TRAIN INTEGRITY AND END OF TRAIN LOCATION VIA RF RANGING

• US 20140277859A1
• Filed: 03/15/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Australian Rail Track Corp. Ltd. (Government of Australia)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: MORRIS, Charles W.
• Granted Patent: US 8,918,237 B2
• Time in Patent Office: Days
• US Class Current: 701/19
• CPC Class Codes: B61L 15/0027 Radio-based, e.g. using GSM-R
• CPC Class Codes: B61L 15/0036 Conductor-based, e.g. using CAN-Bus, train-line or optical fibres
• CPC Class Codes: B61L 15/0054 Train integrity supervision, e.g. end-of-train [EOT] devices
• CPC Class Codes: B61L 15/0072 On-board train data handling
• CPC Class Codes: B61L 23/34 for indicating the distance between vehicles or trains by the transmission of signals therebetween
• CPC Class Codes: B61L 25/02 Indicating or recording positions or identities of vehicles or trains

Abstract

Systems and methods that can be used in a Positive Train Control system to continuously monitor train integrity and end of train location using radio frequency (RF) ranging techniques to determine the line of sight distance between the head end and the end of the train. The systems and methods allow PTC controlled trains to maintain positive length of train awareness and to determine if a portion of the train separates unintentionally. The systems and methods can be implemented on existing RF infrastructure used on trains, without impacting existing messaging traffic, adding bandwidth or power requirements. The systems and methods work on stretched trains running on tangent or straight track, as well as on foreshortened trains running on curved track.

Claims

1. An end of train device, comprising:

a radio frequency transceiver;

at least one mechanism that monitors last car information and that is in communication with the radio frequency transceiver;

a PLL counter and event timer in communication with the radio frequency transceiver.

2. The end of train device of claim 1, wherein the at least one mechanism is configured to monitor brake pipe pressure, last car motion status, battery condition, or marker light status.

3. The end of train device of claim 2, comprising a plurality of the mechanisms that monitor last car information and that are each in communication with the radio frequency transceiver, the plurality of mechanisms include a brake pipe pressure monitor, a motion status monitor, a battery condition monitor, and a marker light monitor.

4. The end of train device of claim 1, wherein the PLL counter and event timer includes a radio frequency counter, a clock and a time stamp device.

5. A system, comprising:

an end of train device mounted at an end car of a train, the end of train device includes;

a radio frequency transceiver;

at least one mechanism that monitors last car information and that is in communication with the radio frequency transceiver;

a PLL counter and event timer in communication with the radio frequency transceiver; and

a head of train control unit mounted at a head end of the train, the head of train control unit includes a head end radio frequency transceiver.

6. The system of claim 5, wherein the head of train control unit includes a PLL counter and event timer in communication with the head end radio frequency transceiver, the PLL counter and event timer in the head of train control unit is identical to the PLL counter and event timer in the end of train device.

7. The system of claim 5, wherein the at least one mechanism is configured to monitor brake pipe pressure, last car motion status, battery condition, or marker light status.

8. The system of claim 7, comprising a plurality of the mechanisms that monitor last car information and that are each in communication with the radio frequency transceiver, the plurality of mechanisms include a brake pipe pressure monitor, a motion status monitor, a battery condition monitor, and a marker light monitor.

9. The system of claim 5, wherein the PLL counter and event timer includes a radio frequency counter, a clock and a time stamp device.

10. A process of determining line of sight distance between a head end of a train and an end of the train, comprising:

sending a radio frequency transmission between the head end and an end of train device at the end of the train;

determining the one way propagation time of the radio frequency transmission between the head end and the end of train device; and

multiplying the determined one way propagation time by the propagation speed of the radio frequency transmission to determine the line of sight distance.

11. The process of claim 10, further comprising the end of train device counting the number of cycles received in the radio frequency transmission;

and the end of train device sending a radio frequency transmission back to the head end, the radio frequency transmission sent by the end of train device includes a time stamp of when the last cycle of the radio frequency transmission from the head end was received and a count of the number of cycles received.

12. The process of claim 11, further comprising the head end determining the line of sight distance using the radio frequency transmission from the end of train device.

13. The process of claim 12, further comprising the head end comparing the determined line of sight distance to an expected line of sight distance.

14. The process of claim 11, wherein the head end determines a time difference between the one way propagation time of the radio frequency transmission from the head end to the end of train device and the one way propagation time of the radio frequency transmission from the end of train device to the head end.

15. The process of claim 10, prior to sending the radio frequency transmission, synchronizing the end of train device and a head end control unit at the head end, initializing the end of train device and the head end control unit, and determining a time bias between a clock of the end of train device and a clock of the head end control unit.