Reducing time and increasing reliability of ambiguity resolution in GNSS

Patent metadata

Field	Value
Publication number	US-9798017-B2
Application number	US-201515320056-A
Country	US
Kind code	B2
Filing date	Apr 9, 2015
Priority date	Apr 9, 2015
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A first plurality of differences (first differences or second differences) of carrier phase measurements of global navigation satellite system (GNSS) signals corresponding to a first measurement epoch is received. A plurality of differences of carrier phase ambiguities of the first plurality of differences of carrier phase measurements is resolved. A first fixed position of the rover is computed. A first plurality of sub-corrections is computed based at least in part on the first fixed position of the rover, a position of the base, a position of each specific GNSS satellite, and the first plurality of differences of carrier phase measurements. The first plurality of sub-corrections is then used to reduce the processing time for ambiguity resolution of carrier phase measurements in subsequent measurement epochs. The sub-corrections can be smoothed, aged, or smoothed and aged.

First claim

The invention claimed is:

1. A method for processing global navigation satellite system (GNSS) signals, the method comprising the steps of:
receiving a first plurality of first differences of carrier phase measurements, wherein the first plurality of first differences of carrier phase measurements is based at least in part on GNSS signals received by a rover from a first plurality of GNSS satellites at a first measurement epoch and GNSS signals received by a base from the first plurality of GNSS satellites at the first measurement epoch;
resolving a plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements;
computing a first fixed position of the rover, wherein the first fixed position of the rover is based at least in part on the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements; and
computing a first plurality of sub-corrections, wherein the first plurality of sub-corrections is based at least in part on the first fixed position of the rover, a position of the base, a position of each specific GNSS satellite in the first plurality of GNSS satellites, the first plurality of first differences of carrier phase measurements, and the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements.

2. The method of claim 1 , further comprising the steps of:
receiving a second plurality of first differences of carrier phase measurements, wherein the second plurality of first differences of carrier phase measurements is based at least in part on GNSS signals received by the rover from a second plurality of GNSS satellites at a second measurement epoch and GNSS signals received by the base from the second plurality of GNSS satellites at the second measurement epoch;
verifying whether the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements is consistent for the second measurement epoch;
upon verifying that the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements is consistent for the second measurement epoch:
outputting a second fixed position of the rover, wherein the second fixed position of the rover is based at least in part on the second plurality of first differences of carrier phase measurements and the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements; and
computing a second plurality of sub-corrections, wherein the second plurality of sub-corrections is based at least in part on the second fixed position of the rover, the position of the base, a position of each specific GNSS satellite in the second plurality of GNSS satellites, the second plurality of first differences of carrier phase measurements, and the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements; and

upon verifying that the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements is not consistent for the second measurement epoch:
computing a plurality of first differences of corrected carrier phase measurements by applying the first plurality of sub-corrections to the second plurality of first differences of carrier phase measurements;
attempting to resolve a plurality of first differences of carrier phase ambiguities of the plurality of first differences of corrected carrier phase measurements; and
upon resolving a plurality of first differences of carrier phase ambiguities of the plurality of first differences of corrected carrier phase measurements:
computing and outputting a second fixed position of the rover, wherein the second fixed position of the rover is based at least in part on the plurality of first differences of carrier phase ambiguities of the plurality of first differences of corrected carrier phase measurements; and
computing a second plurality of sub-corrections, wherein the second plurality of sub-corrections is based at least in part on the second fixed position of the rover, a position of the base, a position of each specific GNSS satellite in the second plurality of GNSS satellites, the second plurality of first differences of carrier phase measurements, and the plurality of first differences of carrier phase ambiguities of the plurality of first differences of corrected carrier phase measurements.

3. The method of claim 1 , further comprising the steps of:
receiving a second plurality of first differences of carrier phase measurements, wherein the second plurality of first differences of carrier phase measurements is based at least in part on GNSS signals received by the rover from a second plurality of GNSS satellites at a second measurement epoch and GNSS signals received by the base from the second plurality of GNSS satellites at the second measurement epoch;
verifying whether the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements is consistent for the second measurement epoch;
upon verifying that the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements is consistent for the second measurement epoch:
outputting a second fixed position of the rover, wherein the second fixed position of the rover is based at least in part on the second plurality of first differences of carrier phase measurements and the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements; and
computing a second plurality of sub-corrections, wherein the second plurality of sub-corrections is based at least in part on the second fixed position of the rover, the position of the base, a position of each specific GNSS satellite in the second plurality of GNSS satellites, the second plurality of first differences of carrier phase measurements, and the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements; and

upon verifying that the plurality of first differences of carrier phase ambiguities of the first plurality of first differences of carrier phase measurements is not consistent for the second measurement epoch:
generating an aged plurality of sub-corrections by aging the first plurality of sub-corrections from the first measurement epoch to the second measurement epoch;
computing a plurality of first differences of corrected carrier phase measurements by applying the aged first plurality of sub-corrections to the second plurality of first differences of carrier phase measurements;
attempting to resolve a plurality of first differences of carrier phase ambiguities of the plurality of first differences of corrected carrier phase measurements; and
upon resolving a plurality of first differences of carrier phase ambiguities of the plurality of first differences of corrected carrier phase measurements:
computing and outputting a second fixed position of the rover, wherein the second fixed position of the rover is based at least in part on the plurality of first differences of carrier phase ambiguities of the plurality of first differences of corrected carrier phase measurements; and
computing a second plurality of sub-corrections, wherein the second plurality of sub-corrections is based at least in part on the second fixed position of the rover, a position of the base, a position of each specific GNSS satellite in the second plurality of GNSS sa

Assignees

• Llc “Topcon Positioning Systems”
• Topcon Positioning Systems Inc

Inventors

• Zhodzishsky Mark Isaakovich
• Nevzorov Roman Anatolyevich
• Averin Sergey Vladislavovich
• Plenkin Andrey Valerievich
• Veitsel Viktor Abramovich

Classifications

• G01S19/04

  providing carrier phase data · CPC title

• G01S19/44 Primary

  Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method · CPC title