Research On Cei-based Precise Orbit Determination

Short baseline connected-element interferometry (CEI) has the advantages of high angular precision, baselines of short length, flexible network distribution, nearly real-time processing, which can be adopted to complement and enhance the measurement and control system of geostationary satellites and other satellites at present. The CEI-based orbit determination precision of GEO, MEO, IGSO, LEO satellite is mainly discussed. The main work is summarized as follows:1) As to the CEI system, the characteristics, several techniques, precision of angular measurement, differences between CEI and other orbit measurement techniques, measurement principle of CEI are introduced.2) The analysis of precision of GEO is the emphasis, the contents are as follows: feasibility of the solution of the ambiguity, the correlation between systematic errors and orbit parameters, analysis of the orbit determination precision while integrating CEI with SLR, the strategy of fast orbit recovery, analysis of the orbit determination precision while considering the ambiguity, relative orbit determination of collocation satellites.3) The orbit determination precision of MEO, IGSO is analyzed. The method of orbit determination model with additional ambiguity parameters is designed to solve the problem of the ambiguity. The conclusions are as follows: Two sets of short dual-orthogonal baselines should be distributed respectively in the east and west boundary of our country to improve the precision of GEO, MEO. The precision of GEO in radial component and crros-track component can reach to magnitude of one decimeter with the sample rate of one minute, while 10 meters in along-track positional component. The precision of MEO in crros-track component can reach to magnitude of one decimeter with the sample rate of 30 seconds, while one centimeter in radial component and along-track positional component. Only one set of the baselines need to be distributed near the satellite subset point (SSP) of IGSO, in which case the precision in radial component and crros-track component can reach to magnitude of one decimeter with the sample rate of one minute, while one meter in along-track positional component.4) As to the spacecraft rendezvous, in the course of long distance navigation, the method of batch processing is adopted to the precise orbit determination, while the method of kalman filter is adopted to the real-time orbit determination. Observation type contains phase-delay data and phase-delay rate data in the method of batch processing. The relative orbit precision can be decreased to no more than 100m when the observation data are abundant. In the method of kalman filter, firstly the absolute position and velocity precision of both spacecraft can be acquired by the absolute filter, then the relative orbit can be acquired by subtraction, the relative position precision can reach to magnitude of 10 meters, the relative velocity precision can reach to magnitude of one centimeter per second.5) In the course of short distance navigation, relative filter is adopted to the real-time relative orbit determination. The method of real-time solving ambiguity parameters is designed to solve the problem of ambiguity, that is to get the floating point values firstly, which can converge after several minutes, then get the fixed values. The initial orbit precision of the target spacecraft can have a great influence on the relative orbit precision, the method of relative filter associated with absolute filter should be designed to solve this problem.