METHOD AND SYSTEM FOR REDUCING AUTONOMOUS TIME TO FIX OF A MULTI-STANDARD GNSS RECEIVER

• US 20120075144A1
• Filed: 03/11/2011
• Published: 03/29/2012
• Est. Priority Date: 09/28/2010
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Diggelen, Frank van, Abraham, Charles
• Granted Patent: US 8,525,726 B2
• Time in Patent Office: Days
• US Class Current: 342/357.66
• CPC Class Codes: G01S 19/28 Satellite selection
• CPC Class Codes: G01S 19/31 Acquisition or tracking of other signals for positioning
• CPC Class Codes: G01S 19/33 Multimode operation in different systems which transmit time stamped messages, e.g. GPS/GLONASS

Abstract

A multi-standard GNSS receiver, handle different global navigation satellite systems (GNSSs), determines with respect to a current time instant, the earliest broadcast timing based on corresponding satellite broadcast cycles for satellites in the different GNSSs. The multi-standard GNSS receiver acquires fresh broadcast ephemeris at the determined earliest broadcast timing to determine its own first position. A search order is determined based on the corresponding satellite broadcast cycles and the current time instant. The multi-standard GNSS receiver may selectively utilize appropriate satellite receivers such as the GPS receiver and the GLONASS receiver to search for satellite signals based on the determined search order. Channels for different GNSSs are scanned to identify transmitting satellites based on the corresponding satellite broadcast cycles for ephemeris downloading. The satellite search is prioritized by comparing the current time instant with the corresponding satellite broadcast cycles.

Claims

1. A method for processing signals, the method comprising:

in a multi-standard global navigation satellite system (GNSS) receiver that is operable to handle a plurality of different global navigation satellite systems (GNSSs);

determining with respect to a current time instant, an earliest time for acquiring fresh broadcast ephemeris from one of the plurality of different global navigation satellite systems based on corresponding satellite broadcast cycles for satellites in said different GNSSs.

acquiring said fresh broadcast ephemeris at said determined earliest time instant; and

determining a first position of said multi-standard global navigation satellite system (GNSS) receiver based on said acquired fresh broadcast ephemeris.

2. The method of claim 1, wherein said current time instant is determined from navigation data acquired from one or more of said satellites in said different GNSSs or from a clock associated with said multi-standard GNSS receiver.

3. The method according to claim 2, comprising determining a search order for said multi-standard GNSS receiver based on said corresponding satellite broadcast cycles and said current time instant.

4. The method according to claim 3, comprising searching for signals from said satellites in said different GNSSs based on said determined search order.

5. The method according to claim 4, comprising selectively utilizing one or more GNSS receivers associated with said multi-standard GNSS receiver for said searching.

6. The method according to claim 1, wherein said corresponding satellite broadcast cycles are associated with channels for said satellites in said different GNSSs.

7. The method according to claim 6, comprising scanning said channels for said satellites in said different GNSSs to identify one or more transmitting GNSS satellites based on said corresponding satellite broadcast cycles.

8. The method according to claim 7, comprising:

downloading said fresh broadcast ephemeris from said identified one or more transmitting GNSS satellites; and

calculating said first position for said multi-standard GNSS receiver utilizing said downloaded fresh broadcast ephemeris.

9. The method according to claim 1, comprising comparing said current time instant with said corresponding satellite broadcast cycles for said satellites in said different GNSSs

10. The method according to claim 9, comprising prioritizing a manner in which said fresh broadcast ephemeris is acquired from said satellites in said different GNSSs based on said comparison.

11. A system for processing signals, the system comprising:

one or more circuits for use in a multi-standard global navigation satellite system (GNSS) receiver that is operable to handle a plurality of different global navigation satellite systems (GNSSs), said one or more circuits being operable to;

determine with respect to a current time instant, an earliest time for acquiring fresh broadcast ephemeris from one of the plurality of different global navigation satellite systems based on corresponding satellite broadcast cycles for satellites in said different GNSSs;

acquire said fresh broadcast ephemeris at said determined earliest time instant; and

determine a first position of said multi-standard global navigation satellite system (GNSS) receiver based on said acquired fresh broadcast ephemeris.

12. The system according to claim 11, wherein said current time instant is determined from navigation data acquired from one or more of said satellites in said different GNSSs or from a clock associated with said multi-standard GNSS receiver.

13. The system according to claim 12, wherein said one or more circuits are operable to determine a search order based on said corresponding satellite broadcast cycles and said current time instant.

14. The system according to claim 13, wherein said one or more circuits are operable to search for signals from said satellites in said different GNSSs based on said determined search order.

15. The system according to claim 14, wherein said one or more circuits are operable to selectively utilize one or more GNSS receivers associated with said multi-standard GNSS receiver for said searching.

16. The system according to claim 11, wherein said corresponding satellite broadcast cycles are associated with channels for said satellites in said different GNSSs.

17. The system according to claim 16, wherein said one or more circuits are operable to scan said channels for said satellites in said different GNSSs to identify one or more transmitting GNSS satellites based on said corresponding satellite broadcast cycles.

18. The system according to claim 17, wherein said one or more circuits are operable to download said fresh broadcast ephemeris from said identified one or more transmitting GNSS satellites;

and calculate said first position for said multi-standard GNSS receiver utilizing said downloaded fresh broadcast ephemeris.

19. The system according to claim 11, wherein said one or more circuits are operable to compare said current time instant with said corresponding satellite broadcast cycles for said satellites in said same GNSS and/or for said satellites in said different GNSSs.

20. The system according to claim 19, wherein said one or more circuits are operable to prioritize a manner in which said fresh broadcast ephemeris is acquired from said satellites in said different GNSSs based on said comparison.