U.S. patent application number 17/157523 was filed with the patent office on 2021-07-29 for methods and systems for ultra-wideband (uwb) based rail line sensing and safety.
The applicant listed for this patent is Metrom Rail, LLC. Invention is credited to Richard C. Carlson, Kurt A. Gunther.
Application Number | 20210229716 17/157523 |
Document ID | / |
Family ID | 1000005398199 |
Filed Date | 2021-07-29 |
United States Patent
Application |
20210229716 |
Kind Code |
A1 |
Carlson; Richard C. ; et
al. |
July 29, 2021 |
METHODS AND SYSTEMS FOR ULTRA-WIDEBAND (UWB) BASED RAIL LINE
SENSING AND SAFETY
Abstract
Systems and methods are provided for ultra-wideband (UWB) based
rail line sensing and safety.
Inventors: |
Carlson; Richard C.;
(Manchester-by-the-sea, MA) ; Gunther; Kurt A.;
(Woodstock, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Metrom Rail, LLC |
Crystal Lake |
IL |
US |
|
|
Family ID: |
1000005398199 |
Appl. No.: |
17/157523 |
Filed: |
January 25, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62964830 |
Jan 23, 2020 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B61L 29/32 20130101;
B61L 3/125 20130101; B61L 27/0038 20130101 |
International
Class: |
B61L 27/00 20060101
B61L027/00; B61L 3/12 20060101 B61L003/12; B61L 29/32 20060101
B61L029/32 |
Claims
1. A system for train control, comprising: a detection control
module configured for deployment on or near rail tracks in a rail
network, the detection control module comprising: one or more
antennas; one or more transceivers configured for transmitting
and/or receiving wireless signals via the one or more antennas; and
one or more circuits; signaling gateway module comprising one or
more circuits; wherein: the signaling gateway module is configured
to control a safety device deployed at a crossing on a rail track;
and one or both of the detection control module and the signaling
gateway module are configured to: communicate signals with any
train-based transceiver that comes within communication range, the
signals comprising ultra-wideband (UWB) signals; obtain based on at
least processing of received UWB signals range measurements
corresponding to a train traveling on the rail track; and generate
control signals for controlling safety device based on the range
measurements.
2. The system of claim 1, further comprising one or more sensors
attached to the rail track, wherein each sensor is configured to
generate a coupling signal in response to a train traveling on the
rail track, the coupling signal is communicated to the detection
control module.
3. The system of claim 2, the detection control module is
configured to generate one or more output signals based on coupling
signals received from the one or more sensors, wherein each output
signal is generated based on one or more characteristics of at
least one corresponding coupling signals.
4. The system of claim 1, wherein the safety device includes a
gate.
5. The system of claim 1, wherein one or both of the detection
control module and the signaling gateway module are configured to
generate at least one control signal for controlling or adjusting
timing of the safety device.
6. The system of claim 1, wherein one or both of the detection
control module and the signaling gateway module are configured to:
determine based on the range measurements train-related information
associated with the train; and generate or adjust the control
signals based on the train-related information.
7. The system of claim 1, wherein one or both of the detection
control module and the signaling gateway module are configured to
communicate to the train information relating to the safety device
and/or operation of the safety device.
8. The system of claim 1, wherein one or both of the detection
control module and the signaling gateway module are configured to
communicate to one or more vehicles approaching the crossing
information relating to the safety device and/or operation of the
safety device.
9. The system of claim 1, wherein the signaling gateway module
further comprises: one or more antennas; and one or more
transceivers configured for transmitting and/or receiving wireless
signals via the one or more antennas; and wherein the signaling
gateway module is configured to communicate with one or both of the
detection control module and the safety device using wireless
signals.
10. A system for train control, comprising: a plurality of
detection control modules configured for deployment on or near rail
tracks in a rail network, wherein each detection control module
comprises: one or more antennas; one or more transceivers
configured for transmitting and/or receiving wireless signals via
the one or more antennas; and one or more circuits; wherein: the
plurality of detection control modules comprises at least a first
detection control module and a second detection control module; the
first detection control module is deployed physically closer to a
crossing on a rail track than a second detection control module;
the second detection control module is configured to: generate in
response to physical detection of a train traveling on the rail
track, a detection signal; and communicate the detection signal to
the first detection control module; and the first detection control
module is configured to: communicate signals with any train-based
transceiver that comes within communication range, the signals
comprising ultra-wideband (UWB) signals; and obtain based on at
least processing of received UWB signals range measurements
corresponding to a train traveling on the rail track; and wherein
the range measurements and the detection signal are used in
controlling a safety device deployed at the crossing.
11. The system of claim 10, further comprising a signaling gateway
module configured to control the safety device; and wherein the one
or both of the signaling gateway module and the first detection
control module are configured to generate control signals for
controlling safety device based on the range measurements and the
detection signal.
12. The system of claim 11, wherein one or both of the first
detection control module and the signaling gateway module are
configured to generate at least of control signal for controlling
or adjusting timing of the safety device.
13. The system of claim 11, wherein one or both of the first
detection control module and the signaling gateway module are
configured to: determine based on the range measurements
train-related information associated with the train; and generate
or adjust the control signals based on the train-related
information.
14. The system of claim 11, wherein the signaling gateway module
further comprises: one or more antennas; and one or more
transceivers configured for transmitting and/or receiving wireless
signals via the one or more antennas; and wherein the signaling
gateway module is configured to communicate with one or both of the
first detection control module and the safety gate using wireless
signals.
15. The system of claim 10, wherein the first detection control
module is configured to communicate to the train information
relating to the safety device and/or operation of the safety
device.
16. The system of claim 10, further comprising one or more sensors
attached to the rail track, wherein each sensor is configured to
generate a coupling signal in response to a train traveling on the
rail track, the coupling signal is communicated to the second
detection control module.
17. The system of claim 16, the first detection control module is
configured to the detection signal based on coupling signals
received from the one or more sensors.
18. The system of claim 10, wherein the safety device includes a
gate.
Description
CLAIM OF PRIORITY
[0001] This patent application makes reference to, claims priority
to, and claims benefit from U.S. Provisional Patent Application
Ser. No. 62/964,830, filed on Jan. 23, 2020. The above identified
applications is incorporated herein by reference in its
entirety.
TECHNICAL FIELD
[0002] Aspects of the present disclosure relate to control
solutions used in railway systems. More specifically, various
implementations of the present disclosure relate to methods and
systems for ultra-wideband (UWB) based rail line sensing and
safety.
BACKGROUND
[0003] Various issues may exist with conventional solutions for
controlling operation of systems and devices used for managing
train crossings. Further limitations and disadvantages of
conventional and traditional approaches will become apparent to one
of ordinary skill in the art, through comparison of such systems
with some aspects of the present disclosure as set forth in the
remainder of the present application with reference to the
drawings.
BRIEF SUMMARY
[0004] System and methods are provided for ultra-wideband (UWB)
based rail line sensing and safety, substantially as shown in
and/or described in connection with at least one of the figures, as
set forth more completely in the claims.
[0005] These and other advantages, aspects and novel features of
the present disclosure, as well as details of an illustrated
embodiment thereof, will be more fully understood from the
following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 shows a bird's eye schematic view of a rail line
sensing and safety system.
[0007] FIG. 2 shows a bird's eye schematic view of a rail line
sensing and safety system.
[0008] FIG. 3 shows an angled top view of a sensing device, also
referred to as a detection module.
[0009] FIG. 4 shows a bird's eye schematic view of a detection
module.
[0010] FIG. 5 shows an exploded, angled side view of a detection
module.
[0011] FIG. 6 shows an angled top view of a detection module.
[0012] FIG. 7 shows an angled top view of a detection module,
mounted to a rail.
[0013] FIG. 8 shows a cross-sectional side view of a detection
module, mounted to a rail.
[0014] FIG. 9 shows a bird's eye view of a detection module,
mounted to a rail.
[0015] FIG. 10 shows an exploded side view of a mounting system for
a detection module.
[0016] FIG. 11 shows an exploded, angled top view of a mounting
system for a detection module.
[0017] FIG. 12 shows an angled top view of a detection module and a
mounting system.
[0018] FIG. 13 shows an angled top view of a detection module,
mounted to a rail.
[0019] FIG. 14 shows a circuit diagram of circuitry that may be
associated with sensors located inside a detection module.
[0020] FIG. 15 shows a sinewave that may be produced by an
oscillator that may be part of the circuitry associated with
sensors located inside a detection module.
[0021] FIG. 16 shows a timing relationship that may result between
a voltage in the circuitry, associated with sensors located inside
a detection module, and one of the circuitry's output pulses.
[0022] FIG. 17 shows a timing relationship that may result between
a voltage in the circuitry, associated with sensors located inside
a detection module, and one of the circuitry's output pulses.
[0023] FIG. 18 shows output pulses that may be generated by
circuitry associated with sensors located inside a detection
module.
[0024] FIG. 19A shows a block diagram of a remote module.
[0025] FIG. 19B shows a block diagram of a remote module.
[0026] FIG. 20 shows a block diagram of a remote module in relation
to a detection module and a rail.
[0027] FIG. 21 shows the installation location of at least some
subcomponents of a remote module.
[0028] FIG. 22 shows the installation location of at least some
subcomponents of a remote module.
[0029] FIG. 23 shows a block diagram of a control module.
[0030] FIG. 24 shows a block diagram of a control module.
[0031] FIG. 25 shows a schematic view of an ultra-wideband (UWB)
based rail line sensing and safety system.
[0032] FIG. 26 shows a schematic view of another example
ultra-wideband (UWB) based rail line sensing and safety system.
DETAILED DESCRIPTION
[0033] As utilized herein the terms "circuits" and "circuitry"
refer to physical electronic components (e.g., hardware), and any
software and/or firmware ("code") that may configure the hardware,
be executed by the hardware, and or otherwise be associated with
the hardware. As used herein, for example, a particular processor
and memory (e.g., a volatile or non-volatile memory device, a
general computer-readable medium, etc.) may comprise a first
"circuit" when executing a first one or more lines of code and may
comprise a second "circuit" when executing a second one or more
lines of code. Additionally, a circuit may comprise analog and/or
digital circuitry. Such circuitry may, for example, operate on
analog and/or digital signals. It should be understood that a
circuit may be in a single device or chip, on a single motherboard,
in a single chassis, in a plurality of enclosures at a single
geographical location, in a plurality of enclosures distributed
over a plurality of geographical locations, etc. Similarly, the
term "module" may, for example, refer to physical electronic
components (e.g., hardware) and any software and/or firmware
("code") that may configure the hardware, be executed by the
hardware, and or otherwise be associated with the hardware.
[0034] As utilized herein, circuitry or module is "operable" to
perform a function whenever the circuitry or module comprises the
necessary hardware and code (if any is necessary) to perform the
function, regardless of whether performance of the function is
disabled or not enabled (e.g., by a user-configurable setting,
factory trim, etc.).
[0035] As utilized herein, "and/or" means any one or more of the
items in the list joined by "and/or". As an example, "x and/or y"
means any element of the three-element set {(x), (y), (x, y)}. In
other words, "x and/or y" means "one or both of x and y." As
another example, "x, y, and/or z" means any element of the
seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y,
z)}. In other words, "x, y and/or z" means "one or more of x, y,
and z." As utilized herein, the term "exemplary" means serving as a
non-limiting example, instance, or illustration. As utilized
herein, the terms "for example" and "e.g." set off lists of one or
more non-limiting examples, instances, or illustrations.
[0036] Rail lines, such as railroads for trains, create safety
concerns where they intersect with roads, other rail lines or other
paths of travel. These intersections (crossings) are notorious for
collisions between vehicles. Various types of safety devices (for
example, lights and crossing gates) are used to warn approaching
vehicles of a potential collision. In this regard, safety devices
are also referred by the Federal Railway Administration as a
"crossing warning system". However, current systems for sensing an
approaching train and activating a safety device are not
sufficiently reliable under certain operating conditions.
[0037] The following disclosure describes a rail line sensing and
safety system adapted to reliably sense the presence, as well as
the direction and speed, of vehicles, including high-speed
vehicles, traveling on a rail line. The rail line sensing and
safety system then indicates whether a safety device, such as
crossing gates, lights, bells, visual, audio or physical warnings,
and combinations thereof, should be activated.
[0038] In one embodiment, the rail line sensing and safety system
comprises at least one sensing device (also referred to as a
detection module) for a rail line. The sensing device in turn
comprises: (1) a first sensor capable of detecting a vehicle
traveling on the rail line and signaling a first detection event;
(2) a second sensor capable of detecting the vehicle traveling on
the rail line and signaling a second detection event, wherein the
second sensor is located a fixed distance away from the first
sensor; (3) electrical circuitry that accepts signals from the two
sensors; and (4) electrical connections that electrically connect
the two sensors and the electrical circuitry.
[0039] In one example of the sensing device, the first sensor and
the second sensor may be inductive sensors, each sensor comprising
wire wound on a ferrite core, and wherein the wire is Litz Wire,
and wherein each sensor is capable of generating a magnetic field
that extends a distance above the sensor, and wherein the
electrical circuitry is capable of detecting an interruption in the
magnetic field of either the first sensor, the second sensor, or
both. The ferrite core may be, for example, a PQ-style ferrite
core.
[0040] In another example of the sensing device, the first sensor
and the second sensor may comprise a coil of wire operable to
inductively couple to at least one part of the vehicle traveling on
the rail line, and wherein the electrical circuitry is configured
to generate, for the first sensor, a first coupling signal and a
first output pulse signal, the magnitude of the first coupling
signal being based on the amount of inductive coupling between the
coil of wire of the first sensor and the vehicle, the first output
pulse signal being an output pulse triggered in response to the
first coupling signal indicating that the amount of inductive
coupling between the coil of wire of the first sensor and the
vehicle is approximately at a maximum, and wherein the electrical
circuitry is configured to generate, for the second sensor, a
second coupling signal and a second output pulse signal, the
magnitude of the second coupling signal being based on the amount
of inductive coupling between the coil of wire of the second sensor
and the vehicle, the second output pulse signal being an output
pulse triggered in response to the second coupling signal
indicating that the amount of inductive coupling between the coil
of wire of the second sensor and the vehicle is approximately at a
maximum.
[0041] In this example, as the vehicle gets closer to the sensor's
coil of wire, the amount of inductive coupling between the coil of
wire and the vehicle increases and the Q factor of the coil of wire
decreases, and wherein the magnitude of the coupling signal
increases when the amount of inductive coupling between the coil of
wire and the vehicle increases.
[0042] In this example, the first output pulse signal generated by
the circuitry for the first sensor corresponds to the signaling of
the first detection event, and the second output pulse signal
generated by the circuitry for the second sensor corresponds to the
signaling of the second detection event.
[0043] In this example, the electrical circuitry may comprise, for
each of the first sensor and the second sensor, a peak-and-hold
detector that is operable to detect a peak in the magnitude of the
coupling signal, and trigger the output pulse signal when the peak
in the magnitude of the coupling signal is detected. The electrical
circuitry may comprise, for each of the first sensor and the second
sensor, a capacitor located between the wire carrying the coupling
signal and the peak-and-hold detector, and wherein the capacitor
removes a DC component of the coupling signal, allowing only an AC
component of the coupling signal to pass through to the
peak-and-hold detector, and wherein the capacitor ensures that
static DC-signal drift in the coupling signal is not introduced to
the peak-and-hold detector.
[0044] In this example, the electrical circuitry may comprise, for
each of the first sensor and the second sensor, an amplifier
operable to amplify the coupling signal, the amplifier comprising a
feedback path having a Zener diode to produce a logarithmic
transfer characteristic of the amplifier such that the amplifier is
capable of accurately handling the coupling signal regardless of
whether its magnitude is large or small. The electrical circuitry
may also comprise, for each of the first sensor and the second
sensor, a comparator operable to terminate the output pulse when
the magnitude of the coupling signal falls from a peak magnitude to
below a threshold value. The electrical circuitry may also be
operable to detect an error or a fault in the electrical circuitry
and to generate an error signal when the error or fault is
detected.
[0045] In another example of the sensing device, the sensing device
further comprises a sensor package that houses at least the two
sensors, the electrical circuitry and the electrical connections,
wherein the sensor package includes an upper casing and a lower
casing such that when the two casings are affixed together, a
cavity is defined between them, wherein the sensor package includes
an attachment device for attaching the sensor package to the rail
line.
[0046] In this example, the attachment device may be an energy
absorbing mounting system comprised of: (1) a clamp assembly for
attaching the sensor package to the rail line; (2) aluminum shims
and vibration absorption pads disposed between the sensor package
and the clamp assembly, wherein the vibration absorption pads are
composed of rubber or an elastomeric material or other vibration
absorbing material; (3) cap screws that run vertically through the
sensor package, the aluminum shims, the vibration absorption pads,
and into the clamp assembly, wherein the cap screws apply clamping
force to attach the sensor package to the rest of the attachment
device and to hold the parts of the attachment device together; and
(4) lock pins that are inserted horizontally into the side of the
sensor package to prevent the cap screws from rotating.
[0047] In another example of the sensing device, the electrical
circuitry of the sensing device may include a signal processor. The
signal processor may be programmed to calculate the direction,
speed or both of the vehicle traveling on the rail line by
detecting the order of the first detection event in relation to the
second detection event, and measuring the time period between the
detection events.
[0048] In another example of the sensing device, the sensing device
may further comprise at least one additional sensor capable of
detecting the vehicle traveling on the rail line and signaling at
least one additional detection event, wherein the electrical
circuitry also accepts signals from the at least one additional
sensor, wherein the electrical connections also electrically
connect the at least one additional sensor.
[0049] In one embodiment of the rail line sensing and safety
system, the system comprises: (1) at least one sensing device for a
rail line according to claim 1, wherein each sensing device outputs
one or more signals that indicate at least one of the presence,
direction and speed of a vehicle traveling on the rail line; (2) at
least one remote module that accepts signals outputted by at least
one of the sensing devices, wherein the remote module processes
signals and transmits one or more signals, wherein the remote
module is located near the sensing device from which it accepts
signals; and (3) a control module that accepts signals outputted by
at least one of the remote modules, wherein the control module
performs operations based on signals and outputs one or more
signals, wherein the signals outputted by the control module
indicate, among other things, whether one or more safety devices
should be activated, the safety devices being lights, gates, bells,
visual, audio or physical warnings, and combinations thereof,
wherein the control module and the safety devices are located near
an intersection of a rail line and a road, a second rail line, or
other path of travel.
[0050] In one example, the rail line sensing and safety system
further comprises one or more solar panels electrically connected
to one or more devices or modules, including the sensing device,
the remote module and the control module; and one or more battery
packs electrically connected to one or more devices or modules,
including the sensing device, the remote module and the control
module.
[0051] In another example of the rail line sensing and safety
system, the signals outputted by the control module are sent
directly to the one or more safety devices, and wherein the rail
line sensing and safety system provides primary control signals for
the safety devices. In this example, the rail line sensing and
safety system may further comprise at least one backup sensing
device, wherein at least one sensing device located on either side
of the safety devices is backed up, as a form of redundancy, by the
at least one backup sensing device, wherein the backup sensing
device is located a distance away from the sensing device that it
backs up, wherein the backup sensing device outputs signals that
indicate at least one of the presence, direction and speed of a
vehicle traveling on the rail line.
[0052] In another example of the rail line sensing and safety
system, the system is adapted to be a supplemental or backup system
to a separate existing system, wherein the signals outputted by the
control module are sent to the existing system, and wherein the
existing system controls one or more safety devices. The existing
system may attempt to detect the vehicle traveling on the rail line
by sending one or more electrical signals down one or more rails of
the rail line, whereby the rail operates as a conductor for the one
or more signals to travel through. In this example, the rail line
sensing and safety system may further comprising at least one
backup sensing device, wherein at least one sensing device located
on either side of the safety devices is backed up, as a form of
redundancy, by the at least one backup sensing device, wherein the
backup sensing device is located a distance away from the sensing
device that it backs up, wherein the backup sensing device outputs
signals that indicate at least one of the presence, direction and
speed of a vehicle traveling on the rail line.
[0053] In another example of the rail line sensing and safety
system, the system may further comprise at least one sensor that
monitors health of at least one device or module in the system,
including the sensing device and the remote module, wherein the
signals transmitted by the remote module and sent to the control
module periodically include information regarding health of at
least one device or module, wherein the control module is adapted
to accept signals and information regarding health of devices or
modules.
[0054] In another example of the rail line sensing and safety
system, the control module may include computing equipment capable
of data logging and self-diagnostics. Additionally, the system may
further comprise a display that is part of the control module,
wherein the display conveys system diagnostics and status
indicators.
[0055] In another example of the rail line sensing and safety
system, the remote module may transmit one or more signals using a
frequency hopping radio. Alternatively, the remote module may
transmit one or more signals using a cellular network.
Alternatively, the remote module may transmit one or more signals
using a licensed frequency.
[0056] In another example of the rail line sensing and safety
system, the sensing device may be located a distance away from the
one or more safety devices that the sensing and safety system
controls, wherein the distance is between 3,800 feet and 4,500
feet. In this regard, the distance where the sensing located may be
determined and/or set based on various conditions and/or parameters
associated with operation of trains on the track. For example, the
distance may be proportional to the maximum allowable train speed
on the track. At distance of 3,800 feet, for example, with an
allowance of 5 seconds for the entire system to initiate the
crossing gates, and a maximum train speed of 79 mph, the gates may
initiate their warning less than 28 seconds before the train
arrives (assuming constant train speed).
[0057] The rail industry could benefit from a system, according to
this disclosure, that addresses concerns such as safety,
reliability, efficiency, ease of control and cost. These concerns
only increase with the introduction of high speed vehicles
traveling on rail lines.
[0058] The following disclosure describes a rail line sensing and
safety system (RLSSS) adapted to reliably sense the presence, as
well as the direction and speed, of vehicles, including high-speed
vehicles, traveling on a rail line. The rail line sensing and
safety system then indicates whether a safety device, such as
crossing gates, lights, bells, visual, audio or physical warnings,
and combinations thereof, should be activated.
[0059] FIG. 1 shows a rail line sensing and safety system (RLSSS) 2
according to an embodiment of the disclosure. The rail line sensing
and safety system 2 comprises at least one detection module (DM) 4,
at least one remote module (RM) 6, and at least one control module
(CM) 8. Typically, the rail line sensing and safety system 2 will
include two detection modules and two remote modules, one of each
located on each side of a safety device 10; however, it should be
noted that the rail line sensing and safety system 2 may contain
more detection modules and remote modules. Typically, the rail line
sensing and safety system 2 will include a single control module 8,
adapted to accept signals sent from multiple remote modules 6,
however, it should be noted that the rail line sensing and safety
system 2 may contain more than one control module 8. Additionally,
although the following description may refer to the safety device
10 as a crossing gate or other type safety device, it should be
understood that the safety device 10 may comprise many types of
safety and warning devices, such as crossing gates, lights, bells,
visual, audio or physical warnings, and combinations thereof.
[0060] The detection modules 4 are each generally connected, in
close proximity, with their closest remote module 6, for example by
a hard-wired connection 12. In one example, the detection module 4
is hard-wired by a short cable 12 to the remote module 6, instead
of utilizing a wireless connection. One benefit of a hard-wired
connection, instead of a wireless connection, is that the
hard-wired connection can be used to feed power, in addition to
electrical signals, to the detection modules 4. In this setup, the
detection modules 4 may be powered by one or more solar panels 312,
battery packs 322, and a power control module that are part of the
closest remote module 6 (see FIGS. 19A, 19B and 20). Alternatively,
in this setup, the detection modules 4 may be powered by a power
source located in or near the control module 8, provided that the
wireless link 14 is replaced by a wired connection.
[0061] In operation, the detection module 4 detects a vehicle
traveling on the rail 11 and sends one or more signals, for
example, by a wired communication link 12, to a nearby remote
module 6. The remote module 6 contains circuitry that processes
signals received from the detection module 4. The remote module 6
then transmits one or more signals to the control module 8, for
example by a radio link 14. The remote module may also detect the
direction of movement of the vehicle traveling on the rail. In this
regard, a vehicle moving away from the crossing is not cause to
initiate the warning devices, whereas one moving towards the
crossing is cause to initiate a warning, at the appropriate time
based upon the speed of the approach. The processing to determine
direction may be calculated elsewhere, as explained below. In some
installations, the connection between the remote modules 6 and the
control module 8 may be by a wired connection instead of a radio
link. The control module 8 also operates in communication, for
example by a wired communication link 16, with a safety device 10,
either directly or indirectly as a backup or supplement to an
existing sensing and safety system (ESSS).
[0062] The detection modules 4 are mounted a distance 9 down the
track from the centerline 7 between the two safety devices 10. This
distance is typically between 3,800 feet and 4,500 feet, although
other distances may allow the detection modules 4 to function
properly. In general, the greater the distance 9, the more time is
allowed for transmission of the wireless communications, and more
transmission time provides additional operating margin to be sure
that, after the vehicle passes a detection module 4, the safety
device 10 then engages before (for example, approximately 30
seconds in advance) the vehicle traveling on the rail reaches the
safety device 10. In this regard, the time for transmission of
wireless communications may not be a limiting factor. The distance
9 may be necessary to provide sufficient advance warning by the
safety devices 10. For example, the Federal Railway Administration
requires the crossing warning system to indicate the approach of a
train at least 20 seconds prior to the train's arrival at the
crossing. Thus, detection of the train must happen more than 20
seconds prior to its arrival to allow for detection and processing
delays, as well as the response time of the crossing warning
device(s). The maximum speed of an approaching train and the
processing time determines the minimum allowable distance. As one
example, the nominal distance of 4,000 feet has been tested and has
proved to offer a beneficial operating margin for train speeds no
greater than 80 mph.
[0063] The remote modules 6 are generally installed at the same
distance 9 down the track that the detection modules 4 are
installed, although the installation location of the remote modules
6 may vary.
[0064] FIGS. 3-6 show a sensing device, also referred to as a
detection module (DM) 4, according to the disclosure. The detection
module 4 is designed to reliably detect if a wheel, for example, of
a rail vehicle has passed over a specific location on a rail, and
if so the detection module 4 may determine the direction and speed
at which the vehicle was traveling. It is also possible that the
detection module 4 may be configured to detect the presence of
another part of a rail vehicle instead of a wheel, for example an
axle.
[0065] The detection module 4 is comprised of a sensor package 114,
two discreet magnetic or inductive sensors 102, signal processing
circuitry 104 located near the sensors, a mounting system 106, and
a wire conduit 107 and wire hole 108 to channel wires out of the
sensor package 114. Sensor package 114 includes an upper casing 112
and a lower casing 110 that when affixed together, create a cavity
between the two casings 112, 110. Sensor package 114 houses, inside
this cavity, the signal processing circuitry 104 and the two
sensors 102, along with any hardware required to mount the sensors
102 inside the package 114, such as brackets, gaskets, screws,
washers, etc. Optionally, the sensor package 114 may house other
standard components such as an analog-to-digital converter.
[0066] The two discrete sensors 102 of the detection module 4 are
mounted, inside the package 114, at a fixed spacing 116 from each
other (see FIGS. 4 and 5). This spacing 116 allows the two sensors
102 and related circuitry to sense time-separated detection events,
allowing for the calculation of the speed and direction of a
passing rail vehicle. While the following descriptions discuss only
two sensors per detection module, it should be understood that a
detection module 4 (and its package 114) could contain more than
two sensors 102, sometimes referred to as a "sensor array".
Additionally, although this disclosure refers separately to sensors
102 and circuitry 104, it should be understood that there may not
be a defined separating point between a sensor 102 and its
associated circuitry 104. For example, the sensor 102 may include,
as explain below, a coil of wire and the circuitry 104 may include
a signal processing circuit, but the sensor item 102 may also
include some or all of the circuit components of circuitry item
104. If sensor item 102 contains all the circuitry components of
item 104 then the two items would, in effect, be one module,
including the sensor item 102 and the circuitry item 104.
[0067] Referring to FIGS. 7-9, the detection module sensor package
114, including all of its inner components, is mounted onto a rail
11 (see also FIG. 1) utilizing a rail attachment device. The rail
attachment device can be a clamp, flange, bracket, or other
fastener. Preferably, the detection module sensor package 114 is
attached to the rail with an energy absorbing mounting system 106.
The mounting system 106 may include a clamp, flange, bracket, or
other fastener for attaching the sensor package to a rail 11. In
one example, this mounting system 106 clamps to the lower flange
120 of a rail 11, and suspends the detection module sensor package
114 up off the rail flange 120 a vertical distance 122.
[0068] FIGS. 10-11 show a more detailed example of an energy
absorbing mounting system 106. The mounting system 106 may be
further comprised of a clamp assembly 124, aluminum shims 126,
vibration absorption pads 128, lock pins 130 and cap screws 132.
The detection module sensor package 114 is mounted on top of the
absorption pads 128, which are designed to absorb vibrations from
the rail 11. The absorption pads 128 may be made of a variety of
vibration absorbing materials, including rubber or some other
elastomeric material. Lock pins 130 are inserted horizontally from
the side of the package 114 into the detection module sensor
package 114 and rest against the heads of the four cap screws 132.
The cap screws 132 apply clamping force to the package 114 to
fasten the package 114 to the rest of the mounting system 106 and
to fasten the parts of the mounting system 106 together. In one
example, the four cap screws 132 are not tightened conventionally,
but are instead tightened to a specific rotation angle after
contact is made between the sensor package 114 and the absorption
pads 128. The cap screws 132 are then prevented from unscrewing by
the lock pins 130 which are inserted once the mounting system 106
is assembled. The lock pins 130 key on the heads of the cap screws
132, preventing the cap screws from rotating.
[0069] Referring to FIGS. 7-13, once the detection module sensor
package 114 has been mounted to a rail 11 using a mounting system
106, for example, the wire conduit 107 has room to freely curve in
the gap that exists between the two pillars 123 of the mounting
system 106. The wire conduit 107 attaches to the underside of the
lower casing 110 of the package 114 at the location of the wire
hole 108 (see FIGS. 5 and 10). From that point, the wire conduit
107 curves from a generally vertical downward direction to a
generally horizontal direction toward the center of the railway
140. From there, a water-tight tube 142 adapted to enclosing wires
attaches to the wire conduit 107. The tube 142 curves from a
generally horizontal direction downward and then back on itself.
Tube 142 then runs through a channel 143 created by and between
rail ties 141, below the rail 11, and then away toward the nearest
remote module 6. The combination of the wire hole 108 (see FIGS.
3-4), the wire conduit 107 and the tube 142 creates a path whereby
wired connections may run from inside the detection module sensor
package 114 out to the nearest remote module 6. Although the
preceding explanation refers to specific angles and curving of the
wire conduit 107 and tube 142, it should be understood that other
angles, curvings, and wiring paths may work.
[0070] Signal processing circuitry 104 is disposed inside the
detection module sensor package 114, near the sensors. It should be
understood that while some processing of the signals produced by
sensors 102 may be done by circuitry 104 contained in the detection
module sensor package 114, all or some of the processing may be
done by circuitry or firmware contained in the remote module 6. The
sensors 102, in combination with circuitry generally located inside
the detection module 4, detect the speed of a vehicle traveling on
the rail 11 by measuring the time between sensor events. Likewise,
the sensors and circuitry measure direction by looking at which
sensor event occurred first. A "sensor event" refers to a signal
produced by an individual sensor 102 that the circuitry, located
either inside the detection module, inside the remote module, or
both, determines fulfills the appropriate detection criteria, that
is, the circuitry determines whether the detection event is
valid.
[0071] Thus, in operation, when a vehicle passes at a distance
above the first and second sensors 102 of a detection module 4, the
presence, speed and direction of the vehicle are calculated with
circuitry located within the detection module sensor package 114,
within the remote module 6, or a combination of both. The detection
module 4 produces and sends to the remote module 6 one or more
output pulses 323 (see FIG. 20) predictably synchronized with the
passing of the vehicle traveling on the rail. These output pulses
323 are produced utilizing sensors 102 and other circuitry 104
disposed inside the detection module sensor package 114. In
general, a successful sequence of sensor pulses is referred to as a
"transit."
[0072] Detection events are generated by the detection modules 4
and/or remote modules 6 at the start and end of a vehicle passing
by a detection module 4 on the rail 11, and the remote module 6
then transmits information about these detection events as signals
to the control module 8. Alternatively, the detection modules 4 and
remote modules 6 may generate events and transmit signals for each
discrete axle of the vehicle.
[0073] Considering the inner workings of a detection module 4,
sensors 102, can be one of several different types of proximity
sensors, such as Piezo electric sensors, magnetic sensors or
inductive sensors. In one embodiment of the disclosure, sensors 102
utilize active inductive sensor technology that is
self-compensating and resistant to drift because it constantly
resets (e.g., recalibrates) its trip threshold.
[0074] FIG. 14 shows a high-level circuit diagram of circuitry 203
associated with a sensor 102.
[0075] Circuitry 203 constitutes at least some of the total
circuitry 104 that is associated with a sensor 102. Circuitry 203
includes an oscillator 202, for example a Colpitts oscillator. In
general, an oscillator is an electronic circuit that produces a
repetitive electronic signal, often a sine wave or a square wave.
An oscillator circuit often consists of an inductor and a capacitor
connected together in the form of a resonant tank. Charge flows
back and forth between the capacitor's plates through the inductor,
so the circuit can store electrical energy oscillating at its
resonant frequency. However, there are small energy losses in the
circuit, and so an amplifier compensates for those losses and
supplies the power for the output signal.
[0076] The oscillator 202 operates in continuous wave (CW) mode,
for example in the 140-180 kHz range, which is defined by
characteristics of the resonant tank comprised of an inductive
proximity "pickup coil" 204, an RF rectifier 208 and an automatic
level control (ALC) amplifier 206. FIG. 15 shows an example of a
sinewave, as illustrated by trace 240, produced by the oscillator
202. In this example, the sinewave can have a peak-to-peak voltage
value of approximately 1.4 Volts and a frequency of approximately
148.8 KHz, which is close to the lower end of the range disclosed
above.
[0077] Pickup coil 204, essentially an inductor, includes wire
wound on one half of a ferrite core, a PQ-style ferrite core for
example, so that an AC magnetic field generated by the coil extends
outward a distance (the coils sensing area), extending above the
sensor for example. In this respect, the coil may magnetically
couple with nearby metallic objects. It should be understood that
other core styles may be used instead of a PQ-style ferrite core.
For example, a variant of a "pot core" could be used. A pot core
has a magnetic structure that almost completely surrounds the
winding of wire, and only small slots are present in the structure
to allow wires to enter and/or exit. This magnetic structure tends
to contain the magnetic field in a more controlled fashion. Other
variants of pot cores that may be applicable to this implementation
include ER, DS, RM, and EP cores.
[0078] Construction of the coil is tailored to achieve relatively
high Q factor (Quality Factor), which is a measure of energy loss
at the operating frequency. Pickup coil 204 preferably utilizes a
special type of wire, called "Litz Wire", to achieve high
sensitivity and very low power consumption. Litz Wire is comprised
of many small-diameter conductors in parallel such that the
combined skin effect loss of the conductors is significantly
reduced compared to the skin effect loss experienced by other types
of wire. Less skin effect loss results in, among other benefits,
lower power consumption. More specifically, in regards to the
circuitry of the detection module 4, less skin effect loss results
in "low-losses" such that the oscillator achieves a high Q
resonance with minimal power. Thus, the use of Litz Wire allows the
pickup coil 204 to achieve a Q factor as high as possible.
[0079] Because the pickup coil 204 has a high Q factor when no
detection object is present in the pickup coil's sensing area, very
little energy needs to be added in each oscillation cycle to
sustain oscillations, and thus the micropower operation of the
circuitry 203 in "Idle" state (no object detected) is very low
(less than 1 milliwatt). In operation, when a metallic object, for
example a wheel of a vehicle traveling on a rail 11, approaches the
pickup coil 204 and intrudes the pickup coil's 204 sensing area,
the energy loss of the oscillator 202 will increase because some of
the energy will be coupled into the object and lost as heat. The
amount of energy loss is dependent on both the magnetic properties
of the intruding object, and the distance between the pickup coil
204 and the object.
[0080] This increased energy loss exhibits itself as a drop in the
Q factor of the pickup coil 204. As the Q of the pickup coil 204
drops due to approach of an object, the magnitude (i.e. amplitude)
of the oscillator's 202 oscillations starts to decrease
proportionally. In response, circuit 203 utilizes an ALC loop 207,
consisting of a RF rectifier 208 and an ALC amplifier 206, to
ensure that just enough energy is delivered to the resonant tank of
oscillator 202 to sustain oscillations of relatively constant
magnitude (i.e. amplitude) for all reasonable values of Q. As the
oscillation magnitude (i.e. amplitude) drops, the ALC loop tries to
compensate via negative feedback action by producing a DC voltage
proportional to the magnitude (i.e. amplitude) of the oscillator's
202 output, which is then amplified and used to control the
operating point of the oscillator 202 by increasing the
oscillator's 202 operating current. More specifically, a decrease
in oscillations magnitude (i.e. amplitude) causes the DC voltage
produced by the rectifier 208 to also decrease. In response, the
ALC amplifier 206 increases the current through the oscillator's
transistor (essentially increasing the amount of energy which is
injected into the resonant tank) until the magnitude (i.e.
amplitude) of oscillations is back at the predefined level
(negative feedback).
[0081] In other words, a reduction in the pickup coil's Q-factor,
caused by an intruding object is proportionally represented by an
increase in the ALC's drive voltage. The closer the object is to
the coil's sensing surface, the higher are the losses due to
magnetic coupling, the higher the ALC control voltage will be,
while the magnitude (i.e. amplitude) of the RF oscillations remains
relatively constant. Therefore, output voltage of the ALC amplifier
206 can be treated as a close representation of the pickup coil's
Q, and consequently, representation of the detection object's
proximity. For a dynamic (moving) object, like a railcar wheel, the
profile of variations in the ALC control voltage would therefore
closely follow the wheel's proximity curve.
[0082] A capacitor 210 is typically located between the ALC control
voltage (i.e. the output of amplifier 206) and amplifier 212.
Capacitor 210 may act as a "DC-blocking capacitor" to the ALC
control voltage such that it removes the DC component (DC offset),
in whole or in part, from the AC/DC mixture, allowing only (or
primarily) the AC component to pass through to amplifier 212. Thus,
the capacitor 210 ensures that only (or primarily) variable signals
caused by moving (dynamic) objects are passed downstream in
circuitry 203, while static DC level shifts (drift) that may be
caused by interference from static or slow-moving objects (for
example, the sensor package or the rail) are blocked, in whole or
in part. In this respect, only (or primarily) the AC component of
the ALC control voltage variations, which indicates the proximity
of a high-speed detection object, is amplified by amplifier
212.
[0083] In certain embodiments where the circuitry 203, specifically
capacitor 210, filters out all or some of the DC voltage drift,
this filtering feature may provide a benefit over older proximity
sensors that may just compare a proximity-based voltage to a static
threshold, using the threshold to determine whether an object is
sufficiently close. Accounting for DC voltage drift, like the
circuitry 203 does in these embodiments, may increase the accuracy
and repeatability of the proximity sensing.
[0084] Although the previous description explains a feature whereby
the circuitry 203, specifically capacitor 210, may completely
filter out the DC voltage from the AC/DC mixture, it should be
understood that some embodiments may allow some DC voltage to pass
downstream. In these embodiments, the ability to sense the DC
aspect, or at least very low frequency components, may be
useful.
[0085] While the circuit 203 is in its "Idle" state (no object
detected), the profile of the V_Q voltage 214 is a flat line, close
to the circuit's virtual ground level. The threshold of comparator
216 is chosen such that the ENABLE signal 218 (i.e. the output of
comparator 216) is inactive in the "Idle" state, holding the output
228 of the flip-flop 220 in a "Reset" state and the storage
capacitor 222 of the peak-and-hold circuit 224 discharged.
[0086] In operation, the passing of a railcar wheel above the
pickup coil 204 introduces a bell-shaped variation in the V_Q
voltage 214. In order to provide consistent synchronization of the
output pulses 323 with the top of the bell-shaped voltage curve
(which coincides, for example, with a wheel's closest location),
circuitry 203 utilizes a peak-and-hold detector, whereby the
following sequence of events transpires in circuitry 203: (1) As
soon as the V_Q voltage 214 rises significantly above the noise
level of the Idle state, comparator 216 raises the ENABLE signal
218 and keeps it active until the V_Q voltage 214 falls back under
the detection threshold, which occurs as the detection object
recedes. (2) The active ENABLE signal 218 activates in turn the
peak-and-hold circuit 224 by connecting its storage capacitor 222
to the output of the peak detector 226 in the peak-and-hold circuit
224. Also, flip-flop 220 is released from the "Reset" state
(however, the state of output 228 does not change until a trigger
pulse is generated by comparator 230). Differential driver 232 is
also activated at this point. (3) On the rising slope of the V_Q
voltage 214, the output (V_PEAK) 234 of the peak-and-hold circuit
224 follows the V_Q voltage 214 closely, with a slight lag.
Comparator 230 maintains its low output state, since the V_Q
voltage 214 input to the comparator 230 is always slightly above
the V_PEAK 234 input.
[0087] (4) When the V_Q voltage 214 tops off (i.e., the top of the
bell-shaped voltage curve) and begins to fall back, the
peak-and-hold circuit 224 can no longer follow it and holds the
maximum level that V_Q voltage 214 has reached in this detection
cycle. As soon as the divergence between the falling V_Q voltage
214 and the "frozen" V_PEAK 234 becomes large enough to overcome
the hysteresis of the comparator 230, the comparator's 230 output
state changes, producing a trigger pulse for the flip-flop 220. (5)
Flip-flop 220 then changes its output state to "high", producing a
pulse at its output 228, which is further converted to differential
format by the differential driver 232. (6) This state is preserved
until the V_Q voltage 214 drops below comparator's 230 detection
threshold, which then terminates the flip flop's 220 output pulse
and resets the circuit back into its "Idle" state, whereby
circuitry 203 is ready for a next detection event. FIG. 18 shows an
example of the output pulses 323 that result from the detection of
a metallic object by the circuitry 203. The trace labeled 250
corresponds to one of the outputs of the differential driver 232
while the trace labeled 252 corresponds to the other output of the
differential driver 232.
[0088] Referring to FIG. 16, there is shown an example of the
timing relationship that results between the V_Q voltage 214, which
is illustrated by trace 242, and one of the output pulses 323,
which is illustrated by trace 244, when the sequence of events
described above transpires in circuitry 203. In this example, when
a metallic object passes above the pickup coil 204 at a distance of
approximately two inches (2''), the start of the pulse in trace 244
coincides with the peak of the bell-shaped curve of trace 242.
[0089] In other words, the output pulse 323 that is generated
indicates, by its starting time, the peak of the V_Q voltage 214
and, therefore, the moment at which the metallic object is closest
to the sensor 102.
[0090] In the event that the oscillator 202 malfunctions or
operates incorrectly because of a damaged inductive proximity
pickup coil 204 or other defects that lead to a loss in
oscillations, the voltage of the ALC loop will likely rise to the
maximum or close to the maximum of the operating voltage range. The
circuitry 203 can be configured to detect those instances, and when
detected, circuitry 203 can be configured to force both outputs 323
from the differential driver 232 to zero (or another defined
state), and generate a signal that indicates that a fault in the
oscillator 202 has been detected.
[0091] With respect to the embodiment of circuitry 203 associated
with sensor 102 illustrated by FIG. 14, the oscillator 202 can be
built around a first transistor Q1 (not shown) and a
voltage-controlled resistor (not shown) in the emitter path of Q1.
The voltage-controlled resistor can be implemented using a second
transistor Q2. The sinewave produced by the oscillator 202 is
converted to DC by the RF rectifier 208 and applied to the input of
the ALC amplifier 206 in such a polarity that an increase in the
magnitude (i.e. amplitude) of oscillations results in a decrease in
the output of the ALC amplifier 206 (V_ALC), thus reducing the
conductance of the voltage-controlled resistor. Similarly, a
decrease in the magnitude (i.e. amplitude) of oscillations results
in an increase in the output of the ALC amplifier 206, which
increases the conductance of voltage-controlled resistor.
Therefore, any drop in the Q factor of the inductive proximity
pickup coil 204 in response to the presence of a nearby metallic
object can be compensated by the ALC loop by increasing the
conductance of the voltage-controlled resistors, which reduces the
emitter resistance in Q1. Since the base of Q1 can be kept at a
fixed reference potential, a reduction of emitter resistance can
cause the DC operating point to move such that there is an
increased current draw and more energy is deposited into the
resonant tank at each cycle. A thermally sensitive resistor (not
shown), also referred to as a thermistor, can be used with the
oscillator 202 to maintain the voltage of the ALC loop at
approximately the middle of the operating voltage range during
"Idle" operation.
[0092] Also with respect to the embodiment of circuitry 203
illustrated by FIG. 14, the amplifier 212 can be configured or be
operable to have a sufficiently high gain, for example 30 dB at 25
degrees Centigrade, so that small variations in the output of the
ALC amplifier 206 can be amplified by the amplifier 212 to an
magnitude (i.e. amplitude) of approximately a few hundred
millivolts during normal detection events. A thermistor (not shown)
associated with the amplifier 212 can compensate or neutralize the
effect that the thermistor in the oscillator 202 has on the overall
gain of the analog track of the circuitry 203.
[0093] Moreover, because of the high gain of the amplifier 212, if
the sensor 106 is mounted so that the wheels pass very close to the
pickup coil 204, the output from the ALC amplifier 206 can cause
the output of the amplifier 212 to saturate, clipping V_Q voltage
214. Such clipping could cause the generation of incorrectly
positioned differential output pulses 323. To address this possible
condition, a Zener diode (not shown) can be placed in a feedback
path of the amplifier 212 to give it a logarithmic transfer
characteristic for large-magnitude (i.e. large-amplitude) signals.
As a result, a strong proximity voltage signal would be somewhat
flattened at the top instead of being hard-clipped, allowing for
correct operation of the follow-up peak detection. FIG. 17 shows an
example of the timing relationship that results between the V_Q
voltage 214, which is illustrated by trace 246, and one of the
output pulses 323, which is illustrated by trace 248, when a
metallic object passes above the inductive proximity pickup coil
204 at a distance of less than one inch (1''). In such instance,
the logarithmic transfer characteristics of the amplifier 212
flatten the top of the V_Q voltage 214 such that the
synchronization of the output pulse 323 and the V_Q voltage 214 is
not exact but produces an acceptable result.
[0094] FIGS. 19A and 19B show the remote module (RM) 6. The primary
function of the remote module 6 is to receive and process signals
received from the detection module 4 and to send appropriate data
and signals to the control module 8. The remote module 6 includes 2
main subcomponents, a connection box 306 that is typically located
close to the tracks, and a utility pole 308 (or other similar
structure or tower which elevates the antenna 310 to improve
wireless propagation distances) that is typically located further
away from the tracks and connected by an underground connection
(see FIG. 22) to the connection box 306.
[0095] Referring to FIG. 19A, the connection box 306 may contain a
junction box 311 and a control board 307, preferably enclosed in an
environmentally sealed enclosure. Referring to FIG. 19B, the
control board 307 may also be mounted, preferably within an
environmentally sealed enclosure, on the utility pole 308, further
away from the tracks, instead of being disposed inside a structure
(for example, connection box 306) that is mounted close to the
tracks.
[0096] The junction box 311 contains mainly adaptors and
connections to create a removable connection to the detection
module 4, which aids in the installation and removal of the
detection module 4, for example, removal of the detection module 4
to perform track maintenance. It should be understood that although
FIG. 19A shows the junction box 311 contained within a structure
(for example, connection box 306) that also contains the control
board 307, the connections of the junction box 311 and the junction
box itself may be contained either inside the structure that houses
the control board 307, outside that structure, or a combination of
both. Additionally, referring to FIG. 19B, in the example where the
control board 307 is mounted on the utility pole 308, the junction
box 311 may be the only component located near the tracks, such
that the junction box 311 is not actually contained within a
separate box (for example, connection box 306) as shown in FIG.
19B, but instead the junction box 311 would stand alone as the only
module near the tracks, such that it is directly connected to the
utility pole 308.
[0097] Referring to FIG. 20, the control board 307 contains most or
all of the circuitry components contained within the remote module
6. In one example, all of the circuitry components of the remote
module 6 are disposed on a single circuit board. The control board
307 can contain circuitry 314 adapted for processing signals
received from the detection module, a wireless radio transmitter
circuit 316, a power module 318, and a monitoring and control
module 320. The circuitry 314 is in connection with the detection
module 4 (see FIG. 20) and further includes signal detecting and
control logic, a timer, and signal processing and filtering logic.
The circuitry 314 is also in communication with the radio
transmitter circuit 316, and may send it vehicle presence, speed
and direction information of a nearby vehicle. The radio
transmitter circuit 316 is in connection with a radio transmitter
antenna 310, located on the utility pole 308. The power interface
318 may be connected to power components contained on the utility
pole 308, including one or more solar panels, battery packs or
both. Furthermore, the power interface 318 may contain power
monitoring and charging logic as well as a power supply to power
the other components contained in the connection box 306 and
optionally to feed power to the detection module 4. The monitoring
and control module 320 further contains a service interface and a
system monitoring and control unit that may communicate system
information (for example, diagnostics about the detection module
and the remote module) to the radio transmitter 316.
[0098] It should be understood that while some processing of the
detection module sensor signals may be done inside the detection
module sensor package 114, all or some of the processing may be
done by circuitry contained in the remote module 6. Typically, the
detection module produces one or more output pulses 323 predictably
synchronized with passing of a vehicle on the rail. Then circuitry
inside the detection module 4 or inside the remote module 6 or both
computes whether the signals generated by the detection module
sensors fulfill the appropriate detection criteria, that is,
whether a vehicle detection event is valid. Detection events are
generated by the detection modules and remote modules at the start
and end of a vehicle traveling on the rail, and the remote modules
transmit these detection events as signals to the control module.
Alternatively, the detection modules and remote modules may
generate events and transmit signals for each discrete axle of the
vehicle.
[0099] FIG. 19A shows a utility pole 308, which includes a wireless
radio transmission antenna 310, a solar panel 312, and battery
packs 322. It should be understood that even though this disclosure
and FIG. 19A refers to a utility "pole" 308, the utility pole 308
is actually comprised of a physical pole 309 as well as the devices
that are mounted to the pole 309, such as the wireless radio
transmission antenna 310, the solar panel 312, and the battery
packs 322. Throughout this disclosure, the phrase "on the utility
pole 308" shall be understood to mean either mounted on the
physical pole 309 or located in close vicinity to the physical pole
309. Additionally, a variety of styles of physical poles may be
used, such as a hinged metal pole that allows erection of the
antenna and solar panel without requiring a lift truck, such that
all work on the mounted components can be done at ground level.
[0100] The solar panel 312 derives energy from the environment, and
stores that energy in the battery packs 322 or other rechargeable
batteries. The battery packs 322 are enclosed in a vented enclosure
that is adapted to be mounted on a pole. Furthermore, the battery
packs 322 are sized for over 30 days of operation in the event the
solar cell is damaged or otherwise incapacitated. Together, the
solar panel 312 and the battery packs 322 provide power to the
other modules that make up the remote module and detection
module.
[0101] Referring to FIG. 20, the transmitter 324, which includes a
radio transmission antenna 310 and a radio transmitter circuit 316,
processes signals generated by the remote module 6 and transmits
signals to control module 8 utilizing either a wired or a wireless
communication. For example, a wireless communication could be
established by a frequency hopping radio, transmitting at a radio
frequency (RF) such as a 900 Mhz band. In another example, a
wireless communication could be established using a wider cellular
interface and cellular network. Frequency hopping radios are
preferable for wireless communications over a distance of three
miles or less. For longer distances, it may be preferable for the
wireless communication to be established over licensed frequencies
that allow higher power transmissions than are allowable on
unlicensed frequencies. Additionally, for longer distances, the
wireless communication may be established by an interface to a
cellular network.
[0102] Transmitter 324 is mainly referred to, throughout this
disclosure, as a "transmitter" because it typically operates to
transmit signals. Likewise, transmission antenna 310 and
transmitter circuit 316 typically operate to transmit signals.
However, it should be understood that transmitter 324, transmission
antenna 310 and transmitter circuit 316 may also operate to receive
signals, and in this respect they may actually be transceiver
components. Thus, it should be understood that although these
components (324, 310, 316) are referred to throughout this
disclosure as "transmitter" or "transmission" components, they may
actually be transceiver components.
[0103] One benefit of the wireless antenna and solar panel features
of this embodiment is that installation of the rail line sensing
and safety system 2 is much easier than if, for example, wired
connections had to be run from the remote module to the control
module or from a power source to the remote module. This wireless
and solar powered installation is especially useful in remote
locations where currently, installing rail sensing systems is cost
prohibitive due to lack of power and interface infrastructure.
[0104] Although the wireless installation is often preferred, in
certain instances, it may be desirable to install a "wired" version
of the rail line sensing and safety system 2. This wired version
may be preferable in certain environments or circumstances where
the wireless space is "noisy" or where other obstructions may
attenuate a wireless signal or link. In this wired configuration,
the wireless radio links 14 (the wireless radio transmitter 324 and
the wireless radio transceiver 405 are replaced by wired
connections, for example, utilizing a twisted wire pair and
differential drivers, such as EIA-485. Likewise, in a wired
configuration, the solar panels 312 and battery packs 322 on the
utility pole 308 may be eliminated, and instead, DC power may be
fed to the remote modules and detection modules through the wired
connection from the control module, for example, utilizing a wire
pair as the wired connection. In the wired installation, the power
supply at the control module may still include solar panels and
battery packs, or may include a more permanent power supply from a
power generator.
[0105] The remote module 6 may also utilize power saving features.
For example, the remote module 6 may operate in a mode whereby
processing circuitry, for example circuitry included on control
board 307, is at times put to "sleep." Because the wireless
transmitter 324 in the remote module 6 has sufficient built-in
intelligence to maintain a wireless link without requiring constant
transmission and processing of substantive signals about vehicles,
the processing circuitry in the remote module 6 may sleep when
there is inactivity in the system. The wireless link is maintained
autonomously while the processing circuitry is powered down. If the
remote module 6 needs to communicate substantively with the control
module 8, for example with a status update or a detection of a
vehicle on the rail, the processing circuitry in the remote module
6 may be signaled to "wake up."
[0106] FIGS. 21 and 22 show the installation location of the main
remote module subcomponents (connection box 306 and utility pole
308) in relation to a rail line 11, a detection module 4 and each
other. The connection box 306 and utility pole 308 are each located
a distance 330, 332 (respectively) away from the center line of the
rail 334 in a perpendicular direction to the center line 334.
Distances 330 and 332 may vary. The utility pole 308 may be
installed a distance away from other remote module components
(located in the connection box 306 near the rail 11) if, for
example, there is not enough space near the rail 11 to install the
utility pole 308, with its antenna, battery packs and a solar
panels. Other factors that may determine the location of the
utility pole include the need to establish a sufficient wireless
link and the need for access to direct sunlight. In one example,
the connection box 306 is located a distance 330 of approximately 8
feet from the rail, and the utility pole 308 is located a distance
332 of approximately 25 feet from the rail.
[0107] The connection box 306 and the utility pole 308 are
installed at approximately a distance 9 (see FIGS. 1 and 21) down
the track from the centerline 7 between the two safety devices 10,
approximately the same distance 9 at which the detection modules
are installed. This distance is typically between 3,800 feet and
4,500, although other distances may allow the system modules to
function properly.
[0108] Referring to FIG. 22, the connection box 306 and the utility
pole 308 are connected by an underground conduit 339. The conduit
may run in a variety of directions, angles and depths.
[0109] Additionally, the conduit may be formed from a variety of
materials such as metal, plastic and PVC. Furthermore, the conduit
may be formed from a single piece of material, or from several
segments joined together. In the example shown in FIG. 22, the
conduit starts at the connection box 306 and extends, by a PVC
segment 340, vertically downward below the line of the ground 350.
At approximately a depth of 3 to 4 feet, PVC segment 340 connects
by a 90 degree elbow 346 to another PVC segment 342. PVC segment
342 runs horizontally toward the utility pole 308, and once it
reaches the utility pole 308, it connects by a 90 degree elbow 347
to another PVC segment 344. PVC segment 344 runs vertically upward
and meets the utility pole 308 at its base.
[0110] FIG. 23 shows the control module (CM) 8, the central control
center for the rail line sensing and safety system 2. The main
purpose of this module is to process signals transmitted from the
remote module's and then control a safety device 10, either
directly (see FIG. 24) or indirectly (see FIG. 23) as a backup or
supplement to an existing sensing and safety system (ESSS).
Typically, the rail line sensing and safety system 2 contains only
one control module, but it may contain more than one, for example,
one for each side of the safety device 10. Although the following
discussion refers to a single control module, it should be
understood that there could be more than one.
[0111] In typical installations of this rail line sensing and
safety system 2, at least one remote module 6 is located down the
track on each side of the control module 8. The signals sent by the
remote modules 6 are typically received by the control module 8
from opposite directions. Thus, the rail line sensing and safety
system 2 typically utilizes two directional antennas so each can be
pointed directly toward its associated remote module 6. For this
reason, as shown in FIG. 23, the control module 8 is comprised of
at least two radio transceiver antennas 402, typically one to
receive signals from each remote module 6 located on opposite sides
of the safety device 10.
[0112] The control module 8 further comprises a wireless
transceiver circuit 404, a signal and data processing circuit 406,
a monitoring and control module 408, a safety system interface 410,
and a power supply 412. The wireless transceiver circuit 404
further contains a splitter/combiner that combines (or selects) the
signals from (or between) multiple radio transceiver antennas 402,
a radio transceiver such as a base FHSS radio transceiver, a
communication management circuit and optionally a cellular link and
a GPS module. The wireless transceiver circuit 404 together with a
radio transceiver antenna 402 constitutes a wireless transceiver
405 that communicates with the wireless transmitter 324 of a remote
module 6, typically to receive signals sent from the remote module
6 to the control module 8 (see FIG. 1).
[0113] The signal and data processing circuit 406 further contains
a real-time clock which may have a WWV receiver for automatic time
synchronization, and a data processor circuit that processes
signals from the remote modules regarding vehicles traveling on the
rail. (Note: WWV is the call sign of the United States National
Institute of Standards and Technology's shortwave radio station,
and WWV continuously transmits official U.S. Government frequency
and time signals.) The monitoring and control module 408 further
contains a user interface, a service interface such as a microSD
slot, USB port or Ethernet port, a configuration management module
and a data and event logging module. The data and event logging
module may log system information and diagnostic about remote
modules as well as the control module itself. The power supply 412
may contain power handling circuitry including a temperature
compensated circuit for transferring power from solar panels to a
rechargeable battery.
[0114] The control module 8 receives vehicle detection events from
the remote modules 6 which include time-stamped track
identification, and information about the presence, speed, and
direction of vehicles traveling on the rail. Detection events are
generated by the detection modules and remote modules at the start
and end of a vehicle traveling on the rail, and the remote modules
6 transmit these detection events as signals to the control module
8. Alternatively, the detection modules and remote modules may
generate events and transmit signals with data for each discrete
axle of the vehicle.
[0115] The control module data processor circuit 406 analyzes and
validates incoming detection events and determines whether to
generate a signal to a safety device (either directly or
indirectly), such as a signal to lower a gate or activate an alarm
(see FIG. 23). The control module data processor circuit 406 also
may contain fault detection functionalities whereby it recognizes
and logs anomalous combinations of events which may or may not
indicate an error or other failure in the rail line sensing and
safety system 2. For example, if the control module detects an
outbound vehicle (at the detection module on one side of the safety
device) with no associated inbound detection (at the detection
module on the other side of the safety device), an error or a
"fault" may exist in the system.
[0116] The rail line sensing and safety system 2 may also
incorporate this fault detection functionality at the sensor level.
In this example, the signals detected from one of the sensors
inside a detection module package is compared to the signals
detected from the other sensor inside the same detection module
package. Circuitry located inside the detection module, the remote
module, the control module or some combination of these, compares
the signals from each of the sensors within a detection module
package and recognizes and logs anomalous combinations of events.
For example, if one of the sensors within a detection module
package is indicating a nearby, large, fast-moving object and the
other sensor in the same package is outputting no signal, an error
or a "fault" may exist in detection module package or in the
system.
[0117] In one embodiment of the disclosure, the control module 8 is
mounted inside an existing control bungalow 3 (see FIGS. 1 and 23)
located on either side of a safety device 10 (for example, crossing
gates). One benefit of this type of mounting is that installation
is easy because no additional housings need to be built to contain
the control modules. Additionally, it may be possible for the
existing power source inside the control bungalow 3 to feed power
to the control module 8. The existing power source may, for
example, come from the existing sensing and safety system.
[0118] Referring to FIG. 24, if the control module 8 is unable to
receive power from an existing power source, the control module may
contain its own power module 420. Power module 420 may contain
solar panels, battery packs or both. The solar panels may be
mounted on a pole, similar to the setup of the utility pole 308 or
the remote module 6. The same pole may also support the radio
transceiver antennas 402.
[0119] The control module 8 and/or the remote module 6 may also
utilize power saving features. For example, because the wireless
transceiver (in the control module 8) and/or the wireless
transmitter (in the remote module 6) may draw a large amount of
current, the control module 8 and/or the remote module 6 may
operate in a mode where the transceiver (in the control module 8)
and/or the wireless transmitter (in the remote module 6) is
normally powered down ("sleep mode") and where the transceiver
and/or transmitter are "woken up" and synchronize each time a
vehicle is detected. However, it should be noted that if the
transceiver and/or transmitter synchronization takes too long after
the transceiver and/or transmitter is "woken up", such that system
integrity (i.e. there is concern that the synchronization will not
complete before the vehicle reaches the safety device) becomes a
concern, the control module 8 and/or the remote module 6 may
operate in a mode where the wireless transceiver and/or wireless
transmitter are operational ("awake") at all times.
[0120] Another example of a power saving feature that the control
module 8 and/or the remote module 6 may utilize is a mode of
operation where the control module 8 and/or the remote module 6
puts its main control processor to "sleep." Because the wireless
transceiver (in the control module 8) and/or the wireless
transmitter (in the remote module 6) have sufficient built-in
intelligence to maintain a wireless link without requiring constant
transmission and processing of substantive signals about vehicles,
the main control processor in the control module 8 and/or the
remote module 6 may sleep when there is inactivity in the system.
The wireless link is maintained autonomously while the main
processor is powered down. If the remote module 6 requires any
substantive communication with the control module 8, such as a
status update or a detection of a vehicle on the rail, it can wake
up its own processor and/or signal to the control module 8, through
the wireless radio link, to wake up its processor.
[0121] Referring to FIG. 23, in one embodiment, an external system
(e.g., the rail line sensing and safety system 2 of FIG. 1) is
installed as a backup or supplemental system to an existing sensing
and safety system (ESSS) 414. In this embodiment, the control
module 8 may interface with the card racks that are currently
available inside the existing control bungalow 3. For example, the
control module may plug into existing auxiliary inputs of the
existing sensing and safety system. In operation, if the existing
sensing and safety system either fails completely to detect an
incoming train or is late in lowering the gates, the
backup/supplemental system will provide an input signal to lower
the gates, and then the existing sensing and safety system may
activate and control the gates.
[0122] Referring to FIG. 24, in another embodiment, the rail line
sensing and safety system 2 is installed as a primary control to a
safety device 10 that may include gates, bells, lights, etc. In
this embodiment, the control module 8 interfaces directly with the
safety device 10, whereby the control module 8 interfaces with the
safety device 10 such that the control module 8 instructs the
safety device 10 to engage. For example, the control module 8 may
directly instruct the safety system 10 to lower its gates.
[0123] As explained above, and considering FIG. 1, the rail line
sensing and safety system 2 may have a single detection module 4
mounted a distance down the rail on each side of the safety device
10. Furthermore, as explained above, the rail line sensing and
safety system 2 may have, one per side, a single radio link,
including a transmitter located in the remote module 6 and
transceiver located in the control module 8.
[0124] Alternatively, and considering FIG. 2, the rail line sensing
and safety system 2 may be configured with added redundancy 20. The
added redundancy 20 may consist of at least one additional
detection module 22 mounted a distance down the rail 11 on each
side of the safety device 10, such that each side has at least 2
detection modules 4, 22. Additionally, the added redundancy 20 may
consist of at least one additional radio link 24 (transmitter and
transceiver) on each side of the safety device 10. Each redundant
radio link may operate on a different frequency than the initial
radio link. Although the redundancy 20 is portrayed and explained
as only one additional detection module per side and one additional
radio link per side, it should be understood that the redundancy
could be increased to include more than one detection module per
side and more than one radio link per side. Additionally, the
redundancy could include duplicates of other parts of the rail line
sensing and safety system 2, to further enhance the reliable
detection of light, fast-moving vehicles.
[0125] The redundancy 20 may be especially important if the rail
line sensing and safety system 2 is installed as the primary
control to a safety device 10, as shown in FIG. 24 and as explained
above. In this embodiment, the rail line sensing and safety system
2 replaces an existing sensing and safety system completely or is
installed instead of a more expensive system. Because no other
sensing and safety system is installed, the redundancy 20,
importantly, enhances the reliability of the detection modules and
the radio links, such that the safety device 10 activates when a
vehicle travels on the rail past the detection modules.
[0126] Although the redundancy 20 may be especially preferred when
the rail line sensing and safety system 2 is installed as the
primary control to a safety device 10, it may also be used in the
embodiment (shown in FIG. 23 and explained above) where the rail
line sensing and safety system 2 is installed as a backup or a
supplement to an existing sensing and safety system. In this setup,
the redundancy 20 acts as an additional layer of backup.
[0127] Regardless of whether the rail line sensing and safety
system 2 is configured as a primary control to a safety device, or
as a backup/supplement to an existing sensing and safety system,
and regardless of whether the rail line sensing and safety system 2
is configured to included redundancies, the rail line sensing and
safety system 2 provides several advantages over existing/current
railroad sensing and safety systems.
[0128] It should be understood in regards to the following
descriptions of an "existing system" or a "current system" that
these current systems as described are examples of systems that the
rail line sensing and safety system 2 of this disclosure may backup
or supplement in the embodiment described herein where the rail
line sensing and safety system 2 is configured to backup or
supplement an existing sensing and safety system. Thus, the
existing sensing and safety systems described in this disclosure
may be similar to the current system described as follows,
including the disadvantages of the current system.
[0129] The advantages of the rail line sensing and safety system 2
over the current system can be seen by looking at how the current
system in use at many railroad crossing locations detects an
approaching train. The current system sends an electrical signal
down a rail, whereby the rail is used as a conductor for the signal
to travel through. When a train approaches, the signal is shorted
by a metallic wheel of the approaching train. This shorting
requires that an electrical contact be made between the metallic
rail and the metallic wheel. The change in the signal due to this
shorting is then processed by the system to determine if a train is
present, and if so, the system signals the crossing gates to
lower.
[0130] There are several drawbacks to the current system that are
not present if the rail line sensing and safety system is used. One
drawback to the current system is that due to "interference" (for
example, corrosion of the rail, weather or other environmental
factors), the wheel of the train may not contact the rail with
sufficient contact force to establish the required electrical
connection between the wheel and the rail. In the best case
scenario, this interference causes inconsistent readings in the
system. In the worst case scenario, the system does not detect the
approaching train and the crossing gate is never lowered, or it is
lowered too late to prevent a collision with a vehicle crossing the
tracks. In the current system, attempts are sometimes made to
improve consistency by adding additional axles (cars) to the train
to add additional electrical contacts as well as additional weight
and additional contact force. However, these extra cars often
travel empty, resulting in higher operating costs due to reduced
fuel economy.
[0131] Another drawback to the current system is that the rated
speed at which it can operate (i.e. at which trains can travel) is
relatively low, currently limited to between 60 and 80
miles-per-hour. The current system requires this lower speed
because, at a lower speed, the chances are higher of establishing
the required electrical connection between the wheel and the rail.
At higher train speeds, the train wheels may lose contact with the
rail for longer periods as the wheels travel over minute hills and
valleys (natural variations) in the rail.
[0132] The rail line sensing and safety system 2 does not suffer
from the disadvantages of the current system. Interference with an
electrical connection between the wheel and the rail is not an
issue in the rail line sensing and safety system because the rail
line sensing and safety system may use an advanced induction
proximity sensor. This proximity sensor does not rely on the rail
as a conductor and operates reliably even if the rail is
contaminated. Therefore, by using the rail line sensing and safety
system, the vehicles traveling on the rail need not carry
additional empty cars nor limit their speed.
[0133] FIG. 25 shows a schematic view of an ultra-wideband (UWB)
based rail line sensing and safety system. Shown in FIG. 25 is an
ultra-wideband (UWB) based crossing warning enhancement (CWE)
system 500.
[0134] The CWE system 500 may comprise suitable components
(including circuitry) for providing rail line sensing and safety.
In this regard, the CWE system 500 may be similar rail line sensing
and safety systems described above--e.g., the rail line sensing and
safety system (RLSSS) 2 of FIG. 1. However, the CWE system 500 may
be configured for using ultra-wideband (UWB) based
signals/communications in conjunction with rail line sensing and
safety functions, such as with respect to providing warnings to
trains approaching crossings. In this regard, use UWB may be
desirable for various reasons, such as due to its wide frequency
bandwidth, which makes UWB communications and/or signals
particularly resistant to conditions associated with railway
systems.
[0135] For example, UWB communications and/or signals may be
un-effected by the normal mechanical obstructions and interfaces
that may be present in train locations, such as supporting beams
and other structures normally found in a subway tunnels or other
track locations. Further, UWB communications and/or signals may be
used for different purposes--e.g., for communication of data,
ranging (e.g., time of flight based ranging), in which precise
distances may be measured, and rates of closure can be calculated,
such as for collision avoidance applications, etc.
[0136] The use of UWB in rail line sensing and safety systems may
enhance the functions of these systems. For example, in the
embodiments described with respect to FIGS. 1-24, the devices of
the rail line sensing and safety systems may function as backup to
crossing gate system, with axle counters used to locate the train
and determine its speed at that location, and sending a wireless
notice to the existing crossing bungalow where the legacy system is
located, and notifying it to lower the gates if it did not assert
the system at the proper point. In systems implemented in
accordance with the present disclosure (e.g., the CWE system 500 of
FIG. 25), use of UWB is added and/or incorporated into the sensing
system, providing a redundant sensing path, which may improve the
accuracy of the gate timing. Such enhancement (to gate timing) may
be desirable as it may provide added protection in instances where
persons (pedestrians, drivers, etc.) may ignore that gates--e.g.,
where somebody attempts to drive around crossing gates is if the
train's arrival is delayed, as the current system is not very
accurate as far as the gate timing is concerned, particularly if
the train changes speed as it approaches the crossing.
[0137] In various implementations, the CWE system 500 may comprise
at least one wheel detector (WD) 504, which is substantially
similar to the detection module (DM) 4 as described above, at least
one detection control module (DCM) 506, which is substantially
similar to the remote module (RM) 6 as described above, and at
least one signaling gateway module (SGM) 508, which is
substantially similar to the control module (CM) 8 as described
above. The CWE system 500 may also incorporate UWB radios (and
related circuitry), which may be incorporated into the various
components of the system, to provide UWB based signals and/or
communications.
[0138] In the example implementation shown in FIG. 25, the CWE
system 500 comprises a single SGM 508 (e.g., deployed in an
existing crossing bungalow 503) and two wheel detectors and two
DCMs, one of each located on each side of a safety device 510, each
substantially similar to the safety device 10 as described above.
However, as with the systems described with respect to the figures,
above, in other implementations the CWE systems may be arranged
differently--e.g., comprising more than one SGM 508, more wheel
detectors and DCMs on one or both sides of the crossing. The single
SGM 508 may be configured to accept signals sent from multiple DCMs
506. Additionally, although the following description may refer to
the safety device 510 as a crossing gate or other type safety
device, it should be understood that the safety device 510 may
comprise many types of safety and warning devices, such as crossing
gates, lights, bells, visual, audio or physical warnings, and
combinations thereof.
[0139] Each wheel detectors 504 may be connected with the closest
DCM 506, such as via wireless and/or wired connection(s) 512. For
example, in one example implementation, each wheel detectors 504
may be connected with the closest DCM 506 via a hard-wired
connection. As described above, the wheel detectors 504 may be
powered by the peer DCM 506. In this regard, in some
implementations, the DCMs 506 may comprise power related
components, such as solar panel(s), battery pack(s), power control
module(s), etc. Alternatively, the wheel detectors 504 may be
powered by other power sources--e.g., a power source located in or
near the SGM 508.
[0140] In operation, the CWE system 500 may provide sensing and
safety functions as described above--that is, with the wheel
detectors 504, the DCMs 506, and the SGM 508 detecting (sensing)
approaching trains (e.g., train 501 in FIG. 25 operating on track
511) and controlling safety devices 510 in substantially similar
manner as described above with respect to the rail line sensing and
safety system (RLSSS) 2. However, in the CWE system 500, the UWB
radios incorporated into the train 501, the DCMs 506, and the SGM
508 may provide redundant sensing, as described above, to enhance
performance of the systems--e.g., with respect to timing of the
safety devices 510.
[0141] Use of UWB based signaling may enhance the gate timing as
the range and reliability of UWB signals may allow for controlling
of the opening/closing of the gate from the train adaptively--e.g.,
where the speed at which the train approaches the crossing would
affect the timing of the gate operation on a continuous basis.
[0142] For example, in an example use scenario where the train is
approaching the railroad crossing slowly, such as 15 mph, and the
wheel detectors are located 4,000 feet in advance of the crossing.
At the current speed, the train will require three minutes to reach
the crossing. If the desired actuation timing is 30 seconds prior
to arrival, the processing in the SGM 508 will delay for 150
seconds (21/2 minutes) before triggering the crossing gates safety
device 510. In this regard, in the context of this use scenario the
150 seconds allows for a 2 second delay in the safety device 510
response because at distance of 4,000 ft, a trains traveling at 15
mph will take .about.181.8 seconds to reach the crossing. Thus,
with a delay 150 seconds, it will be .about.31.8 seconds before the
train arrives at crossing. If the train accelerates after passing
the DCM 506, it may reach the crossing before the gate is even
actuated.
[0143] Continuous monitoring of the approach train speed in the DCM
may allow the CWE system 500 to reduce the delay to ensure that the
safety device 510 is actuated far enough in advance to properly
protect the crossing. If, however, the train is of minimal length,
the train wheels may clear the wheel detector 504 while the train
is still accelerating, resulting in improper timing (late
triggering) of the safety device.
[0144] UWB range measurements between the train 501 and the SGM in
the bungalow 503 allows the CWE system 500 to continuously and
dynamically maintain the desired 30 second advanced triggering of
the safety device 510.
[0145] In some implementations, UWB communication links between the
train 501 and the CWE system 500 may allow for communication of
sensing and safety related information. For example, the train may
receive confirmation about gate operation, such as if the gates are
lowered, if there is a vehicle there blocking the crossing, etc.
Such information may be conveyed to the engineer operating the
locomotive, alerting the engineer that additional safety actions
may be required, such as increased operation of the train whistle,
or braking the train to avoid, or in the case where the train
cannot stop prior to the crossing, braking to reduce the severity
of collision.
[0146] In some implementations, UWB communication links between the
train and the system may also be used for communication of sensing
and safety related information to external applications. This
exported data may be configured for use with online applications.
For example, data obtained based on sensing and safety related UWB
communications may be utilized to notify apps such as Waze and
Google Maps of what is happening at the crossings (e.g., whether
the gates deployed, which direction the train is coming from,
etc.). This allows the reduction of traffic congestion due to slow
trains blocking railroad crossings for extended periods. Traffic
may instead be diverted to routes which avoid the crossing, such as
roads which have a tunnel below or a bridge above the railroad
tracks. Alternatively, such exported data may be used for safety
enhancement, such as to properly equipped vehicles to enhance
safety--e.g., a school bus or petroleum tank truck. For example,
such exported data may be used for safety enhancement by providing
warning notifications directly to an operator of a vehicle, such as
indications that a train is approaching a nearby crossing, and the
expected time of arrival of the train.
[0147] The UWB transceiver in the remote sensing DCM 506 may also
be used in a radar sensing mode of operation after the UWB-equipped
train engine passes as it heads for the railroad crossing. The
large, metallic rail cars following the train engine provide a
robust radar reflection target, allow the DCM to continue
measurement of the train speed (and even direction) using the
Doppler effect as the trailing cars pass the DCM.
[0148] Because of regulatory restrictions on UWB transmitting power
and/or topological conditions in the track on the approach between
the DCM 506 and the crossing, the UWB ranging system in the SGM 508
may not be capable of reliably completing range measurements with
the UWB antenna in the train 501 until the train approaches
relatively close to the crossing. Thus, in some implementations, a
secondary UWB-only sensing system (e.g., similar to the DCM 506)
may be installed closer to the crossing on both approaches to the
crossing. Use of such auxiliary sensing location may facilitate
improved accuracy of timing of the safety device 510 for short
and/or slower speed trains.
[0149] The secondary UWB-only sensing DCM 506 may be particularly
advantageous in heavily populated areas where there are significant
numbers of pedestrians and/or vehicles which may be waiting at
crossings, some impatiently. A delay in train arrival after
initiation of signals may result in people crossing the tracks
after erroneously concluding that a train is not approaching. In
the event of a short train, UWB range measurements may be performed
repeatedly as the train approaches, providing highly accurate and
continuous measurements of the train speed and direction. This may
provide more accurate triggering of the crossing safety device 510,
as well as detect train reversal. An example implementation is
shown in FIG. 26.
[0150] FIG. 26 shows a schematic view of another example
ultra-wideband (UWB) based rail line sensing and safety system.
Shown in FIG. 26 is an ultra-wideband (UWB) based crossing warning
enhancement (CWE) system 600.
[0151] The CWE system 600 may be substantially similar to the CWE
system 500 of FIG. 25, and may be configured to operate in
substantially similar manner. The CWE system 600, however, is
modified to provide a standalone rail line sensing and safety, as
described above. Specifically, in the CWE system 600 there may not
be an existing sensing system. Rather, the system comprises an
outer detection site 620 and an inner detection site 606, which may
be deployed in proximity of the track. In this regard, the spacing
between each of the crossing, the outer detection site 620, and the
inner detection site 606 may be selected or determined based on
pertinent conditions or parameters--e.g., topology of the section
of the track, existing structures, etc.
[0152] The outer detection site 620 may comprise suitable
circuitry, other hardware and the like for supporting detection
functions performed thereby as described herein. For example, the
outer detection site 620 may comprise one or more controllers
(comprising suitable circuity for, e.g., processing input,
supporting communication functions, etc.), power sources (e.g.,
battery, solar panels, etc.), and antenna(s) (as well as suitable
transceiver(s) for facilitating use of the antennas). In this
regard, as shown in FIG. 26, the outer detection site 620 comprises
redundant vital controllers, a battery and solar panel for
providing power, and two data antennas.
[0153] The inner detection site 606 may comprise suitable
circuitry, other hardware and the like for supporting detection
functions performed thereby as described herein. For example, the
inner detection site 606 may comprise one or more controllers
(comprising suitable circuity for, e.g., processing input,
supporting communication functions, etc.), power sources (e.g.,
battery, solar panels, etc.), and antenna(s) (as well as suitable
transceiver(s) for facilitating use of the antennas). In this
regard, as shown in FIG. 26, the inner detection site 606 comprises
a single vital controller, a battery and solar panel for providing
power, and single data antenna and a dual-channel (e.g., for
ranging and data communication) antenna.
[0154] Vital (redundant) set of wheel sensors 604 (e.g., axle
counters) may be installed on the track, for use in detecting
approaching train (e.g., train 601 in FIG. 26), and may be
connected to the outer detection site 620. The redundant vital
controllers of the outer detection site 620 process the wheel
sensor output and detect when a train is approaching the crossing
as well as the speed of the train. The outer detection site 620 may
then take action in adaptive manner. For example, when the train is
moving slowly, data from the outer detection site 620 does not
trigger an immediate actuation of safety device(s) 610 at the
crossing.
[0155] When it is determined based on the information relating to
the approaching train (e.g., the train is moving fast) that the
safety device(s) 610 need to be actuated, the outer detection site
620 may trigger an immediate actuation of the safety devices 610.
This may be done via a signal site 608, with the data being
communicated thereto. In this regard, the data may be communicated
(relayed) via the inner detection site 606.
[0156] The signal site 608 may comprise suitable circuitry, other
hardware and the like for controlling operation of the safety
devices (e.g., facilitating actuation thereof). For example, the
signal site 608 may comprise one or more controllers (comprising
suitable circuity for, e.g., processing input, supporting
communication functions, etc.), power sources, and antenna(s). In
this regard, as shown in FIG. 26, the signal site 608 comprises a
dual vital controllers (e.g., for redundancy), a battery for
providing power, and two data antennas.
[0157] At the inner detection site 606, an UWB ranging measurement
installation may be used for automatic adjustment of the warning
time when there are drastic reductions in the speed of an
approaching train. To that end, the trains may be configured to
support UWB communication (e.g., using suitable UWB transceiver(s)
and antenna(s) deployed therein). UWB ranging allows continuous
high-resolution range measurements at distances greater than a
quarter mile distance prior to the wayside UWB radio. By combining
multiple range measurement results and the elapsed time between
measurements, the resulting "delta-range" values allow
determination of the train speed and direction. This additional
data allows for accurate determination of the expected arrival time
of a slower moving train at the grade crossing.
[0158] In some implementations, there may be more than one inner
detection site 606 installed on the approach to the crossing to
allow an extended range of UWB measurement capability.
[0159] An example system for train control, in accordance with the
present disclosure comprises a detection control module, configured
for deployment on or near rail tracks in a rail network, and
signaling gateway module. The detection control module comprises
one or more antennas, one or more transceivers configured for
transmitting and/or receiving wireless signals via the one or more
antennas, and one or more circuits. The signaling gateway module
comprising one or more circuits. The signaling gateway module is
configured to control a safety device deployed at a crossing on a
rail track, and one or both of the detection control module and the
signaling gateway module are configured to communicate signals with
any train-based transceiver that comes within communication range,
the signals comprising ultra-wideband (UWB) signals, obtain based
on at least processing of received UWB signals range measurements
corresponding to a train traveling on the rail track, and generate
control signals for controlling safety device based on the range
measurements.
[0160] In an example implementation, the system further comprises
one or more sensors attached to the rail track, wherein each sensor
is configured to generate a coupling signal in response to a train
traveling on the rail track, the coupling signal is communicated to
the detection control module.
[0161] In an example implementation, the detection control module
is configured to generate one or more output signals based on
coupling signals received from the one or more sensors, wherein
each output signal is generated based on one or more
characteristics of at least one corresponding coupling signals.
[0162] In an example implementation, the safety device includes a
gate.
[0163] In an example implementation, one or both of the detection
control module and the signaling gateway module are configured to
generate at least one control signal for controlling or adjusting
timing of the safety device.
[0164] In an example implementation, one or both of the detection
control module and the signaling gateway module are configured to
determine based on the range measurements train-related information
associated with the train, and generate or adjust the control
signals based on the train-related information.
[0165] In an example implementation, one or both of the detection
control module and the signaling gateway module are configured to
communicate to the train information relating to the safety device
and/or operation of the safety device.
[0166] In an example implementation, one or both of the detection
control module and the signaling gateway module are configured to
communicate to one or more vehicles approaching the crossing
information relating to the safety device and/or operation of the
safety device.
[0167] In an example implementation, the signaling gateway module
further comprises one or more antennas, and one or more
transceivers configured for transmitting and/or receiving wireless
signals via the one or more antennas, the signaling gateway module
being configured to communicate with one or both of the detection
control module and the safety device using wireless signals.
[0168] An example system for train control, in accordance with the
present disclosure comprises a plurality of detection control
modules configured for deployment on or near rail tracks in a rail
network, with each detection control module comprising one or more
antennas, one or more transceivers configured for transmitting
and/or receiving wireless signals via the one or more antennas, and
one or more circuits. The plurality of detection control modules
comprises at least a first detection control module and a second
detection control module, with the first detection control module
deployed physically closer to a crossing on a rail track than the
second detection control module, the second detection control
module is configured to generate in response to physical detection
of a train traveling on the rail track, a detection signal, and
communicate the detection signal to the first detection control
module, the first detection control module is configured to
communicate signals with any train-based transceiver that comes
within communication range, the signals comprising ultra-wideband
(UWB) signals, and obtain based on at least processing of received
UWB signals range measurements corresponding to a train traveling
on the rail track. The range measurements and the detection signal
are used in controlling a safety device deployed at the
crossing.
[0169] In an example implementation, the system further comprises a
signaling gateway module is configured to control the safety
device, and wherein the one or both of the signaling gateway module
and the first detection control module are configured to generate
control signals for controlling safety device based on the range
measurements and the detection signal.
[0170] In an example implementation, one or both of the first
detection control module and the signaling gateway module are
configured to generate at least of control signal for controlling
or adjusting timing of the safety device.
[0171] In an example implementation, one or both of the first
detection control module and the signaling gateway module are
configured to determine based on the range measurements
train-related information associated with the train, and generate
or adjust the control signals based on the train-related
information.
[0172] In an example implementation, the signaling gateway module
further comprises one or more antennas, and one or more
transceivers configured for transmitting and/or receiving wireless
signals via the one or more antennas, the signaling gateway module
being configured to communicate with one or both of the first
detection control module and the safety gate using wireless
signals.
[0173] In an example implementation, the first detection control
module is configured to communicate to the train information
relating to the safety device and/or operation of the safety
device.
[0174] In an example implementation, the system further comprises
one or more sensors attached to the rail track, wherein each sensor
is configured to generate a coupling signal in response to a train
traveling on the rail track, the coupling signal is communicated to
the second detection control module.
[0175] In an example implementation, the first detection control
module is configured to the detection signal based on coupling
signals received from the one or more sensors.
[0176] In an example implementation, the safety device includes a
gate.
[0177] Aspects of the techniques described herein may be
implemented in digital electronic circuitry, computer software,
firmware, or hardware, including the structures disclosed herein
and their structural equivalents, or in various combinations.
Aspects of the techniques described herein may be implemented using
a non-transitory computer readable medium and/or storage medium,
and/or a non-transitory machine readable medium and/or storage
medium, having stored thereon, a machine code and/or a computer
program having at least one code section executable by a machine
and/or a computer, thereby causing the machine and/or computer to
perform the processes as described herein.
[0178] Each of the computer programs may have, for example, one or
more sets of program instructions residing on or encoded in the
non-transitory computer-readable storage medium for execution by,
or to control the operation of, one or more processors of the
machine or the computer. Alternatively or in addition, the
instructions may be encoded on an artificially-generated propagated
signal, for example, a machine-generated electrical, optical, or
electromagnetic signal that may be generated to encode information
for transmission to a suitable receiver apparatus for execution by
one or more processors.
[0179] A non-transitory computer-readable medium may be, or be
included in, a non-transitory computer-readable storage device, a
non-transitory computer-readable storage substrate, a random or
serial access memory array or device, various combinations thereof.
Moreover, while a non-transitory computer-readable medium may or
may not be a propagated signal, a non-transitory computer-readable
medium may be a source or destination of program instructions
encoded in an artificially-generated propagated signal. The
non-transitory computer-readable medium may also be, or be included
in, one or more separate physical components or media (for example,
CDs, disks, or other storage devices).
[0180] Certain techniques described in this specification may be
implemented as operations performed by one or more processors on
data stored on one or more computer-readable mediums or received
from other sources. The term "processor" may encompass various
kinds of apparatuses, devices, or machines for processing data,
including by way of example a central processing unit, a
microprocessor, a microcontroller, a digital-signal processor,
programmable processor, a computer, a system on a chip, or various
combinations thereof. The processor may include special purpose
logic circuitry, for example, a field programmable gate array or an
application-specific integrated circuit.
[0181] Program instructions (for example, a program, software,
software application, script, or code) may be written in various
programming languages, including compiled or interpreted languages,
declarative or procedural languages, and may be deployed in various
forms, for example as a stand-alone program or as a module,
component, subroutine, object, or other unit suitable for use in a
computing environment. Program instructions may correspond to a
file in a file system. Program instructions may be stored in a
portion of a file that holds other programs or data (for example,
one or more scripts stored in a markup language document), in a
dedicated file or in multiple coordinated files (for example, files
that store one or more modules, sub-programs, or portions of code).
Program instructions may be deployed to be executed on one or more
processors located at one site or distributed across multiple sites
connected by a network.
[0182] The present technology has now been described in such full,
clear, concise and exact terms as to enable any person skilled in
the art to which it pertains, to practice the same. It is to be
understood that the foregoing describes preferred embodiments and
examples of the present technology and that modifications may be
made therein without departing from the spirit or scope of the
invention as set forth in the claims. Moreover, it is also
understood that the embodiments shown in the drawings, if any, and
as described above are merely for illustrative purposes and not
intended to limit the scope of the invention. As used in this
description, the singular forms "a," "an," and "the" include plural
reference such as "more than one" unless the context clearly
dictates otherwise. Where the term "comprising" appears, it is
contemplated that the terms "consisting essentially of" or
"consisting of" could be used in its place to describe certain
embodiments of the present technology. Further, all references
cited herein are incorporated in their entireties.
[0183] Accordingly, various embodiments in accordance with the
present invention may be realized in hardware, software, or a
combination of hardware and software. The present invention may be
realized in a centralized fashion in at least one computing system,
or in a distributed fashion where different elements are spread
across several interconnected computing systems. Any kind of
computing system or other apparatus adapted for carrying out the
methods described herein is suited. A typical combination of
hardware and software may be a general-purpose computing system
with a program or other code that, when being loaded and executed,
controls the computing system such that it carries out the methods
described herein. Another typical implementation may comprise an
application specific integrated circuit or chip.
[0184] Various embodiments in accordance with the present invention
may also be embedded in a computer program product, which comprises
all the features enabling the implementation of the methods
described herein, and which when loaded in a computer system is
able to carry out these methods. Computer program in the present
context means any expression, in any language, code or notation, of
a set of instructions intended to cause a system having an
information processing capability to perform a particular function
either directly or after either or both of the following: a)
conversion to another language, code or notation; b) reproduction
in a different material form.
[0185] While the present invention has been described with
reference to certain embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted without departing from the scope of the present
invention. In addition, many modifications may be made to adapt a
particular situation or material to the teachings of the present
invention without departing from its scope. Therefore, it is
intended that the present invention not be limited to the
particular embodiment disclosed, but that the present invention
will include all embodiments falling within the scope of the
appended claims.
* * * * *