基于FrFT-Keystone运动补偿的OFDM声纳高速微弱目标相参积累检测算法

Coherent integration and detection algorithm for high-speed weak targets in OFDM sonar based on FrFT-Keystone motion compensation

针对水下目标探测中使用的正交频分复用信号,提出了一种针对高速微弱目标的相参积累算法,以解决多脉冲积累下由目标机动引起的较大相位变化和由水下环境中信噪比低导致的相参积累增益不足的问题。所提算法利用分数阶傅里叶变换来估计目标的运动参数并进行补偿,并结合Keystone变换,实现对高速微弱目标的多脉冲相参积累。理论推导和仿真实验结果表明,所提算法能够有效补偿高速目标脉冲间的相位移动,并在低信噪比环境下取得较好的能量积累效果。

A coherent integration algorithm for high-speed weak targets is proposed towards orthogonal frequency division multiplexing(OFDM)signals in underwater target detection.The algorithm solves the problem of insufficient coherent integration gain,which is caused by significant phase changes caused by target maneuvering under multi pulse integration and low signal to noise ratio(SNR)in underwater environments.The proposed algorithm utilizes fractional Fourier transform(FrFT)to estimate the motion parameters of the target and compensate for it,and combines Keystone transform(KT)to achieve multi pulse coherent integration for high-speed weak targets.Through theoretical derivation and simulation experiments,the results show that the proposed algorithm can effectively compensate for the phase shift between high-speed target pulses and achieve good energy integration effect in low SNR environments.