System and method for computing positioning protection levels

Patent metadata

Field	Value
Publication number	US-12085654-B2
Application number	US-202318217954-A
Country	US
Kind code	B2
Filing date	Jul 3, 2023
Priority date	Jul 24, 2021
Publication date	Sep 10, 2024
Grant date	Sep 10, 2024

Abstract

A method or system can include or be configured to receive a set of satellite observations, receiving sensor data, determining a position estimate and associated positioning error for a rover based on the set of satellite observations and the sensor data, determine a protection level associated with the position estimate based on a set of potential faults, and optionally provide an alert when the positioning error exceeds the protection level.

First claim

We claim:

1. A system comprising a processor configured to:
determine a delayed positioning solution for a rover comprising:
receiving satellite observations tracked by an antenna mounted to a rover; and
determining the delayed positioning solution by:
determining a set of carrier phase ambiguity hypothesis for each satellite observation of the satellite observations; and
selecting a carrier phase ambiguity of the set of carrier phase ambiguity hypotheses based on results of a hypothesis test comparing carrier phase ambiguities of the set of integer phase ambiguity hypotheses; and
calculating the delayed positioning solution and a delayed positioning solution covariance using the satellite observations and the selected carrier phase ambiguities; and

determine a real-time positioning solution for the rover by:
receiving sensor data measured by an inertial measurement unit of the rover;
correcting the sensor data for a sensor bias determined based on the delayed positioning solution;
propagating a previous real-time positioning solution to the real-time positioning solution based on the corrected sensor data; and
propagating the delayed positioning solution covariance.

2. The system of claim 1 , wherein the delayed positioning solution is delayed by at most 1 second relative to the real-time positioning solution.

3. The system of claim 1 , wherein determining the real-time positioning solution for the rover further comprises determining a protection level associated with the real-time positioning solution.

4. The system of claim 3 , where the protection level is determined based on a set of potential faults comprising potential satellite faults and potential sensor faults.

5. The system of claim 4 , wherein the potential satellite faults comprise multipath events, interference errors, cycle slips, data corruption, code carrier incoherency, satellite clock faults, satellite clock drift, unscheduled satellite maneuvers, jump drift, antenna pattern changing, non-line of sight faults, receiver clock offset jumps, evil waveform, or combinations thereof.

6. The system of claim 4 , wherein the potential sensor faults comprise sensor bias instabilities, scale factor errors, clipping problems, update failures, accelerometer error, gyroscope error, signal jamming, signal spoofing, misalignment errors, cross axis errors, thermal gradient errors, acceleration errors, coning errors, sculling errors, centrifugal acceleration effects, or combinations thereof.

7. The system of claim 3 , wherein determining the protection

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where TIR is a target integrity risk, N is a number of events, P(E>PL|H i ) is the impact of event i, PL is the protection level, P(H i ) is the probability of event i occurring, P md (H i ) is the probability of not detecting event i.

8. The system of claim 7 , wherein solving

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comprises iteratively solving

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Assignees

• Swift Navigation Inc

Inventors

• Reimer Christian
• Brocard Philippe

Classifications

• G01S19/44

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

• G01S19/20

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

• G01S19/40

  Correcting position, velocity or attitude · CPC title

• G01S19/47 Primary

  the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial · CPC title