Autonomous positioning based on pulsar timing model

The general pulsar timing model and the time difference of arrival (TDOA) model were discussed. Taking into account low complexity and real time requirement, an autonomous positioning algorithm which be of MLE closed-form solution was introduced by selecting the liner TDOA expression and the first-order timing forecast model. Also, an improved method for the ambiguity resolution was put forward in case of the internal clock of the spacecraft can be considered stable enough to be a valid reference and a previous coarse knowledge of the spacecraft position is acquired. At last, the positioning simulation was done and results indicate the feasibleness of this technique in finding the 3D location of the spacecraft.