基于分数阶傅里叶变换水下目标距离及速度的联合估计

摘要

针对分数阶傅里叶变换(FRFT)在主动探测系统中应用问题,本文研究了基于FRFT的水下目标距离和速度的联合估计方法及其敏感性能.给出了线性调频信号的FRFT,揭示了真实信号参数与离散计算时归一化参数之间的关系,推导了脉冲信号的FRFT.在此基础上提出并推导了基于FRFT的目标距离/速度与回波信号FRFT的峰值所在位置的密切关系,最后用仿真数据和水池实测数据验证了该方法利用一个脉冲就可同时有效估计目标的距离和径向速度,并讨论了估计参数的敏感性.%A joint range/radial velocity estimation method based on Fractional Fourier Transform ( FRFT) of underwater target was developed for active SONAR/RADAR. The FRFT of linear frequency modulated signal was given, and the relationship between the real signal parameter and the generalized parameter of discrete computation was shown. During discrete computation, the scaling was involved. And further, the FRFT of pulse signal was derived. The joint estimated radial velocity and range were proposed and derived , which are closely related with the location of maximum FRFT spectrum of echo. The simulation data and the measured data of water tank were used to demonstrate that the new approach can use one pulse ( positive or negative LFM ) simultaneously to estimate target range and radial velocity . At last, the sensitivity of estimated parameters was discussed.