Method and apparatus using slant-path water delay estimates to correct global positioning satellite survey error
First Claim
1. In a system having a plurality of radio transmitters, at least one radio receiver, and means for calculating a position based upon signals received at said radio receiver from said plurality of radio transmitters, the improvement wherein said position calculating means comprises:
- means for reducing position calculation errors corresponding to atmospheric water delays, wherein said reducing means using data selected from a group consisting of multipath-corrected radiometer measurements, results from a boundary layer refractivity model, tomography profiles, atmospheric water vapor measurements obtained from at least one other radio receiver and, combinations thereof.
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Abstract
An atmospheric water vapor sensing system uses Global Positioning Satellites (GPS) to determine the refractivity and Slant-path Water Vapor Delay (SWD) between an Earth-based GPS receiver and a plurality of satellite-based GPS transmitters. The system provides improved precision in position calculation measurements by eliminating the refractivity effects of water vapor. No other system inputs are required apart from conventional GPS satellite signals and conventional satellite orbit data to implement the method. SWD arises from the refractivity in the integrated atmospheric water vapor in a column of atmosphere at an acute angular line-of-sight path between the Earth-based GPS receiver and any one of the plurality of satellite-based GPS transmitters. The system is especially useful in monitoring the Earth'"'"'s crustal deformation.
46 Citations
22 Claims
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1. In a system having a plurality of radio transmitters, at least one radio receiver, and means for calculating a position based upon signals received at said radio receiver from said plurality of radio transmitters, the improvement wherein said position calculating means comprises:
means for reducing position calculation errors corresponding to atmospheric water delays, wherein said reducing means using data selected from a group consisting of multipath-corrected radiometer measurements, results from a boundary layer refractivity model, tomography profiles, atmospheric water vapor measurements obtained from at least one other radio receiver and, combinations thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A high precision method of GPS surveying, said method comprising the steps of:
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measuring a plurality of signal propagation times sufficient to permit calculation of a position from said signal propagation times; correcting said plurality of signal propagation times for slant-path atmospheric water vapor delay to provide a corresponding plurality of corrected signal propagation times; and calculating a position based upon said plurality of signal propagation times, wherein said step of calculating a position includes reducing position calculation errors corresponding to atmospheric water delays through the use of data selected from a group consisting of multipath-corrected radiometer measurements, results from a boundary layer refractivity model, tomography profiles, atmospheric water vapor measurements obtained from at least one other radio receiver and, combinations thereof. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification