Relative position measuring techniques using both GPS and GLONASS carrier phase measurements

• US 5,914,685 A
• Filed: 04/25/1997
• Issued: 06/22/1999
• Est. Priority Date: 04/25/1997
• Status: Expired due to Term

• Current Assignee: MiTAC International Corporation (MiTAC Holdings Corp.)
• Original Assignee: Magellan Corporation (Thales SA)
• Inventors: Kozlov, Dmitry, Povaliaev, Alexander, Rapoport, Lev, Sila-Novitsky, Stanislav, Yefriemov, Vladimir
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US08/846,023
• Time in Patent Office: 788 Days
• Field of Search: 342/357, 701/215
• US Class Current: 342/357.26
• CPC Class Codes: G01S 19/425 by combining or switching between signals derived from different satellite radio beacon positioning systems
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

A technique of accurately determining the relative position of two points using carrier phase information from receivers capable of making code and carrier phase measurements on the L1 and L2 frequencies of signals from either or both GPS and GLONASS satellites. These signals are processed by a receiving system to determine relative position, for the purpose of surveying or otherwise, with the accuracy of carrier phase measurements being obtained. Signal processing similar to that used in existing GPS carrier phase based relative positioning receivers is used with GLONASS signals as well, with a modification that takes into account the unique and different frequencies of the signals from individual GLONASS satellites. Surface acoustic wave ("SAW") filters are also employed in an intermediate frequency receiver section in order to avoid imparting different delays to the GLONASS signals of different frequencies.

Claims

1. A method of determining relative position information of at least two locations, comprising:

receiving signals at each of said at least two locations over a common time period from a plurality of satellites including at least one GLONASS satellite, and

processing said received signals from each of said plurality of satellites, by a method that includes;

forming a metric that depends upon values of the relative position information of at least one of said at least two locations and upon carrier phase measurements of the signals received from said plurality of satellites; and

determining the relative position information of said at least two locations by determining the values of the relative position information that optimizes said metric.

2. The method according to claim 1, wherein:

forming the metric additionally includes unknown constants proportional to an unknown number of cycles of the carriers of the plurality of received satellite signals, and

determining the relative position information includes;

determining values for said unknown constants that optimize said metric, and

determining values of said relative position information that optimizes said metric with at least one of said unknown constants set to fixed values substantially equal to values of the unknown constants that were previously determined to optimize said metric.

3. The method according to claim 2, wherein said unknown constants are integers.

4. The method according to claim 3, wherein determining values for said unknown integer constants includes:

forming a plurality of double difference phase relationships of carriers of the signals received from said plurality of satellites that includes terms proportional to a receiver clock offset and of said unknown integer constants, and

solving said double difference phase relationships for fixed values of the unknown integer constants that optimize said metric.

5. The method according to claim 4, wherein determining values for said unknown integer constants additionally includes:

forming at least one single difference relationship including pseudorange measurements, and

estimating terms relating to clock offsets at said at least two locations by using said at least one single difference relationship including pseudorange measurements.

6. The method according to any one of claims 1 through 5, wherein processing said received signals includes establishing a communication link with at least one of said at least two locations.

7. The method according to claim 6, wherein quantities related to at least one of carrier phase measurements, pseudorange measurements and residuals of the signals received from said plurality of satellites at said at least one of said at least two locations are transmitted over the communication link.

8. The method according to claim 6 wherein said communication link is established by use of a data radio transmitter and data radio receiver.

9. The method according to claim 6 wherein said communication link is established by use of a telephone data link.

10. The method according to claim 6 wherein said communication link is established by use of a data cable.

11. The method according to any one of claims 1 through 5, wherein the relative position information that is determined of said at least two locations includes relative fixed positions of said at least two locations.

12. The method according to any one of claims 1 through 5, wherein the relative position information that is determined of said at least two locations includes determining a relative trajectory between said at least two locations.

13. The method according to any one of claims 1 through 5, wherein forming the metric includes calculating a sum of squares of differences between values related to the relative position information and said carrier phase measurements.

14. The method according to any one of claims 1 through 5, wherein determining the relative position information includes optimizing the metric by minimizing said metric.

15. The method according to any one of claims 1 through 5, wherein determining the relative position information includes optimizing the metric by minimizing a vector norm between the calculated and observed quantities.

16. The method according to claim 15, wherein the vector norm is a p-norm, wherein the constant p is greater than or equal to 1.

17. The method according to any one of claims 1 through 5, wherein determining the relative position information includes optimizing the metric by minimizing a quantity related to a vector norm between s the calculated and observed quantities.

18. The method according to claim 17, wherein said vector norm is a weighted p-norm.

19. The method according to claim 15, wherein the vector norm is a weighted least squares norm.

20. The method according to any one of claims 1 through 5, wherein determining the relative position information includes optimizing the metric by determining a sum of squares of differences between calculated and observed quantities.

21. The method according to any one of claims 1 through 5, wherein determining the relative position information includes optimizing the metric by maximizing a vector norm between the calculated and observed quantities.

22. The method according to any one of claims 1 through 5, wherein at least one of said at least two locations is fixed with respect to earth.

23. The method according to claim 22, wherein individual antennas of the receivers are positioned at said at least two locations and operate continuously.

24. The method according to any one of claims 1 through 5, wherein at least one of said at least two locations moves with respect to earth.

25. The method according to any one of claims 1 through 5, wherein at least two of said at least two locations moves with respect to each other.

26. The method according to any one of claims 1 through 5, wherein at least one of said carrier phase measurements, pseudorange measurements and residuals of the signals received from said plurality of satellites at said at least one of said at least two locations are transmitted over a communication link to at least one additional location.

27. The method according to any one of claims 1 through 5, wherein said at least two locations includes at least one static location and one kinematic location.

28. The method according to any one of claims 1 through 5, which additionally comprises using the determined relative position information to monitor relative movements of continental plates of the earth.

29. The method according to claim 28, wherein the relative movements being monitored are being caused by at least one of a group of conditions including crustal deformation, plate tectonics, and continental drift.

30. The method according to claim 28, wherein the relative movements are used to monitor at least one of a group of natural hazards including earthquakes, volcanos and floods.

31. The method according to any one of claims 1 through 5, which additionally comprises using the determined relative position information to monitor a body of water on earth.

32. The method according to claim 31 wherein a buoy is collocated on the body of water with said at least one of at least two locations.

33. The method according to claim 31 wherein a tide gauge is collocated on the body of water with said at least one of at least two locations.

34. The method according to any one of claims 1 through 5, wherein said at least one of said at least two locations is located on or about a large engineering structure, and additionally comprising using the relative position information to measure at least one of a group of characteristics including position, changes in position, geometry and changes in geometry of said large engineering structure.

35. The method according to claim 34, wherein said large engineering structure is a dam.

36. The method according to claim 34, wherein said large engineering structure is a bridge.

37. The method according to claim 34, wherein said large engineering structure is a building.

38. The method according to claim 34, wherein said large engineering structure is a pipeline.

39. The method according to any one of claims 1 through 5, wherein said at least one of said at least two locations is located on or about an aircraft, and additionally comprising using the relative position information to measure at least one of a group of characteristics including position, changes in position, geometry, changes in geometry, orientation, and changes in orientation of said aircraft.

40. The method according to any one of claims 1 through 5, wherein said at least one of said at least two locations is located on or about a water vessel, and additionally comprising using the relative position information to measure at least one of a group of characteristics including position, changes in position, geometry, changes in geometry, orientation, and changes in orientation of said water vessel.

41. The method according to any one of claims 1 through 5, wherein said at least one of said at least two locations is located on or about an earth moving vehicle, and additionally comprising using the relative position information to measure at least one of a group of characteristics including position, changes in position, geometry, changes in geometry, orientation, and changes in orientation of said earth moving vehicle.

42. The method according to any one of claims 1 through 5, wherein processing said received signals additionally includes:

choosing a frequency plan of individual receivers positioned at said at least two locations that insures an initial heterodyne carrier bias for GPS and GLONASS constellations that is the same,

making use of a double difference phase relationship between GPS and GLONASS carriers, and

solving said double difference phase relationship for fixed value integers which optimize said metric.

56. The method according to any one of claims 1 through 5 wherein the metric is formed to additionally depend upon code pseudo-range measurements of the signals received from said plurality of satellites.

57. The method according to any one of claims 1 through 5 wherein the metric is formed additionally from both L1 and L2 signals from said plurality of satellites.

58. The method according to any one of claims 1 through 5 wherein receiving signals includes passing signals from the plurality of satellites through at least one filter that is characterized by a frequency independent phase shift over a range of frequencies including those of the satellite signals.

59. The method according to claim 58, wherein passing signals through at least one filter includes passing said signals through a SAW filter.

43. A satellite signal receiving system for determining relative position information of at least first and second locations, comprising:

first and second receivers having respective first and second antennas positionable at respective ones of said at least first and second locations, and

a signal processor including means responsive to receipt by said receivers of signals from a plurality of satellites over a common time period including at least one GLONASS satellite for forming a metric that depends upon values of the relative position information of at least one of said at least two locations and upon carrier phase measurements of the signals received from said plurality of satellites, and means for determining the values of the relative position information that optimize said metric, thereby to determine the relative position information of said at least two locations.

44. The system of claim 43, wherein said metric forming means additionally includes means for including in the metric unknown constants proportional to an unknown number of cycles of the carriers of the plurality of received satellite signals, and said relative position information determining means includes means for determining values of said unknown constants that optimize said metric, and means for determining values of said relative position information that optimize said metric with at least some of said unknown constants set to fixed values substantially equal to values of the unknown constants determined to optimize said metric.

45. The system of claim 44, wherein said means for including unknown constants in the metric includes means for including integers as said unknown constants.

46. The system of claim 45, wherein said means for determining values of the unknown constants includes means for forming a plurality of double difference phase relationships of carriers of the signals received from said plurality of satellites that includes terms of receiver clock offset and of said unknown constants, and means for solving said double difference phase relationships for fixed values of the unknown constants that optimize said metric.

47. The system of claim 46, wherein said means for determining values of the unknown constants additionally includes means for forming at least one single difference relationship including pseudorange measurements, and means for estimating terms relating to clock offsets at said at least two locations by using said at least one single difference relationship including pseudorange measurements.

48. The system of any one of claims 43-47 wherein at least one of said first and second receivers includes a radio and intermediate frequency section tuned to receive signals within a frequency band of GLONASS satellite signals, including at least one filter that is characterized by a frequency independent phase shift over a range of frequencies including those of the satellites and providing digital data of received GLONASS signals to said signal processor.

49. The system of claim 48, wherein said at least one of said first and second receivers additionally includes an additional radio and intermediate frequency section tuned to receive signals of GPS satellites, including a at least one filter that is characterized by a frequency independent phase shift over a range of frequencies including those of the satellites and providing digital data of received GPS signals to said signal processor.

60. The system of any one of claims 43 through 47 wherein the metric is formed to additionally depend upon code pseudo-range measurements of the signals received from said plurality of satellites.

61. The system of any one of claims 43 through 47 wherein the metric is formed additionally from both L1 and L2 signals from said plurality of satellites.

62. The system of claim 48, wherein the said receivers including at least one filter include a SAW filter.

63. The system of claim 49, wherein the said receivers including at least one filter include a SAW filter.

50. A satellite signal receiving system for determining relative position information of at least first and second locations, comprising:

first and second receivers having respective first and second antennas positionable at respective said first and second locations, each of said receivers including means capable of receiving signals within a frequency band of both GLONASS satellite and GPS satellite signals for providing digital data of received GLONASS and GPS signals, and

a signal processor receiving the GLONASS and GPS digital data that forms therefrom a plurality of double difference phase relationships of carriers of received GLONASS and GPS signals with terms of clock offsets of the first and second receivers and integer ambiguities, solves said double difference phase relationships for fixed value integers, and determines said relative position information by use of the fixed value integers.

51. The system of claim 50, wherein the signal receiving means of each of said receivers includes at least one filter that is characterized by a frequency independent phase shift over a range of frequencies including those of the satellites.

64. The system of claim 51, wherein the signal receiving means of each of said receivers including at least one filter includes a SAW filter.

52. A satellite signal receiving system for determining relative position information of at least first and second locations, comprising:

first and second receivers having respective first and second antennas positionable at respective said first and second locations, each of said receivers including;

a first section tuned to receive signals within a frequency band of GLONASS satellite signals and provide digital data of received GLONASS signals, and

a second section tuned to receive signals of GPS satellites and provide digital data of received GPS signals, and

a signal processor receiving the GLONASS and GPS digital data that forms therefrom a plurality of double difference phase relationships of carriers of received GLONASS and GPS signals with terms of clock offsets of the first and second receivers and integer ambiguities, solves said double difference phase relationships for fixed value integers, and determines said relative position information by use of the fixed value integers.

53. A receiver of positioning system satellite signals, comprising:

a first section tuned to receive signals within a frequency band of GLONASS satellite signals and provide digital data of received GLONASS signals while maintaining their individual frequency characteristics,

a second section tuned to receive signals of GPS satellites and provide digital data of received GPS signals while maintaining their individual frequency characteristics, and

a signal processor receiving the digital data of both of the received GLONASS and GPS signals for providing data of observables of individual ones of both GLONASS and GPS signals including carrier phase.

54. The receiver of claim 53, wherein the signal processor providing data of observables of individual ones of both GLONASS and GPS signals includes the processor additionally providing such data of one of pseudorange and carrier frequency.

55. The receiver of either of claims 53 or 54, wherein at least the first section includes at least one filter that is characterized by a frequency independent phase shift over a range of frequencies including those of the satellites.

65. The receiver of claims 55, wherein at least the first section including at least one filter includes a SAW filter.