A New Algorithm of ISAR Range Alignment Based on Real Time Delay

Motion compensation is a key step in ISAR imaging, which usually includes range alignment and phase correction, while range alignment is the basis of phase correction. The correlation is the most widely used in range alignment. In the traditional correlation the range shift, which is fractional usually, can be handled as integer only. Real time delay algorithm is proposed to align signals with real time delay precisely. The real time delay algorithm compensates the time delay in frequency domain, since delay in time domain represents itself as a linear additional phase with frequency. A new range alignment algorithm for ISAR range, applying real time delay compensation is proposed in this paper. The proposed algorithm applies real time delay compensation by the phase compensation factor in frequency domain, and finally obtains the aligned two-dimensional data after IFFT. Simulation results demonstrate the effectiveness of the proposed algorithm.