Deep Integrated Navigation And Two-Directional Velocimetry Method Using X-Ray Pulsar

Pulsar is a rapidly rotating neutron star with extremely high frequency stability.Pulsar periodically radiates multi-band electromagnetic signals,of which X-ray signals can be detected by miniaturized equipment on spacecraft and provide high-precision and autonomous navigation information.This paper studies the integration of XNAV and the traditional astronomical integrated navigation system and the theory of Doppler velocimetry using a single Pulsar.The main contents and achievements are as follows:(1)Aiming at the problem of the position and velocity divergence of the traditional INS/CNS integrated navigation system for ballistic missiles,the DNS and XNAV are used to provide velocity and position information respectively.An INS/CNS/DNS/XNAV deep integrated navigation method is proposed.Aiming at the pulsar TOA’s drift bias,this paper establishes a pulsar TOA drift bias model and optimizes the navigation filter parameters.The experimental results show that INS/CNS/DNS/XNAV deep integrated navigation can achieve low-cost and highprecision navigation in a highly dynamic environment with low-precision sensors.(2)In the traditional X-ray pulsar Doppler velocimetry method,a single pulsar only provides the velocity information of the LOS of the pulsar.For nonlinear orbits,the velocity error on the vertical plane of the pulsar also causes the profile distortion of the X-ray pulsar.Given this phenomenon,a two-directional Doppler velocimetry method is proposed.A single X-ray pulsar is used to provide two-velocity information.A two-level velocity estimation algorithm based on DF is developed to measure Doppler velocity in two directions.The experimental results show that the twodirectional Doppler velocimetry method provides high-precision velocity information in two directions.In addition,compared with the traditional epoch folding,the calculation time of DF is reduced by about 70%.