基于伪随机序列的多波束水声探测系统的信道估计技术

多波束水声探测系统不同方向回波信号的同时检测,可以理解为通信中的信道估计问题。在水下多径传播环境中,多径信道的时延参数和幅度衰减参数的估计是多波束探测系统实现目标探测、定位和识别的基础,而抑制来自其它波束的多址干扰(MAI)是信道估计算法的重要目标。将直接序列码分多址(Direct Sequence Code-Division Multiple Access,简称DS-CDMA)通信系统模型应用于水声多波束探测系统。建立了基于伪随机序列的水下多波束探测系统的信号模型,研究了基于子空间方法的超分辨率信道估计算法。并给出了数值仿真实现,分析了信噪比、多址干扰及发射波束数等对信道估计算法性能的影响。仿真结果表明,该算法具有抑制多址干扰的性能,信道参数的估计方差逼近Cramer-Rao下界。这种信道估计技术尤其适合应用于多波束参量阵探测系统。

Channel estimation for multi-beam underwater acoustic detection system based on pseudo-noise sequence

In an underwater acoustic multi-beam detection system, detection of echoes from different directions at the same time can be considered as channel estimation in communication systems. This paper applies a DS-CDMA communication system to underwater acoustic multi-beam detection system. Time delay and magnitude attenuation estimation is fundamental in underwater detection and recognition. It is a key performance that the algorithm can suppress multiple-access interference (MAI). The model of a multi-beam underwater acoustic detection system based on pseudo-noise sequence is presented. Subspace-based channel estimation is discussed, and simulation results given. The effects of SNR, MAI and the number of beams are analyzed. It is shown that the proposed algorithm is robust against MAI, and the estimated variance approaches the Cramer-Rao bound. This channel estimation technique is especially applicable to multi-beam parametric array detection.