Research On Radar Imaging Of Ship Targets

Inverse Synthetic Aperture Radar (ISAR) can obtain 2-D (range-azimuth) high resolution at the same time. It could provide image information of ship target at sea, so that offer support to navigation and other activities. Therefore, research of ISAR is essential.The aim of research is processing received data to obtain useful ISAR images. ISAR signal model is developed in the first place, and then key processes including motion compensation and imaging algorithm are introduced according to the signal model. Afterwards, a set of data is used to testify the algorithm.A method for selecting optimal imaging time is proposed to solve the problem of imaging ambiguity when there is random sway of ship target in high sea condition. The method calculates Doppler center from real echoes of ship target, then chooses optimal imaging time according to the Doppler center's change. This paper develops the process of realizing the method, and then applies it to a set of real data. The result shows that by applying the method proposed by this paper, the Cross-range resolution of ISAR picture is enhanced, and calculation burden could be relieved while the quality of the picture remained the same.Finally, the Adaptive Chirplet Decomposition (ACD) algorithm and its modified form (MACD) is presented. As optimal imaging interval selection could provide information to parameter estimation, a method of ISAR imaging method of parameter estimation based on optimal imaging period is developed. The result of estimation on real data manifests that better ISAR image can be acquired by applying the method proposed.