A modified Kalman filter based on augmentation state for X-ray pulsar phase-differenced measurement

Abstract

To reduce the measurement noise and the correlation between the process and measurement noises caused by time-differenced measurement, we study an X-ray pulsar navigation method using phase-differenced measurement, which calculates phases of pulsar signal in frequency domain and is more accurate than time-differenced measurement. A modified Kalman filter based on augmentation state is proposed to solve the issue of the correlation. The simulation results show that the proposed method can not only reduce the system biases but also solve the correlation of the process noise with the measurement noises effectively.