最低限度通信中多普勒频偏估计算法

An algorithm of Doppler frequency shift estimation in very low bit rate communication

针对最低限度通信中多普勒频偏估计范围不足、估计精度较低的问题,提出一种改进的基于相关FFT的直扩信号同步捕获算法。该算法通过补零运算提高算法的估计精度、采用正交扩频序列优化算法的性能。数值分析表明,在低信噪比环境下,改进后的算法能够以较高的精度捕获较大频偏。

Focus on the requirement of wide range and high accuracy of Doppler frequency shift estimation in the very low bit rate communication,an improved synchronization acquisition algorithm is proposed based on FFT direct sequence spread spectrum（DSSS） signal.The insertion of zero is adopted so as to improve the estimation precision and orthogonal spread spectrum was applied to optimize algorithm performance.Simulation results show that,in the low signal-to-noise ratio,the improved algorithm achieves a bigger frequency measured with the higher estimation accuracy.