U.S. patent application number 16/817441 was filed with the patent office on 2020-07-02 for aerial vehicle detection system.
The applicant listed for this patent is Flirtey Holdings, Inc.. Invention is credited to John R FOGGIA, Allison Jade MALLOY, Matthew SWEENY.
Application Number | 20200209375 16/817441 |
Document ID | / |
Family ID | 63714118 |
Filed Date | 2020-07-02 |
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United States Patent
Application |
20200209375 |
Kind Code |
A1 |
FOGGIA; John R ; et
al. |
July 2, 2020 |
AERIAL VEHICLE DETECTION SYSTEM
Abstract
Embodiments described herein are concerned with system for
identifying an aerial vehicle. The system comprises: a radar
sub-system, the radar sub-system comprising at least one radar
connectable to a static support member and a transceiver configured
to transmit data indicative of one or more targets identified by
the radar within an airspace; a receiver arranged to receive the
data indicative of one or more targets identified by the radar; and
a processing system configured to process said data, whereby to
identify at least one aerial vehicle. In some embodiments the radar
comprises a marine radar.
Inventors: |
FOGGIA; John R; (Reno,
NV) ; MALLOY; Allison Jade; (Reno, NV) ;
SWEENY; Matthew; (Reno, NV) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Flirtey Holdings, Inc. |
Reno |
NV |
US |
|
|
Family ID: |
63714118 |
Appl. No.: |
16/817441 |
Filed: |
March 12, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/US2018/050935 |
Sep 13, 2018 |
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16817441 |
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62558167 |
Sep 13, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G08G 5/0069 20130101;
G08G 5/0082 20130101; G01S 13/04 20130101; G01S 13/937 20200101;
G08G 5/0026 20130101; G08G 5/045 20130101; G01S 13/72 20130101;
G08G 5/0013 20130101; G01S 13/781 20130101; G01S 13/872 20130101;
G01S 13/91 20130101; B64C 39/024 20130101; G01S 13/726 20130101;
G01S 5/0027 20130101 |
International
Class: |
G01S 13/04 20060101
G01S013/04; G01S 13/91 20060101 G01S013/91; G01S 13/78 20060101
G01S013/78; G01S 13/72 20060101 G01S013/72; G08G 5/04 20060101
G08G005/04; G08G 5/00 20060101 G08G005/00 |
Claims
1. A system for identifying an aerial vehicle, the system
comprising: a radar sub-system, the radar sub-system comprising at
least one radar connectable to a static support member and a
transceiver configured to transmit data indicative of one or more
targets identified by the radar within an airspace; a receiver
arranged to receive the data indicative of one or more targets
identified by the at least one radar; and a processing system
configured to process said data, whereby to identify at least one
aerial vehicle.
2. A system according to claim 1, wherein the at least one radar is
configured to receive, as a continuous input, data indicative of a
fixed location, the fixed location being the location of the radar
when connected to the static support member.
3. A system according to claim 2, wherein the at least one radar
comprises a marine radar.
4. A system according to any preceding Claim, wherein said data
indicative of one or more targets identified by the at least one
radar within an airspace comprises course, speed, closest point of
approach and time of closest point of approach, for each
target.
5. A system according to any preceding Claim, wherein the at least
one radar has a usable swept volume and a vertical beam width, and
is connectable to the static support member via an adjustable
connector, the adjustable connector being arranged such that the
vertical beam width is rotatable with respect to a centre of the
adjustable connector and about an axis that is perpendicular to a
longitudinal axis of the static support member and is aligned with
the centre of the adjustable connector so as to control an overlap
between the usable swept volume and the ground.
6. A system according to any preceding Claim, wherein the radar
sub-system comprises a plurality of radars, each connectable to a
respective static support member and positioned with respect to
another of the radars such that the plurality of radars
collectively provide contiguous coverage over a predetermined
volume within the airspace.
7. A system according to claim 6, wherein each radar has a usable
swept volume, and is positioned with respect to another of the
radars such that overlap between respective usable swept volumes
excludes areas occupied by objects on the ground and/or at sea
level.
8. A system according to claim 7, wherein the processing system is
configured to output a location associated with the identified at
least one aerial vehicle to a graphical user interface, the
graphical user interface being configured to display a map of a
region including respective locations of at least the or each radar
and its usable swept volume.
9. A system according to claims 6 to 8, wherein the processing
system comprises a correlator configured to correlate data
indicative of one or more targets identified by a first radar with
data indicative of one or more targets identified by a second
radar, whereby to generate first correlated data associated with at
least one aerial vehicle.
10. A system according to claim 9 dependent on claim 8, wherein the
correlator is configured to identify a first vehicle location
associated with the first correlated data and to output the first
vehicle location to the graphical user interface for display on the
map.
11. A system according to any preceding Claim, further comprising
an automatic dependent surveillance-broadcast (ADS-B) receiver
arranged to receive tracking information from aerial vehicles
equipped with an ADS-B transceiver, wherein the processing system
is further configured to process said tracking information received
from the ADS-B receiver, whereby to identify at least one aerial
vehicle.
12. A system according to claim 11 dependent on claim 9, wherein
the correlator is configured to correlate data indicative of one or
more targets identified by a first radar and/or data indicative of
one or more targets identified by a second radar with the tracking
information received from the ADS-B receiver, whereby to generate
second correlated data associated with at least one aerial vehicle
and to identify at least a second vehicle location for display on
the map.
13. A system according to any preceding Claim, further comprising a
telemetry receiver arranged to receive telemetry data from aerial
vehicles equipped with a radio modem, wherein the processing system
is further configured to process said telemetry data received from
the telemetry receiver, whereby to identify at least one aerial
vehicle.
14. A system according to claim 13 dependent on claim 9, wherein
the correlator is configured to correlate data indicative of one or
more targets identified by a first radar and/or data indicative of
one or more targets identified by a second radar with the telemetry
data received from the telemetry receiver, whereby to generate
third correlated data associated with at least one aerial vehicle
and to identify at least a third vehicle location for display on
the map.
15. A system according to claim 13 dependent on claim 12, wherein
the correlator is configured to correlate the telemetry data
received from the telemetry receiver with second correlated data
associated with at least one aerial vehicle whereby to generate
fourth correlated data associated with at least one aerial vehicle
and to identify at least a fourth vehicle location for display on
the map.
16. A system according to claims 10 to 15, wherein the graphical
user interface is responsive to input received from an input device
to display selected ones of the first, second, third and fourth
vehicle locations.
17. A system according to claims 10 to 16, wherein the correlated
data comprises vector data indicative of direction and speed, and
the correlator is configured to identify a given vehicle location
in the event that the vector data are within predetermined
ranges.
18. A system according to claim 17 dependent on claim 13, wherein
the processing system is configured to determine a potential
collision between two aerial vehicles based on the vector data, and
to generate instructions for transmission via the telemetry
receiver to change a flight path of one of the aerial vehicles.
19. A method of identifying an aerial vehicle on a graphical user
interface configured to display a map of a region, the method
comprising: receiving data indicative of one or more targets
identified by at least one radar, the data comprising one or more
of course, speed, closest point of approach and time of closest
point of approach, for each target in the region; receiving data
indicative of an automatic dependent surveillance-broadcast (ADS-B)
receiver arranged to receive tracking information from aerial
vehicles equipped with an ADS-B transceiver in the region;
correlating the data indicative of the one or more targets
identified by the radar with the tracking information received from
the ADS-B receiver, whereby to generate first correlated data
associated with at least one aerial vehicle and to identify at
least a first vehicle location for display on the map.
20. A method according to claim 19, further comprising receiving
data indicative of one or more targets identified by a plurality of
radars and correlating data indicative of one or more targets
identified by a first radar and/or data indicative of one or more
targets identified by a second radar with the tracking information
received from the ADS-B receiver, whereby to generate second
correlated data associated with at least one aerial vehicle and to
identify at least a second vehicle location for display on the
map.
21. A method according to claim 20, further comprising receiving
telemetry data from aerial vehicles equipped with a radio modem,
and correlating data indicative of one or more targets identified
by a first radar and/or data indicative of one or more targets
identified by a second radar and/or the tracking information
received from the ADS-B receiver with the telemetry data received
from the telemetry receiver, whereby to generate third correlated
data associated with at least one aerial vehicle and to identify at
least a third vehicle location for display on the map.
22. A method according to any one of claim 19 to claim 21, in which
the correlated data comprises vector data indicative of direction
and speed of an aerial vehicle, the method further comprising
determining a potential collision between two aerial vehicles based
on the vector data.
23. A method according to claim 22 dependent on claim 21, further
comprising generating instructions for transmission via the
telemetry receiver to change a flight path of one of the aerial
vehicles.
24. A computer readable medium comprising a set of instructions,
which, when executed by a processing system, causes the processing
system to perform the method according to any one of claim 19 to
claim 23.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International
Application No. PCT/US2018/050935, filed Sep. 13, 2018, which
claims the benefit of U.S. Provisional Application No. 62/558,167,
filed Sep. 13, 2017, under 35 U.S.C. .sctn. 119(a). Each of the
above-referenced patent applications is incorporated by reference
in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to an aerial vehicle detection
system, and has particular, but not exclusive, applicability to
detecting aerial vehicles present in the uncontrolled airspace,
such as the Class G airspace.
BACKGROUND
[0003] Ground control stations track and analyze various aerial
vehicles, such as Unmanned Aerial Vehicles (UAVs), airplanes, or
helicopters. Aerial vehicles can be tracked by a computer using
various tracking technologies. These tracking technologies can
generally be classified under either cooperative surveillance
technology or non-cooperative surveillance technology. Cooperative
surveillance technology includes a device installed on an aerial
vehicle that provides information about a vehicle so that air
traffic control can track the vehicle. The device installed on an
aerial vehicle for cooperative surveillance may include an
automatic dependent surveillance-broadcast (ADS-B) transceiver, a
Mode-S transceiver, or a Mode-C transceiver, or via other active
transmission of identity and position information. The operators of
the aerial vehicle with cooperative surveillance technology
participate in the collective surveillance of the system by
electronically making known certain tracking information, for
example, the position and presence of the aerial vehicle.
Non-cooperative aerial vehicles do not make known their tracking
information, e.g., because these vehicles may operate without
onboard transceivers, or the onboard transceivers on these vehicles
may have failed, or the onboard transceivers on these vehicles may
be inadvertently turned off. Examples of non-cooperative aerial
vehicles include crop sprayers, gliders and paragliders, hot air
balloons, and UAVs operated by individuals and enterprises ranging
from hobbyists to commercial delivery companies. Furthermore, many
UAVs are not equipped with onboard imaging technology.
[0004] As a result, such UAVs are flying blind and they are
typically invisible to other airborne vehicles. And while an
operator can control flight of a UAV within the airspace that is
visible to the operator, UAVs--in particular those deployed by
commercial enterprises--are required to fly beyond line of sight.
Even if a UAV is equipped with imaging processing technology for
detect and avoid, it is often too late to avoid a collision by e.g.
changing course only when a vehicle has been detected. It would be
desirable to address these problems.
SUMMARY
[0005] Aspects of the present disclosure provide a system, method
and computer software according to the appended claims.
[0006] A first aspect discloses a system for identifying an aerial
vehicle, the system comprising: a radar sub-system, the radar
sub-system comprising at least one radar connectable to a static
support member and a transceiver configured to transmit data
indicative of one or more targets identified by the radar within an
airspace; a receiver arranged to receive the data indicative of one
or more targets identified by the at least one radar; and a
processing system configured to process said data, whereby to
identify at least one aerial vehicle.
[0007] In certain embodiments the radar comprises a marine radar,
which is configured to receive, as a continuous input, data
indicative of a fixed location, which is the location of the radar
when connected to the static support member. It will be appreciated
that selection of a marine radar to identify aerial vehicles is an
unconventional choice. Marine radars are affixed to moving objects,
namely ships, and typically rely upon a continuous feed of the
position of the ship on which the marine radar is installed. By
contrast, the location of the radar sub-system according to
embodiments described herein is fixed and, in most cases, will be
positioned on land. The inventors have realised that it is possible
to configure the radar so as to receive, as a continuous input,
data indicative of a fixed location, the fixed location being the
location of the radar when connected to the static support
member.
[0008] In some examples the at least one radar has a usable swept
volume and a vertical beam width and is connectable to the static
support member via an adjustable connector. The adjustable
connector may be arranged such that the vertical beam width is
rotatable with respect to a centre of the adjustable connector and
about an axis that is perpendicular to a longitudinal axis of the
static support member and is aligned with the centre of the
adjustable connector so as to control an overlap between the usable
swept volume and the ground.
[0009] Preferably the radar sub-system comprises a plurality of
radars, each connectable to a respective static support member and
positioned with respect to another of the radars such that the
plurality of radars collectively provide contiguous coverage over a
predetermined volume within the airspace. More particularly, each
radar is positioned with respect to another of the radars such that
overlap between respective usable swept volumes excludes areas
occupied by objects on the ground and/or at sea level.
[0010] In some examples the processing system is configured to
output a location associated with the identified at least one
aerial vehicle to a graphical user interface, the graphical user
interface being configured to display a map of a region including
respective locations of at least the or each radar and its usable
swept volume.
[0011] Preferably the processing system comprises a correlator
configured to correlate data indicative of one or more targets
identified by a first radar with data indicative of one or more
targets identified by a second radar, whereby to generate first
correlated data associated with at least one aerial vehicle.
Further, a first vehicle location associated with the first
correlated data can be identified and output to the graphical user
interface for display on the map.
[0012] Some example embodiments comprise an automatic dependent
surveillance-broadcast (ADS-B) receiver arranged to receive
tracking information from aerial vehicles equipped with an ADS-B
transceiver, wherein the processing system is further configured to
process said tracking information received from the ADS-B receiver,
whereby to identify at least one aerial vehicle. In these examples
the correlator is configured to correlate data indicative of one or
more targets identified by a first radar and/or data indicative of
one or more targets identified by a second radar with the tracking
information received from the ADS-B receiver, whereby to generate
second correlated data associated with at least one aerial vehicle
and to identify at least a second vehicle location for display on
the map.
[0013] Other example embodiments comprise a telemetry receiver
arranged to receive telemetry data from aerial vehicles equipped
with a radio modem, wherein the processing system is further
configured to process the telemetry data received from the
telemetry receiver, whereby to identify at least one aerial
vehicle. In these examples the correlator is configured to
correlate data indicative of one or more targets identified by a
first radar and/or data indicative of one or more targets
identified by a second radar with the telemetry data received from
the telemetry receiver, whereby to generate third correlated data
associated with at least one aerial vehicle and to identify at
least a third vehicle location for display on the map. Further, the
correlator may be configured to correlate the telemetry data
received from the telemetry receiver with second correlated data
associated with at least one aerial vehicle whereby to generate
fourth correlated data associated with at least one aerial vehicle
and to identify at least a fourth vehicle location for display on
the map.
[0014] Conveniently the graphical user interface is responsive to
input received from an input device to display selected ones of the
first, second, third and fourth vehicle locations. When the
correlated data comprises vector data indicative of direction and
speed, a given vehicle location can be identified in the event that
the vector data are within predetermined ranges. Furthermore, the
processing system is configured to determine a potential collision
between two aerial vehicles based on the vector data, and to
generate instructions for transmission via the telemetry receiver
to change a flight path of one of the aerial vehicles.
[0015] According to a further aspect of the present disclosure
there is provided a method of identifying an aerial vehicle on a
graphical user interface configured to display a map of a region,
the method comprising:
[0016] receiving data indicative of one or more targets identified
by at least one radar, the data comprising one or more of course,
speed, closest point of approach and time of closest point of
approach, for each target in the region;
[0017] receiving data indicative of an automatic dependent
surveillance-broadcast (ADS-B) receiver arranged to receive
tracking information from aerial vehicles equipped with an ADS-B
transceiver in the region;
[0018] correlating the data indicative of the one or more targets
identified by the radar with the tracking information received from
the ADS-B receiver, whereby to generate first correlated data
associated with at least one aerial vehicle and to identify at
least a first vehicle location for display on the map.
[0019] The method may comprise receiving data indicative of one or
more targets identified by a plurality of radars and/or telemetry
data from aerial vehicles equipped with a radio modem; this then
enables the correlation process to take account of target data from
other sources and display additional vehicles on the map. When the
correlated data comprises vector data indicative of direction and
speed of an aerial vehicle, potential collisions between two aerial
vehicles can be determined based on the vector data. This then
enables instructions to be generated to change a flight path of one
or more of the aerial vehicles, which can be transmitted to the
radio modem(s) of these vehicles and thereby avoid a collision.
[0020] Further features and advantages of the invention will become
apparent from the following description of preferred embodiments of
the invention, given by way of example only, which is made with
reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a schematic block diagram depicting components of
a system for identifying an aerial vehicle according to an
embodiment;
[0022] FIGS. 2a and 2b are schematic diagrams showing various
deployments of a radar of the system for identifying an aerial
vehicle of FIG. 1;
[0023] FIG. 2c is a schematic diagram showing a side view depiction
of the projected swept volume for a vertical beam width of .theta.
when the radar is positioned a) substantially horizontally and b)
at a non-zero tilt angle from the horizontal;
[0024] FIG. 3 is a schematic block diagram depicting components of
a system for identifying an aerial vehicle according to a further
embodiment;
[0025] FIG. 4 is an aerial view of coverage provided by the three
radars of FIG. 3;
[0026] FIG. 5 is a graph depicting usable, or half-power extent, of
the volume swept out by the radar of FIG. 2 for a radome height of
6 m and 15 m above sea level; and
[0027] FIG. 6 is a plan view of an output from a processing system
of the system for identifying an aerial vehicle of FIG. 1 onto a
graphical user interface.
DETAILED DESCRIPTION
[0028] Embodiments described herein are concerned with identifying
airborne targets flying within the sub-400 feet airspace, and
within a delivery range of approximately 5 km/3 statute miles.
Targets of particular concern include non-cooperative aerial
vehicles such as crop sprayers, other UAVs, hot air balloons,
gliders and the like.
[0029] FIG. 1 shows a system for identifying an aerial vehicle
according to an embodiment. The system comprises a radar sub-system
101, which includes a radar 103 connectable to a static support
member 105 and a transceiver 107 configured to transmit data
indicative of one or more targets identified by the radar 103
within an airspace. The support member 105 can be a radio tower,
cellular towers, existing buildings or bespoke structures. When the
support member 105 is embodied as a pole-based structure it may be
desirable to improve stability and solidity by providing
stabilising parts, examples of which are depicted schematically as
parts 106a, 106b. The radar 103 is connectable to the support
member 105 via a rigid plate 104, such as an I-section plate, or a
plate having an integral female coupling component that
interconnects with a corresponding male coupling component that is
part of the support member 105. More particularly, the radar 103
may be connectable to the support member 105 via a plate 104
comprising an adjustable connector (not shown), e.g. in the form of
a rotatable hinge or the like, enabling rotation of the radar 103
and thence the vertical beam width with respect to a centre of the
adjustable connector and about an axis X-X that is perpendicular to
a longitudinal axis Y-Y of the support member and is aligned with
the centre of the adjustable connector 104. This enables the
overlap between the usable swept volume and the ground to be
controlled, as will be described in more detail below.
[0030] The radar 103 has its own local control electronics,
processor and electrical I/O connections, enabling data and control
signals to be transmitted to and from a processing system 109 under
control of radar software (not shown) particular to the radar 103.
Connections C1 are depicted as logical connections via dotted lines
in the Figure; it is to be understood that these connections can be
wired or wireless and utilize any known technology or combinations
of technologies. In preferred arrangements the transceiver 107 is
connected to the processing system 109 via a router and an LTE
radio over a Virtual Private Network (VPN), so that the radar
software and the processing system 109 is on the same class B
network.
[0031] A particularly desirable operating condition is to provide
contiguous coverage of an airspace volume of interest. This is a
function of the line-of-sight of the radar(s). In certain
environments, and as depicted in FIG. 1, a single radar 103 may be
sufficient, for example if the sub-system 101 is positioned in a
non-urban area.
[0032] In a preferred embodiment the radar 103 is a marine radar
that radiates in the superhigh frequency (SHF) band, with
wavelengths in the centimeter range (1-10 cm), allowing detection
of small objects without requiring extreme power pulses. Further,
the marine radar 103 is capable of detecting targets within a
minimum of 4 statute miles detection range, preferably 6 statute
miles, and has fine--and configurable--range resolution. The latter
is a function of beam width, scanning speed, and array scanning
technique; most preferably the marine radar 103 is a phased-array
radar, owing to its excellent target resolution, relatively low
power requirements, and safe levels of close-in radiation.
Furthermore, the marine radar 103 is preferably disposed within a
radome, which makes for simpler transportation, and enables more
ruggedized packaging than is possible with an open-array radar.
[0033] In one particular example the marine radar 103 is a
Furuno.TM. DRS4D-NXT radar, which is a solid-state phased array
radar, with maximum range of 36 nautical miles, and which operates
in the microwave X-band, at 9.4 GHz with a scan frequency of 24 RPM
(0.4 Hz), or a target revisit rate of once every 2.5 s. Further,
the Furuno.TM. DRS4D-NXT radar has a capability to narrow the
effective horizontal beam width to 2.degree., allowing resolution
of very small targets, including low-radar reflectivity birds.
[0034] Preferably the software internal to the marine radar 103
comprises along-propagation path Doppler processing, so that
Doppler-assisted decisions can be made when determining which
targets to track. The Furuno.TM. DRS4D-NXT radar includes
proprietary Target Analyzer.TM. function to near-instantly identify
targets in this manner and Fast Target Tracking.TM., which enables
tracking of up to 100 targets, simultaneously. The onboard Doppler
processing includes Automatic Radar Plotting Aid (ARPA)
functionality to determine targets' course and speed, as well as
the Closest Point of Approach (CPA) and time of CPA. Referring
again to FIG. 1, the output from the marine radar 103 is course,
speed, closest point of approach and time of closest point of
approach, for each target, and is received by the processing system
109 to identify at least one aerial vehicle as will be described in
detail below.
[0035] It should be appreciated that selection of a marine radar
103 to identify aerial vehicles is an unconventional choice. Marine
radars are affixed to moving objects, namely ships, and the
aforementioned Doppler processing relies upon a continuous feed of
the position of the ship on which the marine radar is installed. By
contrast, the location of the marine radar sub-system 101 according
to embodiments described herein is fixed and, in most cases, will
be positioned on land. The inventors have realised that it is
possible to configure the marine radar 103 so as to receive, as a
continuous input, data indicative of a fixed location, the fixed
location being the location of the marine radar 103 when connected
to the support member. In a particular configuration the fixed
location is sent from the processing system 109 to the marine radar
103 over connection C1, which, as shown, is bidirectional. In this
way, it is possible to make use of the Doppler processing
technology despite the fact that the marine radar 103 is
static.
[0036] A further difference and complication arises from the fact
that marine radars provide output in two dimensions only, since
they are designed to identify targets at sea level, whereas
embodiments described herein are concerned with identifying targets
that are airborne. Moreover, it is a desired objective to exclude
ground-based objects from the set of candidate targets. However,
because many ground-based targets move, absent specific
engineering, the marine radar 103 will detect these ground-based
targets. The inventors have addressed this problem in two ways,
each of which may be used alone or in combination. First, by
identifying a range of angles at which the radar 103 is to be
positioned, relative to the ground. This then informs the specific
positioning and orientation of the radar 103 relative to the
support member. In one example the vertical beam width is 25
degrees, which means that the usable swept volume of the radar can
be focused on airspace above ground coverage.
[0037] FIGS. 2a and 2b depict the radar 103 positioned at different
angles, when affixed to the side of (FIG. 2a) and above (FIG. 2b)
the support member 105.
[0038] FIG. 2c is a sideview showing the effects of varying the
angle of the radar 103. The left hand diagram shows the radar
positioned substantially horizontally, so that the radar tilt angle
from the horizontal (.PHI.)=0, at a height z from the ground. The
bottom of the radar beam intersects the ground at a distance Z/tan
(.theta./2) from the longitudinal (vertical, in this diagram) axis
of the radar 103.
[0039] The right hand diagram shows the radar 103 with a non-zero
tilt angle .PHI.. The height of the bottom of the radar beam,
h.sub.B and of the top of the radar beam h.sub.T can be calculated
from the following equations:
tan ( .PHI. + .theta. 2 ) = hT d ( 1 ) hT = d tan ( .PHI. + .theta.
2 ) ( 2 ) tan ( .PHI. - .theta. 2 ) = hB d ( 3 ) hB = d tan ( .PHI.
- .theta. 2 ) ( 4 ) ##EQU00001##
so that the bottom of the radar beam above the ground, h.sub.BG, is
given by
h BG = h B + Z ##EQU00002## h BG = d tan ( .PHI. - .theta. 2 ) + Z
##EQU00002.2##
and the top of the radar beam above the ground, h.sub.TG, is given
by
h TG = h T + Z ##EQU00003## h TG = d tan ( .PHI. + .theta. 2 ) + Z
##EQU00003.2##
[0040] As noted above, the plate on which the radar 103 is mounted
can include control electronics which enables its orientation to be
adjusted relative to the support member 105, and thereby adjust the
region occupied by the vertical beam width of the radar 103.
Accordingly the tilt angle, .PHI., can be set at the processing
system 109, and instructions sent via connection C1 to cause the
radar 103 to rotate, e.g. about the horizontal axis X-X as shown in
FIGS. 2a and 2b. This enables the processing system 109 to generate
an augmented view of the airspace and/or terrain in the vicinity of
any given radar 103.
[0041] The second solution to this problem is of utility when the
radar sub-system comprises more than one radar 103. This
arrangement has particular application in urbanised environments,
when it may be preferable to deploy more than one radar 103 in
order to achieve a contiguous line of sight operating condition.
Generally speaking three radars 103 will provide the desired
contiguous line of sight operating condition. Referring to FIG. 3,
each radar 103 is part of the radar sub-system 101, is connected
via a respective connection C2, C3 to the processing system 109,
and is affixed to its respective support member, which may be
similar to, or different from, the support members employed by
other marine radars 103 in the sub-system. FIG. 4 is a plan view of
an exemplary three-radar coverage, where each ring 401a, 401b, 401c
represents 6 mile ranges. An advantage of deploying more than one
radar 103 in the radar sub-system is that each radar can be
positioned (latitude, longitude and azimuth) and angled to maximize
the knowledge for its respective location. The radars will be at
different distances from each other, at different heights off the
ground, the terrain will be different and so the resulting coverage
will be different. When the height and angle as well as the terrain
information is known, the areas with radar ground coverage can be
determined. More specifically, the coverage overlap for the three
radars can be determined and used to set geographic zones where the
coverage from one radar can be considered a) air and ground or b)
air only. Then, when a detection is made by a given radar the
processing system 109 can determine if the target is in the air or
on the ground. This can be repeated for each radar, thereby leading
to an improved determination over a larger geographic area. With
this knowledge the position of individual radars 103, relative to
one another, can be such that the overlap in usable swept volume
between respective radars excludes terrestrial regions. In this
scenario any target identified by more than one radar 103 in the
sub-system 101 will be airborne.
[0042] FIG. 5 is a graph depicting usable volumes (-3 dB) at
half-power swept by an exemplary marine radar 103, positioned at 6
m and 15 m above sea level. With the marine radar 103 positioned
such that the nominal center of the vertical beam is parallel to
the local ground plane, a 6 m (.about.20 ft) radome height above
ground produces a detectable surface starting approximately 27 m
(90 ft) from the radar. At 400 m (0.25 sm) from the radar, the top
of the observable volume (-3 dB), is approximately 90 m (.about.300
ft), and at 800 m from the radar (0.5 sm) targets can be detected
at approximately 180 m (.about.600 ft) and below. When the marine
radar 103 is positioned at 15 m (.about.50 ft) radome height above
the ground, detections on the surface start at 68 m (.about.220 ft)
from the radar with the top of the radar volume at 400 m (1/4 sm)
at 102 m (.about.340 ft), and at 800 m (1/2 sm) targets could be
detected at approximately 189 m (.about.630 ft). As will be
appreciated from the problems addressed by solutions one and two,
it is desirable to minimise surface detection, so it is preferable
to position the marine radar 103 higher above sea level.
[0043] Having described components of the radar sub-system 101,
attention will now be turned to features of the processing system
109. Returning to FIG. 1, the processing system 109 comprises an
adapter component 111, configured to communicate with the radar
software e.g. via an API over connection C1. In addition, the
processing system 109 comprises storage DB1, which may be cache
and/or random-access memory, configured to store data received from
the radar 103. In particular, and as noted above, this data
includes course, speed, closest point of approach and time of
closest point of approach, for each target identified by the radar
103. The adapter component 111 is configured to output a location
associated with a target to a graphical user interface component
113 on a display 114, which displays a map of a region including
respective locations of at least the radar(s) and the corresponding
usable swept volume. An exemplary output of the graphical user
interface component 113 is shown in FIG. 6. Targets identified by a
radar are labelled with "R", so e.g. R-34 and R-08 are targets
identified by the radars. The processing system 109 also includes a
correlator component 115, which is configured to correlate data
indicative of one or more targets identified by a first radar 103a
with data indicative of one or more targets identified by a second
radar 103b. For example, if the direction, speed and location
(vector data) of targets are within an acceptable range of one
another, the correlator component 115 can correlate the targets and
show them as a single target on the user interface component
113.
[0044] The graphical user interface component 113 includes display
controls (not shown) that enable user selection of raw locations
processed by the adapter component 111 and/or only correlated
locations, as output by the correlator component 115. Since
correlated locations by definition have a higher degree of
confidence, it is possible to chart locations of targets with
varying degrees of confidence.
[0045] The processing system 109 may also include an automatic
dependent surveillance-broadcast (ADS-B) adapter 117, which
receives input from an ADS-B receiver (not shown) arranged to
receive tracking information from aerial vehicles equipped with an
ADS-B transceiver. As noted in the background section, few UAVs are
equipped with ADS-B transceivers, but for those that are, being
able to receive input therefrom and correlate it with input from
the radars using the correlator component 115 can improve the
fidelity of the tracking data overall. Returning to FIG. 6, targets
that are identified by the ADS-B adapter 117 are labelled with "A",
so e.g. A-10 and A-13 are targets identified by means of ADS-B
surveillance technology.
[0046] Further, the processing system 109 may include a telemetry
adapter 119, which receives input from a telemetry receiver (not
shown) arranged to receive telemetry data from aerial vehicles
equipped with a radio modem, such as an LTE modem. By way of
example only, such vehicles may be those that are native to the
system 101 (also referred to herein as "own ship"), and e.g. are
configured to transmit e.g. real-time GPS coordinates, derived
using on-board telemetry devices and sensors over the cellular
network. In this case the processing system 109 may be configured
as a secure cloud based service and accessible by means of client
software configured on the vehicle, which collects the telemetry
data and sends it to the service using known protocols. The
cooperating telemetry adapter 119 may input the telemetry data to
the correlator component 115, which then correlates the telemetry
data with input from the radar(s) and/or from the ADS-B
surveillance technology.
[0047] In the example shown in FIG. 6, targets identified via
labels A-10 and R-34 match up with the target identified as
"FLIRTEY-02", which was identified by means of the telemetry
adapter 119. A further own ship target is identified as
"FLIRTEY-09" in FIG. 6, together with a series of tracks TR1-TR8,
with connected way-points. These depict a route that "FLIRTEY-09"
is known to be following, e.g. as part of scheduled delivery of a
package. These tracks are rendered on the graphical user interface
113 by means of routing software 121 and may be depicted in a
particular colour, e.g. green to indicate that the route is
pre-approved. In addition to depicting routes the software 121 is
preferably configured to determine a potential collision between
two aerial vehicles based on the vector data (as noted above, speed
and direction); when one of those aerial vehicles is an own ship
vehicle, the routing software 121 will generate instructions for
transmission via the telemetry receiver of the relevant own ship to
change its flight path. These instructions can be real-time flight
instructions provided by an operator, which is particularly
convenient if e.g. the telemetry data includes image data from an
onboard camera or LiDAR with computer assisted vision technology,
enabling the operator to see--in real-time--where the own ship is
heading. Alternatively, the instructions can be a new set of
coordinates, which is essentially a new course, which, when
received by the control electronics of the own ship, causes the UAV
to navigate in accordance with the new set of coordinates.
[0048] As noted above, the graphical user interface component 113
includes display controls that enable user selection of raw
locations processed by the adapter component 111 and/or only
correlated locations and/or correlated locations of a certain type
(e.g. "exclude if from radar only"). In addition, the graphical
user interface component 113 is configured to notify users, via a
series of alerts, to potential collisions, and is responsive to
user input to generate the afore-mentioned instructions for
transmission via the telemetry receiver of the relevant own ship to
change its flight path. Suitable alerts include visual alerts on
the graphical user interface 113, audible alerts via the display
device 114, haptic feedback, delivered e.g. wirelessly from the
processing system 109 to garments/chairs/headsets with which
operators are associated.
Non-Limiting Additional Implementation Details
[0049] As described above, in a preferred embodiment the radars
103a, 103b, 103c are phased-array radars, and in a particular
example the radars may be Commercial Off-the-Shelf (COTS) radar
units such as Furuno.TM. DRS4D-NXT, suitably adapted as described
above. However, it should be appreciated that other marine radars
could be utilised, or indeed other types of radars. At the current
filing date, exemplary alternative COTS radars include Fortem.TM.
TrueView ground based radar, Echodyne.TM. Echoguard ground based
radar. Unlike the Furuno.TM. marine radar, the Fortem.TM. radar
outputs locations of targets in three dimensions, meaning that it
is not necessary to angle the radar or otherwise in order to obtain
overlapping swept areas of respective radars, which, as described
above, is desirable when the location data of targets that is
output from the radar is two dimensional.
[0050] The processing system 109 may include additional software,
for example, that comprises a set of instructions, which, when
processed, causes the processing system 109 to calculate a Figure
of Merit (FoM) for each identified aerial vehicle. For example,
such software could be configured to calculate FoM based on one or
more of a distance, a distance of the one or more radar antennas
from the identified aerial vehicle, a distance of the one or more
radar antennas from the one identified aerial vehicle, an update
rate of the radar, a radar frequency, a pulse repetition rate, a
horizontal beam width, and a vertical beam width across a number of
radar antennas. Further, the correlator component 115 could be
configured to compare FoM values calculated based on data from the
radar sub-system with FoM values calculated based on data received
from the ADS-B receiver and indeed with FoM values calculated based
on data received from the telemetry system and use these
comparisons in the correlation calculations.
[0051] One benefit of comparing FoMs obtained from an ADS-B
transceiver and calculated from the radar sub-system is that it
enables identification and comparison of the accuracy of and
information being reported about deployed own ships. In some
embodiments, when an own ship is equipped with an ADS-B transceiver
or a similar system of self-identification and reporting location
over e.g. LTE, the processing system 109 may be configured to
prioritise the self-reporting via LTE over tracking information
transmitted by the own ship ADS-B transceiver, which in turn is
prioritized over the data received from the radar sub-system.
However, the preference for using the self-reporting via LTE or
ADS-B tracking information over the radar detection information may
depend on the FoM completeness, accuracy, or timeliness of
information associated with the self-reporting via LTE, ADS-B
system and the radar sub-system. In some embodiments, the
processing system 109 is configured to use the data from the radar
sub-system for an unknown UAV if the FoM for the data received from
the radar sub-system is higher than the FoM for the ADS-B tracking
information. The FoM of the ADS-B transceiver may be lower than the
FoM of the data received from the radar sub-system if, for example,
the ADS-B transceiver of a given UAV is not transmitting tracking
information due to a malfunction. Conversely it may be expected
that the FoM of the data received from the radar sub-system may be
lower than the FoM for the tracking information received from the
ADS-B transceiver if, for example, the UAV is relatively far away
from the radars.
[0052] In some embodiments, the processing system 109 is configured
to combine at least a portion of the ADS-B tracking information may
be combined with a portion of the data received from the radar
sub-system. For example, the GPS information obtained from the
ADS-B tracking information may be combined with the speed
information obtained from the data received from the radar
sub-system. As a further example, position information (e.g.,
including x, y, z . . . ) received from different sources may be
combined into a precise or estimated target position using spatial
weighting algorithms that consider several variables. These
variables may include, for example, position FoM of the various
UAVs, altitude filtering, target distance from an active sensor for
radar or machine vision, and GPS Dilution of Precision (DOP). In
addition to the radar sub-system, the ADS-B transceiver and the
telemetry system, suitable sources may include near-field
EO/IR-based Machine Vision.
[0053] In addition to processing and presenting vector data
relating to aerial vehicles detected by one or more of the radar
sub-system, the ADS-B transceiver and the telemetry system, the
processing system 109 can be configured to receive data indicate of
weather that is local to the components of the radar sub-system.
For example, a weather station may be provisioned via ground based
sensors that may be at the same location as the radars 103 or on a
separate fixture at a known location relative to the radars. This
can be very useful in providing additional contextual information
in not only calculating/recalculating flight paths for UAVs, but
also in the selection of UAVs to deploy. This has particular
application to own ship UAVs, which are deployed to deliver
packages, and, when, based upon location and availability, there
are several candidate own ship UAVs that can be selected for the
package delivery.
[0054] In order to transmit telemetry data, a UAV can be equipped
with a cellular transceiver and/or a satellite transceiver, which
collectively transmit data to the above-mentioned telemetry
receiver. The cellular connection between the telemetry receiver
and the UAV can be a primary network and the satellite connection
between the telemetry receiver and the UAV can be a secondary
network. For example, an Iridium satellite connection can act as a
secondary network when the primary LTE or Mesh LTE link is lost or
becomes unavailable. Alternatively, the UAV can be equipped with a
first cellular transceiver and a second cellular transceiver. For
example, a dedicated UAS cellular network may be used as a primary
network with a commercial cellular LTE network as a secondary
network. As a yet further example the UAV can be equipped with
multiple cellular transceivers or LTE modems that may connect to
two independent commercial cellular networks, such as Verizon and
AT&T. The two cellular networks may function as primary and
secondary networks, and communication with the telemetry receiver
can switch from primary to secondary networks dependent upon
network availability, detected as the UAV is flying. In yet another
example, the UAV can be equipped with a single modem accepting more
than one subscriber identity module (SIM) card. A failed connection
on a primary network of the first SIM card may initiate a
reconnection process. The reconnection process attempts to
reconnect to the primary network up to a pre-determined number of
times. If reconnection process fails, the first SIM card is
switched by the modem to the second SIM card associated with the
secondary network. The UAV may be configured with a mission
function board (MFB) processor that may terminate a delivery and
initiate a flight path along a pre-programmed route when the MFB
processor senses that the UAV cannot establish communication with
the telemetry receiver.
[0055] Although at least some aspects of the embodiments described
herein with reference to the drawings comprise computer processes
e.g. in the form of processing systems, agents or processors, the
invention also extends to computer programs, particularly computer
programs on or in a carrier, adapted for putting the invention into
practice. The program may be in the form of non-transitory source
code, object code, a code intermediate source and object code such
as in partially compiled form, or in any other non-transitory form
suitable for use in the implementation of processes according to
the invention. The carrier may be any entity or device capable of
carrying the program. For example, the carrier may comprise a
storage medium, such as a solid-state drive (SSD) or other
semiconductor-based RAM; a ROM, for example a CD ROM or a
semiconductor ROM; a magnetic recording medium, for example a hard
disk; optical memory devices in general; etc.
[0056] It will be understood that embodiments described herein may
be executed on a processor or processing system or circuitry which
may in practice be provided by a single chip or integrated circuit
or plural chips or integrated circuits, optionally provided as a
chipset, an application-specific integrated circuit (ASIC),
field-programmable gate array (FPGA), digital signal processor
(DSP), etc. The chip or chips may comprise circuitry (as well as
possibly firmware) for embodying at least one or more of a data
processor or processors, a digital signal processor or processors,
baseband circuitry and radio frequency circuitry, which are
configurable so as to operate in accordance with the exemplary
embodiments. In this regard, the exemplary embodiments may be
implemented at least in part by computer software stored in
(non-transitory) memory and executable by the processor, or by
hardware, or by a combination of tangibly stored software and
hardware (and tangibly stored firmware).
[0057] It is to be understood that any feature described in
relation to any one embodiment may be used alone, or in combination
with other features described, and may also be used in combination
with one or more features of any other of the embodiments, or any
combination of any other of the embodiments. Furthermore,
equivalents and modifications not described above may also be
employed without departing from the scope of the current
disclosure, which is defined in the accompanying claims.
* * * * *