SAL imaging method based on Kirchhoff approximation

Synthenic aperture lidar(SAL) has been widely used for Its high-precision image of remote targets. In order to study the influence of different shapes and different roughness targets on SAL image in Thz band, the SAL images of different with different roughness are numerically simulated in this paper. Rough surface is generated by monte-calro method, and rough object modeling by rough surface. By using Kirchhoff approximation(KA) the back-scattering filed of a rough object is obtained, and the SAL image of a rough object is obtained by the backscattering filed at different azimuth angles and frequencies. In this paper, the SAL image of simple plate target, circular and complex target are simulated, the result of SAL image show that the image can reflect not only the shape of the target but also the roughness of the target, it is specifically analyzed in this paper. During the imaging, different frequency-domain width, frequency-domin sampling accuracy and angular sampling accuracy will affect the SAL image. The wider frequency-domin width, the higher the accuracy, the better the imaging result, but only need to meet the requirements within a reasonable range, this paper analyzed that.