Method for estimating the direction of arrival of navigation signals at a receiver after reflection by walls in a satellite positioning system

Patent metadata

Field	Value
Publication number	US-9229111-B2
Application number	US-201313763718-A
Country	US
Kind code	B2
Filing date	Feb 10, 2013
Priority date	Feb 10, 2012
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

A method includes estimating a position of a receiver, aboard a moving object, on the basis of the navigation signals emitted by satellites received by an antenna in an antenna array placed on the moving object, and using a three-dimensional geographical map to deduce, geometrically, on the basis of the position of the receiver and of a ray casting starting from the receiver, the number of paths reflected on walls of buildings present in a scene corresponding to an environment surrounding the receiver. The determined number of reflected paths is used to initialize an algorithm for estimating angles of arrival of multi-paths to deduce therefrom angles of arrival of the paths reflected on the walls before reaching the receiver. Optionally, the method can comprise making it possible to bound the distance information error due to a multi-path to render the estimation of direction of arrival of the signals more efficacious.

First claim

The invention claimed is:

1. A method for estimating the direction of arrival of navigation signals at a receiver after reflection by walls in a GNSS satellite positioning system, the positioning system comprising at least one satellite able to emit navigation signals, the receiver, placed in a moving object, being able to receive the navigation signals and to estimate the position of the said receiver, said method comprising the following steps:
a. placing an array of antennas comprising at least two antennas on the moving object,
b. placing a three-dimensional geographical map in the receiver of the moving object,
c. receiving the navigation signals on an antenna of the array of antennas and estimating a position of the receiver,
d. from the estimated position of the receiver, selecting, on the three-dimensional geographical map, a scene corresponding to an environment in which the receiver is situated and carrying out a ray casting starting from the receiver,
e. deducing, geometrically, on the basis of the result of the ray casting, the number of paths reflected on walls of buildings present in the scene,
f. selecting an algorithm for estimating the angles of arrival of multi-paths, the multi-paths corresponding to signals reflected by walls, initializing this algorithm by the number of reflected paths determined in step e and deducing therefrom the angles of arrival of the paths reflected on the walls before reaching the receiver.

2. The method according to claim 1 , wherein the angles of arrival of the multi-paths are determined, by the selected algorithm, on the basis of an analysis of the signals received by each of the antennas of the array of antennas.

3. The method according to claim 1 , wherein before carrying out step c, the method comprises a preliminary step consisting in estimating a distance information error due to a multi-path, the preliminary step comprising:
step 1: estimating a first pseudo-distance corresponding to a first information item regarding the distance between the satellite and the receiver obtained from a processing of the signal received by a first antenna of the array of antennas,
step 2: estimating a second pseudo-distance corresponding to a second information item regarding the distance between the satellite and the receiver obtained from a processing of the signal received by a second antenna of the array of antennas,
carrying out a difference between the two estimations obtained in steps 1 and 2 and deducing therefrom a mathematical standard deviation corresponding to this difference, and
bounding the distance information error due to a multi-path by an indicator dependent on the mathematical standard deviation.

Assignees

• Thales Sa
• Centre Nat Etd Spatiales

Inventors

• Monnerat Michel
• Ries Lionel

Classifications

• G01S19/22 Primary

  Multipath-related issues · CPC title

• G01S5/00

  Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations {(using active systems G01S13/00, G01S15/00, G01S17/00)} · CPC title

• G01S5/14

  Determining absolute distances from a plurality of spaced points of known location · CPC title

• G01S19/42

  Determining position · CPC title