Point location method for a vehicle moving on a constrained trajectory and associated system

Patent metadata

Field	Value
Publication number	US-10481276-B2
Application number	US-201715726292-A
Country	US
Kind code	B2
Filing date	Oct 5, 2017
Priority date	Oct 6, 2016
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

A point location method for a vehicle moving on a constrained trajectory, implemented by a location device comprises tachometry means, odometry means, a group of at least one satellite geopositioning receiver and a time base synchronized to a satellite geopositioning system, the location device detecting the passage of the vehicle closest to a predetermined position by exploiting knowledge of the displacement of the vehicle, by predicting the form of a set of satellite geopositioning signals at the predetermined position and by testing the match between the predicted signals and those received by the group of at least one satellite geopositioning receiver, the displacement of the vehicle being determined from data supplied by the odometry means and a mapping of the trajectory.

First claim

The invention claimed is:

1. A point location method for a vehicle moving on a constrained trajectory of known route, said method making it possible to detect the point of passage of the vehicle closest to a predetermined position and being implemented by a location device performing measurements of distance and of speed of the vehicle along the trajectory, and at least one geopositioning receiver receiving positioning signals from at least one satellite of a satellite geopositioning system, and comprising a local time base measuring the current time, synchronized to the time of said satellite geopositioning system, said method comprising:
a step Etp 0 , during which use is made of the information on speed and position of the vehicle on its trajectory, supplied by the location device, to estimate, at the current time, the moment of passage closest to said predetermined position (T cpa ) by taking account of the uncertainties on the time base of the location device;
a step Etp 1 , during which several possible moments of passage of the vehicle closest to the predetermined position are estimated, said possible moments being located around the estimated moment of passage closest to said predetermined position (T cpa );
a step Etp 2 , during which the estimation of the possible positions of the vehicle on the trajectory is performed for each of the possible moments of passage closest to the predetermined position, by taking account of the uncertainties on speed of the vehicle and on position on the trajectory estimated at the current time and extrapolated to the estimated moment of passage of the vehicle closest to the predetermined position (T cpa ), said possible positions being included in a range of positions centred on the predetermined positon;
a step Etp 3 , during which a prediction is made, for each of said possible positions, as to the form of a set of satellite geopositioning signals corresponding to the set of geopositioning signals expected for this position at the corresponding moment;
a step Etp 4 , during which, for each possible moment of passage of the vehicle closest to the predetermined position, the spatial match between the expected geopositioning signals and those received by the geopositioning receiver at the current time is tested, by suitable filtering;
the estimated possible position for which the match is maximal being considered as the point of passage closest to the predetermined position and the corresponding current time as the moment of passage closest to the determined position.

2. The location method according to claim 1 , wherein, for each of the possible moments of passage of the vehicle closest to the predetermined position, the spatial match between the geopositioning signals expected for each of the possible positions associated with the possible moment of passage considered and those received by the geopositioning receiver at each current time of the displacement is performed by multiple correlation, said multiple correlation allowing the detection of a correlation peak; the position of passage and the current time for which, after spatial interpolation, the greatest correlation peak is detected, being considered as the point of passage and the moment of passage closest to the predetermined position.

3. The location method according to claim 1 , comprising an additional step of readjustment of the odometry means of the location device embedded on board the vehicle, the readjustment being performed by considering the deviation between the position of the point of passage closest to the predetermined position and the position delivered by the odometry means corresponding to the current time determined as being the moment of passage closest to the predetermined position.

4. The point location device for a vehicle moving on a constrained trajectory of known plot comprising:
tachometry means configured to deliver a signal representative of the speed of the vehicle along said constrained trajectory,
odometry means configured to deliver a signal representative of the displacement of the vehicle along said constrained trajectory,
at least one geopositioning receiver configured to receive and process satellite geopositioning signals,
a time base, measuring the current time, synchronized to the GNSS time via the geopositioning receiver,
at least one computation module configured to implement a paint location method according to claim 1 by using the data supplied by the tachometry and odometry means and by the geopositioning receiver.

5. The point location device according to claim 4 , wherein said device is configured to implement the point location method when the distance between the vehicle and the predetermined position considered is below a predetermined given value.

6. A computer program product comprising computer-readable instructions which, when they are executed on a processor, cause the processor to execute the method according to claim 1 .

Assignees

• Thales Sa

Inventors

• Revol Marc

Classifications

• G01P3/465

  by using dynamo-electro tachometers or electric generator · CPC title

• B61L25/025

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

• H04W64/006

  with additional information processing, e.g. for direction or speed determination · CPC title

• G01C25/00

  Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass (testing, calibrating or compensating compasses G01C17/38) · CPC title

• G01S19/11

  wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters · CPC title