基于海面散射模型的全极化合成孔径雷达海洋环境探测关键技术参数设计仿真研究

摘要

技术参数设计研究是提升全极化SAR海洋环境探测能力的有效途径.本文通过分析噪声等效后向散射系数和辐射分辨率与海洋环境探测的地球物理联系,提出一种全极化SAR关键技术参数设计方法.采用全极化海面散射模型计算不同海洋环境条件下的雷达后向散射系数,据此确定全极化SAR对海探测的噪声等效后向散射系数,再将其作为合成孔径雷达方程输入参数,以辐射分辨率和信噪比的函数关系为约束条件,开展信噪比、辐射分辨率和系统功率孔径积等技术参数设计研究.论文通过全极化海面散射模型的仿真计算,发现对海探测的噪声等效后向散射系数设计为-35.0 dB,可满足全极化SAR不同海洋环境条件的探测需求.通过研究辐射分辨率与信噪比的函数关系,发现对海探测的最优信噪比为8.0 dB. C波段机载全极化SAR设计结果表明,由于兼顾了海洋环境探测需求,本文设计方法使得全极化SAR技术参数同时满足了海洋环境应用需求和系统设计要求.%Technical parameter design is an effective approach to improve marine environment sounding capability for fully polarimetric synthetie apertuer radar (SAR). By analyzing geophysical contact between noise-equated backscattering co-efficient and marine environment sounding, and that between radiometric resolution and marine environment sounding, we present the key technical parameters design method for fully polarimetric SAR. We first calculate radar backscat-tering coefficient in different marine environments by using the fully polarimetric ocean surface scattering model, and accordingly determine the noise-equated backscattering coefficient of fully polarimetric SAR ocean sounding. Then the noise-equated backscattering coefficient is used as an input parameter in SAR equation, and the function relationship between radiometric resolution and signal to noise ratio is used as a constraint condition, we thus can carry out technical parameter design, such as for signal to noise ratio, radiometric resolution and system power aperture product. By simu-lation calculation of fully polarimetric ocean surface scattering, we find that the noise-equated backscattering coefficient of ocean sounding is designed to -35.0 dB, which can meet the needs of fully polarimetric SAR sounding in different marine environments. Studying the function relationship between radiometric resolution and signal to noise ratio, we find that the optimal signal to noise ratio of ocean sounding is 8.0 dB. Results of C-band airborne fully polarimetric SAR design show that the above method can make technical parameter of fully polarimetric SAR meet both the need for marine environment application and system design, because of taking into account the needs of marine environment sounding.