基于NDFT的步进频率雷达信号处理

步进频率脉冲信号可以在发射较小瞬时带宽信号情况下，通过脉冲压缩而合成分辨率较高的距离像，因而在高分辨雷达系统中得到广泛的应用。但是，直接采用DFT方法合成距离像．其分辨性能并不理想。利用Chirp-z方法也存在一些缺点。本文提出了利用非均匀傅里叶变换(Nonuniform Discrete Fourier Transform，NDFT)方法来处理频率步进信号以改善雷达的分辨性能，解决了直接利用DFT方法和Chirp-z方法合成目标距离像时所存在的问题。文中给出了NDFT的定义及在重点观测区域内的采样方法，进行了针对多种情况的仿真实验。仿真结果显示，利用NDFT进行处理可以明显改善步进频率雷达的距离分辨性能。

Stepped Frequency Radar Signal Processing Based on NDFT

Since the stepped frequency pulse signal can be synthesized to obtain high resolution range profile for transmitting the narrow instantaneous bandwidth signal, it is widely used in high resolution radar system. However, the performance loss of the synthesized range profile can be induced when processing the signal by conventional DFT directly. And the result of using the Chirp-z method is not ideal also. In this paper, a method for processing the stepped frequency radar signal by NDFT is proposed to improve the range resolution performance. The definition of NDFT is given, and the sampling method in interesting range is discussed. The simulation results show that the radar range resolution can be significantly improved by this method.