Fast decimeter-level GNSS positioning

• US 20090184868A1
• Filed: 01/26/2009
• Published: 07/23/2009
• Est. Priority Date: 10/28/2003
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Klose, Soeren Uif, Vollath, Ulrich, Liu, Junjie, West, Peter Ian
• Granted Patent: US 8,130,143 B2
• Time in Patent Office: Days
• US Class Current: 342/357.270
• CPC Class Codes: G01S 19/32 Multimode operation in a single same satellite system, e.g. GPS L1/L2
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

Methods and apparatus for processing of data from GNSS receivers are presented. A post-processing engine and a post-processed accuracy predictor are described. The post-processing engine provides high accuracy GNSS (GPS) position determination with short occupation time for GIS applications. The post-processed accuracy predictor calculates during data collection an estimate of the accuracy likely to be achieved after post-processing. This helps to optimize productivity when collecting GNSS data for which post-processed accuracy is important. The predictor examines the quality of carrier measurements and estimates how well the post-processed float solution will converge in the time since carrier lock was obtained.

Claims

1-54. -54. (canceled)

55. A method of determining position of a rover from observations of GNSS signals, comprising:

a. obtaining observations of GNSS signals at a rover location,

b. obtaining observations of the GNSS signals at plurality of reference stations, each reference station defining a respective baseline between the rover location and a reference station location,

c. for each reference station, determining a respective differentially-corrected rover position, and

d. preparing a weighted combination of the differentially-corrected rover positions.

56. The method of claim 55, further comprising determining a quality measure for each of the differentially-corrected rover positions and preparing the weighted combination as a function of the quality measures.

57. The method of claim 56, wherein the quality measure is an inverse covariance.

58. The method of claim 55, wherein at least one of the differentially-corrected rover positions is based on a single-frequency observable combination.

59. The method of claim 55, wherein at least one of the differentially-corrected rover positions is based on a multiple-frequency ionosphere-free observable combination.

60. The method of claim 55, wherein at least one of the differentially-corrected rover positions is based on a multiple-frequency code-phase observable combination.

61. The method of claim 55, wherein at least one of the differentially-corrected rover positions is based on a single frequency carrier-phase and code-plus-carrier-phase combination.

69. An article of manufacture comprising a computer-readable medium having instructions stored therein for causing a machine to perform the method of claim 55.

62. Apparatus for determining position of a rover from observations of GNSS signals collected at a rover location and at a plurality of reference stations, each reference station defining a respective baseline between the rover location and a reference station location, comprising

a. an element to determine, for each reference station, a respective differentially-corrected rover position, and

b. an element to prepare a weighted combination of the differentially-corrected rover positions.

63. The apparatus of claim 62, further comprising an element to determine a quality measure for each of the differentially-corrected rover positions, wherein the weighted combination is prepared as a function of the quality measures.

64. The apparatus of claim 62, wherein the quality measure is an inverse covariance.

65. The apparatus of claim 62, wherein at least one of the differentially-corrected rover positions is based on a single-frequency observable combination.

66. The apparatus of claim 62, wherein at least one of the differentially-corrected rover positions is based on a multiple-frequency ionosphere-free observable combination.

67. The apparatus of claim 62, wherein at least one of the differentially-corrected rover positions is based on a multiple-frequency code-phase observable combination.

68. The apparatus of claim 62, wherein at least one of the differentially-corrected rover positions is based on a single frequency carrier-phase and code-plus-carrier-phase combination.