The Rsearch On Intersatellite Ranging And Navigation Satellite Autonomous Orbit Determination

The intersatellite ranging is the base for the application of satellite to satellite recovering gravity, navigation satellite autonomous orbit determination and satellite formation flying. And now, the satellite to satellite tranking for gravity research and the BeiDou2 navigation satellite system are in developing in China. The ground tracking stations of GPS can be arranged wordwidly to achieve high-precision orbit determination based on ground, but it is not the same for the Chinese BeiDou2 satellite navigation system. In order to get accurate orbit information, the use of both ground stations and inter-satellite range measurement information is an ideal way for precision orbit determination. And based on the distance measurement information of inter-satellite range, we can accomplish autonomous orbit determination. So, it is very importment for the research on the intersatellite ranging technology and the BeiDou2 navigation satellite autonomous orbit determination based on intersatellite ranging. The main achievements and contributions are as follows:1. In the static dynamic situation, a high-precision inter-satellite ranging technology named GIPR(Gradully Improving Precision Ranging) which is based on pseudo-random code and carriers, ambiguity-free, and be able of gradually improving the accuracy is proposed. Gives out a criterion for ambiguity-free frequencies selection and proves that when the carrier phase measurement accuracy is better than about1/4√2 circle, according to the frequency selection criteria given in the text, the accuracy can always be gradually improved. Experiments and simulation results show that after two times of the distance measurement, the accuracy can reach micron-level which can meet the most of the current range measurement accuracy requirements.2. In the dynamic situation, the paper shows that it is impossible to get the instantaneous inter-satellite range (distance between two satellites at a same time point) with high accuracy through only the inter-satellite distance measurement. In high dynamic environments, we can only accurately measure the distance between the two time points when a signal was launched and the other was received. Two ranging methods are proposed:one is based on one direction and the other is based on double directions. The effect of clock error on the range measurement precision of GNSS intersatellites is researched.3. In the weak dynamic situation, here presents an appropriate ranging method named WD_DOWR(Weak Dynamic_Double One Way Ranging) used to measure the instant intersatellite range. It combines the theory that the velocity of light is constant and the DOWR ranging technology. Gives out the relationship of the measurement precise,the distance and relative velocity.For the autonomous orbit determination technology of the global navigation satellite system, two central difference methods for inter-satellite ranging based autonomous orbit determination are proposed:4. The first automous orbit determination method is based on estimating the initial conditions, and named CDBFOD(Central-Difference Bayesian Filter based Orbit Determination) which exerts linear processing on dynamic model of the navigation satellite using the first-order Stirling interpolation formula and using the Bayesian filter to estimate the satellites init conditions which include the satates and paraments. In essence, it uses central difference approximation instead of Jacobi matrix to eliminate the process of solving the Jacobian matrix.5. The second method is named CDFOD which is a real-time orbit determination method. Approximate the dynamic model with a first-order Stirling interpolation firstly. Then use the central difference filters DD1 (first Divided Difference) and DD2(second Divided Difference) methods in nonlinear filtering techniques without the linear processing on the observation equation. Compared with traditional Kalman filter method, this scheme is not only simple but also has higher precision. Lastly, uses the self-dveloped simulation software on aotomous orbit determination based on intersatellite range named AOD V1.0 verifying the CDFOD method performance.