X-ray pulsar relative navigation approach based on extended Kalman filter

X-ray pulsar as a nature timing standard has excellent period-stability, and pulsar navigation has important application prospect. An improved relative navigation approach which selects the previous position as the navigation reference is presented to solve the integer ambiguity problem in absolute navigation and the storages problem of the phase and the nominal orbit in relative navigation. The information filtering is implied to estimate the precise relative position and velocity by stabling the orbit dynamics model. Finally, the simulations are performed, which show that the accuracy of the improved relative navigation reaches 1 km. The interferences of the initial error and the orbital elements are rapidly suppressed by the filter, which is uniformly asymptotically stabilized. The navigation program is verified to be valid and feasible.