Research Of Station Optimization Method In Orbit Determination Based On The Value Of DOP

The distribution of the ground stations will directly affect the precision of navigation satellite orbit and the performance of satellite positioning and navigation. All countries with navigation satellite system attaches great importance to the distribution and construction of the ground stations(monitoring network). Based on the DOP value of GNSS satellite orbit determination equation, the distribution model and the screening model of the optimal distribution of the ground station is studied. The main research content is as follows:(1) The mutual transformation relationship in the system of space and time of the GNSS satellite system is given, the calculation formula of the precise orbit determination of GNSS satellite system is deduced, and the precision evaluation function of the satellite orbit parameters is given. Finally, the main factors influencing the precision of GNSS orbit determination on the basis of precision evaluation function is analyzed: one is the allocation strategy of the proportion of the observed values of the weights; the second is the relative geometry of the satellites stations.(2) With the minimum DOP value of orbit determination equation of GNSS for the principle, index function to measure the precision of the satellite orbit parameters by solving GNSS observation data is derived. Through in the three regions(Asia, Asia and North America, globe) to select the same number of visual experiment station data, the validity of the index function is verified.(3) With selecting ground station of Beidou satellite navigation system in the global as an example, the global optimal layout of station distribution theory and the method is studied. First of all, a grid optimization method for the selected stations on the criterion of minimizing ODOP is put forward. This method to choose the ground stations compares with exhaustive method. The correctness of the grid optimization method is verified. However, when selecting a plurality of selected ground stations, the grid optimization method requires a lot of computing time. So using genetic algorithm to improve the grid optimization, the grid optimization method based on genetic algorithm is proposed. This method can quickly select the optimum distribution of the location of the station, and the correctness and validity of the method was verified. Finally, when using this method to select 17 Beidou global ground stations, computing takes about 35 hours.(4) GNSS data analysis center need high precision and timeliness of the fast, super-fast track product. The current situation of global tracking station distribution are inhomogeneity. The measures and formulas of data quality analysis is given, and multi-system data quality analysis software is written. Then the formula of the optimal station orbit determination based on the satellite orbit determination equations is deduced. A new optimization selection model on the basis of sub-network optimization method is proposed. Found by experiment, orbit determination precision of 72 optimal stations selected by the optimal station distribution screening model is nearly equivalent to 216 stations. The time of calculating 72 optimal stations spend only a third of time of calculating 216 stations.