Detection and Correction of Anomalous Measurements and Ambiguity Resolution in a Global Navigation Satellite System Receiver
First Claim
1. A method for processing measurements in a global navigation satellite system comprising a first navigation receiver located in a rover and a second navigation receiver located in a base station, the method comprising the steps of:
- receiving a first plurality of measurements based on a first plurality of carrier signals received by the first navigation receiver from a plurality of global navigation satellites;
receiving a second plurality of measurements based on a second plurality of carrier signals received by the second navigation receiver from the plurality of global navigation satellites, each carrier signal in the second plurality of carrier signals corresponding to a carrier signal in the first plurality of carrier signals, and each measurement in the second plurality of measurements corresponding to a measurement in the first plurality of measurements;
calculating a first plurality of single differences based on the first plurality of measurements and the second plurality of measurements;
determining a state vector based on the first plurality of single differences;
calculating a second plurality of single differences based on an observation model;
calculating a plurality of residuals based on the first plurality of single differences and the second plurality of single differences;
determining whether the first plurality of measurements and the second plurality of measurements are consistent with the observation model; and
in response to determining that the first plurality of measurements and the second plurality of measurements are not consistent with the observation model, detecting anomalous measurements.
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Abstract
A global navigation system includes a first navigation receiver located in a rover and a second navigation receiver located in a base station. Single differences of measurements of satellite signals received at the two receivers are calculated and compared to single differences derived from an observation model. Anomalous measurements are detected and removed prior to performing computations for determining the output position of the rover and resolving integer ambiguities. Detection criteria are based on the residuals between the calculated and the derived single differences. For resolving integer ambiguities, computations based on Cholesky information Kalman filters and Householder transformations are advantageously applied. Changes in the state of the satellite constellation from one epoch to another are included in the computations.
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Citations
30 Claims
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1. A method for processing measurements in a global navigation satellite system comprising a first navigation receiver located in a rover and a second navigation receiver located in a base station, the method comprising the steps of:
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receiving a first plurality of measurements based on a first plurality of carrier signals received by the first navigation receiver from a plurality of global navigation satellites; receiving a second plurality of measurements based on a second plurality of carrier signals received by the second navigation receiver from the plurality of global navigation satellites, each carrier signal in the second plurality of carrier signals corresponding to a carrier signal in the first plurality of carrier signals, and each measurement in the second plurality of measurements corresponding to a measurement in the first plurality of measurements; calculating a first plurality of single differences based on the first plurality of measurements and the second plurality of measurements; determining a state vector based on the first plurality of single differences; calculating a second plurality of single differences based on an observation model; calculating a plurality of residuals based on the first plurality of single differences and the second plurality of single differences; determining whether the first plurality of measurements and the second plurality of measurements are consistent with the observation model; and in response to determining that the first plurality of measurements and the second plurality of measurements are not consistent with the observation model, detecting anomalous measurements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for processing measurements in a global navigation satellite system comprising a first navigation receiver located in a rover and a second navigation receiver located in a base station, the apparatus comprising:
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means for receiving a first plurality of measurements based on a first plurality of carrier signals received by the first navigation receiver from a plurality of global navigation satellites; means for receiving a second plurality of measurements based on a second plurality of carrier signals received by the second navigation receiver from the plurality of global navigation satellites, each carrier signal in the second plurality of carrier signals corresponding to a carrier signal in the first plurality of carrier signals, and each measurement in the second plurality of measurements corresponding to a measurement in the first plurality of measurements; means for calculating a first plurality of single differences based on the first plurality of measurements and the second plurality of measurements; means for determining a state vector based on the first plurality of single differences; means for calculating a second plurality of single differences based on an observation model; means for calculating a plurality of residuals based on the first plurality of single differences and the second plurality of single differences; means for determining whether the first plurality of measurements and the second plurality of measurements are consistent with the observation model; and means for, in response to determining that the first plurality of measurements and the second plurality of measurements are not consistent with the observation model, detecting anomalous measurements. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A computer readable medium storing computer program instructions for processing measurements in a global navigation satellite system comprising a first navigation receiver located in a rover and a second navigation receiver located in a base station, the computer program instructions defining the steps of:
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receiving a first plurality of measurements based on a first plurality of carrier signals received by the first navigation receiver from a plurality of global navigation satellites; receiving a second plurality of measurements based on a second plurality of carrier signals received by the second navigation receiver from the plurality of global navigation satellites, each carrier signal in the second plurality of carrier signals corresponding to a carrier signal in the first plurality of carrier signals, and each measurement in the second plurality of measurements corresponding to a measurement in the first plurality of measurements; calculating a first plurality of single differences based on the first plurality of measurements and the second plurality of measurements; determining a state vector based on the first plurality of single differences; calculating a second plurality of single differences based on an observation model; calculating a plurality of residuals based on the first plurality of single differences and the second plurality of single differences; determining whether the first plurality of measurements and the second plurality of measurements are consistent with the observation model; and in response to determining that the first plurality of measurements and the second plurality of measurements are not consistent with the observation model, detecting anomalous measurements. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification