System and method for determining position of radar apparatus based on reflected signals

• US 7,468,689 B2
• Filed: 06/28/2005
• Issued: 12/23/2008
• Est. Priority Date: 06/28/2004
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ma, Yugang, Sun, Xiaobing, Xu, Jin, Okada, Kanzo
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Chen, Shelley
• Application Number:
  US11/169,119
• Publication Number:
  US 20080218404A1
• Time in Patent Office: 1,274 Days
• Field of Search: 342/146
• US Class Current: 342/146
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/06 Systems determining position data of a target

Abstract

A system and method for determining position of, for example, a robot based on reflected signals comprises a transmitter for transmitting signals in a number of directions within a range of directions and a receiver for receiving echoes of the signals from any direction in the range. The transmitter has a first rotatable antenna and the receiver has a second rotatable antenna which is mechanically couplable to the second antenna. The received echoes are processed by a processor to derive echo data signals indicative of the distance of the system to one or more reflective surfaces and the direction of the reflective surface(s) relative to the system. The processor is arranged to determine the position of the system relative to a starting position from the derived echo data signals indicative of the distance of the system to the reflective surface(s) and the direction of the reflective surface(s) relative to the system.

Claims

1. A system comprising:

a transmitter for transmitting signals in a number of directions within a range of directions;

wherein the transmitter comprises a first rotatable antenna;

a receiver for receiving echoes of the signals from any direction in the range;

wherein the receiver comprises a second rotatable antenna, the first antenna being mechanically couplable to the second antenna; and

a processor for processing the received echoes to derive echo data signals indicative of the distance of the system to one or more reflective surfaces and the direction of the one or more reflective surfaces relative to the system;

wherein the processor is arranged to determine the position of the system relative to a starting position from the derived echo data signals indicative of the distance of the system to one or more of the one or more reflective surfaces and the direction of the one or more of the one or more reflective surfaces relative to the system,

wherein the circle of rotation of the first rotatable antennae and the circle of rotation of the second ratatable antennae are divided into a same plurality of sectors,

wherein the first rotatable antennae sequentially generates a pulse of signals in each of the plurality of sectors,

wherein when the system is at a position other than an origin, the origin being a position at which directions and delays of major reflections detected in one rotation of the first antenna and the second antenna are estimated and recorded, the distance of the system to one or more reflective surfaces is calculated using a known direction that has been estimated at the origin.

2. A system according to claim 1,

wherein the processor further comprises a storage means for storing data indicative of the distances and directions of the system relative to one or more of the one or more reflective surfaces.

3. A system according to claim 1,

wherein the processor being arranged to process the received echoes in each sector sequentially.

4. A system according to claim 1,

wherein the receiver comprises an envelope detection stage for detecting an envelope of waveforms corresponding to each of the received echo signals.

5. A system according to claim 4, wherein the receiver further comprises an amplitude threshold stage couplable to the envelope receiving stage and arranged to slice the envelope of each waveform corresponding to each of the received echo signals at a reference level relative to an average level of the received echo signals in a selected sector of rotation of the first antennae and the second antennae.

6. A system according to claim 5,

wherein the receiver further comprises a first filter couplable to the amplitude threshold stage for filtering in the time domain each sliced waveform.

7. A system according to claim 6,

wherein the receiver further comprises a second filter couplable to the first filter to filter in the space domain each sliced waveform filtered in the time domain and to group in the space domain the reflected signals according to the reflective surface from which each signal was reflected, the second filter having an output.

8. A system according to claim 7,

wherein the receiver further comprises a Gaussian fitting stage for determining a Gaussian function fitting the space domain filtered and outputted from the second filter.

9. A system according to claim 8,

wherein the Gaussian fitting stage determines a Gaussian function fitting the space domain filtered and outputted from the second filter using a least squares method.

10. A system according to claim 8,

the receiver further comprising a peak determination stage couplable to the Gaussian fitting stage to determine a peak of the Gaussian function corresponding to the direction of the one or more of the one or more reflective surfaces relative to the system.

11. A system according to claim 10,

the receiver further comprising a time measuring stage for measuring time taken from transmission of a signal by the transmitter to reception of an echo signal received by the receiver corresponding to the transmitted signal to determine a distance indicative of the distance of the system to a reflective surface from which the received echo signal is reflected.

12. A system according to claim 1,

wherein the transmitted signals comprise any one or more of ultrawide band signals, radio frequency signals, ultrasound, or infrared.

13. A system according to claim 1,

wherein the first and/or the second antenna comprises a directional antenna.

14. A system according to claim 13,

wherein the first antennae and/or the second antennae comprise one or more mechanically rotatable antennae each having an associated beam pattern gain associated with a beam pattern,

the system further comprising one or more electrically rotatable antennae,

wherein the one or more electrically rotatable antennae are arranged to be rotatable by varying the gain of the beam patterns of the one or more mechanically rotatable antennae.

31. The system according to claim 1, wherein the one or more reflective surfaces are located within a positioning area.

32. The system according to claim 31, wherein the positioning area has a fixed peripheral shape in a first plane, the first and second antennae being rotatable in the first plane.

33. The system according to claim 32 wherein the positioning area has a polygonal peripheral shape in the first plane.

34. The system according to claim 33, wherein the processor further comprises an origin determining stage for determining an origin position for the system.

35. The system according to claim 34, wherein the processor is further arranged to determine if two or more reflected echo signals have maintained their directions relative to the system.

36. The system according to claim 35, wherein the processor is further arranged to select a pair of the two or more reflected echo signals determined to have maintained their directions relative to the system as determined at the origin position.

37. The system according to claim 36, wherein the selected pair of the two or more reflected echo signals differ in their directions by at least π

/4.

38. The system according to claim 36, wherein the processor is arranged to determine a change in distance of the system from the reflective surfaces causing the reflected echo signals of the selected pair.

39. The system according to claim 38, wherein the processor is arranged to determine the position of the system relative to the origin based on the determined change in distance of the system from the reflective surfaces.

40. The system according to claim 35, wherein the processor is arranged to select any two or more pairs of the two or more reflected echo signals which have been determined to have maintained their directions relative to the system, and determining the position of the system relative to the origin based on an average of the position determined from each pair.

41. The system according to claim 34, wherein the processor is arranged to determine if any of the one or more reflective surfaces have not changed their direction relative to the system from the direction measured at the origin position, and if it is determined that none of the one or more reflective surfaces has not changed its direction the processor is arranged to determine the position of the system based on the change in the distance(s) of the one or more reflective surfaces from a previously measured position.

42. The system according to claim 41, wherein the processor is arranged to select a pair of reflected echo signals determined not to have changed their directions relative to the system as determined at the previously measured position.

43. The system according to claim 42, wherein the selected pair of the two or more reflected echo signals differ in their directions by at least ≧

π

/4.

44. The system according to claim 41, wherein the processor is arranged to determine a change in distance of the system from the reflective surfaces causing the reflected echo signals of the selected pair.

45. The system according to claim 44, wherein the processor is arranged to determine the position of the system relative to the previously measured position based on the determined change in distance of the system from the reflective surfaces.

46. The system according to claim 41, wherein the processor is arranged to select any two or more pairs of the two or more reflected echo signals which have been determined to have maintained their directions relative to the system at the previously measured position, and determining the position of the system relative to the origin based on an average of the position determined from each pair.

47. The system according to claim 41, wherein the processor is arranged to determine the position of the system relative to the origin by adding the changes in position determined from a previously measured position to the position determined previously.

15. A method for determining the position of a system comprising:

transmitting signals in a number of directions within a range of directions using a transmitter comprising a first rotatable antenna;

receiving echoes of the signals from any direction in the range using a receiver;

wherein the receiver comprises a second rotatable antenna, the first antenna being mechanically couplable to the second antenna; and

processing the received echoes to derive echo data signals indicative of the distance of the system to one or more reflective surfaces and the direction of the one or more reflective surfaces relative to the system;

wherein the step of processing comprises determining the position of the system relative to a starting position from the derived echo data signals indicative of the distance of the system to one or more of the one or more reflective surfaces and the direction of the one or more of the one or more reflective surfaces relative to the system,

wherein the circle of rotation of the first rotatable antennae and the circle of rotation of the second ratatable antennae are divided into a same plurality of sectors,

wherein the first rotatable antennae sequentially generates a pulse of signals in each of the plurality of sectors,

wherein when the system is at a position other than an origin, the origin being a position at which directions and delays of major reflections detected in one rotation of the first antenna and the second antenna are estimated and recorded, the distance of the system to one or more reflective surfaces is calculated using a known direction that has been estimated at the origin.

16. A method according to claim 15,

wherein the processing step further comprises storing data indicative of the distances and directions of the system relative to one or more of the one or more reflective surfaces.

17. A method according to claim 15,

further comprising processing the received echoes in each sector sequentially.

18. A method according to claim 15,

wherein the processing step further comprises detecting in the receiver an envelope of waveforms corresponding to each of the received echo signals.

19. A method according to claim 15,

wherein the processing step further comprises slicing in an amplitude threshold stage in the receiver the envelope of each waveform corresponding to each of the received echo signals at a reference level relative to an average level of the received echo signals in a selected sector of rotation of the first and second antennae.

20. A method according to claim 19,

wherein the processing step further comprises filtering in the time domain each sliced waveform using a first filter.

21. A method according to claim 20,

wherein the processing step further comprises filtering using a second filter in the space domain each sliced waveform filtered in the time domain and grouping in the space domain the reflected signals according to the reflective surface from which each signal was reflected, the filter having an output.

22. A method according to claim 21,

wherein the processing step further comprises determining a Gaussian function fitting the space domain filtered and outputted from the filter.

23. A method according to claim 22,

wherein the Gaussian function determination step comprises determining a Gaussian function fitting the space domain filtered and outputted from the filter using a least squares method.

24. A method according claim 22,

wherein the processing step further comprises determining a peak of the Gaussian function corresponding to the direction of one or more of the one or more reflective surfaces relative to the system whose position is being determined.

25. A method according to claim 24,

wherein the processing step further comprises measuring time taken from transmission of a signal by the transmitter to reception of an echo signal received by the receiver corresponding to the transmitted signal to determine a distance indicative of the distance of the system to a reflective surface from which the received echo signal is reflected.

26. A method according to claim 15,

wherein the transmitting step comprises transmitting signals comprised of any one or more of ultrawide band signals, radio frequency signals, ultrasound, or infrared.

27. A method according claim 15,

wherein the transmitting step comprises transmitting signals from a directional antenna.

28. A method according to claim 15,

wherein the receiving step comprises receiving signals using a directional antenna.

29. A method according to claim 27,

wherein the transmitting step comprises transmitting signals from one or more mechanically rotatable antennae each having an associated beam pattern gain associated with a beam pattern,

the transmitting step further comprising transmitting signals from one or more electrically rotatable antennae by varying the gain of the beam patterns of the one or more mechanically rotatable antennae.

30. A method according to claim 27,

wherein the receiving step comprises receiving signals using one or more mechanically rotatable antennae each having an associated beam pattern gain associated with a beam pattern,

the receiving step further comprising receiving signals using one or more electrically rotatable antennae by varying the gain of the beam patterns of the one or more mechanically rotatable antennae.

48. The method according to claim 15, wherein the one or more reflective surfaces are located within a positioning area having a peripheral shape in a first plane, the first and second antennae being rotatable in the first plane, the processing step further comprising determining an origin position for the system whose position is to be determined.

49. The method according to claim 48, wherein the positioning area has a polygonal peripheral shape in the first plane, and wherein the processing step further comprises determining if two or more reflected echo signals have maintained their directions relative to the system whose position is to be measured.

50. The method according to claim 49, wherein the processing step further comprises selecting a pair of the two or more reflected echo signals determined to have maintained their directions relative to the system as determined at the origin position.

51. The method according to claim 50, wherein selecting step comprises selecting a pair of the two or more reflected echo signals which differ in their directions by at least π

/4.

52. The method according to claim 50, wherein the processing step further comprises determining a change in distance of the system from the reflective surfaces causing the reflected echo signals of the selected pair.

53. The method according to claim 52, wherein the processing step further comprises determining the position of the system relative to the origin based on the determined change in distance of the system from the reflective surfaces.

54. The method according to claim 49, wherein the processing step further comprises selecting any two or more pairs of the two or more reflected echo signals which have been determined to have maintained their directions relative to the system, and determining the position of the system relative to the origin based on an average of the position determined from each pair.

55. The method according to claim 48, wherein the processing step further comprises determining if any of the one or more reflective surfaces have not changed their direction relative to the system from the direction measured at the origin position, and if it is determined that none of the one or more reflective surfaces has not changed its direction, determining the position of the system based on the change in the distance(s) of the one or more reflective surfaces from a previously measured position.

56. The method according to claim 55, wherein the processing step further comprises selecting a pair of reflected echo signals determined not to have changed their directions relative to the system as determined at the previously measured position.

57. The method according to claim 56, wherein the step of selecting comprises selecting a pair of the two or more reflected echo signals which differ in their directions by at least π

/4.

58. The method according to claim 55, wherein the processing step determines a change in distance of the system from the reflective surfaces causing the reflected echo signals of the selected pair.

59. The method according to claim 58, wherein the processing step further comprises determining the position of the system relative to the previously measured position based on the determined change in distance of the system from the reflective surfaces.

60. The method according to claim 55, wherein the processing step further comprises selecting any two or more pairs of the two or more reflected echo signals which have been determined to have maintained their directions relative to the system at the previously measured position, and determining the position of the system relative to the origin based on an average of the position determined from each pair.

61. The method according to claim 60, wherein the processing step further comprises determining the position of the system relative to the origin by adding the changes in position determined from a previously measured position to the position determined previously.