Method of optimization of processing of location data in the presence of a plurality of satellite positioning constellations

• US 7,646,338 B2
• Filed: 12/28/2006
• Issued: 01/12/2010
• Est. Priority Date: 12/29/2005
• Status: Expired due to Fees

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Monnerat, Michel
• Primary Examiner(s): Tarcza, Thomas H
• Assistant Examiner(s): Nguyen, Nga X
• Application Number:
  US11/617,072
• Publication Number:
  US 20070236387A1
• Time in Patent Office: 1,111 Days
• Field of Search: 342/356, 34235701-35717
• US Class Current: 342/357.66
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/33 Multimode operation in different systems which transmit time stamped messages, e.g. GPS/GLONASS

Abstract

The present invention concerns a method of optimization of processing of signals from satellite positioning systems in the case where at least two satellite systems cohabit and are utilized to obtain the position of a receiver.

One of the systems is given preference on the basis of a criterion of performance and the satellites of the other systems are eliminated that are situated at an azimuth/elevation angle difference less than a threshold relative to the satellites of the preferred system.

Claims

1. Method of management of positioning satellite signals (15a, 15b, 15c) coming from a first constellation of satellites (GPS, 26) and a second constellation of satellites (Galileo, 25) of a first and a second satellite location system for locating a mobile terminal (27) of a cellular communication network capable of exchanging satellite signals with the first and second satellite location systems (GPS, Assisted GPS, Galileo, Assisted Galileo), said method comprising:

determining an approximate pre-location of the terminal;

estimating the position of the satellites of said first and second constellations;

resolving a list of satellites visible from the terminal as a function of the approximate pre-location of the terminal and the estimated position of the satellites;

calculating the elevation and the azimuth of each satellite from the list of satellites visible from the terminal as a function of the approximate pre-location of the terminal; and

sorting the satellites from the list of visible satellites by;

giving preference to one of said satellite constellations on the basis of a performance criterion, excluding (24) from the list of visible satellites all of the satellites belonging to the constellations other than the preferred constellation having positions in azimuth and in elevation from the point of view of the terminal confined within a predetermined angular range relative to one of the satellites of the preferred constellation.

2. Method according to claim 1, characterized in that the qualification of the constellation as the preferred constellation is effected by the construction of N groups of satellites belonging to the list of satellites visible from the terminal, where N corresponds to the number of satellite positioning constellations used in the calculation of the position of the user, a group of satellites being defined in that all the satellites of the same group belong to the same constellation, the preferred constellation assuming a preferred quality index 1 and having physical signal characteristics more favorable to positioning performance.

3. Method according to claim 2, wherein the step of sorting of the satellites, for each satellite Sat_i of the constellations 2 to N, includes:

calculation (22) of the angular difference between the azimuth of the satellite Sat_i and the azimuth of all of the satellites of the constellation 1, calculation (23) of the angular difference between the elevation of the satellite Sat;

and the elevation of all of the satellites of the constellation 1, elimination (24) of the satellite Sat_i from the list of satellites visible from the position of the terminal if the elevation and azimuth angular differences are less than a respective given value (AO, EO).

4. Method according to claim 1 characterized in that the step (16) of determining an approximate pre-location of the terminal utilizes the result of a triangulation within the cellular communication network to deduce the pre-location therefrom.

5. Method according to claim 1, characterized in that the step (16) of determining an approximate pre-location of the terminal utilizes an earlier pre-location of the terminal.

6. Method according to claim 1, further comprising a step of the mobile terminal processing satellite signals from each satellite from the list of visible satellites, minus those that have been excluded.

9. Method according to claim 1 characterized in that the step (16) of determining an approximate pre-location of the terminal utilizes location information coming from the position of a base station of the cell in which the terminal is situated.

10. Method according to claim 2 characterized in that the step (16) of determining an approximate pre-location of the terminal utilizes either the result of a triangulation within the cellular communication network to deduce the pre-location therefrom, or location information coming from the position of a base station of the cell in which the terminal is situated.

11. Method according to claim 3 characterized in that the step (16) of determining an approximate pre-location of the terminal utilizes either the result of a triangulation within the cellular communication network to deduce the pre-location therefrom, or location information coming from the position of a base station of the cell in which the terminal is situated.

7. System for management of positioning satellite signals (15a, 15b, 15c) coming from a first constellation of satellites (GPS, 26) and a second constellation of satellites (Galileo, 25) of a first and a second satellite location system for locating a mobile terminal (27) of a cellular communication network capable of exchanging satellite signals with the first and second satellite location systems (GPS, Assisted GPS, Galileo, Assisted Galileo), characterized in that said management system comprises:

means (28) for determination of an approximate pre-location of the terminal,

means (29) for estimation of the position of the satellites of said first and second constellations,

means (30) for resolution of the list of satellites visible from the terminal as a function of the approximate pre-location of the terminal that has been determined and from the estimated position of the satellites,

means (31) for calculation of the elevation and the azimuth of each satellite from the list of satellites visible from the terminal as a function of the approximate pre-location of the terminal,

means (32) for sorting of the satellites from the list of visible satellites by;

giving preference to one of said satellite constellations on the basis of a performance criterion,

excluding from the list of visible satellites all of the satellites belonging to the constellations other than the preferred constellation having positions in azimuth and in elevation from the point of view of the terminal confined within a predetermined angular range relative to one of the satellites of the preferred constellation, and

means (9, 10) for transmission to the terminal (27) of assistance data relating to the list of satellites visible from the terminal, minus the excluded satellites.

8. System according to claim 7, characterized in that the system comprises an assistance data server (34) that integrates said means (28) for determination of an approximate pre-location of the terminal, said means (29) for estimation of the position of the satellites of said first and second constellations, said means (30) for resolution of the list of satellites visible from the terminal as a function of the approximate pre-location of the terminal that has been determined and the estimated position of the satellites, said means (31) for calculation of the elevation and the azimuth of each satellite from the list of satellites visible from the terminal as a function of the approximate pre-location of the terminal, said means (32) for sorting the satellites from the list of visible satellites, and means (35) for transmission to the terminal of assistance data relating to the list of satellites visible from the terminal, minus the excluded satellites.

12. A method of management of positioning satellite signals coming from a plurality of constellations for locating a mobile terminal of cellular communication network comprising:

determining an approximate pre-location position of a mobile terminal;

estimating the positions of satellites a plurality constellations;

resolving a list of visible satellites visible from the terminal as a function of the approximate pre-location of the terminal and the estimated positions of the satellites;

calculating the elevation and the azimuth of each of the visible satellites as a function of the approximate pre-location position of the terminal;

forming N groups of satellites belonging to the list of visible satellites, where N corresponds to the number of satellite positioning constellations used in the calculation of the position of the terminal, a group of satellites being defined as belonging to the same constellation;

designating the group having signal characteristics most favorable to positioning performance as constellation 1; and

forming a revised list of visible satellites, wherein for each satellite Sat_i of the constellations 2 to N the forming includes;

calculating the angular difference between the azimuth of the satellite Sat_i

and the azimuth of all of the satellites of the constellation 1, calculating the angular difference between the elevation of the satellite Sat₁; and

the elevation of all of the satellites of the constellation 1, and eliminating the satellite Sat_i from the list of visible satellites if the elevation and azimuth angular differences are less than respective threshold values.

13. Method according to claim 12, wherein the determining of the approximate pre-location of the terminal utilizes the result of a triangulation within the cellular communication network.

14. Method according to claim 12, wherein the determining of the approximate pre-location of the terminal utilizes location information coming from the position of a base station of a cell in which the terminal is situated.

15. Method according to claim 12, wherein determining of the approximate pre-location of the terminal utilizes an earlier pre-location of the terminal.

16. Method according to claim 12, further comprising the terminal processing satellite signals from each satellite from the revised list of visible satellites.