基于FRFT的末制导雷达海面动目标检测方法

Detection of Moving Target at Sea for Terminal Guidance Radar via Fractional Fourier Transform

为有效提高反舰导弹动目标检测性能,利用分数阶Fourier变换(FRFT)对线性调频(LFM)信号良好能量聚集性的特点,提出了基于FRFT的末制导雷达海面微动目标检测方法。首先,针对舰船目标的不同运动状态,分别建立目标平动(匀速和匀加速)以及三维转动(横滚、俯仰和偏航)模型,得到动目标回波的多普勒和微多普勒频率,在短的观测时间范围内,可近似建模为LFM信号。其次,通过计算雷达回波信号在不同变换阶数下的FRFT,形成二维参数平面,在此平面内,采用非参量恒虚警检测器形成自适应门限,并进行动目标判决。最后,仿真分析了算法的性能和影响因素。

In order to improve detection performance of moving target for anti-ship missile, detection method for terminal guidance radar via fractional Fourier transform（FRFT） is proposed, making use of good energy concentration property of FRFT on linear frequency modulation（LFM） signal. Firstly, models of translation movement（ uniform and accelerated movements） and three dimensional movement（pitch, roll and yaw movements） are established according to different moving states of target. Both Doppler and micro- Doppler of moving target can be obtained, which can be approximated as LFM signal during short observation time. Then, two dimensional parameters plane is formed after calculating the FRFT of radar echo with dif- ferent transform orders. Adaptive threshold is obtained by nonparametric constant false alarm ratio（CFAR） detector, with which target is declared. Finally, performance and influence factor of the method are analyzed by simulation.