Multi-function device with positioning system and shared processor

• US 20050231424A1
• Filed: 02/07/2005
• Published: 10/20/2005
• Est. Priority Date: 11/01/2002
• Status: Active Grant

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Van Roy, Benjamin, Bloebaum, Scott, Chou, Andrew
• Granted Patent: US 7,212,156 B2
• Time in Patent Office: Days
• US Class Current: 342/357.770
• CPC Class Codes: G01S 19/25 involving aiding data received from a cooperating element, e.g. assisted GPS
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: H04B 1/7102 with transform to frequency domain
• CPC Class Codes: H04B 2201/70715 with application-specific features

Abstract

A multi-function device with a positioning function and a real time positioning engine is disclosed. The device contains also a shared processor used by the positioning function and other functions of the device, such as a mobile radio-communication function. The positioning engine performs in real time the most computational intensive calculations of the positioning function, such as downsampling, Doppler mixing and correlation calculations. Since the received signal need not be stored, the memory requirements of the positioning function are significantly reduced if aiding data is available.

Claims

1. A multi-function device receiving a positioning signal, comprising:

a positioning engine that performs real-time calculations with said positioning signal;

a memory for storing in real time a plurality of positioning engine results generated by said positioning engine; and

a shared processor that processes said positioning engine results and generates positioning information.

2. The device of claim 1, wherein said device further performs a radio-communication function and said shared processor further performs calculations for said radio-communication function.

3. The device of claim 1, wherein said positioning engine comprises a fast fourier engine that calculates a plurality of correlation values.

4. The device of claim 2, wherein said positioning engine comprises a fast fourier engine that calculates a plurality of correlation values.

5. The device of claim 1, wherein said memory is contained in said positioning engine.

6. The device of claim 1, wherein said memory is external to said positioning engine.

7. The device of claim 2, wherein said memory is shared with said radio-communication function.

8. The device of claim 1, wherein said positioning engine accumulates a plurality of periods of a rotated signal.

9. The device of claim 8, further comprising a fast fourier engine.

10. The device of claim 2, wherein said positioning engine accumulates a plurality of periods of a rotated signal and further comprises a fast fourier engine.

11. The device of claim 1, wherein said real-time calculations are performed for a plurality of source-doppler pairs each processed in one timeslot from a plurality of consecutive timeslots.

12. The device of claim 1, wherein said positioning engine results are associated with a plurality of source-doppler pairs and said shared processor allocates a memory block for each source-doppler pair to store said positioning engine results.

13. The device of claim 2, wherein said positioning engine results are associated with a plurality of source-doppler pairs and said shared processor allocates a memory block for each source-doppler pair to store said positioning engine results.

14. The device of claim 1, wherein the device performs a direct memory access function.

15. The device of claim 1, wherein said positioning engine comprises a direct memory access controller.

16. The device of claim 1, wherein:

said positioning engine comprises a fast fourier engine that calculates a plurality of correlation values; and

said real-time calculations are performed for a plurality of source-doppler pairs each processed in one timeslot from a plurality of consecutive timeslots.

17. The device of claim 16, wherein said device further performs a radio-communication function and said shared processor further performs calculations for said radio-communication function.

18. The device of claim 2, wherein said device receives aiding data for reducing a code-phase search range and a Doppler search range.

19. The device of claim 18, wherein said positioning engine further comprises a direct memory access controller.

20. The device of claim 18, wherein:

said positioning engine comprises a fast fourier engine that calculates a plurality of correlation values; and

said real-time calculations are performed for a plurality of source-doppler pairs each processed in one timeslot from a plurality of consecutive timeslots.

21. The device of claim 20, wherein said positioning engine further comprises a direct memory access controller.

22. The device of claim 3, wherein a sequence of correlation values from said plurality of correlation values corresponding to a selected source-doppler pair are coherently combined into a plurality of refined correlation values associated with a plurality of refined doppler frequencies.

23. The device of claim 22, wherein said coherently combining is performed by said fast fourier engine.

24. The device of claim 4, wherein a sequence of correlation values from said plurality of correlation values corresponding to a selected source-doppler pair are coherently combined into a plurality of refined correlation values associated with a plurality of refined doppler frequencies.

25. The device of claim 24, wherein said coherently combining is performed by said fast fourier engine.

26. The device of claim 1, wherein said positioning engine comprises a downsampler for converting the positioning signal from an intermediate frequency to baseband.

27. The device of claim 1, wherein said positioning engine stores a plurality of frequencies to be excluded from a calculation of a plurality of correlation values.

28. The device of the previous claim, wherein said frequencies to be excluded are obtained by a narrowband noise detection method.

29. The device of claim 28, wherein said narrowband noise detection method comprises the step of calculating a fast fourier transform of a plurality of signal segments.

30. The device of claim 28, wherein said positioning engine comprises a fast fourier engine that calculates the fourier transform of a plurality of signal segments for estimating said plurality of frequencies to be excluded.

31. The device of claim 30, wherein said device further performs a radio-communication function and said shared processor further performs calculations for said radio-communication function.

32. A positioning engine to process a received positioning signal in real time, said positioning engine comprising:

a downsampler to convert said received positioning signal from an intermediate frequency, to yield a baseband signal;

a fast fourier engine to calculate a plurality of correlation values.

33. The device of claim 32, further comprising registers for storing a plurality of frequencies to be excluded from a correlation calculation.

34. The device of claim 32, further comprising a direct memory access controller for writing said plurality of correlation values to a memory in real time.

35. The device of claim 34, wherein a plurality of source-doppler pairs are processed sequentially by allocating one timeslot to each source-doppler pair.

36. The device of claim 35, further comprising registers for storing a plurality of frequencies to be excluded from a correlation calculation.

37. The device of claim 32, further comprising means for rotating and accumulating said baseband signal.

38. The device of claim 32, wherein a plurality of source-doppler pairs are processed sequentially by allocating one timeslot to each source-doppler pair.

39. A method to calculate a location, comprising:

allocating a plurality of memory blocks for a plurality of source-doppler pairs;

correlating in real time a plurality of primitive segments with a plurality of reference signals to yield a plurality of primitive correlation values;

writing in real time said primitive correlation values to said memory blocks;

processing said primitive correlation values to calculate positioning information;

estimating location information based on said positioning information.

40. The method of claim 39, further comprising the step of transmitting said positioning information to a server.

41. The method of claim 39, wherein said estimating is performed at a server.

42. The method of claim 39, further comprising the step of receiving aiding data.

43. The method of claim 39, further comprising the step of excluding a plurality of frequencies from said correlating.

44. The method of claim 39, further comprising the step of coherently combining said primitive correlation values to yield a plurality of refined correlation values associated to a plurality of refined doppler frequencies.

45. The method of claim 40, further comprising the step of coherently combining said primitive correlation values to yield a plurality of refined correlation values associated to a plurality of refined doppler frequencies.

46. A method to mitigate the effects of narrowband noise in a received positioning signal comprising:

calculating fast fourier transforms of a plurality of received signal segments;

combining said fast fourier transforms to generate a fourier transform of an extended segment obtained by combining said plurality of received signal segments;

collapsing the power spectrum of said fourier transform of said extended segment onto the spectral lines of a reference code, to yield a collapsed power spectrum;

comparing said collapsed spectrum to a threshold, to yield a plurality of frequencies to be excluded from a correlation calculation.

47. A method to mitigate the effects of narrowband noise in a received positioning signal comprising:

calculating a fourier transform of an extended signal segment extracted from said received positioning signal;

collapsing the power spectrum of said fourier transform onto the spectral lines of a reference code, to yield a collapsed power spectrum;

comparing said collapsed spectrum to a threshold, to yield a plurality of frequencies;

excluding said plurality of frequencies from a correlation calculation of said received positioning signal with said reference code.

48. The method of claim 47, wherein said plurality of frequencies to be excluded is stored in a plurality of memory registers.

49. The method of claim 47, wherein said calculating comprises the steps of:

decomposing said extended signal segment into a plurality of signal chunks;

calculating fast fourier transforms of said plurality of signal chunks;

combining said fast fourier transforms to generate said fourier transform of said extended signal segment.

50. A multi-function device comprising:

means for receiving a positioning signal;

means for performing real-time correlations with said positioning signal;

means for storing the results of said real-time correlations; and

means for calculating positioning information based on said results of said real-time correlations.

51. The device of claim 50, further comprising means for performing a radio-communication function.

52. The device of claim 51 further performing the step of receiving aiding data.

53. The device of claim 51 further comprising means for obtaining aiding data.

54. The device of claim 51 further performing the step of transmitting said positioning information to a server.

55. A device to process a received positioning signal in real time comprising:

means for downsampling said positioning signal from an intermediate frequency, to yield a baseband signal;

means for mixing and accumulating said baseband signal, to yield an accumulated signal;

means for correlating said accumulated signal with a reference signal, to yield a plurality of correlation values;

means for writing said plurality of correlation values to a memory.

56. The device of claim 55, further comprising means to store a plurality of frequencies to be excluded from a correlation calculation.