基于改进差分能量检测器的移动直扩水声通信研究

摘要

针对时变大多普勒干扰提出了基于直扩信号结构的多普勒估计方法,通过相邻接收扩频符号的匹配相关运算及能量检测可实现对接收扩频信号中的多普勒实时估计.同时,该方法充分利用扩频处理增益,在低信噪比条件下仍然可以完成多普勒估计.在此基础上,提出改进差分能量检测器接收机算法,通过比较接收端相关器输出能量完成解码,可有效应对多普勒效应带来的快速载波相位跳变干扰以及时变的多途扩展干扰,从而保证了直扩水声通信系统在复杂干扰条件下稳定可靠工作.通过计算机仿真及实际海试实验,成功实现了-10 dB信噪比时大多普勒干扰条件下的直扩水声通信,验证了所提算法的有效性和稳健性.%A Doppler estimation method based on the structural features of spread spectrum signal was proposed,which could achieve real-time Doppler estimation for received spread spectrum signals by energy detecting the result of matching correlation calculation of adjacent received spreading symbols.In addition,this method made full use of the spread spectrum processing gain and could do Doppler estimation under low SNR condition.Improved differential energy detector was further proposed,which can effectively deal with the rapid cartier phase fluctuation interference caused by Doppler effect and time-varying multi-path interference by detecting the output energy of two correlators.Simulation verified the robustness of improved differential energy detector algorithm and the Doppler estimation method based on spread spectrum signal.At-sea data shows that improved differential energy detector combined with the proposed Doppler estimation method can achieve low bit error rate communication for direct-sequence spread spectrum underwater acoustic communication with large time-varying Doppler interference when SNR is-10 dB.