Method and apparatus for managing time in a satellite positioning system
View Patent ↗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.
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.