System, method, and apparatus for generating a timing signal

• US 20030207681A1
• Filed: 05/03/2002
• Published: 11/06/2003
• Est. Priority Date: 05/03/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Rowitch, Douglas Neal
• Granted Patent: US 6,788,663 B2
• Time in Patent Office: Days
• US Class Current: 455/404.2
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/07 providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]

Abstract

A method of wireless communications according to one embodiment of the invention includes obtaining a first time base (e.g. obtaining a code phase) from a signal received from a ground transmitter (e.g. a CDMA base station). A predetermined offset based on at least a propagation delay of the received signal is applied to the first time base to obtain a second time base. For example, the second time base may be aligned to a time base of a positioning satellite system (e.g. the NAVSTAR GPS). A timing signal is generated that has a code phase based on the second time base.

Claims

1. A method of wireless communications, said method comprising:

obtaining a first time base of a signal received from a ground transmitter;

applying a predetermined offset to the first time base to obtain a second time base; and

generating a timing signal,

wherein the predetermined offset is based on a propagation delay of the received signal, and

wherein a code phase of the timing signal is based on the second time base.

2. The method of wireless communications according to claim 1, wherein the second time base is aligned with a time base of a positioning satellite system.

3. The method of wireless communications according to claim 2, wherein generating a timing signal includes spreading the timing signal with a spreading code of the positioning satellite system.

4. The method of wireless communications according to claim 3, wherein the timing signal is modulated by data representing time information arranged in a data format of the positioning satellite system.

5. The method of wireless communications according to claim 1, wherein generating a timing signal includes spreading the timing signal with a pseudorandom noise code.

6. The method of wireless communications according to claim 1, wherein said obtaining a first time base includes obtaining a code phase of the received signal.

7. The method of wireless communications according to claim 1, wherein said method includes decoding a time information message from the received signal.

8. The method of wireless communications according to claim 1, wherein said obtaining a first time base includes obtaining a code phase from a first channel of the received signal;

and

wherein said method further comprises decoding a time information message from a second channel of the received signal, the second channel being different from the first channel.

9. The method of wireless communications according to claim 8, wherein the first channel is spread with a first spreading code, and

wherein the second channel is spread with a second spreading code, the second spreading code being different from the first spreading code.

10. The method of wireless communications according to claim 8, wherein the first channel is covered with a first covering code, and

wherein the second channel is covered with a second covering code, the second covering code being different from the first covering code.

11. The method of wireless communications according to claim 1, wherein the timing signal is modulated by data representing information identifying a location at which said obtaining a first time base is performed.

12. The method of wireless communications according to claim 1, said method further comprising transmitting the timing signal,

wherein said generating a timing signal includes spreading the timing signal with a spreading code, and

wherein said transmitting the timing signal includes periodically varying a power level of the timing signal.

13. The method of wireless communications according to claim 1, said method further comprising at least one among (A) synchronizing an oscillator according to the first time base and (B) adjusting a code generator according to the first time base.

14. The method of wireless communications according to claim 1, said method further comprising at least one among (A) synchronizing an oscillator according to the second time base and (B) adjusting a code generator according to the second time base.

15. The method of wireless communications according to claim 1, wherein said obtaining a first time base from a signal received from a ground transmitter includes receiving the signal at a terrestrial location.

16. A method of wireless communications, said method comprising:

receiving a signal from a base station of a CDMA network for cellular telephony;

obtaining a first time base from the received signal;

applying a predetermined offset to the first time base to obtain a second time base; and

generating a timing signal,

wherein the predetermined offset is based on a propagation delay of the received signal, and

wherein a code phase of the timing signal is based on the second time base.

17. The method of wireless communications according to claim 16, wherein the predetermined offset is based on at least one signal processing delay.

18. The method of wireless communications according to claim 16, wherein the second time base is aligned with a time base of a positioning satellite system.

19. The method of wireless communications according to claim 16, wherein said obtaining a first time base includes obtaining a code phase of the received signal.

20. The method of wireless communications according to claim 16, wherein said obtaining a first time base includes obtaining a code phase from a first channel of the received signal, and

wherein said method further comprises decoding a time information message from a second channel of the received signal, the second channel being different from the first channel.

21. The method of wireless communications according to claim 16, wherein the timing signal is modulated by data representing information identifying a location at which said obtaining a first time base is performed.

22. The method of wireless communications according to claim 16, wherein the timing signal is modulated by a predetermined pattern at a data rate of the positioning satellite system.

23. The method of wireless communications according to claim 16, said method further comprising at least one among (A) synchronizing an oscillator according to the second time base and (B) adjusting a code generator according to the second time base.

24. An apparatus for wireless communications, said apparatus comprising:

means for receiving a signal from a ground transmitter;

means for obtaining a first time base from the received signal;

means for applying a predetermined offset to the first time base to obtain a second time base; and

means for generating a timing signal,

wherein the predetermined offset is based on a propagation delay of the received signal, and

wherein a code phase of the timing signal is based on the second time base.

25. The apparatus for wireless communications according to claim 24, wherein the predetermined offset is based on at least one signal processing delay.

26. The apparatus for wireless communications according to claim 24, wherein the second time base is aligned with a time base of a positioning satellite system.

27. The apparatus for wireless communications according to claim 24, wherein said means for obtaining a first time base includes means for obtaining a code phase of the received signal.

28. The apparatus for wireless communications according to claim 24, wherein said means for obtaining a first time base includes means for obtaining a code phase from a first channel of the received signal, and

wherein said apparatus further comprises means for decoding a time information message from a second channel of the received signal, the second channel being different from the first channel.

29. An apparatus for wireless communications, said apparatus comprising:

a receiver configured and arranged to receive a signal from a ground transmitter;

a time base processor configured and arranged to apply a predetermined offset to a time base of the received signal to obtain a second time base; and

a timing signal generator configured and arranged to generate a timing signal,

wherein a code phase of the timing signal is based on the second time base.

30. The apparatus for wireless communications according to claim 29, said apparatus further comprising a searcher configured and arranged to obtain a code phase of the received signal.

31. The apparatus for wireless communications according to claim 29, said apparatus further comprising a decoder configured and arranged to decode a time information message from the received signal.

32. The apparatus for wireless communications according to claim 31, wherein said decoder is further configured and arranged to output a strobe signal indicating a coincidence between code phases of a spreading code of the signal being decoded and a corresponding GPS C/A code.

33. The apparatus for wireless communications according to claim 29, wherein the second time base is aligned with a time base of a positioning satellite system.

34. The apparatus for wireless communications according to claim 33, wherein said timing signal generator is further configured and arranged to spread the timing signal with a spreading code of the positioning satellite system.

35. The apparatus for wireless communications according to claim 29, wherein said time base processor is further configured and arranged to perform at least one among the acts of (A) synchronizing an oscillator according to the time base of the received signal and (B) adjusting a code generator according to the time base of the received signal.

36. The apparatus for wireless communications according to claim 29, wherein said time base processor is further configured and arranged to perform at least one among the acts of (A) synchronizing an oscillator according to the second time base and (B) adjusting a code generator according to the second time base.

37. A transceiver, comprising:

a receiver configured and arranged to receive a signal from a ground transmitter;

a searcher configured and arranged to obtain a code phase of the received signal;

a time base processor configured and arranged to apply a predetermined offset to a first time base to obtain a second time base;

a timing signal generator configured and arranged to generate a timing signal; and

a transmitter configured and arranged to transmit the timing signal,

wherein the first time base is based on the code phase of the received signal, and

wherein a code phase of the timing signal is based on the second time base.

38. The transceiver according to claim 37, wherein the receiver is configured and arranged to receive a signal of a base station of a CDMA network for cellular telephony.

39. The transceiver according to claim 37, wherein the second time base is aligned with a time base of a positioning satellite system, and

wherein the timing signal generator is configured and arranged to spread the timing signal with a spreading code of the positioning satellite system.

40. The transceiver according to claim 39, wherein the timing signal generator is further configured and arranged to modulate the timing signal by a predetermined pattern at a data rate of the positioning satellite system, and

wherein the transmitter is configured and arranged to transmit the timing signal over a carrier having a frequency of the positioning satellite system.

41. An apparatus comprising a data storage medium, said medium having a set of instructions executable by an array of logic elements, said instructions defining a method of wireless communications including:

obtaining a first time base of a signal received from a ground transmitter;

applying a predetermined offset to the first time base to obtain a second time base; and

generating a timing signal,

wherein the predetermined offset is based on a propagation delay of the received signal,

wherein a code phase of the timing signal is based on the second time base.

42. A method of wireless communications, said method comprising:

obtaining a time base of a signal received from a ground transmitter; and

generating a timing signal, wherein a code phase of the timing signal is based on the time base, and,

wherein generating a timing signal includes spreading the timing signal with a spreading code of a positioning satellite system.