Study Of Ship ISAR Imaging Algorithm Based On Measured Data

Inverse synthetic aperture radar (ISAR) based on the prototype of uniform rotation is a technique that can be used to obtain target images such as aircraft, missile, and ship objects. ISAR theory and technique have seen great developments in recent years. We set off our discussion and research work to the problem in ship ISAR imaging .For a moving ship, the changes of three dimensions are characterized by periodicity and randomicity. Therefore, the echoes have an obvious time-variant character. Based on the periodicity of Doppler frequency, the whole dwell time is divided into several intervals. The optimum imaging time is different when imaging based on Doppler frequency component and imaging based on chirp rate component. The imaging results of the measured data demonstrate the effectiveness of the algorithm.The imaging condition of ship is more complicated than plane due to the complexity of the ship movement, and the conventional ISAR imaging algorithm to the plane can not be satisfactory to the ship. So, a new method based on Spare representations with Chirplets via maximum likelihood estimation is proposed here, the instantaneous ISAR ship image is obtained.