Systems and methods for real time kinematic satellite positioning

Patent metadata

Field	Value
Publication number	US-2020271795-A1
Application number	US-202016817196-A
Country	US
Kind code	A1
Filing date	Mar 12, 2020
Priority date	Oct 27, 2014
Publication date	Aug 27, 2020
Grant date	—

Abstract

A method for Real Time Kinematic satellite positioning includes receiving navigation satellite carrier signals, receiving phase correction signals from a reference station, calculating a set of integer phase ambiguities from double-differenced measurements of pseudo-range and phase, and calculating a relative position of the mobile receiver from the set of integer phase ambiguities and the double-differenced measurements of pseudo-range and phase.

First claim

We claim:

1 . A method for Real Time Kinematic satellite positioning comprising:
at a mobile receiver, receiving a plurality of navigation satellite carrier signals, wherein each navigation satellite carrier signal is associated with a navigation satellite from a plurality of navigation satellites; at the mobile receiver, receiving a plurality of correction signals from a reference station, wherein each correction signal corresponds to a navigation satellite of the plurality of navigation satellites; determining a phase and a pseudo-range for each of the navigation satellite carrier signals; calculating a set of integer phase ambiguity hypotheses from the pseudo-range and the phase using a measurement equation that does not include a baseline vector; wherein calculating the set of integer phase ambiguity hypotheses comprises:
performing hypothesis testing on the set of integer phase ambiguity hypotheses, comprising:
ceasing hypothesis testing when a ratio between probabilities of a highest and a next highest integer phase ambiguity hypothesis exceeds a threshold value; and

generating a second set of integer phase ambiguity hypotheses in response to a hypothesis search space becoming smaller than a threshold value; and
calculating a position of the mobile receiver from the set of integer phase ambiguity hypotheses and the double-differenced measurements of pseudo-range and phase.

2 . The method of claim 1 , wherein performing hypothesis testing further comprises removing an integer phase ambiguity hypothesis from further testing based on a pseudo-likelihood of the integer phase ambiguity hypothesis passing a removal threshold.

3 . The method of claim 1 , wherein calculating the set of integer phase ambiguity hypotheses further comprises performing a decorrelating reparameterization of the hypothesis search space.

4 . The method of claim 1 , wherein the probabilities are computed as single precision values.

5 . The method of claim 1 , wherein calculating the set of integer phase ambiguity hypotheses is performed at the mobile receiver.

6 . A method for Real Time Kinematic satellite positioning comprising:
at a mobile receiver, receiving a plurality of navigation satellite carrier signals, wherein each navigation satellite carrier signal is associated with a navigation satellite from a plurality of navigation satellites; receiving a plurality of correction signals from a reference station, wherein each correction signal corresponds to a navigation satellite of the plurality of navigation satellites; determining a phase and a pseudo-range for each of the navigation satellite carrier signals; generating a set of integer phase ambiguity hypotheses from the pseudo-ranges and the phases using a measurement equation that does not include a baseline vector; calculating a position of the mobile receiver from the set of integer phase ambiguity hypotheses and the double-differenced measurements of pseudo-range and phase.

7 . The method of claim 6 , further comprising estimating a baseline vector based on the phase for each navigation satellite carrier signal and an integer phase ambiguity hypothesis from the set of integer phase ambiguity hypotheses, wherein the measurement equation includes the estimated baseline vector.

8 . The method of claim 6 , wherein generating the set of integer phase ambiguity hypotheses comprises generating the set of integer phase ambiguity hypotheses without a dynamic transition model.

9 . The method of claim 6 , further comprising testing a subset of the set of integer phase ambiguity hypotheses.

10 . The method of claim 9 , wherein testing the subset of integer phase ambiguity hypotheses further comprises testing the subset of integer phase ambiguity hypotheses using a Bayesian update algorithm.

11 . The method of claim 9 , wherein testing the subset of integer phase ambiguity hypotheses further comprises:
generating an updated subset of integer phase ambiguity hypotheses; and testing the updated subset of integer phase ambiguity hypotheses.

12 . The method of claim 11 , wherein generating the updated subset comprises computing an outer product of the subset of integer phase ambiguity hypotheses and a second subset of integer phase ambiguity hypotheses, wherein the second subset of integer phase ambiguity hypotheses includes at least one integer phase ambiguity hypothesis corresponding to an additional navigation satellite, wherein the subset of integer phase ambiguity hypotheses does not include an integer phase ambiguity hypothesis corresponding to the additional navigation satellite.

13 . The method of claim 12 , further comprising initializing a probability of the updated subset based on a probability of the subset of integer phase ambiguity hypotheses and a number of integer phase ambiguity hypotheses in the updated subset.

14 . The method of claim 9 , further comprising:
ceasing testing of the subset of integer phase ambiguity hypotheses when a ratio between probabilities of a highest and a next-highest probability integer phase ambiguity hypothesis exceeds a threshold.

15 . The method of claim 9 , wherein testing the subset of integer phase ambiguity hypotheses comprises testing the subset of integer phase ambiguity hypotheses in logarithmic space.

16 . The method of claim 9 , wherein testing the subset of integer phase ambiguity hypotheses further comprises determining a probability for each integer phase ambiguity hypothesis in single precision.

17 . The method of claim 6 , wherein the pseudo-range and the phase comprise double differenced measurements of the pseudo-range and the phase.

18 . The method of claim 6 , wherein generating the set of integer phase ambiguity hypotheses comprises generating the set of integer phase ambiguity hypotheses using a Kalman filter.

19 . The method of claim 6 , wherein generating the set of integer phase ambiguity hypotheses comprises generating the set of integer phase ambiguity hypotheses using means and covariances generated by a Bierman-Thornton filter and at least one of a LAMBDA and an MLAMBDA algorithm.

20 . The method of claim 6 , further comprising reparametrizing the set of integer phase ambiguity hypotheses to decorrelate each integer phase ambiguity hypothesis.

Assignees

• Swift Navigation Inc

Inventors

• Horn Ian Maxwell
• Noble Fergus Macpherson

Classifications

• G01S19/51

  Relative positioning · CPC title

• G01S19/44 Primary

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