Systems and Methods for Synthesizing GPS Measurements to Improve GPS Location Availability
First Claim
1. A method for synthesizing global positioning system (GPS) measurements, the method comprising:
- receiving GPS signals from signal sources by a navigation device;
estimating pseudorange (PR) and delta pseudo range (DPR) based on the received GPS signals; and
calculating a position fix using the estimated PR and DPR in a navigation solution.
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Abstract
There are situations where GPS signals are received from less than four satellites. In order to improve the GPS location availability, disclosed here are systems and methods for synthesizing GPS measurements, which, together with fewer than four available real GPS signals, can be used to calculate a position fix. In particular, GPS range measurements for lost satellites, which are satellites that were previously tracked but are now not tracked, are synthesized to improve GPS signal availability. The synthesized measurements are used along with real measurements to enable accurate position fix even when GPS satellite availability is poor. Different synthesized measurement generation schemes, depending on whether an INS/DR aiding system is available, are further described herein.
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Citations
25 Claims
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1. A method for synthesizing global positioning system (GPS) measurements, the method comprising:
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receiving GPS signals from signal sources by a navigation device; estimating pseudorange (PR) and delta pseudo range (DPR) based on the received GPS signals; and calculating a position fix using the estimated PR and DPR in a navigation solution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A system for synthesizing global positioning system (GPS) measurements comprising:
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a GPS receiver that is configured to receive GPS signals and estimate pseudorange (PR) and delta pseudo range (DPR) based on the received GPS signals; and a server in an Assisted GPS (AGPS) operation mode that is configured to; receive the estimated PR and DPR from the GPS receiver, and calculate a position fix based on the received estimated PR and DPR. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A GPS receiver comprising:
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an antenna that is configured to receive GPS signals from at least four signal sources; and a baseband digital signal processing that is configured to; receive the GPS signals from the antenna, calculate pseudoranges (PRs) and delta pseudo ranges (DPRs) associated with the GPS signals from three or less signal sources of the at least four signal sources, determine whether the GPS signals are received from the three or less signal sources of the at least four signal sources, responsive to determining that the GPS signals are received from the three or less signal sources of the at least four signal sources, determine which signal source was lost from the at least four signal sources, and estimate PR and DPR for the lost signal source based on the calculated PRs and DPRs, and calculate a position fix using the calculated PRs and DPRs, and the estimated PR and DPR in a navigation solution.
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Specification