Method for determining the location of a railway vehicle and associated system

Patent metadata

Field	Value
Publication number	US-10661817-B2
Application number	US-201815910284-A
Country	US
Kind code	B2
Filing date	Mar 2, 2018
Priority date	Mar 2, 2018
Publication date	May 26, 2020
Grant date	May 26, 2020

Abstract

The invention concerns a method for determining the location of a railway vehicle comprising a first navigation module determining a regular resolution position of the railway vehicle with a first accuracy measurement and a second navigation module determining a high resolution position of the railway vehicle with a second accuracy measurement, using the received signals. The method comprises the steps of determining a first confidence area around the regular resolution position, based on the first accuracy measurement, of determining a second confidence area around the high precision position, based on the second accuracy measurement, and of assigning a weight of confidence to the knowing of the actual location of the railway vehicle, by analyzing the overlay of the first and the second confidence areas and the first and the second accuracy measurements.

First claim

The invention claimed is:

1. A method for determining an actual location of a railway vehicle comprising a first navigation module and a second navigation module, each navigation module receiving navigation signals from a global navigation satellite system; the first navigation module determining a regular resolution position of the railway vehicle with a first accuracy measurement, using the received navigation signals; the second navigation module determining a high resolution position of the railway vehicle with a second accuracy measurement, using the received navigation signals; the method comprising the following steps:
providing an estimation of the actual location of the railway vehicle;
determining a first confidence area around the regular resolution position, based on the first accuracy measurement;
determining a second confidence area around the high precision position, based on the second accuracy measurement;
assigning a weight of confidence to the estimation of the actual location of the railway vehicle, by analyzing the overlay of the first and the second confidence areas and the first and the second accuracy measurements; and
communicating the weight of confidence with the estimation of the actual location of the railway vehicle.

2. The method according to claim 1 , wherein during the step of assigning of a weight of confidence,
a very high weight is assigned to the estimation of the actual location of the railway vehicle, if the first confidence area overlays the second confidence area, and both accuracy measurements are less than a predetermined threshold;
a high weight is assigned to the estimation of the actual location of the railway vehicle, if the first confidence area overlays the second confidence area, the second accuracy measurement is less than the predetermined threshold and the first accuracy measurement is greater than the predetermined threshold;
a low weight is assigned to the estimation of the actual location of the railway vehicle, if one of the confidence areas overlays the other confidence area, and the second accuracy measurement is greater than the predetermined threshold;
a very low weight is assigned to the estimation of the actual location of the railway vehicle, if the confidence areas overlay partially, and both accuracy measurements are greater than the predetermined threshold.

3. The method according to claim 1 , wherein the step of assigning a weight of confidence further comprises comparing a track map with the first and the second confidence areas.

4. The method according to claim 1 , wherein each of the first and the second confidence areas is formed by a circle.

5. The method according to claim 4 , wherein the radius of the each circle is defined by the corresponding accuracy measurement.

6. The method according to claim 1 , wherein each of the first and the second accuracy measurements corresponds to a horizontal dilution of precision of the corresponding navigation module.

7. The method according to claim 1 , wherein each navigation module receives navigation signals from a Global Positioning System (GPS).

8. The method according to claim 7 , wherein the regular resolution position is obtained using publically available encrypting codes.

9. The method according to claim 8 , wherein the high resolution position is obtained using encrypting codes with a restricted access.

10. The method according to claim 8 , wherein the high resolution position is obtained using additional satellites or ground stations.

11. The method according to claim 1 , further comprising a preliminary step comprising converting the regular resolution position and the high resolution position so as these positions correspond to a same location, the conversion is performed using a known distance between the first navigation module and the second navigation module.

12. A system for determining an actual location of a railway vehicle comprising a first navigation module and a second navigation module, each navigation module receiving navigation signals from a global navigation satellite system; the first navigation module determining a regular resolution position of the railway vehicle with a first accuracy measurement, using the received navigation signals; the second navigation module determining a high resolution position of the railway vehicle with a second accuracy measurement, using the received navigation signals; wherein the system comprises an analyzing module configured for:
providing an estimation of the actual location of the railway vehicle;
determining a first confidence area around the regular resolution position, based on the first accuracy measurement;
determining a second confidence area around the high precision position, based on the second accuracy measurement;
assigning a weight of confidence to the estimation of the actual location of the railway vehicle, by analyzing the overlay of the first and the second confidence areas and the first and the second accuracy measurements; and
communicating the weight of confidence with the estimation of the actual location of the railway vehicle.

Assignees

• Alstom Transp Tech

Inventors

• Salinas Maximo
• Cooper Jared
• Jorgensen Nels

Classifications

• B61L2205/04

  Satellite based navigation systems, e.g. global positioning system [GPS] · CPC title

• G01S19/50

  whereby the position solution is constrained to lie upon a particular curve or surface, e.g. for locomotives on railway tracks · CPC title

• G01S19/33

  Multimode operation in different systems which transmit time stamped messages, e.g. GPS/GLONASS · CPC title

• B61L25/025 Primary

  Absolute localisation, e.g. providing geodetic coordinates · CPC title

• G01S19/421

  by combining or switching between position solutions or signals derived from different satellite radio beacon positioning systems; by combining or switching between position solutions or signals derived from different modes of operation in a single system · CPC title