A robust motion compensation algorithm for ISAR imaging of sea-surface targets by Airborne Radar

Motion compensation is the most critical part of Inverse Synthetic Aperture Radar (ISAR) processing in Airborne Radars. For an X-band Airborne Radar where resolution requirement is not sub-metric, Range-Doppler algorithm is the preferred choice to generate ISAR images due to small rotation angle requirement. In addition when both the radar platform and target are expected to move at nearly steady course and speed within the image formation interval, the use of highly sophisticated motion compensation algorithms is not desirable. This paper presents a robust and computationally efficient algorithm for translational motion compensation based on batch profile correlation. The algorithm is robust to background noise and target scintillation effects. It removes the problem of error accumulation inherent in peak-tracking method and avoids limitation of range-shift in integer steps. The effectiveness of the approach is verified by applying the algorithm to simulated ISAR data as well as actual ISAR data collected by an X-band airborne radar. The ISAR data simulation and processing are carried out using MATLAB. Different noise levels and target amplitude fluctuation are added to the simulated ISAR data to test the robustness of the algorithm.