Gnss Signal Processing Methods and Apparatus
First Claim
Patent Images
1. A method of processing a set of GNSS signal data received from multiple satellites at multiple reference stations, comprising:
- a. for each reference station,applying to the GNSS signal data a station geometry filter to estimate values for local states representing parameters unique to that reference station and for common states representing parameters common to all reference stations,providing values for the common states and their covariance to a master filter, andpreparing updated estimates for the local states when updated values for the common states are provided by a master filter, andb. applying to the values for the common states and their covariances a master filter to estimate updated values for the common states, and to provide the updated values to the station geometry filters.
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Abstract
Methods and apparatus for processing of data from a network of GNSS reference stations are presented. An ionosphere-free, federated geometry filter is employed so that computation time increases only linearly with the increase in number of reference stations, significantly reducing processing time as compared to a centralized filter approach.
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Citations
33 Claims
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1. A method of processing a set of GNSS signal data received from multiple satellites at multiple reference stations, comprising:
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a. for each reference station, applying to the GNSS signal data a station geometry filter to estimate values for local states representing parameters unique to that reference station and for common states representing parameters common to all reference stations, providing values for the common states and their covariance to a master filter, and preparing updated estimates for the local states when updated values for the common states are provided by a master filter, and b. applying to the values for the common states and their covariances a master filter to estimate updated values for the common states, and to provide the updated values to the station geometry filters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Apparatus for processing a set of GNSS signal data received from multiple satellites at multiple reference stations, comprising:
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a. for each reference station, a station geometry filter having local states representing parameters unique to that reference station and common states representing parameters common to all reference stations, wherein the station geometry filter is operative to estimate values for the local states and for the common states, to provide values for the common states and their covariance to a master filter, and to prepared updated estimates for the local states when updated values for the common states are provided by a master filter, and b. a master filter having common states representing parameters common to all reference stations, the master filter being operative to receive values for the common states and their covariances from the station geometry filters, to estimate from the received values and their covariances updated values for the common states, and to provide the updated values to the station geometry filters. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A network correction data stream prepared by processing a set of GNSS signal data derived from signals having at least two carrier frequencies and received from two or more satellites at two or more reference stations over multiple epochs, wherein the data stream is prepared by:
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a. for each reference station, applying to the GNSS signal data a station geometry filter to estimate values for local states representing parameters unique to that reference station and for common states representing parameters common to all reference stations, providing values for the common states and their covariance to a master filter, and preparing updated estimates for the local states when updated values for the common states are provided by a master filter; b. applying to the values for the common states and their covariances a master filter to estimate updated values for the common states, and to provide the updated values to the station geometry filters; c. combining states values from the station geometry filters to obtain an array of ionosphere-free ambiguity estimates and associated statistical information; d. forming a geometry-free combination of the GNSS signal data and applying a bank of geometry-free filters to the geometry-free combination to obtain geometry-free ambiguity estimates and associated statistical information; and e. combining the ionosphere-free ambiguity estimates and associated statistical information with the geometry-free ambiguity estimates and associated statistical information to determine a combined array of ambiguity estimates and associated statistical information; f. repeating a.-e. for each of multiple epochs to update the ambiguity estimates and associated statistical information; and g. combining the ambiguity estimates with the set of GNSS signal data to produce a set of network broadcast data for use by GNSS receivers within the network area.
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29. (canceled)
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30. (canceled)
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31. A virtual-reference-station correction data set prepared by processing a set of GNSS signal data derived from signals having at least two carrier frequencies and received from two or more satellites at two or more reference stations over multiple epochs, wherein the data stream is prepared by:
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a. for each reference station, applying to the GNSS signal data a station geometry filter to estimate values for local states representing parameters unique to that reference station and for common states representing parameters common to all reference stations, providing values for the common states and their covariance to a master filter, and preparing updated estimates for the local states when updated values for the common states are provided by a master filter; b. applying to the values for the common states and their covariances a master filter to estimate updated values for the common states, and to provide the updated values to the station geometry filters; c. combining state values from the station geometry filters to obtain an array of ionosphere-free ambiguity estimates and associated statistical information; d. forming a geometry-free combination of the GNSS signal data and applying a bank of geometry-free filters to the geometry-free combination to obtain geometry-free ambiguity estimates and associated statistical information; e. combining the ionosphere-free ambiguity estimates and associated statistical information with the geometry-free ambiguity estimates and associated statistical information to determine a combined array of ambiguity estimates and associated statistical information; f. repeating a.-e. for each of multiple epochs to update the ambiguity estimates and associated statistical information; and g. combining the ambiguity estimates with the set of GNSS signal data to produce a set of correction data for use by a GNSS receiver at a mobile GNSS receiver location within the network area.
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32. (canceled)
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33. (canceled)
Specification