GPS数据处理软件软件介绍.ppt

Service Specifications The observations processed are selected from the submitted RINEX file in the following order: 1. L1 and L2 pseudo-range and carrier phase observations 2. L1 pseudo-range observation An L1 pseudo-range only solution will be performed in case of failure of the L1 and L2 pseudo-range and carrier phase solution. Failure to detect one of the above two observation sets results in an unsuccessful job termination. Availability of Precise Orbits and Clocks The PPP application can only process GPS observations if precise GPS orbits and clocks products are available. It will use the best products available at the time the data is submitted. The Availability Table below lists the solutions that can be obtained. It is important to note that the quality of the GPS orbit and clock estimates, and consequently of the PPP derived positions, has improved from 10cm and several nanoseconds in 1994 to about 2cm and 0.1 nanoseconds in 2003. PPP Availability Table 适用性 Since PPP processing is based on precise GPS orbit and clocks products that are global in nature it may be used to process GPS observations made anywhere on or near Earth, at anytime of day. Observation session duration is subject to the following restrictions: Minimum duration of GPS data set There is no minimum length for a GPS observation session . However, the quality of a PPP computed positions will not be optimal until the carrier phase ambiguities have converged. For short data sets, positions will effectively be calculated using only the pseudo-range observations. Longer data sets make it possible to resolve the ambiguities required to recover positions using the more precise carrier phase observations. Maximum duration of GPS data set Data sets up to six days long can be processed with PPP providing the uncompressed RINEX observation file is less than 100Mb. Submission of a file exceeding 100Mb will result in an unsuccessful job termination. 数据压缩 File Compression Since both the RINEX and Compa