Research on modeling and simulation of semi-autonomous orbit determination for satellite navigation constellation

The traditional satellite orbit determination system, which depends on ground stations and estimates every satellitepsilas states separately, can not meet the requirement of autonomous satellite navigation system. To solve this problem, the method of semi-autonomous orbit determination for whole satellite constellation by using the intersatellite crosslink and a few stations activated stochastically was proposed. After establishing the dynamic state equation, observations equation and the filtering model, a flow of simulation was designed. And the simulation result verified that this method can reduce dependence on ground station, and avoid the deficiency problem of the datum mark and still it can improve the orbit determination accuracy.