Dechirp及频谱分析技术的目标分辨率分析

Analysis of Resolution of Dechirp and Spectral Analysis Technology

Dechirp(去调频)及频谱分析是大带宽线性调频信号的一种常用处理方式,在高分辨率雷达,如合成孔径雷达和逆合成孔径雷达中得到广泛应用。Dechirp处理的一个优点是可以降低输入信号的带宽,从而减小了接收机中A/D变换器在变换速度上的压力。本文的目的是分析、研究经Dechirp及频谱分析而得到的两点目标间的分辨率与匹配滤波得到的两点目标间的分辨率之间的关系;说明了从时域上看,如何从概念上理解在时宽一定的条件下,调频率越大,经Dechirp及谱分析处理后的目标间分辨率也越高。文中还通过仿真说明了Dechirp及频谱分析技术的目标分辨特性。

Dechirp and spectral analysis technology is a common processing method of chirp signal with large bandwidth. It has been widely used in Synthetic Aperture Radar(SAR) and Inverse Synthetic Aperture Radar(ISAR). Dechirp processing has the advantage of decreasing the bandwidth of input signal, which can relieve the pressure on analogdigital conversion speed. In this paper, the relationship between the resolution of two pointtarget signals after the processing of Dechirp and spectral analysis and the resolution after the processing of match filtering has been investigated and analyzed. It is illuminated how to understand in concept that the larger the frequency modulation rate, the higher the resolution is, with the same waveform duration after the Dechirp and spectral analysis processing, viewed from timedomain. Some simulations are presented to demonstrate the resolution property of Dechirp and spectral analysis processing technology.