Telecommunications-assisted satellite positioning system

• US 6,256,475 B1
• Filed: 03/15/2000
• Issued: 07/03/2001
• Est. Priority Date: 09/11/1997
• Status: Expired due to Term

• Current Assignee: IDPA Holdings Incorporated (InterDigital, Inc.)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Vannucci, Giovanni
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US09/525,969
• Time in Patent Office: 475 Days
• Field of Search: 455/12.1, 455/13.1, 455/13.2, 455/11.1, 455/13.3, 455/502, 455/427, 455/429, 455/430, 455/428, 342/125, 342/146, 342/357.01, 342/353, 342/352.05, 342/385, 342/402, 342/357.02, 342/357.03, 375/208, 375/209, 375/326, 375/341, 375/366, 375/367, 701/213, 701/215
• US Class Current: 455/12.1
• 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 19/25 involving aiding data received from a cooperating element, e.g. assisted GPS
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/0063 of measured values, i.e. measurement on base station and position calculation on mobile

Abstract

A wireless terminal and auxiliary system are disclosed that enable the wireless terminal to determine its location based on signals transmitted from navigation satellites. In particular, the tasks of signal acquisition and signal processing required of a wireless terminal in the prior art are divided between the wireless terminal and the auxiliary system in accordance with the illustrative embodiment. The auxiliary system assists the wireless terminal by acquiring information about the satellites'"'"' ephemerides, by partially processing it and by transmitting the partially processed information to the wireless terminal in a form that is useful to the wireless terminal. The wireless terminal then uses the partially processed information from the auxiliary system to assist the wireless terminal in acquiring the ranging signals from the navigation satellites quickly and when they are weak.

Claims

1. A wireless terminal comprising:

a telecommunications receiver for receiving a code synchronization estimate for a ranging signal from a satellite from an auxiliary system over a wireless telecommunications link; and

a field receiver for receiving and processing said ranging signal using said code synchronization estimate.

2. The wireless terminal of claim 1 wherein said telecommunications receiver also receives a Doppler shift estimate for said ranging signal from said auxiliary system, and wherein said field receiver uses said Doppler shift estimate in processing said ranging signal.

3. The wireless terminal of claim 1 wherein said telecommunications receiver also receives a modulation bit sequence for said ranging signal from said auxiliary system, and wherein said field receiver uses said modulation bit sequence in processing said ranging signal.

4. The wireless terminal of claim 1 wherein said telecommunications receiver also receives a system timing signal from said auxiliary system, and wherein said field receiver uses said system timing signal in processing said ranging signal.

5. The wireless terminal of claim 1 wherein said telecommunications receiver also receives a system timing signal from an independent timing source, and wherein said field receiver uses said system timing signal in processing said ranging signal.

6. The wireless terminal of claim 1 wherein said wireless terminal uses said code synchronization estimate and said ranging signal to determine a position of said wireless terminal.

7. The wireless terminal of claim 6 further comprising a telecommunications transmitter for transmitting said position of said wireless terminal to said auxiliary system.

8. The wireless terminal of claim 6 further comprising a visual display for conveying said position of said wireless terminal to a user of said wireless terminal.

9. The wireless terminal of claim 1 wherein said wireless terminal creates a partially processed ranging signal based on said synchronization estimate and said ranging signal;

and further comprising a telecommunications transmitter for transmitting said partially processed ranging signal to said auxiliary system.

10. The wireless terminal of claim 1 wherein said wireless terminal creates a ranging estimate based on said synchronization estimate and said ranging signal;

and further comprising a telecommunications transmitter for transmitting said ranging estimate to said auxiliary system.

11. The wireless terminal of claim 1 wherein said field receiver uses:

said code synchronization estimate to facilitate the creation of a candidate code;

said candidate code and said ranging signal to create a candidate sinusoidal signal; and

further comprising a discrete fourier transform of said candidate sinusoidal signal for determining when said candidate code is synchronized with said ranging signal.

12. A wireless terminal comprising:

a telecommunications receiver for receiving a modulation bit sequence for a ranging signal from a satellite from an auxiliary system over a wireless telecommunications link; and

a field receiver for receiving and processing said ranging signal using said modulation bit sequence.

13. The wireless terminal of claim 12 wherein said telecommunications receiver also receives a Doppler shift estimate for said ranging signal from said auxiliary system, and wherein said field receiver uses said Doppler shift estimate in processing said ranging signal.

14. The wireless terminal of claim 12 wherein said telecommunications receiver also receives a code synchronization estimate for said ranging signal from said auxiliary system, and wherein said field receiver uses said code synchronization estimate in processing said ranging signal.

15. The wireless terminal of claim 12 wherein said telecommunications receiver also receives a system timing signal from said auxiliary system, and wherein said field receiver uses said system timing signal in processing said ranging signal.

16. The wireless terminal of claim 12 wherein said telecommunications receiver also receives a system timing signal from an independent timing source, and wherein said field receiver uses said system timing signal in processing said ranging signal.

17. The wireless terminal of claim 12 wherein said wireless terminal uses said modulation bit sequence and said ranging signal to determine a position of said wireless terminal.

18. The wireless terminal of claim 17 further comprising a telecommunications transmitter for transmitting said position of said wireless terminal to said auxiliary system.

19. The wireless terminal of claim 17 further comprising a visual display for conveying said position of said wireless terminal to a user of said wireless terminal.

20. The wireless terminal of claim 12 wherein said wireless terminal creates a partially processed ranging signal based on said modulation bit sequence and said ranging signal;

and further comprising a telecommunications transmitter for transmitting said partially processed ranging signal to said auxiliary system.

21. The wireless terminal of claim 12 wherein said wireless terminal creates a ranging estimate based on said modulation bit sequence and said ranging signal;

and further comprising a telecommunications transmitter for transmitting said ranging estimate to said auxiliary system.

22. The wireless terminal of claim 12 wherein said field receiver uses:

a candidate code, said modulation bit sequence, and said ranging signal to create a candidate sinusoidal signal; and

further comprising a discrete fourier transform of said candidate sinusoidal signal for determining when said candidate code is synchronized with said ranging signal.

23. A method of operating a wireless terminal, said method comprising:

receiving a ranging signal from a satellite;

receiving a code synchronization estimate for said ranging signal from an auxiliary system; and

processing said ranging signal using said code synchronization estimate.

24. The method of claim 23 further comprising:

receiving a modulation bit sequence for said ranging signal from said auxiliary system; and

processing said ranging signal using said modulation bit sequence.

25. The method of claim 23 further comprising:

receiving a Doppler shift estimate for said ranging signal from said auxiliary system; and

processing said ranging signal using said Doppler shift estimate.

26. The method of claim 23 further comprising:

receiving from a system timing signal; and

processing said ranging signal using said system timing signal.

27. The method of claim 26 wherein said system timing signal is received from said auxiliary system.

28. The method of claim 26 wherein said system timing signal is received from an independent timing source.

29. The method of claim 23 further comprising determining a position of said wireless terminal based on said code synchronization estimate and said ranging signal.

30. The method of claim 29 further comprising transmitting said position of said wireless terminal to said auxiliary system.

31. The method of claim 29 further comprising visually displaying a position of said wireless terminal to a user of said wireless terminal.

32. The method of claim 23 further comprising:

creating a partially processed ranging signal based on said code synchronization estimate and said ranging signal; and

transmitting said partially processed ranging signal to said auxiliary system.

33. The method of claim 23 further comprising:

creating a ranging estimate based on said code synchronization estimate and said ranging signal; and

transmitting said ranging estimate to said auxiliary system.

34. The method of claim 23 further comprising:

creating a candidate code based on said code synchronization estimate;

creating a candidate sinusoidal signal based on said ranging signal and said candidate code; and

performing spectral analysis on said candidate sinusoidal signal to determine when said candidate code is synchronized with said ranging signal.

35. A method of operating a wireless terminal, said method comprising:

receiving a ranging signal from a satellite;

receiving a modulation bit sequence for said ranging signal from said auxiliary system; and

processing said ranging signal using said modulation bit sequence.

36. The method of claim 35 further comprising:

receiving a code synchronization estimate for said ranging signal from an auxiliary system; and

processing said ranging signal using said code synchronization estimate.

37. The method of claim 35 further comprising:

receiving a Doppler shift estimate for said ranging signal from said auxiliary system; and

processing said ranging signal using said Doppler shift estimate.

38. The method of claim 35 further comprising:

receiving from a system timing signal; and

processing said ranging signal using said system timing signal.

39. The method of claim 38 wherein said system timing signal is received from said auxiliary system.

40. The method of claim 38 wherein said system timing signal is received from an independent timing source.

41. The method of claim 35 further comprising determining a position of said wireless terminal based on said modulation bit sequence and said ranging signal.

42. The method of claim 41 further comprising transmitting said position of said wireless terminal to said auxiliary system.

43. The method of claim 41 further comprising visually displaying a position of said wireless terminal to a user of said wireless terminal.

44. The method of claim 35 further comprising:

creating a partially processed ranging signal based on said modulation bit sequence and said ranging signal; and

transmitting said partially processed ranging signal to said auxiliary system.

45. The method of claim 35 further comprising:

creating a ranging estimate based on said modulation bit sequence and said ranging signal; and

transmitting said ranging estimate to said auxiliary system.

46. The method of claim 35 further comprising:

creating a candidate sinusoidal signal based on said ranging signal and a candidate code; and

performing spectral analysis on said candidate sinusoidal signal to determine when said candidate code is synchronized with said ranging signal.