雷达系统常采用基于快速傅里叶变换的方法实现动目标检测(MTD)滤波器组,其关键是通过加窗降低滤波器副瓣,但普遍存在加窗的结果使滤波器零点产生偏移,不能保证非零速滤波器在零频形成真正零点。文中基于窗函数的理想频率响应构造了简化的目标函数,以零频形成零点为约束实现滤波器峰值旁瓣电平比最大化,采用内点法求解该问题,并推导了窗函数系数的显式表达式。同时,引入了扰动因子,以保证迭代过程的收敛性。仿真表明MTD 滤波器组满足地杂波抑制的需求,且峰值旁瓣电平为-41 dB。该方法为MTD 应用提供了一种新思路。

The method of moving target detection (MTD) with fast Fourier transform (FFT) is usually used in radar signal processing system, whose key factor is to lower the sidelobe by adding a window, while the result of windowing is that the filter zero-point shifts, and thus non-zero-speed filter is not guaranteed to form null at zero frequency point. The simplified objective function, to maximize peak sidelobe ratio, is constructed based on the frequency response of window function, whose constraints is that null is formed at zero frequency point. Interior point method is used to solve the problem, and the explicit expression of windows function coefficient is given. At the same time, in order to prevent divergence of the iterative process, the disturbance factor is introduced. Simulation results show that MTD filter can satisfy the requirements of ground clutter suppression, and the peak sidelobe level meets -41dB. The novel method provides a fresh idea for MTD application.

TN951