鱼雷声引信目标回波高精度频率估计方法

High Precision Frequency Estimation Method of Torpedo Acoustic Fuse Target Echo

针对鱼雷与潜艇交会近场区体目标效应对多普勒频率估计精度的影响,提出了一种快速高精度提取潜艇回波多普勒频率信息的频率估计方法。该方法是基于Rife算法和Quinn算法的联合频率估计方法,充分利用Rife算法运算量小,易工程实现的特点,同时结合Quinn算法良好抗噪性能进行快速频率估计。针对Rife算法和Quinn算法在离散傅立叶变换(DFT)量化频率点附近估计误差偏大的问题,采用对Rife算法和Quinn算法频率修正项进行加权的方法提高该区域的频率估计精度。仿真结果表明,该方法计算量小、频率估计性能稳定且估计均方根误差在整个频段上比Rife算法和Quinn算法更接近克拉美-罗下限,能较好满足反潜鱼雷主动声引信实现精确炸点预测的要求。

The estimation accuracy of Doppler frequency is affected by the body target effect in near field region of submarine and torpedo,therefore a fast and accurate frequency estimation method is presented in this paper to acquire Doppler frequency in submarine target echo.This method is a combined frequency estimation method based on Rife algorithm and Quinn algorithm,making full use of the low computational complexity of Rife algorithm and the good anti-noise performance of Quinn algorithm.Aiming at the problem that Rife algorithm and Quinn algorithm have larger frequency estimation error when signal frequency is close to the discrete frequency of the discrete Fourier transform（DFT）,the modified items of the frequency from Rife algorithm and Quinn algorithm are weighed to improve the fre-quency estimation precision.The simulation result shows that the present method has stable frequency estimation per-formance with less computation,and its root mean square error（RMSE） approaches much closer to Cramer-Rao lower bound（CRLB） than the Rife and Quinn algorithms,which can well meet the requirement of torpedo acoustic fuse for predicting burst point accurately.