Multipath management for global navigation satellite systems

Patent metadata

Field	Value
Publication number	US-11415708-B2
Application number	US-201816957716-A
Country	US
Kind code	B2
Filing date	Dec 21, 2018
Priority date	Dec 28, 2017
Publication date	Aug 16, 2022
Grant date	Aug 16, 2022

Abstract

A positioning device includes a first GNSS receiver; a communication link configured to receive a spatial position, code measurements and carrier phase measurements of a second GNSS receiver; an input interface to a processing logic, the processing logic being configured to: calculate a position of the first positioning device from communicated data; and to estimate one or more parameters representative of multipath at the position of the first positioning device; wherein the communication link is configured to communicate to a second positioning device the parameters representative of multipath at the position of the first positioning device. Described developments comprise the use of multipath severity indicators, the determination of relative distances between receivers, validity conditions in time and/or space of multipath, various embodiments in a train or in a group of vehicles. Software aspects are discussed.

First claim

The invention claimed is:

1. A positioning system comprising:
a first GNSS receiver; and
a second GNSS receiver;
wherein the first GNSS receiver and the second GNSS receiver are mounted on a train;
wherein the first GNSS receiver is configured to receive a spatial position, code measurements and carrier phase measurements of GNSS signals computed by the second GNSS receiver through a communication link;
wherein the first GNSS receiver comprises processing logic configured to:
calculate a position of the first GNSS receiver based on code measurements and carrier phase measurements of GNSS signals computed by the first GNSS receiver and based on the spatial position, the code measurements, and the carrier phase measurements of the GNSS signals received from the second GNSS receiver;
estimate one or more parameters representative of multipath at the position of the first GNSS receiver, the estimated one or more parameters being a residual difference between pseudo ranges measured by the first GNSS receiver and predicted pseudo ranges using said position of the first GNSS receiver, after deduction of modeled errors, wherein the modeled errors comprise satellite clock errors, receiver clock errors, ionospheric errors and tropospheric errors;

wherein the processing logic is further configured to communicate said one or more parameters representative of the multipath estimated at the position of the first GNSS receiver to the second GNSS receiver through the communication link, and
wherein the second GNSS receiver is configured to use said one or more parameters representative of the multipath estimated by the first GNSS receiver to adjust the computed GNSS position when the second GNSS receiver is within a specified range and within a specified timeframe of said spatial position of the first GNSS receiver.

2. The positioning system of claim 1 , wherein the one or more parameters representative of the multipath include one or more multipath severity indicators.

3. The positioning system of claim 1 , wherein the processing logic is further configured to determine a relative distance between the first and the second GNSS receivers.

4. The positioning system of claim 1 , wherein the one or more parameters representative of the multipath are associated with validity conditions in time and/or space.

5. The positioning system of claim 1 , wherein the one or more parameters representative of the multipath are estimated for a plurality of satellites of a GNSS constellation.

6. A computer-implemented method of handling multipath with a first receiver and a second receiver, the method comprising the steps of:
determining, by the second receiver, a spatial position of the second receiver, code measurements of the second receiver, and carrier-phase measurements of the second receiver;
communicating, by the second receiver, the spatial position of the second receiver, the code measurements of the second receiver, and the carrier-phase measurements of the second receiver to a first receiver;
determining, by the first receiver, a spatial position of the first receiver based on the spatial position of the second receiver, the code measurements of the second receiver, the carrier-phase measurements of the second receiver, code measurements of the first receiver, and carrier-phase measurements of the first receiver;
estimating, by the first receiver, multipath parameters at the spatial position of the first receiver;
communicating, by the first receiver, said estimated multipath parameters to the second receiver; and
adjusting, by the second receiver, the spatial position of the second receiver based on said multipath parameters received from the first receiver when the second receiver is within a specified range and within a specified timeframe of said spatial position of the first receiver.

7. The computer-implemented method of claim 6 , further comprising determining and communicating, by the second receiver, an indicator of the estimated accuracy of the spatial position of the second receiver to the first receiver.

8. The computer-implemented method of claim 6 , further comprising determining, by the first receiver, the spatial position of the first receiver based on a differential positioning associated with the second receiver.

9. The computer-implemented method of claim 6 further comprising:
determining, by a third receiver, a spatial position of the third receiver, code measurements of the third receiver, and carrier-phase measurements of the third receiver;
communicating, by the third receiver, the spatial position of the third receiver, the code measurements of the third receiver, and the carrier-phase measurements of the third receiver to a first receiver;
communicating, by the first receiver, said estimated multipath parameters to the third receiver; and
adjusting, by the third receiver, the spatial position of third receiver based on said multipath parameters received from the first receiver when the third receiver is within the specified range and within the specified timeframe of said spatial position of the first receiver.

10. A plurality of computer-readable mediums comprising instructions for carrying out the steps of the method according to claim 6 when said instructions are executed by the first receiver and the second receiver.

11. The positioning system of claim 1 , further comprising:
a third GNSS receiver mounted on the train, wherein:
the processing logic is further configured to communicate said one or more parameters representative of multipath to the third GNSS receiver, and
the third GNSS receiver is configured to use said one or more parameters representative of the multipath to adjust a GNSS position computed by the third GNSS receiver when the third GNSS receiver is within the specified range and within the specified timeframe of said position of the first GNSS receiver.

Assignees

• Centre Nat Etd Spatiales
• Centre Nat Detudes Spatiales Cnes

Inventors

• Rouch Cédric
• Laurichesse Denis
• Marmet François-Xavier

Classifications

• G01S19/22

  Multipath-related issues · 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

• G01S19/071

  DGPS corrections · CPC title

• G01S19/074

  providing integrity data, e.g. WAAS · CPC title

• G01S19/07 Primary

  providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections · CPC title