METHOD FOR DETERMINING THE POSITION AND/OR SPEED OF A GUIDED VEHICLE AND ASSOCIATED SYSTEM

• US 20140333478A1
• Filed: 05/13/2014
• Published: 11/13/2014
• Est. Priority Date: 05/13/2013
• Status: Active Grant

• Current Assignee: Alstom Transport Technologies
• Original Assignee: Alstom Transport SA (Alstom SA)
• Inventors: Bortolotto, Mauro, Andre, Brice
• Granted Patent: US 9,817,127 B2
• Time in Patent Office: Days
• US Class Current: 342/357.67
• CPC Class Codes: G01S 19/20 Integrity monitoring, fault detection or fault isolation of space segment
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/28 Satellite selection

Abstract

A method for selecting usable satellites from among the satellites of a localization constellation, to determine an instantaneous kinematic state of a train, is provided. The method includes determining a measured value and an estimated value of a Doppler coefficient and/or a pseudo-range, then comparing the measured and estimated values and, in case of divergence, deleting the satellite from the usable satellites. The estimated value results from a dynamic model of the train, which uses only a kinematic state at a past moment to calculate an estimated instantaneous kinematic state and that uses a mapping of the track on which the guided vehicle moves.

Claims

1. A method for selecting a set of usable visible satellites from among a set of visible satellites of a constellation of localisation satellites, to determine an instantaneous kinematic state of a guided vehicle, comprising, for each satellite of the set of visible satellites:

calculating an instantaneous measured value of a quantity from among a Doppler coefficient and a pseudo-range, from the signal received from the visible satellites;

determining an instantaneous estimated value of the quantity;

comparing the instantaneous measured and estimated values according to a criterion, and in case of noncompliance with the criterion;

deleting the satellite from a set of usable visible satellites,

the determining an estimated value of the quantity including implementing a dynamic model of the guided vehicle that uses only a kinematic state of the guided vehicle determined at a past moment to calculate an instantaneous estimated kinematic state and that uses a mapping of the track on which the guided vehicle moves.

2. The method as recited in claim 1 wherein the determining an estimated value of the quantity includes using an ephemeris making it possible to estimate the relative position and speed of a satellite from the set of visible satellites and the guided vehicle in the instantaneous estimated kinematic state.

3. The method as recited in claim 1 wherein the comparing the instantaneous measured and estimated values includes determining a deviation between the instantaneous measured and estimated values of the quantity and/or a determination of a covariance between the instantaneous measured and estimated values of the quantity.

4. The method as recited in claim 3 wherein the criterion includes verifying that the deviation is smaller than a threshold deviation and/or that the covariance is below a threshold covariance.

5. A method for calculating an instantaneous kinematic state of a guided vehicle from signals emitted by a set of satellites from a constellation of localisation satellites, the method comprising:

the method as recited in claim 1; and

calculating the instantaneous kinematic state of the guided vehicle only from the signals emitted by the satellites from the list of usable visible satellites (LSVU).

6. A system for determining an instantaneous kinematic quantity of a guided vehicle, onboard the vehicle, comprising:

a receiver for signals emitted by the satellites from a constellation of localisation satellites;

a storage and calculator configured for executing the instructions of a computer program to implement the steps of;

calculating an instantaneous measured value of a quantity from among a Doppler coefficient and a pseudo-range, from the signal received from the visible satellites;

determining an instantaneous estimated value of the quantity;

comparing the instantaneous measured and estimated values according to a criterion, and in case of noncompliance with the criterion;

deleting the satellite from a set of usable visible satellites,

the determining an estimated value of the quantity including implementing a dynamic model of the guided vehicle that uses only a kinematic state of the guided vehicle determined at a past moment to calculate an instantaneous estimated kinematic state and that uses a mapping of the track on which the guided vehicle moves.