A Preliminary Study On Synthetic Aperture Ladar

Synthetic Aperture Ladar (SAL) is a kind of imaging laser radar (Ladar) utilizing synthetic aperture techniques to obtain high resolution images without the installation of large optics. Compared with Synthetic Aperture Radar (SAR) using microwave as radiating source, SAL can achieve dramatic improvements in both resolution and the time to record an image due to its shorter radiative wavelength.This thesis gives a preliminary study on the fundamental theory of SAL. The basic imaging principles of vertical side-looking strip-mode SAL and two-dimensional scan-mode SAL are investigated. Vertical side-looking strip-mode SAL adopts deramp compression and azimuth matched filter imaging algorithm. Two-dimensional scan-mode SAL utilizes two-dimensional Fourier transform imaging algorithm. Based on the theory and imaging algorithm obtained, imaging performances of dot or dot array targets are simulated numerically by means of Matlab software for both mode SAL's. Moreover, the imaging characteristics of both mode SAL's systems are presented. In vertical side-looking strip-mode SAL, only the azimuth resolution of output images results from aperture synthesis, while the range resolution is obtained by pulse compression techniques. In two-dimensional scan-mode SAL, the resolution of both directions is obtained through aperture synthesis. Besides the basic imaging theory of SAL, Besides its fundamental theory, the key techniques in developing a practical SAL system are also discussed briefly.The results obtained in this thesis will be kind of helpful in promoting further researches of SAL development both theoretically and experimentally. Although there probably exist some technical difficulties in developing a SAL system for long range application at present, experimental imaging SAL systems have been implemented in the...