Method and apparatus for managing time in a satellite positioning system

• US 7,626,539 B2
• Filed: 11/16/2007
• Issued: 12/01/2009
• Est. Priority Date: 11/07/2003
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Global Locate Incorporated (Broadcom, Inc.)
• Inventors: de Salas, Javier
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US11/941,552
• Publication Number:
  US 20080169979A1
• Time in Patent Office: 746 Days
• Field of Search: 342/357.02, 342/357.06, 342/357.12, 342/357.15, 342/357.13, 701/213, 701/215
• US Class Current: 342/357.31
• CPC Class Codes: G01S 19/03 Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset

Abstract

A method, apparatus and system for time management in a position-location system is described. The method may include (i) obtaining, at a global-navigation-satellite-system receiver while being served by a first node of a wireless network a first time base, a relative-time difference, and a third time base; and forming a time relation as a function of the first time base, relative-time difference (“RTD”) and third time base. The first time base is associated with the first node, and may be, for example, a time base associated with an air interface for communicating with the first node. The RTD may be a difference between the first time base and a second time base associated with a second node of the wireless network. The third time base is associated with a constellation of satellites, and may be, for example, an absolute time associated with the constellation of satellites. The method may include using knowledge of a GNSS time to enhance sensitivity or time to first position of a GNSS receiver.

Claims

1. A method comprising:

obtaining, at a given global-navigation-satellite-system receiver while being served by a first node of a wireless network, a first time base, wherein the first time base is associated with the first node;

obtaining, at the given global-navigation-satellite-system receiver while being served by the first node, a relative-time difference, wherein the relative-time difference comprises a difference between the first time base and a second time base associated with a second node of the wireless network;

obtaining at the given global-navigation-satellite-system receiver a third time base, wherein the third time base is associated with a constellation of satellites; and

forming a time relation as a function of the first time base, the relative-time difference and the third time base.

2. The method of claim 1, further comprising:

computing, as function of the time relation, at least one position of any of (i) the given global-navigation-satellite-system receiver, and (ii) another global-navigation-satellite-system receiver.

3. The method of claim 2, further comprising:

obtaining, at any of the given global-navigation-satellite-system receiver and the another global-navigation-satellite-system receiver from a database, the time relation.

4. The method of claim 1, further comprising:

providing the time relation to a database.

5. The method of claim 1, further comprising:

storing the time relation at the given global-navigation-satellite-system receiver, wherein the given global-navigation-satellite-system receiver is operable to compute, as a function of the time relation, a position of the given global-navigation-satellite-system receiver.

6. The method of claim 1, wherein the third time base is an absolute time associated with the constellation.

7. The method of claim 1, further comprising:

using the time relation as an estimate of absolute time.

8. The method of claim 1, further comprising:

using the time relation to form an estimate of absolute time; and

using the estimate of absolute time to increase sensitivity of the given global-navigation-satellite-system receiver.

9. The method of claim 1, further comprising:

using the time relation to form an estimate of absolute time; and

using the estimate of absolute time to decrease a time for computing at least one position of any of (i) the given global-navigation-satellite-system receiver, and (ii) a another global-navigation-satellite-system receiver.

10. The method of claim 1, wherein forming the time relation comprises:

applying the first time base to the relative-time difference to determine the second time base; and

forming the time relation as a function of the second and third time bases.

11. The method of claim 10, wherein forming the time relation comprises:

determining a difference between the second and third time bases; and

offsetting the difference from the third time base.

12. The method of claim 11, further comprising:

computing, as function of the time relation, at least one position of any of (i) the given global-navigation-satellite-system receiver being served by the node, and (ii) a another global-navigation-satellite-system receiver being served by the second node.

13. The method of claim 1, further comprising:

using the time relation to acquire at least one satellite of the constellation of satellites.

14. A method comprising:

obtaining at a server a time relation, wherein the time relation is formed as a function of a first time base, a relative-time difference and a third time base;

wherein the first time base is obtained, at a given global-navigation-satellite-system receiver while being served by a first node of a wireless network;

wherein the first time base is associated with the first node;

wherein the relative time difference is obtained at the given global-navigation-satellite-system receiver while being served by the first node;

wherein the relative-time difference comprises a difference between the first time base and a second time base associated with a second node of the wireless network;

wherein the third time base is obtained at the given global-navigation-satellite-system receiver; and

wherein the third time base is associated with a constellation of satellites; and

providing the time relation to any of (i) the given global-navigation-satellite-system receiver when being served by the second node, and (ii) a another global-navigation-satellite-system receiver when being served by the second node.

15. The method of claim 14, further comprising:

computing, as function of the time relation, at least one position of any of (i) the given global-navigation-satellite-system receiver, and (ii) the another global-navigation-satellite-system receiver.

16. The method of claim 14, further comprising:

storing the time relation at the another global-navigation-satellite-system receiver, wherein the another global-navigation-satellite-system receiver is operable to compute, as a function of the time relation, a position of the another global-navigation-satellite-system receiver.

17. The method of claim 14, wherein the third time base is an absolute time associated with the constellation.

18. The method of claim 14, further comprising:

using the time relation as an estimate of absolute time.

19. A global-navigation-satellite-system receiver comprising:

memory adapted to store executable instructions to;

obtain a first time base while being served by a first node of a wireless network, wherein the first time base is associated with the first node;

obtain a relative-time difference while being served by the first node, wherein the relative-time difference comprises a difference between the first time base and a second time base associated with a second node of the wireless network;

obtain a third time base, wherein the third time base is associated with a constellation of satellites; and

form a time relation as a function of the first time base, the relative-time difference and the third time base; and

a processor adapted to (i) obtain from the memory the executable instructions and (ii) execute the executable instructions.

20. The receiver of claim 19, wherein the executable instructions further comprise:

executable instructions to compute, as function of the time relation, at least one position of the given global-navigation-satellite-system receiver.

21. The receiver of claim 19, further comprising:

a transmitter for providing the time relation to a database.

22. The receiver of claim 19, wherein the third time base is an absolute time associated with the constellation.

23. The receiver of claim 19, wherein the executable instructions further comprise:

executable instructions to use the time relation as an estimate of absolute time.

24. The receiver of claim 19, wherein the executable instructions to form the time relation comprise executable instructions to:

apply the first time base to the relative-time difference to determine the second time base; and

form the time relation as a function of the second and third time bases.

25. The receiver of claim 19, wherein the executable instructions to form the time relation comprise executable instructions to:

determine a difference between the second and third time bases; and

offset the difference from the third time base.

26. The receiver of claim 19, wherein the executable instructions further comprise executable instructions to:

use the time relation to acquire at least one satellite of the constellation of satellites.

27. A system comprising a first global-navigation-satellite-system receiver, a another global-navigation-satellite-system receiver, and a server, wherein:

the first global-navigation-satellite-system receiver adapted to;

obtain a first time base while being served by a first node of a wireless network, wherein the first time base is associated with the first node;

obtain a relative-time difference while being served by the first node, wherein the relative-time difference comprises a difference between the first time base and a second time base associated with a second node of the wireless network;

obtain a third time base, wherein the third time base is associated with a constellation of satellites; and

form a time relation as a function of the first time base, the relative-time difference and the third time base; and

the server is adapted to;

obtain the time relation from the first global-navigation-satellite-system receiver; and

provide the time relation to any of (i) the first global-navigation-satellite-system receiver, and (ii) the another global-navigation-satellite-system receiver.