二元正交chirp载波水声通信时变多普勒系数估计

Doppler coefficient estimation for chirp spread spectrum of binary orthogonal keying system

针对水下潜器间相对变速运动时进行声通信导致的宽带多普勒和码元间多普勒不一致的问题,本文提出一种基于二元chirp信号的移动稳健水声通信系统的多普勒估计和解调算法。基于分数阶傅里叶变换(FRFT)对同步信号处理得到初始多普勒系数后,利用相邻码元间的相关性,对相邻码元进行滑动匹配迭代处理,实现对每一个chirp载波的多普勒系数估计,同时在估计多普勒系数的过程中利用中间变量实现对信号的解调。海上通信距离5 km,运动速度为1.5 m/s时,可以达到误码率小于10-4的通信效果。仿真和海上试验结果都证实了该方法的有效性。

For the inconsistency between wideband Doppler and code-element Doppler caused when underwater ve-hicles under relative motion carry out acoustic communication, this paper proposes a Doppler estimation and demod-ulation algorithm for the mobile and robust underwater acoustic communication system based on binary chirp signal. After the initial Doppler was attained by processing synchronous signal based on the fraction order of Fourier trans-form, the relevance between the neighboring code elements was utilized to process neighboring code elements by sliding match and iteration. Thus, the Doppler coefficient estimate for each chirp carrier was realized. To estimate the Doppler coefficient, the intermediate variable was utilized to demodulate signals. Simulation and sea trial results confirm the validity of the proposed approach. A communication effect with bit error rate less than 10 4 was a-chieved via a sea experiment with distance of 5 km and relative velocity of 1. 5 m/s.