Research On Error Correcting Technology For RDSS Subsystem Of Compass Navigation Satellite System

The constructing project of the second generation of the Navigation Positioning System-"Compass Navigation Satellite System" (Code Name: the BD-2) compared with the BD-1 system, the number of GEO satellites is increased to 5. Meantime, the function, performance and precision in the BD-2 system are much better than before. Besides, the BD-2 system can provide both RDSS active position and RNSS passive position.To meet the need of high precision of application services in the BD-2 system, the paper makes plenty of research and presents the method and implement of the error correcting with the observation data in the RDSS system. The main work of the paper as follow:1. Describing the principle of the errors in the process of the electric wave transmission, and summarizing the various combination of the exist errors in the application services. Besides, the space-time model, which is built for the error correcting of observed data in the RDSS subsystem, is presented in the paper.2. Presenting two methods for getting the ionosphere TEC parameter with the observation data in the BD-1 system, and importantly, a method for getting the ionosphere TEC parameter using the data of simple pseudorange data is put forward, which overcomes the disadvantageous effects caused by the unreliability of the time difference.3. Bringing forward the algorithm of calculating zero drift of hardware equipments in the GEO stars and stations, which provides an effective approach for the problem of precision affected by the time delay.4. Validating a variety of algorithms mentioned in the paper, and analyzing the feasibility of these algorithms.5. Analyzing the observation data of the BD-1 system, and pointing out some problem of the BD-1 system, such as the unreliability of measuring the time difference and the zero bias existed in the demodulating unit.Three innovation points have been brought out in the paper: 1. Putting forward the algorithm of calculating the ionosphere TEC parameter with pseudorange data, which overcomes the disadvantage of using unreliable time difference data. And the algorithm also could be a standby approach for the BD-2 system in future.2. Putting forward the algorithm of calculating zero drift with observed data, which would be a solution for zero value drifting.3. Pointing out some problems such as the unreliable time difference data and zero bias in the BD-1 system.The work mentioned above would make a good base for the RDSS errors correcting system and would be a good reference for the next research work.