合成孔徑雷達系統模擬有助於系統參數的設計，此外模擬影像還 有許多其他的應用層面。根據所得到的地面資料，從其中萃取出需要 的資訊，例如局部入射角、地面覆蓋物等，可以模擬出預設系統的雷 達影像。 本研究主要目的在於模擬側視掃描式合成孔徑雷達影像，針對裸 露之粗糙表面作模擬。使用碎形理論來成長出所需要的表面，根據不 同的碎形維度可描述不同粗糙度的表面。粗糙表面以小散射面做片段 線性近似，估計出各散射面的背向散射係數後，根據雷達回波方程式 來成像，此時所得到的影像稱之為原始資料。將原始資料經過匹配濾 波處理後，即可得到單觀點的斜距雷達影像。 考慮到影響成像的因素，本研究改變了地表粗糙度、觀測角、以 及地表覆蓋物之相對介電係數，在上述不同的情況下分別模擬出雷達 影像，以比較其不同，最後再將一強散射點放入觀測區域中，觀察其 成像，以驗證模擬影像的正確性。 It contributes to the design of the radar systematic parameters to form the synthetic aperture radar (SAR) simulated image. It is helpful to mission design of a radar system if we establish the image simulation system. Different from faster practice: let the backscattering coefficient of each pixel be the performance of SAR image, this research formation the SAR image in the view point of radar echo signal processing, in order to try to get more correct result. The purpose of this research is to simulate the HH and VV polarimetric stripmap mode SAR image of a randomly rough surface. The main concept is that according to the information of target area, estimates the backscattering coefficient under different polarization and only concerned surface backscattering. Then combining the backscattering information with radar echo equation the raw data formed. After that, processing raw data by match filtering, we can get a single look slant range SAR image. In this research, the randomly rough surface is constructed by the fractal theory and approached by facet model. Considering the factor influencing formation of image, this research has changed the surface roughness, looking angle, and the relative permittivity of land cover. The radar image happens to differentiate simulation in above-mentioned different cases, in order to compare the differently. At last, verified the exactness of the simulation image by putting a strong scatter into target scene and observing the formation of SAR image. According to the result of simulation, the simulated images have the same geometry structure with the target scene, and the VV polarized image is brighter than the HH one, it is identical with the scattering theory. Besides, it is a satisfactory achievement that the strong backscatter which is put into target scene can be formed correctly in the image.
