| 摘要 |
In a DGPS, accurate post-processed corrections to user receiver locations are made while minimizing the amount of data required to be stored at reference station and user receiver positions. Further, such corrections are available even if reference station corrections cannot be received by the user in real-time. The user receiver acquires in-view GPS satellites, computes, and stores user stand-alone position, time of computation, and acquired satellite identification. Reference stations generate correction data for the same satellites at the same time period, which correction data are broadcast but need not be received by the user in real-time. Almanac information for the relevant satellites is also made available to at least the user receiver. Stand-alone user receiver positional data and the almanac data for the same acquired satellites are used by a CPU, located at a remote site able to receive reference station transmissions and/or in the user receiver, to compute corrections to user receiver positions.
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