Accurate ISAR Scaling for Both Smooth and Maneuvering Targets

Inverse synthetic aperture radar (ISAR) scaling can give the scatterers' absolute coordinate, which is the premise of ascertaining the target's size and recognizing the target. In this paper, we present an accurate ISAR scaling method. First, the signal characteristic in cross-range dimension is analyzed, and the problem of ascertaining the rotational velocity (RV) is converted to the estimation of the chirp rates. Second, to estimate the chirp rates, the integral Lv's distribution and the ordinary least-squares Lv's distribution are proposed for smooth targets and maneuvering targets, respectively. Utilizing the signal characteristic, the proposed algorithms achieve a higher precision and a lower computational burden compared with existing algorithms. Finally, the weighted ordinary least squares is introduced to calculate the RV from the estimated chirp rates for both smooth and maneuvering targets. Simulation and real data experiment validate the effectiveness of the proposed methods.