CHANNEL IMPULSE RESPONSE ESTIMATION

• US 20080281523A1
• Filed: 06/21/2007
• Published: 11/13/2008
• Est. Priority Date: 12/21/2004
• Status: Active Grant

• Current Assignee: Elliptic Laboratories AS
• Original Assignee: Universitetet I Oslo (Kunnskapsdepartementet)
• Inventors: Dahl, Tobias, Eggen, Gudbrand
• Granted Patent: US 7,768,876 B2
• Time in Patent Office: Days
• US Class Current: 702/5
• CPC Class Codes: G01S 15/06 Systems determining the position data of a target
• CPC Class Codes: G01S 15/89 for mapping or imaging
• CPC Class Codes: H04L 25/0212 of impulse response
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0244 with inversion

Abstract

A method of estimating the impulse response of a channel is disclosed. The method includes transmitting an impulse signal to the channel, detecting a received signal from the channel, and calculating an estimate of the impulse response of the channel by applying a calculated inverse matrix of the impulse signal to the received signal.

Claims

1. A method of estimating the impulse response of a channel, the method comprising transmitting an impulse signal to the channel, detecting a received signal from the channel and calculating an estimate of the impulse response of the channel by applying a calculated inverse matrix of the impulse signal to the received signal.

4. The method as claimed in claim 1, comprising transmitting the impulse signal in a continuing manner.

5. The method as claimed in claim 4, comprising transmitting the impulse signal continuously or continually.

6. The method as claimed in claim 1, further comprising calculating the inverse matrix.

7. The method as claimed in claim 1, wherein the calculated inverse matrix comprises a ridge inverse matrix.

8. The method as claimed in claim 1, wherein the calculated inverse matrix comprises a Moore-Penrose inverse matrix.

9. The method as claimed in claim 1, wherein the impulse is an acoustic impulse.

10. The method as claimed in claim 9 wherein the impulse is an ultrasonic impulse.

11. The method as claimed in claim 10 wherein the center of the bandwidth of the impulse is between 20 and 50 kHz.

12. The method as claimed in claim 1, further comprising sampling the received signal using a sliding window.

13. The method as claimed in claim 1, further comprising generating the impulse signal from a non-repeating code.

14. The method as claimed in claim 1, further comprising generating the impulse signal from a code having at least some respective portions linearly independent of one another.

15. The method as claimed in claim 1, wherein the impulse signal comprises white noise.

16. The method as claimed in claim 1, further comprising calculating the inverse matrix prior to transmitting the impulse signal.

17. The method as claimed in claim 1, further comprising limiting the bandwidth of the impulse signal to a fraction of the bandwidth of the transmitter and receiver subsystem.

18. The method as claimed in claim 1, further comprising calculating a subset of rows and/or columns of the inverse matrix and interpolating between the subset to complete the calculated inverse matrix.

19. The method as claimed in claim 1, wherein the calculated inverse matrix comprises a pair of matrices derived from a subset of a singular value decomposition of the impulse signal matrix, the method further comprising multiplying the pair of matrices by a vector containing samples of the received signal.

20. The method as claimed in claim 19, further comprising selecting a subset of samples of the received signal to produce a subset vector and multiplying the pair of matrices by the subset vector.

21. The method as claimed in claim 1, further comprising constructing a position diagram based on an estimated channel response resulting from of the applying of the calculated inverse matrix of the impulse signal to the return signal.

22. The method as claimed claim 1, further comprising driving a plurality of transmitters by respective signals from the same frequency band, and separating the received signals at a receiver.

23. The method as claimed in claim 1, further comprising combining a plurality of estimated channel responses using ellipse or ellipsoid intersection.

24. The method as claimed in claim 1, further comprising sampling the impulse signal and the received response signal at the same rate.

50. A computer readable medium comprising instructions, which, when executed, cause a computer to perform the method of claim 1.

2. A method of mapping an environment, the method comprising transmitting an impulse signal into the environment, detecting a return signal from the environment and applying a calculated inverse matrix of the impulse signal to the return signal.

3. A method of tracking an object, the method comprising transmitting an impulse signal, recording a reflection of the impulse signal from the object and applying a calculated inverse matrix of the impulse signal to the reflected signal.

25. An apparatus configured to estimate a channel response, the apparatus comprising transmission means, receiving means and processing means wherein the processing means is configured to apply a calculated inverse matrix of an impulse signal transmitted by the transmission means to a signal received by the receiving means.

28. The apparatus as claimed in claim 25, wherein the transmitting means is configured to transmit the impulse signal in a continuing manner.

29. The apparatus as claimed in claim 28 wherein the transmitting means is configured to transmit the impulse signal continuously or continually.

30. The apparatus as claimed in claim 25, further comprising means for calculating the inverse matrix.

31. The apparatus as claimed in claim 25, wherein the calculated inverse matrix comprises a ridge inverse matrix.

32. The apparatus as claimed in claim 25, wherein the calculated inverse matrix comprises a Moore-Penrose inverse matrix.

33. The apparatus as claimed in claim 25, further comprising means for generating an acoustic impulse.

34. The apparatus as claimed in claim 33 wherein the impulse is ultrasonic.

35. The apparatus as claimed in claim 28 wherein the center of the bandwidth of the impulse is between 20 and 50 kHz.

36. The apparatus as claimed in claim 25, further comprising means for sampling the received signal using a sliding window.

37. The apparatus as claimed in claim 25, further comprising means for generating the impulse signal from a non-repeating code.

38. The apparatus as claimed in claim 25, further comprising means for generating the impulse signal from a code having at least some respective portions linearly independent of one another.

39. The apparatus as claimed in claim 25, wherein the impulse signal comprises substantially white noise.

40. The apparatus as claimed in claim 25, configured to calculate the inverse matrix prior to transmitting the impulse signal.

41. The apparatus as claimed in claim 25, further comprising means for generating the impulse signal with a bandwidth which is a fraction of the bandwidth of the transmitter and receiver subsystem.

42. The apparatus as claimed in claim 25, further comprising means for selecting a subset of rows and/or columns of the inverse matrix to calculate.

43. The apparatus as claimed in claim 42 comprising means for interpolating between the subset of rows and/or columns in the calculated inverse matrix.

44. The apparatus as claimed in claim 25, further comprising means for decomposing the calculated inverse matrix into a pair of matrices derived from a subset of a singular value decomposition of the impulse signal matrix.

45. The apparatus as claimed in claim 44, further comprising means for selecting a subset of samples of the received signal to produce a subset vector and multiplying the pair of matrices by the subset vector.

46. The apparatus as claimed in claim 25, further comprising means for constructing a position diagram based on an estimated channel response resulting from applying the calculated inverse matrix of the impulse signal to the return signal.

47. The apparatus as claimed in claim 25, further comprising a plurality of transmitters configured to be driven by respective signals from the same frequency band;

the receiver being configured to separate the respective received signals.

48. The apparatus as claimed in claim 25, further comprising means for combining a plurality of estimated channel responses using ellipse or ellipsoid intersection.

49. The apparatus as claimed in claim 25, further comprising means for sampling the impulse signal and the received response signal at the same rate.

26. A tracking apparatus comprising transmission means, receiving means and processing means wherein the processing means is configured to apply a calculated inverse matrix of an impulse signal transmitted by the transmission means to a signal received by the receiving means.

27. A mapping apparatus configured to map an environment, the apparatus comprising means for transmitting an impulse signal into the environment, means for detecting a return signal from the environment and applying a calculated inverse matrix of the impulse signal to the return signal.

51. A computer readable medium comprising instructions, which, when executed, cause a computer to perform a method, the method comprising estimating the impulse response of a channel by applying a calculated inverse matrix of a matrix representing a transmitted signal to a plurality of samples of a received response signal.

52. A computer readable medium comprising instructions, which, when executed, cause a computer to perform a method, the method comprising mapping an environment by applying a calculated inverse matrix of an impulse signal transmitted into the environment to a return signal from the environment, and calculating a representation of the environment from the return signal.

53. A computer readable medium comprising instructions, which, when executed, cause the computer to perform a method, the method comprising tracking an object by applying a calculated inverse matrix of an impulse signal transmitted towards the object to a return signal reflected from the object;

and means for calculating a location of the object from the return signal.