Construction And Precision Analysis Of Ionospheric Delay Function Model In Chinese Region

With the rapid development of GPS and other satellite navigation system as well as the high precise of the navigation positioning, especially SA is cancelled, the effect of ionospheric delay to radio propagation, ionosphere mechanism exploit using satellite and ionosphere monitoring draw more and more attention. The research on the change of ionosphere especially that of total electronic content(TEC) is the central issue.But during the survey of TEC by GPS, the main error is instrument biases(i.e. satellite instrument bias and receiver instrument bias, both called differential code bias(DCB)).the computing result shows that the biggest DCB is up to 7 ns. So the influence of DCB while using GPS to do research on TEC is also considered. The content of this paper is as follows:1. The essay illustrates the overview of the ionosphere research and the development of it simply, at the same time shows the functional principles of GPS and the basic method to research ionosphere using GPS.2. The paper presents several ionosphere delay correction model, their merits and shortcoming partly and the comparison between them.3. Construct the different nets with GPS tracking data and model the polynomial ionosphere model(POLY) over china region, compute the receiver DCB and satellite DCB, establish a set of software and do some relevant analysis. Comparing the post ionosphere product supported by CODE, results shows that the precise of the real-time vertical total electronic content(VTEC) and satellite DCB over China GPS region is up to 2.0 TECu and 0.2 ns. Fix some eyes on the reliability of satellite DCB gained independently over regional net. The comparison between real-time measured satellite DCB and that of CODE shows that in order to gain the reliable result of satellite DCB over regional network, it needs some requirement of the size of regional GPS net.4. In order to choose the suitable sphere harmonic deploy degree, some experiment computations and comparisons have been done. The result shows 4 degrees and orders deploy is right.5. Construct Chinese regional low degree sphere harmonic ionosphere model(LD-SPH) and compute the instrumental bias simultaneously using 26 GPS stations'tracking observatory data. After comparing with CODE, it shows that the precise of VTEC and satellite DCB over Chinese GPS regional network is up to 1.0 TECu and 0.21 ns. That means constructing the Chinese regional LD-SPHM is feasible and reliable.