various embodiments of the present disclosure. For example, the
process 2600 could be performed using the UAS.
[0260] In operation 2605, the system performs rail vision. The rail
vision includes processing images locally or remotely for the
detection of obstructions or faults in the rail system. Rail vision
also includes storing the results locally and transferring the
results for archiving at the command center. The system transmits,
via a plurality of communication towers, a flight plan including a
rail system and a flight path. The rail system can include a
plurality of rails across a geographic location. The flight path is
the path the UAV will travel to monitor the rail system. The flight
path can include flying along tracks, around bridges, through
tunnels, etc. The flight path can begin and end at a set location
or different locations.
[0261] In operation 2610, the system monitors the rail system for
detection of track components and other features. The system can
receive, via the plurality of communication towers, data while the
UAV is monitoring the rail system. The UAV can be connected to
multiple towers, with a minimum amount of two towers. The
communication towers can be connected to based on a signal
strength, a signal quality, etc. The plurality of communication
towers includes an aviation band radio configured to communicate
data with other aerial vehicles.
[0262] The system can detect an interference along the flight path
based on the received data. The received data can include data from
other sources, such as a local airport of the FAA, other aerial
vehicles, etc. The received data can be combined with operator data
to decrease the change of collision or interference with the UAV or
in general flight plan. The received data can includes current air
traffic data, obstruction data, geographic information data,
aviation voice data, weather data, etc.
[0263] In operation 2615, the system performs group flight paths.
The group flight paths include changing heading or speed and
adjusting to avoid gaps in image overlap.
[0264] In operation 2620, the system performs image stitching.
Consecutive images are stitched together for a full understanding
of the rail system. The image stitching also provide for alignment
adequate for analytics.
[0265] In operation 2625, the system performs post-processing on
the images. The results of the images, including geo-location,
time, etc., are collected from the camera and GPS receiver. The
system can detect a fault along the flight path based on the
received data. A rolling window logic for defects is used. The
rolling window logic is comparing consecutive or successive images
for changes in pixel color, pixel density, pixel length between
rails, etc. The system recognizes the pixel color and pixel density
for a rail is different from the pixel color and pixel density of a
rail tie, a ballast, component from the surrounding environment
(e.g., rocks, dirt, mud), etc. The system also recognizes distances
from common components. An example, the system recognizes the
distance between rails and the distance between rail ties, etc. In
operation 2630, the system performs report generation. The report
generation includes HTML navigation and KML display. The report can
be published in any known format, including PDF, CSV, etc.
[0266] In operation 2635, the system performs data transfer. The
data is stored on a local storage in the UAS, which is removed or
downloaded at one of the fixed operator location or the field
operator location.
[0267] Although FIG. 26 illustrates one example of a process 2600
for inspecting railroad assets using an unmanned aerial vehicle,
various changes may be made to FIG. 26. For example, although
depicted herein as a series of steps, the steps of the process
could overlap, occur in parallel, occur in a different order, or
occur multiple times.
[0268] Certain embodiments of the present disclosure are based on a
UAS capable of vertical takeoff and landing. Among other things,
the UAS includes an autopilot system that interfaces with the
system command and control infrastructure. The UAS also processes
navigation information generated from geographic information
systems, and supports various onboard sensors providing location
information. In particular, these sensors are capable of
transmitting and receiving information with an onboard navigation
beacon (ADSB) and a mode C transponder or its equivalent.
[0269] Embodiments of the UAS have sufficient onboard electrical
power generation capability to provide reliable power to all of the
other various aircraft systems, such as the sensor, communications,
and control subsystems. In addition, the UAS preferably has
sufficient liquid fuel capacity to support flight durations in
excess of 8 hours. The UAS also has the payload capability needed
to support multiple sensors for gathering information and the
communications and control subsystems need to pass that information
in real time to a flight operations center. The UAS preferably also
includes onboard information storage media for local storage of
gathered information. In addition, the system includes both onboard
and external subsystems for facilitating emergency maneuvering and
landing of the UAS on the flight corridor.
[0270] In general, the onboard sensors take high resolution precise
location photos no less than two times a second and 1/4 foot or
greater resolution from the operating altitude. Preferably, the
sensor system also has built-in local computational capability, its
own navigation system, and independent communication capability for
communicating with other onboard subsystems including the
autopilot. The sensors may include a photo sensor, a video camera,
a thermal imager, and/or a multispectral sensor. In particular, the
sensor system includes a real time day and night video camera for
pilot situational awareness, which includes at least some limited
real time protection capability.
[0271] The system also includes software focused on rail detection
and analysis of right of way conditions, which advantageously
support the inspection of linear assets, such as track, bridges,
and the like. Among other things, the system software, both onboard
and remote, includes machine vision software trained to understand
and recognize critical conditions within an area with at least two
linear borders. The system software is also capable of validating
normal functional conditions on the linear area.
[0272] More specifically, the onboard software runs on the UAS in a
line between the sensors and the ground based communications
systems. The onboard software processes data collected by sensors,
which is then loaded onto ground based computational systems that
in turn output quantitative and qualitative data about what the
sensors have seen. The software system processes bulk data, creates
another set of geo-located data, and then creates a 3rd set of
data. The system software finally creates several reports that are
associated with the data of interest, creates a geo-location file
that can allow the users to easily map the location of selected
conditions of interest. Preferably, the bulk data remains
unprocessed and the receivers receive only useable data that they
truly need.
[0273] The system software also includes field information
software, which could be used separately of this system or even
with multiple UASs. The field information software embodies an
algorithm that maps functionality and determines what order the
software should perform operations, which advantageously eliminates
human error. In particular, the field information software receives
media generated by the sensor system, transfers those data into a
laptop or other processing system, and then starts the local
software. The local software automatically codes, labels and
transfers the data to a drive and files and appropriately transmits
those data to whoever requires them (e.g., different departments in
an organization). The field information software may be used for
any gathered data related to a field location. The field
information software is preferably based on a networked system,
including a server or set of hardware devices. In some embodiments,
the field information software runs after conclusion of a flight by
the UAS (i.e., performs post-flight data processing). Data may be
distributed among the networked resources, which perform further
analysis and ensure that the data are properly coded and stored.
This helps maintain a chain of custody and minimizes data
errors.
[0274] Right of way, corridors, and towers are important factors in
an aerial railroad inspection system. The present system accesses
the 900 MHz channels used for the Automatic Train Control System
(ATCS) implemented through the AAR, although that is not a strict
requirement for practicing the present principles. The hardware and
software of the present system are optimized to use the low
bandwidth AAR channel in a highly functional manner. For systems
using the preferred AAR channels, the user normally requires a
license, and redundant Ethernet controls including appropriate
channels to communicate with the UAS. These can be implemented with
railroad telecommunications assets.
[0275] The UAS is preferably a vertical takeoff and landing
aircraft and operates (including landings) anywhere along a
railroad asset network. Once the UAS is in the air, the pilot
commands the autopilot to start the flight. The flight commences
and the UAS flies according to a route programmed by geographical
information systems to an actual railroad row and follows that row.
In other words, when the pilot actuates the autopilot, the system
software takes over and flies the UAS as close as possible once
over track. The software system also automatically enables the
sensors to start taking 2 pictures per second of the track. At the
same time, the sensor and software systems control the pitch, yaw,
and roll of UAS such that the appropriate sensor or sensors remain
focused and placed over the track to ensure the required resolution
and overlapping imagery. If analytics software determines after the
flight that there was not enough overlap, or if sections of track
were missed due to right of way occupancy, then the route is
quickly re-flown and the sensor takes more images.
[0276] While the autopilot is on and the sensor are taking photos,
the UAS control system is leveraging space-based GPS, and where
available, ground based GPS error correction, to keep the UAS
positioned over the row and maintain operating altitude and linear
flight path compliance, which both guarantees sensor resolution and
compliance with regulatory requirements regarding heights and width
of flight path.
[0277] Again, preferably the UAS and sensor have independent
navigation systems. Advantageously, when both the UAS and sensor(s)
have independent navigational systems, computational power is
preserved for critical items tasked to each component. For example,
the sensor system may include sensor stabilization software and
hardware.
[0278] Preferably, the UAS broadcasts its location, speed, altitude
and heading via the existing FAA surveillance network (SBS) and
also to other aircrafts equipped to receive these signals. In
addition, the railroad's infrastructure may support supplementing
the FAA SBS system using supplemental ADSB/transponder receivers,
radar and other elements along the right of way. While the UAS is
in flight, its operating condition, location and overall health are
transmitted to the pilot via the command and control link. During
all phases of the flight, the UAS has access to multiple command
and control transceiver locations assuring a level of redundancy of
command and control.
[0279] If the UAS loses connection to the command and control
system, after a period of time as determined by the operator and/or
FAA rules, the UAS can initiate its "lost link profile" and auto
descend and set itself down along the railroad row. The pilot can
be aware of lost link condition and based on the last transmission
form the UAS would notify users on the row and dispatchers of the
aircraft eminent landing. The sensors secondary communications and
navigation systems may also assist with locating the UAS.
[0280] If during flight there are other critical systems failures,
the UAS either automatically initiates one of several
pre-determined flight termination procedures returns to its
launching location or other location of safety as programmed.
During the course of flight, the pilot has the option of utilizing
a second sensor for real time imagery of the row. This secondary
sensor can also be used for some condition analysis, but is
primarily for pilot awareness. If during the course of flight a
critical condition is identified, the UAS's sensor can utilize a
secondary communications channel not connected to the primary to
send immediate notification to the pilots.
[0281] At the end of a specified mission, the pilot engages the
landing procedures, the UAS leverages all of the aforementioned
systems to arrive at the landing site, and engages the landing
procedures for vertical landing. The landing procedure includes the
enablement of an air to ground laser providing the UAS with
precision landing information. In final stages of fight before
landing, the pilot uses the UAS command and control system to
assure a safe landing. The UAS has multiple support systems on
board to assure a safe landing. If anything is present on the
ground or area of landing that would preclude a safe landing, the
landing abort procedure is initiated and alternate landing site is
identified. After a safe landing, the pilot removes the sensor data
storage drives and plugs them into a server. The UAS then commences
an automated process of analytics and data delivery that results in
delivery of customized reports and actionable data sets.
[0282] Although the invention has been described with reference to
specific embodiments, these descriptions are not meant to be
construed in a limiting sense. Various modifications of the
disclosed embodiments, as well as alternative embodiments of the
disclosure, can become apparent to persons skilled in the art upon
reference to the description of the invention. It should be
appreciated by those skilled in the art that the conception and the
specific embodiment disclosed might be readily utilized as a basis
for modifying or designing other structures for carrying out the
same purposes of the present disclosure. It should also be realized
by those skilled in the art that such equivalent constructions do
not depart from the spirit and scope of the disclosure as set forth
in the appended claims.
[0283] It is therefore contemplated that the claims can cover any
such modifications or embodiments that fall within the true scope
of the disclosure.
[0284] The description in this patent document should not be read
as implying that any particular element, step, or function is an
essential or critical element that must be included in the claim
scope. Also, none of the claims is intended to invoke 35 U.S.C.
.sctn. 112(f) with respect to any of the appended claims or claim
elements unless the exact words "means for" or "step for" are
explicitly used in the particular claim, followed by a participle
phrase identifying a function. Use of terms such as (but not
limited to) "mechanism," "module," "device," "unit," "component,"
"element," "member," "apparatus," "machine," "system," "processor,"
"processing device," or "controller" within a claim is understood
and intended to refer to structures known to those skilled in the
relevant art, as further modified or enhanced by the features of
the claims themselves, and is not intended to invoke 35 U.S.C.
.sctn. 112(f).
[0285] It may be advantageous to set forth definitions of certain
words and phrases used throughout this patent document. The terms
"include" and "comprise," as well as derivatives thereof, mean
inclusion without limitation. The term "or" is inclusive, meaning
and/or. The phrase "associated with," as well as derivatives
thereof, may mean to include, be included within, interconnect
with, contain, be contained within, connect to or with, couple to
or with, be communicable with, cooperate with, interleave,
juxtapose, be proximate to, be bound to or with, have, have a
property of, have a relationship to or with, or the like. The
phrase "at least one of," when used with a list of items, means
that different combinations of one or more of the listed items may
be used, and only one item in the list may be needed. For example,
"at least one of: A, B, and C" includes any of the following
combinations: A, B, C, A and B, A and C, B and C, and A and B and
C.
[0286] While this disclosure has described certain embodiments and
generally associated methods, alterations and permutations of these
embodiments and methods can be apparent to those skilled in the
art. Accordingly, the above description of example embodiments does
not define or constrain this disclosure. Other changes,
substitutions, and alterations are also possible without departing
from the spirit and scope of this disclosure, as defined by the
following claims.
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