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本文讨论数字式声呐分裂波束精确定向的问题。利用Piersol提出的互谱法估计时延的原理,给出线阵与圆阵分裂波束系统的信号入射角与等效声中心的时延解算公式。利用这些公式可以根据输入数据,直接给出目标的准确入射角的数值。文中给出估计精度的表达式。它与累加次数、DFT的长度及采样周期有关。同时,还分析了由于对随机信号的截断所带来的误差。提出了对估计量加权、对输入数据加窗和合理选择DFT参数,以提高估计精度的方法。文中还给出系统的方框图及部分计算机模拟的结果。本文所提供的方法可以在数字式声呐中用于实时跟踪多个目标。
This article discusses the problem of the precise orientation of a digital sonar split beam. Based on the principle of estimating the time delay by the cross spectrum method proposed by Piersol, the formulas for calculating the signal angle of incidence and the equivalent acoustic center delay of the linear array and the circular array split beam system are given. The use of these formulas can be based on the input data, the target directly to the value of the angle of incidence. The paper gives the expression of estimation accuracy. It is related to the number of accumulations, the length of the DFT and the sampling period. At the same time, it also analyzes the error caused by truncation of random signal. A method of weighting the estimator, windowing the input data and choosing the DFT parameters rationally is proposed to improve the estimation accuracy. The article also gives the system block diagram and part of the computer simulation results. The methods provided in this article can be used in digital sonar to track multiple targets in real time.