中低轨卫星信号的多普勒频移估计与补偿

针对中低轨卫星信号的多普勒频移具有大范围快速时变的问题,基于航天动力学理论,计算出卫星和接收平台间的相对位置和速度,从而可预先估计卫星信号的多普勒频移.对频移估计的误差进行了分析,给出了一种多普勒频移的快速估计和实时补偿算法,同时也对卫星的可视时间段分情况进行讨论.计算机仿真和工程实践表明,该算法简单、实用,有利于对快变大频偏的卫星信号进行快速跟踪和解调.

Doppler frequency shift estimation and compensation for LEO and MEO satellite signals

Doppler frequency shift of satellite signals in LEO and MEO has a character of long-range changes and quick time-variation.Based on the theories and methods of astrodynamics,the relative positions and velocities between satellites and receiving stations are computed,therefore Doppler frequency shift can be pre-estimated.The error of the estimating method is firstly analyzed;consequently,an algorithm of fast estimation and real-time compensation for Doppler frequency shift is put forward.At the same time,the visual time slices between receiving platforms and observed satellites are explored according to different situations.Simulation results and engineering practices indicate that the algorithm is simple and practical and is available for fast track and correct demodulation of satellite signals with fast and large variable frequency shift.