Establishing And Testing A New Compact Wide Area Differential GPS System In China Area

With the character of precision, real time and low cost, GPS is considered as one of the most important way in navigating system. Three dimension errors under 100m could fit the demand of normal user. But one hand some real-time positioning users, such as marine and land navigation, require much higher position precise. On the other hand, due to the presence of the Selective Availability of the GPS, real-time positioning precise was obviously disturbed. To achieve high positioning accuracies, differential GPS comes to be one of most effective way, which was now used widely.Using GPS observation data from differential GPS reference stations, several errors, which can't modeled, were solved and sent to user around these reference station. There are mainly two kinds of differential GPS, Local area DGPS Systems (LADGPS) and Wide area DGPS Systems (WADGPS). The main disadvantage of LADGPS is that position accuracy degrades as the reference-to-user separation increases. Analysis show that the main error sources for long-range baselines is required as errors in the satellite orbit and ionospheric refraction. Simple correction models for WADGPS were developed in this thesis to achieve precise long-range navigation.The main content of this thesis is as following:1. Introduce several normal Ionospheric model. Then three Ionospheric grid model were discussed in detail.2. Satellite clock and broadcast ephemeris error correction model were introduced briefly. One simple equivalent satellite clock correction modelwas established.The processing results of some real observation data show that simple WADGPS models works well.