Spacecraft Dynamic Orbit Determination Based on X-ray Pulsar

Compared to existing satellite navigation systems X-ray pulsar navigation can enlarge the service scope.And it can improve the anti-jamming characteristic and autonomous navigation capability.In this paper we analyzed the process of dynamic orbit determination using X-ray pulsar measurement systemically.The basic steps of simulating the observation measurement are presented.Quantification analyses are carried out aimed to study the influence of all kinds of error on orbit determination.Results indicate that calculating spacecraft position and clock error simultaneously can reduce the influence of position of datum mark.Because it can absorb the systematical error.But the calculated clock error can not reflect the intrinsical error of atomic clock.So we need other methods to correct the clock error.Phase error and pulsar visibility are the major influence in orbit determination.And when we want to increase the number of observed pulsar,observation error must be take into account in order avoid the decrease of orbit determination precision.