Fast decimeter-level GNSS positioning

• US 8,130,143 B2
• Filed: 01/26/2009
• Issued: 03/06/2012
• Est. Priority Date: 10/28/2003
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Liu, Junjie, Vollath, Ulrich, West, Peter Ian, Klose, Soeren Ulf
• Primary Examiner(s): Tarcza, Thomas
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US12/321,843
• Publication Number:
  US 20090184868A1
• Time in Patent Office: 1,135 Days
• Field of Search: 342/357.03, 342/357.44
• US Class Current: 342/357.44
• 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 are present for determining position of a rover from observations of GNSS signals. Observations of GNSS signals are obtained at a rover location, and observations of the GNSS signals are obtained at a plurality of reference stations, each reference station defining a respective baseline between the rover location and a reference station location. For each reference station, a respective differentially-corrected rover position is determined, wherein at least one of the differentially-corrected rover positions is based on one of (i) a multiple-frequency ionosphere-free observable combination, (ii) a multiple-frequency code-phase observable combination, and (iii) a single-frequency carrier-phase and code-plus-carrier-phase combination. A weighted combination of the differentially-corrected rover positions is prepared.

Claims

1. 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 a 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, wherein at least one of the differentially-corrected rover positions is based on one of (i) a multiple-frequency ionosphere-free observable combination, (ii) a multiple-frequency code-phase observable combination, and (iii) a single-frequency carrier-phase and code-plus-carrier-phase combination, and

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

2. The method of claim 1, 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.

3. The method of claim 2, wherein the quality measure is an inverse covariance.

4. The method of claim 1, wherein at least one of the differentially-corrected rover positions is based on a single-frequency observable combination.

9. An article of manufacture comprising a computer-readable medium having instructions stored therein for causing a machine to perform the method of claim 1.

5. 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, wherein at least one of the differentially-corrected rover positions is based on one of (i) a multiple-frequency ionosphere-free observable combination, (ii) a multiple-frequency code-phase observable combination, and (iii) a single-frequency carrier-phase and code-plus-carrier-phase combination, and

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

6. The apparatus of claim 5, 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.

7. The apparatus of claim 5, wherein the quality measure is an inverse covariance.

8. The apparatus of claim 5, wherein at least one of the differentially-corrected rover positions is based on a single-frequency observable combination.