AN ANALYTICAL METHOD OF COMPUTING THE STATE TRANSITION MATRIX IN ORBIT DETERMINATION
ZHANG Qiang LIU Lin (Department of Astronomy, Nanjing University, Nanjing 210093)
Because of the complexity of force models, the precise ephemeris and the state transition matrix in orbit determination are usually obtained by solving two groups of ordinary differential equations with numerical integration. In this paper, a simplified analytical method for computing the state transition matrix is presented. This method is not only very efficient for the case that the orbit arc is not too long, but also it can avoid the integration of two groups of differential equations at the same time. A practical test justifies the efficiency of the method.