U.S. patent application number 14/871081 was filed with the patent office on 2016-01-21 for automated real-time positive train control track database validation.
The applicant listed for this patent is LOCKHEED MARTIN CORPORATION. Invention is credited to Charles W. MORRIS.
Application Number | 20160016597 14/871081 |
Document ID | / |
Family ID | 51523299 |
Filed Date | 2016-01-21 |
United States Patent
Application |
20160016597 |
Kind Code |
A1 |
MORRIS; Charles W. |
January 21, 2016 |
AUTOMATED REAL-TIME POSITIVE TRAIN CONTROL TRACK DATABASE
VALIDATION
Abstract
Methods and systems are described that can be used to verify a
track database of a train management system, for example that the
track database has not been corrupted, built with critical errors,
or is not being used properly by the software application. In one
embodiment, radio frequency identification (RFID) tags are mounted
on the trackside features contained in the track database. The tags
contain data such as the geographical coordinates of the trackside
features and a unique feature identifier that uniquely identifies
the respective feature. As the train passes the trackside feature,
a tag reader on the train reads the tag to gather the geographical
coordinates and the feature identifier. The train management system
then compares the geographical coordinates and/or the feature
identifier from the tag with the expected geographical coordinates
and/or the expected feature identifier in the track database.
Inventors: |
MORRIS; Charles W.;
(Nokesville, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LOCKHEED MARTIN CORPORATION |
Bethesda |
MD |
US |
|
|
Family ID: |
51523299 |
Appl. No.: |
14/871081 |
Filed: |
September 30, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13839453 |
Mar 15, 2013 |
9174657 |
|
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14871081 |
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Current U.S.
Class: |
246/20 |
Current CPC
Class: |
B61L 25/025 20130101;
B61L 15/0027 20130101; B61L 3/004 20130101; B61L 27/0077 20130101;
B61L 3/125 20130101 |
International
Class: |
B61L 25/02 20060101
B61L025/02; B61L 3/00 20060101 B61L003/00 |
Claims
1. A method comprising: as a train is traveling on a railway track
and passes a trackside feature disposed adjacent to the railway
track, reading a feature identifier that uniquely identifies the
trackside feature and geographical coordinates of the trackside
feature from a radio frequency identification tag disposed on the
trackside feature using a reader located on the train; and
comparing the feature identifier and the geographical coordinates
read by the reader with an expected identifier and expected
geographical coordinates.
2. The method of claim 1, wherein the expected identifier and
expected geographical coordinates are calculated by a processor on
the train.
3. The method of claim 1, wherein the reader is located on the
engine of the train, and the tag is located in a vertical
orientation on the trackside feature.
4. The method of claim 1, further comprising: as the train is
traveling on a railway track, using the reader to read data from
additional radio frequency identification tags that are fixed to
additional trackside features.
Description
FIELD
[0001] This disclosure relates to the field of train management
systems and increasing safety in such systems.
BACKGROUND
[0002] One example of a train management system is the Lockheed
Martin Advanced Train Management System (ATMS) that uses on-train
processing and advanced digital communications to keep track of and
manage the location and speeds of trains on a railway. This permits
railroads to increase capacity by reducing distance between trains
and increase reliability through better on-time performance. In
addition, safety is increased through authority and speed limit
enforcement.
[0003] The ATMS uses a track database containing a variety of data
including geographical coordinates of a number of trackside
features that are disposed along the railway tracks as well as a
unique identifier for each of the trackside features. The track
database is used to create a virtual model of the track in the
control system of the train.
[0004] Track databases have many components that are constructed by
a team of surveyors, software operators, database administrators,
and other staff, and are distributed by radio links to trains from
central data servers. However, the track database can have errors.
The track line's 3-D trajectory can have errors
(location/curvature/heading/grade), which can degrade the ability
to accurately compute offset into track segment. In addition,
errors in feature-coordinate assignments can result in erroneous
visual presentation of upcoming trackside features and track line
characteristics to train crew and can have several unintended
consequences. For example, errors in content can result in
erroneously determining train's track occupancy (parallel track),
computing actual location along a track, affecting braking
enforcement distance calculations, and miss-identifying physical
features used in authority limits.
[0005] Physical trackside features such as kilometer posts,
turnouts, speed limits, passenger platforms, division boundaries,
yard limits, etc. are used for two-way traffic management and speed
management. However, these trackside features can have errors in
their partition offsets which results in track database content
errors. In addition, trackside features such as kilometer posts and
control points can be unintentionally swapped along the track line
(for example kilometer post 130 is actually 129 and vice versa).
For this example, an authority issued between kilometer posts 135
and 130 on single track could cause an unintentional physical
conflict with an opposing train travelling in the opposite
direction, as their movement authorities are generated and
deconflicted by km post value by a train dispatcher/controller, not
by geographic coordinates.
SUMMARY
[0006] Methods and systems are described that can be used to verify
a track database of a train management system, for example that the
track database has not been corrupted, built with critical errors,
or is not being used properly by the software application.
[0007] In some circumstances, software and hardware data of a train
management system have to meet safety integrity level (SIL) 3 and
above compliance. One recognized way to meet SIL requirements for
the underlying ATMS track database is to create and use an
independent database, which has the characteristics of a different
design, different creation method, generated by a different process
with different assets, and maintained by different team
members.
[0008] The described methods and systems provide real time,
continual, train centric techniques to ensure that each train is
using its part of the track database without safety reducing
navigation errors, is processing the track database correctly, and
has correct information on the actual placement of trackside
features so that the actual placements match the track database
contents which is used to construct the virtual model of the
track.
[0009] In one embodiment, radio frequency identification (RFID)
tags are mounted on the trackside features contained in the track
database. The tags contain data such as the geographical
coordinates of the trackside features and a unique feature
identifier that uniquely identifies the respective feature. As the
train passes the trackside feature, a tag reader on the train reads
the tag to gather the geographical coordinates and the feature
identifier. The train management system then compares the
geographical coordinates and/or the feature identifier from the tag
with the expected geographical coordinates and/or the expected
feature identifier in the track database.
[0010] An advantage of the described methods and systems is that
the team or individuals that load the data into the RFID tags can
be independent from the team that created the track database. This
diversity and independence between the two teams are important
attributes for a SIL environment.
[0011] In one embodiment, the RFID tag is mounted on the trackside
feature in a vertical orientation, and the RFID reader on the train
has a wide vertical field of view, and a narrow horizontal field of
view, in order to detect the trackside feature's passing when it is
close to broadside to the train. In one example, the RFID reader is
located in the engine or locomotive of the train, such as adjacent
to the front end of the locomotive. However, the RFID reader can be
located at other locations on the train as long as its location is
accounted for when comparing the read RFID data to the expected
data from the track database. In addition, in some embodiment, more
than one RFID reader may be provided on the train, with each RFID
reader reading the RFID tag as it passes the trackside feature.
[0012] In one specific embodiment, a method of verifying a railway
track database of a train management system is provided. The track
database contains information on a plurality of trackside features
located adjacent to a railway track including an identifier that
uniquely identifies each trackside feature and a geographical
coordinate location of each trackside feature. In this example, the
method includes, as the train is traveling on the railway track,
reading a radio frequency identification tag that is affixed to a
first one of the trackside features using a reader disposed on the
train. The reader obtains from the tag a feature identifier that
uniquely identifies the first trackside feature and geographical
coordinates of the first trackside feature, where the feature
identifier and the geographical coordinates are stored in memory of
the tag. The feature identifier and the geographical coordinates
read by the reader are then compared with an expected identifier
and expected geographical coordinates obtained from the track
database.
[0013] In another specific embodiment, a method includes, as a
train is traveling on a railway track and passes a trackside
feature disposed adjacent to the railway track, reading data from a
radio frequency identification tag disposed on the trackside
feature using a reader located on the train.
[0014] In still another specific embodiment, a method includes
mounting radio frequency identification tags to a plurality of
trackside features adjacent to a railway track, each tag having
memory in which is stored geographical coordinates of the trackside
feature to which the tag is fixed and a feature identifier that
uniquely identifies the trackside feature to which the tag is
fixed.
[0015] In still another specific embodiment, a radio frequency
identification tag includes a tag body, an antenna on the tag body,
and memory on the tag body. The memory includes stored therein
geographical coordinates of a railway trackside feature to which
the RFID tag is intended to be or has been fixed and a feature
identifier that uniquely identifies the railway trackside feature
to which the RFID tag is intended to be or has been fixed.
[0016] In addition, a system includes a plurality of radio
frequency identification tags mounted to a plurality of trackside
features disposed adjacent to a railway track, each tag having
memory in which is stored geographical coordinates of the trackside
feature to which the tag is fixed and a feature identifier that
uniquely identifies the trackside feature to which the tag is
fixed. The system also includes a tag reader mounted on a train,
the tag reader is capable of reading the radio frequency
identification tags as the train passes the trackside features, and
a processor on the train that is connected to the tag reader, the
processor receiving the geographical coordinates and the feature
identifier of each tag from the tag reader.
DRAWINGS
[0017] FIG. 1 illustrates a virtual model of a railway track line
with trackside features.
[0018] FIG. 2 is a diagram illustrating one embodiment of deriving
geographic coordinates from a partition offset using data from a
track database.
[0019] FIG. 3 illustrates an RFID system that can be used to verify
the track database.
[0020] FIG. 4 illustrates one example of verifying a railway track
database.
DETAILED DESCRIPTION
[0021] With reference initially to FIG. 1, a virtual model of a
railway track line 10 as one may see displayed as part of a train
management system is illustrated along with a plurality of
trackside features 12 disposed on either side of the track line.
The track line 10 represents the centerline of the railway on which
a train 14 is travelling in the direction T. FIG. 1 shows the train
at different times as it travels along the track.
[0022] The trackside features 12 can be any structures typically
located along a railway track that are used for such tasks as
traffic and/or speed management including, but not limited to,
kilometer posts, turnouts, speed limits, division boundaries, yard
limits, etc.
[0023] The track line 10 can be any railway track on which a train
travels including, but not limited to cargo, freight, passenger,
and/or commuter train tracks. The train 14 generally includes a
locomotive or engine and one or more additional cars connected to
the locomotive.
[0024] The train 14 is controlled by a train management system on
the train, typically on the locomotive, that includes a track
database that is used to keep track of the location and speed of
the train on the track. The function and construction of track
databases and train management systems is well known to those
having ordinary skill in the art. An example of a track database is
described in U.S. Pat. No. 8,392,103.
[0025] When it is created, the track database contains the
geographical coordinates of some or all of the trackside features
12 as well as a unique identifier for each of the trackside
features in the track database. The train management system
includes a location determination unit (LDU), such as a head end
rail guide, that determines instantaneous offset into track
partition and uses the track database to determine current
geographic coordinates from the offset. For example, with reference
to FIG. 2, the position of the locomotive 16 of the train is shown
as being offset a distance, for example 5000 cm, between two
consecutive trackside features 12a, 12b. The track database knows
the geographical coordinates of the trackside features 12a, 12b
which have been stored in the database. Therefore, the geographical
coordinates of the locomotive at the offset position can be
determined. FIG. 2 illustrates an exemplary calculation that takes
place to determine the geographical coordinates of the locomotive
16 at the offset location. Further information on calculating
partition offset can be found in U.S. Patent Application
Publication 2012/0116616 filed on Nov. 9, 2011, which is
incorporated herein by reference in its entirety.
[0026] This calculation of the geographical coordinates and the use
of the geographical coordinates of the trackside features 12a, 12b
is used by the train management system to help control operation of
the train. However, as indicated above, there could be errors in
the track database that can result in errors in the coordinate
calculations as well as errors in advising the train operators
which trackside features they are coming up on or have passed.
Therefore, a continual, train-based means to validate the data in
the track database would be useful.
[0027] With reference to FIG. 3, the track database can be
validated in real-time using an RFID system. In particular, each of
the trackside features 12 (corresponding to the trackside features
stored in the track database) is provided with an RFID tag 20. The
RFID tag 20 is of standard mechanical and electrical construction
including a tag body 22, an antenna 24 embedded in or otherwise
disposed on the tag body, memory 26 for storing data, and other
conventional elements.
[0028] In one embodiment, the tags 20 are mounted on the trackside
features 12 and programmed by a crew that is independent from the
team involved with creating the track database. This independence
greatly reduces the chances that a common error is made both in the
track database and in the tag 20.
[0029] For each tag 20, the crew loads into the memory 26 a feature
identifier that uniquely identifies the trackside feature 12 to
which that tag will be or has been mounted, as well as the
geographical coordinates of that trackside feature. The loading of
the data into each tag 20 can occur prior to or when the tag is
mounted on the trackside feature. The geographical coordinates for
each trackside feature 12 can be obtained using a conventional GPS
receiver, which are then loaded into the tag memory 26. The loading
of the data into tag memory can occur via wired or wireless means
well known in the art.
[0030] The feature identifier in tag memory can be any identifier
that uniquely identifies the feature, and in one embodiment matches
the feature identifier stored in the track database for the
corresponding feature. The feature identifier can be any number and
combination of alphanumeric characters and symbols.
[0031] The geographical coordinates loaded into the tag memory 26
can be any coordinates that directly or indirectly indicate the
geographical location of the feature. In one embodiment, the
geographical coordinates are 3-D Cartesian coordinates (Earth
Centered Earth Fixed) that indicate the location on Earth, which
can also be represented as Geodetic coordinates by latitude,
longitude and altitude of the trackside feature.
[0032] The RFID system also includes an RFID tag reader 30 that is
used to read the data from the memory 26 of the RFID tags 20 on the
trackside features. The tag reader 30 is mounted on the train at
any location that is suitable for reading the tags 20. In one
embodiment, the tag reader 30 is mounted at or adjacent to the
front or head end of the locomotive or other forwardmost unit of
the train. The tag reader 30 is of conventional construction
including an antenna 32 and suitable communication electronics.
[0033] The tag reader 30 is in communication with a control unit 34
that receives the tag data signals 36 from the tag reader 30. The
control unit 34 includes a microprocessor 38 that is programmed to
take the data from the tag memory 26 and use that data to validate
the data in the track database.
[0034] In one embodiment the RFID tags 20 are mounted on the
trackside features 12 so that the tags 20 extend vertically. In
addition, the reader 30 on the train is designed to have a wide
vertical field of view and a narrow horizontal field of view in
order to detect the trackside feature's passing when it is close to
broadside to the locomotive.
[0035] With reference to FIG. 4, in one process 40 the RFID tags 20
are installed on the trackside features 12. Either prior to or
after mounting the tags, the geographical coordinates and the
unique feature identifier for that feature are loaded into the tag
memory 26.
[0036] In another part of the process, as the train moves down the
track and passes one of the trackside features, the reader 30 reads
the tag 20 on that trackside feature as indicated in box 42. As the
head end of the train sequentially encounters trackside features
with tags, the reader 30 responds with an event time, and reads the
geographical data (e.g. the 3-D Cartesian coordinates or the
Geodetic coordinates latitude/longitude/altitude) and the unique
feature identifier.
[0037] The train management system also determines the expected
location of the train using data from the track database as
indicated at box 44. In this step, the head end LDU captures the
instantaneous offset into track partition at that trackside
feature, and computes equivalent geographic coordinates in the
manner illustrated in FIG. 2.
[0038] The data read from the RFID tag is then compared to the
expected location data as indicated at box 46. The train management
system differences the LDU determined location at the event with
the data read from the tag 20. This can be simplistically stated as
LAT/LON/ALT of the locomotive minus LAT/LON/ALT of the trackside
feature. However, in actuality the Cartesian coordinate components
would be individually differenced.
[0039] If the locomotive is navigating properly (e.g. not built up
an offset error), and if the trackside features and track geometry
model in the complex track database are correct for that partition,
then the coordinates read from the RFID tag will be very close (for
example under 3 meters, or even within 1-2 meters) to those
computed by the train borne computer. This event would be given a
pass. Small differences confirm performance of the train management
system and data correctness in the track database. Therefore, the
geographical coordinates need not be identical in order to
determine that there is a match.
[0040] The unique identifier read from the RFID tag matching the
track database feature identifier confirms the correct trackside
feature known to be at this location.
[0041] Any errors in either the geographical coordinates or the
unique identifier can be logged and sent to a central location,
such as a train management system office, and the train can be
dropped out of automatic control.
[0042] If there is a match of feature identifier and coordinate
locations, that means, at that time and for that train, the LDU's
computed offset into partition is correct, the underlying track
database is correct (at that time), and the train's crew
operational display is correctly showing the track line and
trackside features (but not features ahead of it). This type of
checking is temporal, not continuous, only occurring every 1 km or
less, depending on trackside feature density.
[0043] In an alternate embodiment, one could verify the coordinates
without verifying the identifier, and vice versa.
[0044] This described method of cross checking, being physically
performed on the track, also has beneficial use as a way to verify
proper database content for both the underlying track database, the
data in the tag memory, and LDU navigation performance, after track
physical maintenance and database updates are put in place. In
other words, it is a good test and verification tool to be employed
after track and data changes are implemented on the network.
[0045] In addition to or separately from the track database
validation described above, the systems and methods described
herein can be used for other train management purposes. For
example, since the geographical coordinates of the trackside
features are known and the time between two readings is known,
reading the tags of two consecutive trackside features can be used
to determine the rate of travel between the trackside features and
thus as a check of the speed of the train.
[0046] In addition, although the systems and methods have been
described above as employing a single tag reader on the train, a
train can have multiple tag readers spread along the length of the
train. Each tag reader can read the tag on the trackside feature as
the train passes. Failure of a reader to read the tag can indicate
a potential problem with the train, such as decoupling of cars of
the train from the locomotive.
[0047] The examples disclosed in this application are to be
considered in all respects as illustrative and not limitative. The
scope of the invention is indicated by the appended claims rather
than by the foregoing description; and all changes which come
within the meaning and range of equivalency of the claims are
intended to be embraced therein.
* * * * *