Methods and apparatus for obtaining positional information

• US 7,068,211 B2
• Filed: 02/08/2001
• Issued: 06/27/2006
• Est. Priority Date: 02/08/2000
• Status: Expired due to Term

• Current Assignee: Aveillant Limited (Thales SA)
• Original Assignee: Cambridge Solutions Limited (DXC Technology Company)
• Inventors: Oswald, Gordon Kenneth Andrew, Toutoungi, Danielle Emma, Burchett, Michael Hugh, Clouston, Eric Nicol, Richardson, Alan Trevor
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): ALSOMIRI, ISAM A
• Application Number:
  US10/203,547
• Publication Number:
  US 20030151541A1
• Time in Patent Office: 1,965 Days
• Field of Search: 342/22, 342/27, 342/28, 342 70- 72
• US Class Current: 342/70
• CPC Class Codes: B60R 21/0134 responsive to imminent contact with an obstacle , e.g. using radar systems
• CPC Class Codes: B60R 21/01538 for image processing, e.g. cameras or sensor arrays
• CPC Class Codes: G01S 13/4454 phase comparisons monopulse, i.e. comparing the echo signals received by an interferometric antenna arrangement
• CPC Class Codes: G01S 13/46 Indirect determination of position data
• CPC Class Codes: G01S 13/888 through wall detection
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/468 by Triangulation, i.e. two antennas or two sensors determine separately the bearing, direction or angle to a target, whereby with the knowledge of the baseline length, the position data of the target is determined
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/9322 using additional data, e.g. driver condition, road state or weather data
• CPC Class Codes: G01S 2013/9324 Alternative operation using ultrasonic waves
• CPC Class Codes: G01S 2013/93275 in the bumper area
• CPC Class Codes: G01S 2015/939 vertical stacking of sensors, e.g. to enable obstacle height determination
• CPC Class Codes: H01Q 1/3233 particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 9/28 Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00

Abstract

An apparatus and method obtains positional information about one or more objects in a detection field. An array includes a transmitting element and a plurality of receiving elements. A truncated cross-correlation function may be applied to determine the interval between signals received by a plurality of the receiving elements, thereby to determine an angular position of an object. A warning zone may be defined and it is determined whether an object is within the warning zone. Also disclosed are techniques for stretching received signals, and techniques for obtaining positional information relating to an object using non-Doppler radar.

Claims

1. Apparatus for obtaining positional information relating to an object, comprising:

a warning zone definition stage for defining a warning zone of arbitrary shape within a detection field of the apparatus;

an object location stage for determining the position of a detected object in the detection field, regardless of whether the object is within or outside the warning zone; and

a discrimination stage for determining whether the detected object is within the warning zone by comparison of the determined position with the warning zone;

wherein the warning zone is defined as a three-dimensional region within the detection field, and the warning zone is contained within and is smaller than the detection field.

2. Apparatus according to claim 1, wherein the shape of the warning zone is dissimilar from the shape of the detection field.

3. Apparatus according to claim 1, wherein the warning zone definition stage is adapted to define the warning zone as a function of a coordinate within the detection field.

4. Apparatus according to claim 1, wherein the discrimination stage is adapted to determine the coordinates of the detected object and to compare the determined coordinates with the coordinates of the warning zone to determine whether the object is within the warning zone.

5. Apparatus according to claim 1, wherein the warning zone definition stage is adapted to define a plurality of non-coextensive warning zones.

6. Apparatus according to claim 5, wherein the discrimination stage is adapted to generate an output signal indicative of which of the plurality of warning zones contains the object.

7. Apparatus according to claim 6, wherein the discrimination stage is adapted to apply different logic to at least two of the zones.

8. Apparatus according to claim 1, wherein the warning zone is at least one of non-circular and non-spherical and approximately cuboid.

9. Apparatus according to claim 1, wherein the discrimination stage is adapted to analyze a characteristic of an object outside of the warning zone.

10. Apparatus according to claim 9, wherein the discrimination stage is operable to track an object outside the warning zone and to predict its entry into the warning zone.

11. Apparatus according to claim 10, wherein the apparatus is operable to issue a pre-warning based on the prediction.

12. Apparatus according to claim 1, wherein the warning zone definition stage is adapted to determine the shape and a relevant dimension of the warning zone at least in part in dependence on a corresponding shape and dimension of a vehicle associated with the apparatus.

13. Apparatus according to claim 1, wherein the warning zone definition stage is adapted to define the warning zone to have a lower surface that is substantially planar and spaced above a road surface upon which a vehicle associated with the apparatus is located.

14. Apparatus according to claim 1, wherein the warning zone definition stage is adapted to determine the shape and a relevant dimension of the warning zone in dependence on operating conditions of a vehicle associated with the apparatus.

15. Apparatus according to claim 14, wherein the vehicle operating conditions include at least one of speed, direction of travel, and ambient environmental conditions.

16. Apparatus according to claim 1, wherein the warning zone definition stage is adapted to define a warning zone within a passenger compartment of a vehicle associated with the apparatus.

17. Apparatus according to claim 16, wherein the apparatus is operable to determine the number and position of the occupants of the vehicle.

18. Apparatus according to claim 16, wherein the apparatus is operable, in dependence on whether the object is within the warning zone, to at least one of control deployment of an air bag and detect an intruder and detect movement of a driver of the vehicle.

19. Apparatus according to claim 1, wherein the discrimination stage is operative to generate an output signal indicative that the object is within the warning zone.

20. Apparatus according to claim 1, operable to issue a warning to a user upon detection of an object in the warning zone, wherein said warning is at least one of an audible warning and a visual warning and a tactile warning.

21. Apparatus according to claim 1, wherein the object location stage comprises:

a transmitter for transmitting a probe signal towards the object, the transmitter comprising a transmitting element;

a receiver for receiving the probe signal as returned by the object, the receiver comprising at least one receiving element; and

a processor for processor for processing the received probe signal.

22. Apparatus according to claim 21, wherein the processor is operable to determine a radar cross section of the object and to compare the radar cross section with a threshold value of radar cross section.

23. Apparatus according to claim 21, wherein the processor is operable to compare the received probe signal with a signal threshold.

24. Apparatus according to claim 21, wherein the processor is operable to at least one of determine the evolution of angular position of the object, and predict the path of movement of the object.

25. Apparatus according to claim 21, wherein the processor is operable to compare the received signal with a pattern corresponding to signals received from a known class of objects.

26. Apparatus according to claim 21, wherein the probe signal comprises electromagnetic radiation.

27. Apparatus according to claim 21, wherein the at least one receiving element forms an antenna array which is adapted to be located on a fixed location on a vehicle.

28. Apparatus according to claim 21, wherein the at least one receiving element forms an antenna array which is adapted to be located within a component of a vehicle, such as a non-metallic component.

29. Apparatus according to claim 21, wherein the at least one receiving element forms an antenna array which is adapted to be located within a non-metallic component of a vehicle.

30. Apparatus according to claim 21, wherein the at least one receiving element forms an antenna array which is adapted to be located within a bumper of a vehicle.

31. Apparatus according to claim 21, wherein the at least one receiving element forms an antenna array which is adapted to be located within a nonmetallic bumper of a vehicle.

32. Apparatus according to claim 1, further comprising a display adapted to present a visual representation of a detection field and an object within the detection field.

33. Apparatus according to claim 1, comprising:

a transmitter for transmitting a probe signal towards the object, the transmitter comprising a transmitting element;

a receiver for receiving, at a plurality of spaced apart locations, the probe signal as returned by the object, the receiver comprising a plurality of receiving elements forming an antenna array;

a detector, coupled to the receiver, for detecting the relative timing of the returned probe signals as received at the plurality of spaced apart locations;

whereby angular position information for the object can be determined from the relative timing.

34. Apparatus according to claim 33, wherein the transmitting element and receiving elements are disposed on a common substrate.

35. Apparatus according to claim 34, wherein the receiving elements are arranged such that there is a first pair of the receiving elements and a second pair of the receiving elements, the spacing of the elements in the first pair and in the second pair being unequal and the first and second pairs having dissimilar artifacts in their sensitivity patterns, and the positional information for the object can be determined from the relative timing of the returned probe signals as received at the first pair of the receiving elements, and from the relative timing of the returned probe signals as received at the second pair of the receiving elements.

36. Apparatus according to claim 33, adapted to be contained within a single housing.

37. Apparatus according to claim 33, wherein the receiving elements are spaced apart by distances that are the same order of magnitude as the wavelength λ

of the radiation that the apparatus is intended to transmit and receive.

38. Apparatus according to claim 33, further comprising:

a processor,

wherein the processor and the antenna array are constructed as a single assembly.

39. Apparatus according to claim 33, wherein the receiver comprises at least three receiving elements arranged non-collinearly and such that there is no axis about which the array is symmetrical.

40. Apparatus according to claim 33, wherein the receiving elements are arranged substantially at the vertices of a trapezial locus having long and short parallel sides, the length of the shorter side being approximately the wavelength λ

of the radiation that the array is intended to transmit and receive, and the length of the longer side is approximately 3λ

/2.

41. Apparatus according to claim 33, wherein the receiving elements are arranged substantially at the vertices of a trapezial locus having long and short parallel sides, the short side being between 0.5 and 1.0 times the length of the long side.

42. Apparatus according to claim 33, wherein the frequency of the transmitted signal is within one of the range 0.5 to 77 GHz, the range 2 to 25 GHz, and the range 2 to 2.5 GHz.

43. Apparatus according to claim 42, wherein the frequency of the transmitted signal is one of approximately 0.5 GHz, 1 GHz, 6 GHz, 10 Ghz, and 2.45 GHz.

44. Apparatus according to claim 33, further comprising a processor operable to compare the signals derived from two of the receiving elements and to determine the time difference at which the signals appear most similar.

45. Apparatus according to claim 33, further comprising:

a processor operable to apply a cross-correlation process to the returned probe signals.

46. Apparatus according to claim 45, wherein the cross-correlation process is a truncated cross-correlation process.

47. Apparatus according to claim 1, being operative in an operating cycle for each of m steps in which n=1, 2 . . . m, and including:

a signal generating stage operative, simultaneously with or at a fixed time after a transmitting trigger instant t_n to generate a signal, and a transmitting element to transmit the signal into the detection field;

a plurality of spaced receiving elements operative simultaneously with or at a fixed time after a receiving trigger instant r_n to receive a portion of the signal reflected from one or more objects in the detection field, the interval r_n−

t_n varying as a function of n and having a magnitude in a range corresponding to the times of travel of a signal reflected from an object within the detection field;

a processor for identifying the values of n at which signals reflected from one object are received at two or more receiving elements and thereby detecting the time taken, and therefore the distance traveled, by the signals from the transmitting element to the various receiving elements;

wherein the processor is operable to calculate the position of the object from the various path lengths thereby identified.

48. Apparatus according to claim 47, wherein the range of variation of r_n−

t_n covers a range of time within which it is expected that a signal reflected from an object will be received if the object is somewhere in the detection field.

49. Apparatus according to claim 1, wherein the objection location stage is adapted to use a moving range gate in determining the position of the object.

50. Apparatus according to claim 49, wherein the moving range gate scans the detection field of the apparatus.

51. Apparatus according to claim 1, wherein the positional information comprises at least one of the range, azimuth and elevation of the object.

52. Apparatus according to claim 1 for use in a vehicle.

53. Apparatus according to claim 1, further comprising a processor for obtaining information about objects within or behind a wall.

54. Apparatus according to claim 1, further comprising a display for providing an image of an environment in conditions that human vision is compromised.

55. Apparatus according to claim 54, operable when vision is compromised by at least one of the physiological condition of a user and environmental conditions.

56. A vehicle comprising apparatus according to claim 1.

57. A hand-held tool comprising apparatus according to claim 1.

58. Apparatus for obtaining positional information relating to an object, comprising:

a warning zone definition stage for defining a warning zone of arbitrary shape within a detection field of the apparatus;

a transmitter for transmitting a probe signal towards an object, the transmitter comprising a transmitting element;

a receiver for receiving, at a plurality of spaced apart locations, the probe signal as returned by the object, the receiver comprising a plurality of receiving elements forming an antenna array;

a detector, coupled to the receiver, for detecting the relative timing of the returned probe signals as received at the plurality of spaced apart locations, thereby to determine the position of the object in the detection field, regardless of whether the object is within or outside the warning zone located within the detection field; and

a discrimination stage for determining whether the object is within the warning zone by comparison of the determined position with the warning zone;

wherein the warning zone is defined as a three-dimensional region within the detection field, and the warning zone is contained within and is smaller than the detection field.

59. Apparatus for obtaining positional information relating to an object, the apparatus being adapted to be located on a vehicle and comprising:

a warning zone definition stage for defining a warning zone of arbitrary shape within a detection field of the apparatus;

an object location stage for determining the position of a detected object in the detection field of the apparatus, regardless of whether the object is within or outside the warning zone; and

a discrimination stage for determining whether the detected object is within the warning zone by comparison of the determined position with the warning zone;

wherein the object location stage is located in a single housing or on a common substrate, the single housing or common substrate being adapted to be located within a bumper of the vehicle; and

the warning zone definition stage is operable to define the warning zone as a three-dimensional region within the detection field, contained within and smaller than the detection field, and at least partially surrounding the vehicle when the apparatus is located on the vehicle.

60. Apparatus for obtaining positional information relating to an object, comprising:

a warning zone definition stage for defining a warning zone of arbitrary shape within a detection field of the apparatus;

an object location stage for determining the position of a detected object in the detection field, regardless of whether the object is within or outside the warning zone; and

a discrimination stage for determining whether the detected object is within or outside the warning zone by comparison of the determined position with the warning zone;

wherein the warning zone is a three-dimensional region within and smaller than the detection field, and is within a passenger compartment of the vehicle; and

the apparatus is operable, in dependence on whether the object is within the warning zone, to at least one of control deployment of an air bag and detect an intruder and detect movement of a driver of the vehicle.

61. A method for obtaining positional information relating to an object, comprising:

defining a warning zone of arbitrary shape within a detection field of the apparatus;

determining the position of a detected object in the detection field, regardless of whether the object is within or outside the warning zone; and

determining whether the detected object is within the warning zone by comparison of the determined position with the warning zone;

wherein the warning zone is defined as a three-dimensional region within the detection field, and the warning zone is contained within and is smaller than the detection field.

62. A storage device storing processor-executable instructions for performing the method of claim 61.