Spacecraft Position Determination with X-ray Pulsar Navigation of Geometric Methods

Geometric methods of spacecraft position determination using single phase and double difference measurements in X-ray pulsar navigation are introduced.Through simulating calculation,the influence of errors on precision of position determination are analysed.The influence of phase error is very large.The error of range measurement,ephemeris and clock offset can all lead to 102 m position determination error.Double difference can eliminate the influence of clock offset but magnifies the ephemeris error.The decrease of position error with the increase of the number of observed pulsar is related to the influence of range measurement error.