光学学报, 2019, 39 (7): 0728002, 网络出版: 2019-07-16
天基合成孔径激光雷达成像理论初步 下载: 1120次
Elementary Imaging Theory on Space-Borne Synthetic Aperture Ladar
遥感 雷达图像 天基合成孔径激光雷达 信噪比 图像叠加 remote sensing radar images space-borne synthetic aperture ladar signal-to-noise ratio combining images
摘要
合成孔径激光雷达(SAL)具有成像距离远、分辨率高、速度快等特点,在天基空间目标成像领域有重要的应用前景。针对天基SAL成像中回波信号弱、噪声大、成像质量差等问题,提出在交会点附近连续长时间观测的思路。基于简单假设,建立采用光学外差探测的天基SAL成像理论数学模型,获得回波数据方程,给出成像处理流程、成像分辨率和图像信噪比,数学仿真了不同信噪比下的天基SAL空间目标成像。理论分析和仿真成像结果表明:当回波数据信噪比高时,任何子段数据均可形成空间目标的高分辨率图像;当回波信号微弱、数据信噪比低时,采用连续长时间观测数据形成目标子图像,将所有子图像进行叠加,提升了目标图像信噪比,改善了成像质量。
Abstract
Synthetic aperture ladar (SAL) has the characteristics of long imaging distance, high resolution and fast speed, and plays an important role in the field of space-borne imaging. Aiming at the problems of weak return signal, high noise level and poor imaging quality in space-borne SAL imaging, an idea of continuous long-term observation near the intersection point is presented. A mathematical model of space-borne SAL imaging theory is established by using optical heterodyne detection, and the return signal equation and imaging signal-to-noise ratio (SNR) are obtained. The processing flow, image resolution and mathematical simulation of space-borne imaging with different SNR are given. Theoretical analysis and simulation show that when the SNR is high, any sub-data can form a high-resolution image. When the SNR is low, the target sub-image is formed by continuous long-term observation, and the method of combining all sub-images enhances the SNR of the target image and improves the image quality.
李丹阳, 吴谨, 万磊, 王德宾, 吴童. 天基合成孔径激光雷达成像理论初步[J]. 光学学报, 2019, 39(7): 0728002. Danyang Li, Jin Wu, Lei Wan, Debin Wang, Tong Wu. Elementary Imaging Theory on Space-Borne Synthetic Aperture Ladar[J]. Acta Optica Sinica, 2019, 39(7): 0728002.