Photonics-based radar enables a large operation bandwidth that is particularly favourable for high-resolution synthetic aperture imaging. However, how to implement fast and high-accuracy imaging with photonics-based broadband radar is still an open question. In this Letter, the performance of photonics-based inverse synthetic aperture radar imaging with frequency-domain and time-domain algorithms are experimentally investigated and compared. The results show that, frequency-domain range–Doppler algorithm has fast imaging capability, but the image suffers from defocusing and distortions. Although migration compensation techniques can be applied to improve the imaging accuracy, the imaging speed is significantly reduced. On the other hand, using time-domain back-projection (BP) algorithm can achieve well-focused images, and the imaging speed can be enhanced with fast BP methods. Therefore, the time-domain imaging method is found to be the best choice for fast and high-accuracy synthetic aperture imaging with photonics-based broadband radars.

中文翻译：

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基于光子学的宽带雷达的频域与时域成像

基于光子学的雷达可实现较大的操作带宽，这对于高分辨率合成孔径成像尤其有利。然而，如何利用基于光子学的宽带雷达实现快速，高精度成像仍是一个悬而未决的问题。在这封信中，对频域和时域算法的基于光子学的逆合成孔径雷达成像性能进行了实验研究和比较。结果表明，频域范围多普勒算法具有快速的成像能力，但图像容易散焦和失真。尽管可以应用迁移补偿技术来提高成像精度，但是显着降低了成像速度。另一方面，使用时域反投影（BP）算法可以获得聚焦良好的图像，快速的BP方法可以提高成像速度。因此，发现时域成像方法是使用基于光子学的宽带雷达进行快速，高精度合成孔径成像的最佳选择。