Advanced global navigation satellite systems (GNSS) positioning using precise satellite information

Patent metadata

Field	Value
Publication number	US-9405012-B2
Application number	US-201313793664-A
Country	US
Kind code	B2
Filing date	Mar 11, 2013
Priority date	Apr 12, 2012
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

A method is provided for estimating parameters useful to determine the position of a global navigation satellite system (GNSS) receiver or a change in the position thereof. The method includes the steps of: obtaining at least one GNSS signal received at the GNSS receiver from each of a plurality of GNSS satellites; obtaining, from at least one network node, precise satellite information on: (i) the orbit or position of at least one of the plurality of GNSS satellites, and (ii) a clock offset of at least one of the plurality of GNSS satellites; identifying, among the obtained GNSS signals, a subset of at least one GNSS signal possibly affected by a cycle slip, the identified subset being hereinafter referred to as cycle-slip affected subset; and estimating parameters useful to determine the position of the GNSS receiver or a change in the position of the GNSS receiver using at least some of the obtained GNSS signals which are not in the cycle-slip affected subset, and the precise satellite information.

First claim

The invention claimed is:

1. Method for estimating parameters for determining the position of a global navigation satellite system (GNSS) receiver or a change in the position of the GNSS receiver, the method including the steps of:
obtaining, using a processing unit, information from at least one GNSS signal received at the GNSS receiver from each of a plurality of GNSS satellites;
obtaining, using a communication interface, information on the plurality of GNSS satellites from at least one network node, here referred to as “precise satellite information”, the precise satellite information obtained at a frequency of 1 Hz or more frequently, the precise satellite information including:
(i) the orbit or position of at least one of the plurality of GNSS satellites, and
(ii) a clock offset of at least one of the plurality of GNSS satellites;

identifying, using the processing unit, a subset of at least one GNSS signal affected by a cycle slip from the obtained GNSS signals, the identified subset being hereinafter referred to as cycle-slip affected subset; and
estimating, using the processing unit, the parameters for determining the position of the GNSS receiver or a change in the position of the GNSS receiver using
at least some of the obtained GNSS signals which are not in the cycle-slip affected subset, and
the precise satellite information.

2. Method of claim 1 , wherein the step of obtaining precise satellite information further includes obtaining information on
(iii) biases between the phase of two or more GNSS signals originating from one satellite, for at least one of the plurality of GNSS satellites.

3. Method of claim 1 , wherein the step of obtaining at least one GNSS signal from each of a plurality of GNSS satellites includes
making ranging code observations and carrier phase observations of the GNSS signals.

4. Method of claim 1 , wherein the step of obtaining, from at least one network node, precise satellite information includes:
obtaining the information per GNSS satellite at a frequency of 2 Hz or more frequently.

5. Method of claim 1 , wherein the step of identifying the cycle-slip affected subset includes
detecting cycle slips using at least one of geometry-free carrier phase combinations and geometry-free code-carrier combinations.

6. Method of claim 5 , wherein detecting cycle slips using geometry free carrier phase and code-carrier combinations includes
computing geometry-free ionospheric residual carrier phases.

7. Method of claim 5 , wherein detecting cycle slips using geometry free carrier phase and code-carrier combinations includes
computing geometry-free Melbourne-Wubbena code-carriers.

8. Method of claim 5 , wherein the step of identifying the cycle-slip affected subset makes use of
the obtained precise satellite information.

9. Method of claim 1 , wherein the step of estimating the parameters for determining the position of the GNSS receiver or a change in the position of the GNSS receiver includes
determining a position change of the receiver using time-differenced carrier phase for at least some of the obtained GNSS signals which are not in the cycle-slip affected subset.

10. Method of claim 1 , wherein the step of estimating the parameters for determining the position of the GNSS receiver or a change in the position of the GNSS receiver makes use of:
at least some of the obtained GNSS signals which are not in the cycle-slip affected subset and which are not originating from a satellite having a clock offset or drift exceeding a threshold based on the specification for the satellite's atomic clock stability; and
the obtained precise satellite information.

11. Method of claim 1 , wherein the step of estimating the parameters for determining the position of the GNSS receiver or a change in the position of the GNSS receiver makes use of:
at least some of the obtained GNSS signals which are not in the cycle-slip affected subset and which are not originating from a satellite that has an abnormal clock offset in the sense that an attempt to compute the clock offset using the broadcast clock parameters results in a residual clock error, when compared to a clock offset computed using the precise satellite information, where said residual clock error exceeds a threshold; and
the obtained precise satellite information.

12. Method of claim 1 , wherein the method further includes the steps of:
performing cycle slip fixing on the GNSS signals of the cycle-slip affected subset; and
estimating again the parameters for determining the position of the GNSS receiver or a change in the position of the GNSS receiver as well as the clock offset of the GNSS receiver by using:
at least some of the obtained GNSS signals including at least one GNSS signal of the cycle-slip affected subset for which cycle slip fixing has been performed; and
the obtained precise satellite information.

13. Method of claim 12 , wherein the step of estimating again the parameters for determining the position of the GNSS receiver or a change in the position of the GNSS receiver as well as the clock offset of the GNSS receiver makes use of
ionospheric free code combination and ionospheric free carrier phase combination.

14. Method of claim 12 , wherein the step of estimating again the parameters for determining the position of the GNSS receiver or a change in the position of the GNSS receiver as well as the clock offset of the GNSS receiver makes use of:
at least some of the obtained GNSS signals including at least one GNSS signal of the cycle-slip affected subset for which cycle slip fixing has been performed, but not including GNSS signals originating from a satellite having a clock offset or drift exceeding a threshold based on the specification for the satellite's atomic clock stability; and
the obtained precise satellite information.

15. Method of claim 12 , wherein the step of estimating again the parameters for determining the position of the GNSS receiver or a change in the position of the GNSS receiver as well as the clock offset of the GNSS receiver makes use of:
at least some of the obtained GNSS signals including at least one GNSS signal of the cycle-slip affected subset for which cycle slip fixing has been performed, but not including GNSS signals originating from a satellite that has an abnormal clock offset in the sense that an attempt to compute the clock offset using the broadcast clock parameters results in a residual clock error, when compared to a clock offset computed using the precise satellite information, where said residual clock error exceeds a threshold; and
the obtained precise satellite information.

16. Apparatus for estimating parameters for determining the position of a global navigation satellite system (GNSS) receiver or a change in the position of the GNSS receiver, the apparatus comprising:
a processing unit configured for receiving information from at least one GNSS signal received at the GNSS receiver from each of a plurality of GNSS satellites; and
a communication interface configured for obtaining, from at least one network node, information on the plurality of GNSS satellites, here referred to as “precise satellite information”, the precise satellite information obtained at a frequency of 1 Hz or more frequently, the precise satellite information including:
(i) the orbit or position of at least one of the plurality of GNSS satellites, and
(ii) a clock offset of at least one of the plurality of GNSS satellites;

the processing unit also configured for:
identifying, among the obtained GNSS signals, a subset of at least one GNSS

Assignees

• Trimble Navigation Ltd

Inventors

• Doucet Kenneth Donald
• Landau Herbert

Classifications

• G01S19/22

  Multipath-related issues · CPC title

• G01S19/20 Primary

  Integrity monitoring, fault detection or fault isolation of space segment · CPC title

• G01S19/25 Primary

  involving aiding data received from a cooperating element, e.g. assisted GPS · CPC title

• G01S19/44

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

• G01S19/071

  DGPS corrections · CPC title