System and method for positioning

• US 8,184,504 B2
• Filed: 03/27/2008
• Issued: 05/22/2012
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: EPOS Development Limited (Qualcomm, Inc.)
• Inventors: Altman, Nathan, Agassy, Meir
• Primary Examiner(s): PIHULIC, DANIEL T
• Application Number:
  US12/532,862
• Publication Number:
  US 20100085838A1
• Time in Patent Office: 1,517 Days
• Field of Search: 367/124, 367/128
• US Class Current: 367/124
• CPC Class Codes: G01S 11/08 using synchronised clocks
• CPC Class Codes: G01S 11/14 using ultrasonic, sonic, or infrasonic waves
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0273 using multipath or indirect path propagation signals in position determination
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G01S 5/30 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G06F 3/043 using propagating acoustic waves

Abstract

A system for small space positioning comprises a transmitting device, movable within an approximate range, configured for transmitting a modulated continuous wave, wherein the modulated continuous wave includes a carrier signal and a base-band signal, and a receiving unit configured for receiving signal (s) transmitted by the transmitting device and for determining a position of the transmitting device within the approximate range based on analysis of both the carrier signal and the base-band signal received from the transmitting device.

Claims

1. A system for small space positioning comprising:

a transmitting device, movable within an approximate range, configured for transmitting a modulated continuous wave, wherein the modulated continuous wave is an ultrasound wave and wherein the modulated continuous wave includes a carrier signal and a base-band signal; and

a receiving unit configured for receiving signal(s) transmitted by the transmitting device and for determining a position of the transmitting device within the approximate range based on analysis of both the carrier signal and the base-band signal received from the transmitting device wherein the analysis of the base-band signal provides determining a position with accuracy in the order of magnitude of a wavelength of the carrier signal and analysis of the carrier signal provides improving accuracy of the position within the determined wavelength.

2. The system according to claim 1 wherein the analysis of both the carrier signal and the base-band signal includes phase analysis of the carrier signal.

3. The system according to claim 1 wherein the receiving unit includes a detector, wherein the detector is configured for performing correlation between a modulated continuous wave received by the receiving unit and an expected modulated continuous wave.

4. The system according to claim 3 wherein the modulated continuous wave is pre-determined and the expected modulated continuous wave is a replica of the modulated continuous wave transmitted by the transmitting device.

5. The system according to claim 3 wherein the receiving unit is configured for determining base-band and carrier signal correlation curves from the correlation between the received modulated continuous wave and the expected modulated continuous wave.

6. The system according to claim 5, wherein the correlation curves include absolute and real correlation curves and wherein the receiving unit is configured for determining at least one peak in the absolute correlation curve and at least one peak in the real correlation curve.

7. The system according to claim 6, wherein the receiving unit includes at least one receiver and the receiving unit is configured for determining a line of sight distance between the transmitting device and the at least one receiver.

8. The system according to claim 7 wherein a peak in the absolute correlation curve substantially aligned with a peak in the real correlation curves corresponds to a most likely line of sight distance between the at least one receiver and the transmitting device.

9. The system according to claim 8 comprising an ambiguity resolver configured to select at least one peak from a plurality of peaks in the real correlation curve.

10. The system according to claim 9 wherein the plurality of peaks are obtained from a received signal including several delayed signals whose correlation curves super-impose on each other.

11. The system according to claim 8, comprising an ambiguity resolver, wherein the ambiguity resolver is configured to identify a peak from a plurality of peaks that is closest to the peak of the absolute correlation curve or to decide that there is no suitable peak from the plurality of peaks.

12. The system according to claim 9, wherein the ambiguity resolver is configured to identify a peak from the plurality of peaks that is closest to a rising energy in the absolute correlation curve.

13. The system according to claim 9, wherein the ambiguity resolver is configured to identify a peak from the plurality of peaks based at least one of:

history tracking of peaks, velocity tracking of peaks over time, and acceleration tracking of peaks over time.

14. The system according claim 9, wherein the ambiguity resolver is configured to compare possible line of sight distances calculated from different receivers.

15. The system according to claim 9, wherein the ambiguity resolver is configured to determine a minimum variance or a maximum likelihood of a superimposed wave fitting the received modulated continuous wave.

16. The system according to claim 9, wherein the ambiguity resolver is configured to identify a peak from the plurality of peaks based on a score assigned to at least a portion of the plurality of peaks, wherein the score is based on values of one or more pre-defined parameters calculated by the ambiguity resolver.

17. The system according to claim 1, wherein the base-band signal is different from a base-band signal used in another same system.

18. The system according to claim 17 wherein the receiving unit is configured to distinguish between a modulated signal with a carrier frequency transmitted from the transmitting device of the system and other transmitting devices based on the base-band signal.

19. The system according to claim 1, wherein the receiving unit is configured to store at least one calibration parameter configured for adjusting the expected modulated continuous wave based on transfer function of the system.

20. The system according to claim 1, wherein the modulated continuous wave is an acoustic wave.

21. The system according to claim 1, wherein the modulated continuous wave is an ultrasound wave within the range of 20-100 KHz configured for penetrating through a media other than air.

22. The system according to claim 1, wherein the frequency of the carrier signal is in the same order of magnitude as that of a base-band signal of the modulated continuous wave.

23. The system according to claim 1, wherein the transmitting device is further configured for transmitting a synchronization signal and wherein the synchronization signal defines the start of a time of flight delay.

24. A method for small space positioning comprising:

transmitting a modulated continuous wave from a transmitting device, wherein the modulated continuous wave includes a carrier signal and a base-band signal;

wherein the modulated continuous wave is an ultrasound wave and receiving signals transmitted by the transmitting device with receivers positioned at a predefined distance from each other; and

determining a position of the transmitting device within the approximate range based on analysis of both the carrier signal and the base-band signal received from the transmitting device, wherein one of the transmitting device and receivers is movable within an approximate range and the other is positioned at a predefined location and, wherein the analysis of the base-band signal provides determining a position with accuracy in the order of magnitude of a wavelength of the carrier signal and analysis of the carrier signal provides improving accuracy of the position within the determined wavelength.

25. The method according to claim 24 wherein the analysis of both the carrier signal and the base-band signal includes phase analysis of the carrier signal.

26. The method according to claim 24, comprising performing correlation between a modulated continuous wave received by the receiving unit and an expected modulated continuous wave.

27. The method according to claim 26 wherein the modulated continuous wave is pre-determined and the expected modulated continuous wave is a replica of the modulated continuous wave transmitted.

28. The method according to claim 26 comprising determining an absolute correlation curve and real correlation curve from the correlation between the received modulated continuous wave and the expected modulated continuous wave.

29. The method according to claim 28 comprising determining a peak in the absolute correlation curve and a peak in the real correlation curve.

30. The method according to claim 24 comprising determining a line of sight distance between the transmitting device and at least one of the receivers.

31. The method according to claim 26, comprising determining an absolute correlation curve and a real correlation curve from the correlation, wherein a peak in the absolute correlation curve substantially aligned with a peak in the real correlation curve corresponds to a most likely line of sight distance between at least one of the receivers and the transmitting device.

32. The method according to claim 31 comprising selecting the peak from a plurality of peaks in the real correlation curve.

33. The method according to claim 32, wherein the plurality of peaks are obtained from a received signal including several delayed signals whose correlation curves super-impose on each other.

34. The method according to claim 32 comprising identifying a peak from the plurality of peaks that is closest to the peak of the absolute cross-correlation curve.

35. The method according to claim 32 comprising identifying a peak from the plurality of peaks that is closest to a rising energy in the absolute correlation curve.

36. The method according to claim 32 comprising identifying a peak from the plurality of peaks based on at least one of history tracking of determined line of sight distances, velocity tracking of peaks over time, and acceleration tracking of peaks over time.

37. The method according to claim 32 comprising comparing possible line of sight distances calculated from different receivers.

38. The method according to claim 32 comprising determining a minimum variance or a maximum likelihood of a superimposed wave fitting the received modulated continuous wave.

39. The method according to claim 32 comprising identifying a peak from the plurality of peaks based on a score assigned to at least a portion of the plurality of peaks.

40. The method according to claim 39 wherein the score is based on calculated values of one or more pre-defined parameters.

41. The method according to claim 24 and comprising distinguishing between signals transmitted from different transmitting devices, wherein the distinguishing is based on comparing an expected base-band signal with a received base-band signal.

42. The method according to claim 26 comprising adjusting a template of the expected modulated continuous wave on the fly.

43. The method according to claim 24 wherein the modulated continuous wave is an acoustic wave.

44. The method according to claim 24, wherein the modulated continuous wave is an ultrasound wave within the range of 20-100 KHz.

45. The method according to claim 24 wherein the frequency of the carrier signal is in the same order of magnitude as that of a base-band signal of the modulated continuous wave.

46. The method according to claim 24 comprising transmitting a synchronization signal, wherein the synchronization signal defines the start of a time of flight delay.

47. The method according to claim 28 wherein the expected signal includes a super-imposed multi-path signal with at least one known characteristic, wherein the at least one known characteristic is selected from a group including:

multi-path signal delay and multi-path signal amplitude.