适用于宽带和窄带照射源的无源合成孔径雷达成像方法

无源合成孔径雷达成像利用外部照射源和运动接收机对感兴趣场景进行成像，具有良好的电子对抗性，并可降低系统成本，利于系统小型化，缓解频带拥挤。本文给出基于逆散射理论和微局部分析的无源合成孔径成像统一理论，适用于沿任意轨迹运动的机载接收机和静止或运动的照射源。考虑发射两种发射波形：窄带连续波(Continuous-wave, CW)和宽带脉冲波形，相应给出两种新的无源合成孔径成像模式：针对宽带脉冲波形的合成孔径无源成像(Synthetic aperture hitchhiker, SAH)和针对单频或超窄带连续波的多普勒合成孔径无源成像(Doppler synthetic aperture hitchhiker, DSAH)。首先建立回波相关信号模型，该模型可消除与发射机相关的相位项,然后利用滤波反投影理论和微局部分析对相关回波数据进行反演，对应SAH和DSAH这两种无源模式，分别将相关回波数据反投影到无源距离和无源多普勒等值线上,给出详细的分辨率分析。最后通过仿真实验对成像方法进行验证。

Passive Synthetic Aperture Radar Imaging Methods for Wideband and Narrowband Illuminators of Opportunity

Passive synthetic aperture radar imaging uses illuminators of opportunity and moving receivers to image the scene of interest and has good electronic antagonism. It can also reduce system cost, benefit to system miniaturization and ease frequency band congestion. In this paper, we present a unified theory for passive synthetic aperture radar imaging based on inverse scattering and microlocal analysis. It is suitable for airborne receivers flying along arbitrary flight trajectories and static or moving illuminators of opportunity. Two types of waveforms are considered: narrowband continuous-wave (CW) waveforms and wideband pulsed waveforms. Our theory results in two novel synthetic aperture imaging modalities: Synthetic aperture hitchhiker (SAH) that uses wideband pulsed waveforms and Doppler synthetic aperture Hitchhiker (DSAH) that uses single-frequency or ultra-narrowband CW waveforms. First, we develop measurement models which are able to remove the transmitter-related terms in the phase of the correlated measurements. We use filtered backprojection (FBP) theory and microlocal analysis to develop approximate inversion formulas for SAH and DSAH. The inversion formulas involve backprojection of the correlated measurements onto iso-passive-range and iso-passive-Doppler contours for SAH and DSAH imaging, respectively. Detailed resolution analysis is given. Finally, we present numerical simulations to demonstrate our theoretical results.