Method for positioning using GPS in a restrictive coverage environment
First Claim
1. A GPS system including:
- a base GPS receiver with an antenna that has a clear view of the sky;
one or more remote GPS receivers;
a data processing subsystem that collects range data from the base and remote GPS receivers over a plurality of hours and calculates the positions of the respective GPS receivers, the data processing center batch processing the data received from the respective remote receivers in multiple passes through the data using floating ambiguity filters that after the first pass are initialized with estimated positions that have been previously calculated.
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Accused Products
Abstract
A system consisting of a base GPS receiver with a clear view of the sky, one or more remote GPS receivers with restricted views of the sky and a processing center that batch processes range information provided by the GPS receivers determines the positions of the remote GPS receivers to within tight tolerances. The base GPS receiver and the remote GPS receivers produce range information based on the satellite signals that the respective receivers can track at a given time, and provide the range information to the processing center. The range information includes both code and carrier measurements for each of the signals that are being tracked by the respective GPS receivers. The center collects the range information over an extended period of time, for example, hours, days or weeks, and then batch processes the collected information in multiple passes through the data, to calculate the precise latitude, longitude and height of the receiver. The center batch processes the data using a floating ambiguity filter that, after a first pass through the data, is initialized with the position calculated in an earlier pass. The center also calculates the quality of the collected range information by fixing the position and position covariance of the floating ambiguity filter and using double differences with the base GPS receiver measurements, to ensure that the information used in subsequent position calculations is sufficiently reliable.
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Citations
19 Claims
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1. A GPS system including:
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a base GPS receiver with an antenna that has a clear view of the sky;
one or more remote GPS receivers;
a data processing subsystem that collects range data from the base and remote GPS receivers over a plurality of hours and calculates the positions of the respective GPS receivers, the data processing center batch processing the data received from the respective remote receivers in multiple passes through the data using floating ambiguity filters that after the first pass are initialized with estimated positions that have been previously calculated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of calculating GPS position in a restrictive coverage environment, the method including the steps of:
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receiving range data associated with a clear view of the sky from one or more base GPS receivers;
receiving range data from one or more remote receivers that have restricted views of the sky;
determining the position of a given remote receiver by batch processing the range data received over a plurality of hours in multiple passes through the data using a floating ambiguity filter that after a first pass through the data is initialized with a previously calculated estimated position. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification