Real-time fast decimeter-level GNSS positioning
First Claim
1. A method of predicting post-processed accuracy of observations collected at a rover over multiple epochs from signals of GNSS satellites, comprising:
- a. obtaining observations collected at the rover for a current epoch,b. obtaining a current-epoch satellite position for each satellite,c. obtaining an approximate current-epoch rover position,d. obtaining a current-epoch error model,e. determining a current-epoch error estimate from the current epoch error models and the current-epoch rover position and the current-epoch satellite positions and a prior-epoch error estimate, the current-epoch error estimate representing an estimated rover position error to be expected upon subsequent differential post-processing of the observations of the plurality of epochs with reference data of a corresponding plurality of epochs, andf. providing the current-epoch error estimate for use in determining whether observations of further epochs are needed to obtain a desired rover position error upon said subsequent differential post-processing.
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Abstract
Methods and apparatus for processing of data from GNSS receivers are presented. A real-time GNSS rover-engine, a long distance multi baseline averaging (MBA) method, and a stochastic post-processed accuracy predictor are described.
The real-time GNSS rover-engine provides high accuracy position determination (decimeter-level) with short occupation time (2 Minutes) for GIS applications.
The long distance multi baseline averaging (MBA) method improves differential-correction accuracy by averaging the position results from several different baselines. This technique provides a higher accuracy than any single baseline solution. It was found, that for long baselines (more than about 250 km), the usage of non-iono-free observables (e.g. L1-only or wide-lane) leads to a higher accuracy with MBA compared to the commonly used iono-free (LC) combination, because of the less noisy observables and the cancellation of the residual ionospheric errors.
The stochastic post-processed accuracy (SPPA) predictor calculates during data collection an estimate of the accuracy likely to be achieved after post-processing. This helps to optimize productivity when collecting GNSS data for which post-processed accuracy is important. The predictor examines the quality of carrier measurements and estimates how well the post-processed float solution will converge in the time since carrier lock was obtained.
65 Citations
22 Claims
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1. A method of predicting post-processed accuracy of observations collected at a rover over multiple epochs from signals of GNSS satellites, comprising:
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a. obtaining observations collected at the rover for a current epoch, b. obtaining a current-epoch satellite position for each satellite, c. obtaining an approximate current-epoch rover position, d. obtaining a current-epoch error model, e. determining a current-epoch error estimate from the current epoch error models and the current-epoch rover position and the current-epoch satellite positions and a prior-epoch error estimate, the current-epoch error estimate representing an estimated rover position error to be expected upon subsequent differential post-processing of the observations of the plurality of epochs with reference data of a corresponding plurality of epochs, and f. providing the current-epoch error estimate for use in determining whether observations of further epochs are needed to obtain a desired rover position error upon said subsequent differential post-processing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 22)
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11. Apparatus for predicting post-processed accuracy of observations collected at a rover over multiple epochs from signals of GNSS satellites, comprising,
a. a first element to obtain observations collected at the rover for a current epoch, b. a second element to obtain a current-epoch satellite position for each satellite, c. a third element to obtain a current-epoch rover position, d. a fourth element to obtain current-epoch error models, e. a fifth element to determine a current-epoch error estimate from the current epoch error models and the current-epoch rover position and the current-epoch satellite positions and a prior-epoch error estimate, the current-epoch error estimate representing an estimated rover position error to be expected upon subsequent differential post-processing of the observations of the plurality of epochs with reference data of a corresponding plurality of epochs, and f. a sixth element to provide the current-epoch error estimate for use in determining whether observations of further epochs are needed to obtain a desired rover position error upon said subsequent differential post-processing.
Specification