GPS correction methods, apparatus and signals
First Claim
1. System for generating GPS corrections comprising:
- a. at least one data collection hub for collecting measurements from a plurality of reference stations;
b. at least one network processor for processing the measurements to produce corrections by determining network corrections from the measurements, determining residual errors at one or more of the reference stations comprising a vernier cell, and preparing vernier-cell corrections to compensate the residual errors within a vernier-cell region; and
c. a distribution system for distributing the corrections for use by mobile units wherein the reference stations are organized in a plurality of regional subnets, the reference stations of each regional subnet having a set of common-visibility GPS satellites, and the regional subnets overlapping such that each adjacent pair of regional subnets includes at least one reference station in common.
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Accused Products
Abstract
Methods and apparatus are described and illustrated for producing GPS corrections, comprising: collecting measurements from a plurality of network reference stations; determining network corrections from the measurements; determining residual errors at one or more vernier-cell reference stations; and preparing vernier-cell corrections to compensate the residual errors within a vernier-cell region. Network correction streams are described and illustrated which contain network corrections derived from a plurality of network reference stations and residual error corrections derived from one or more vernier-cell reference stations. Methods and apparatus are described for employing such network correction streams in a virtual reference station to produce corrections and/or virtual measurements for use in a GPS receiver.
166 Citations
42 Claims
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1. System for generating GPS corrections comprising:
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a. at least one data collection hub for collecting measurements from a plurality of reference stations;
b. at least one network processor for processing the measurements to produce corrections by determining network corrections from the measurements, determining residual errors at one or more of the reference stations comprising a vernier cell, and preparing vernier-cell corrections to compensate the residual errors within a vernier-cell region; and
c. a distribution system for distributing the corrections for use by mobile units wherein the reference stations are organized in a plurality of regional subnets, the reference stations of each regional subnet having a set of common-visibility GPS satellites, and the regional subnets overlapping such that each adjacent pair of regional subnets includes at least one reference station in common. - View Dependent Claims (2, 3, 4)
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5. System for generating GPS corrections comprising:
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a. at least one data collection hub for collecting measurements from a plurality of reference stations;
b. at least one network processor for processing the measurements to produce corrections by determining network corrections from the measurements, determining residual errors at one or more of the reference stations comprising a vernier cell, and preparing vernier-cell corrections to compensate the residual errors within a vernier-cell region; and
c. a distribution system for distributing the corrections for use by mobile units wherein a plurality of reference stations is located within the vernier-cell region and wherein geographical density of reference stations located within the vernier-cell region is greater than geographical density of reference stations located outside the vernier-cell region.
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6. A method for producing GPS corrections, comprising:
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a. collecting measurements from a plurality of GPS reference stations;
b. determining network corrections from the measurements;
c. determining residual errors at one or more of the reference stations located within a vernier-cell region; and
d. preparing vernier-cell corrections to compensate residual errors within the vernier-cell region, wherein the reference stations located within the vernier-cell region are of geographically greater density than the reference stations located outside the vernier-cell region. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. Apparatus for producing GPS corrections, comprising:
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a. means for collecting measurements from a plurality of GPS reference stations;
b. means for determining network corrections from the measurements;
c. means for determining residual errors at one or more of the reference stations located within a vernier-cell region; and
d. means for preparing vernier-cell corrections to compensate residual errors within the vernier-cell region, wherein the reference stations located within the vernier-cell regions are of geographically greater density than the reference stations located outside the vernier-cell regions. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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26. Apparatus for producing GPS corrections, comprising:
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a. means for collecting measurements from a plurality of GPS reference stations;
b. means for determining network corrections from the measurements;
c. means for determining residual errors at one or more of the reference stations located within a vernier-cell region; and
d. means for preparing vernier-cell corrections to compensate residual errors within the vernier-cell region, wherein the vernier-cell region has a centroid and wherein the means for preparing vernier-cell corrections determines a centroid component which defines an error field for a satellite visible in the vernier-cell region.
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27. Apparatus for producing GPS corrections, comprising:
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a. means for collecting measurements from a plurality of GPS reference stations;
b. means for determining network corrections from the measurements;
c. means for determining residual errors at one or more of the reference stations located within a vernier-cell region; and
d. means for preparing vernier-cell corrections to compensate residual errors within the vernier-cell region, wherein the vernier cell has a centroid and wherein the means for preparing vernier-cell corrections determines a centroid component, an east-west slope, and a north-south slope, such that the centroid component the east-west slope, and the north-south slope define an error field for a satellite visible in the vernier-cell region.
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28. Apparatus for producing GPS corrections, comprising:
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a. means for collecting measurements from a plurality of GPS reference stations;
b. means for determining network corrections from the measurements;
c. means for determining residual error at one or more of the reference stations located within a vernier-cell region; and
d. means for preparing vernier-cell corrections to compensate residual errors within the vernier-cell region, wherein the means for preparing vernier-cell corrections determines error-field parameters for a satellite visible in the vernier-cell region from a set of clock-adjusted instantaneous range error values for at least three reference stations located within the vernier-cell region.
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29. Apparatus for producing GPS corrections, comprising:
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a. means for collecting measurements from a plurality of GPS reference stations;
b. means for determining network corrections from the measurements;
c. means for determining residual errors at one or more of the reference stations located within a vernier-cell region; and
d. means for preparing vernier-cell corrections to compensate residual errors within the vernier-cell region, wherein the means for preparing vernier-cell corrections computes a set of error-field parameters for a satellite visible in the vernier-cell region from a set of data comprising a clock error for the satellite and measurements for the satellite from each of at least three reference stations located within the vernier-cell region.
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30. Apparatus for producing GPS corrections, comprising:
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a. means for collecting measurements from a plurality of GPS reference stations;
b. means for determining network corrections from the measurements;
c. means for determining residual errors at one or more of the reference stations located within a vernier-cell region; and
d. means for preparing vernier-cell corrections to compensate residual errors within the vernier-cell region, wherein the vernier-cell corrections comprise a set of error-field parameters for a plurality of satellites visible in the vernier-cell region, and wherein the apparatus further comprises means for checking the vernier-cell corrections by;
calculating a position fix for each of a plurality of reference stations located within the vernier-cell region using the network corrections and the error-field parameters; and
comparing the calculated position fix with the known position of the reference station to determine a residual error after application of the vernier-cell corrections.- View Dependent Claims (31)
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32. Method of using a network correction stream in a navigator to produce corrected position fixes, comprising:
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a. receiving network correction data derived from a plurality of network reference stations and residual error corrections derived from one or more vernier-cell reference stations; and
b. preparing from the network correction data and residual error corrections a set of corrections suitable for a declared location, wherein the residual error corrections are derived from reference stations located within a plurality of vernier-cell regions in which the reference stations are of geographically greater density than the reference stations located outside the vernier-cell regions. - View Dependent Claims (33, 34, 35)
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36. Method of using a network correction stream up a navigator to produce corrected position fixes, comprising:
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a. receiving network correction data derived from a plurality of network reference stations and residual error corrections derived from one or more vernier-cell reference stations; and
b. preparing from the network correction data and residual error corrections a set of corrections suitable for a declared location, wherein the vernier cell has a centroid and the error field of the vernier cell is defined by a centroid component.
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37. Method of using a network correction stream in a navigator to produce corrected position fixes, comprising:
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a. receiving network correction data derived from a plurality of network reference stations and residual error corrections derived from one or more vernier-cell reference stations; and
b. preparing from the network correction data and residual error corrections a set of corrections suitable for a declared location, wherein the vernier cell has a centroid, and the error field about the centroid is defined by a centroid component, an east-west slope, and a north-south slope. - View Dependent Claims (38)
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39. Method of using a network correction stream in a navigator to produce corrected position fixes, comprising:
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a. receiving network correction data derived from a plurality of network reference stations and residual error corrections derived from one or more vernier-cell reference stations; and
b. preparing from the network correction data and residual error corrections a set of corrections suitable for a declared location, further comprising;
determining a calculated L1 pseudorange for a GPS satellite;
applying the residual error corrections derived from one or more vernier-cell reference stations to determine a difference between the L1 pseudorange and a virtual measurement of L1 pseudorange at the declared location; and
applying the difference to the calculated L1 pseudorange to obtain a virtual L1 pseudorange.- View Dependent Claims (40, 41, 42)
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Specification