In irregular pulse repetition interval (PRI) radar, successive pulses each with different PRIs are used as the transmission waveform. After analyzing the signal model of irregular PRI radar, we propose a coherent integration method based on Radon-iterative adaptive approach (Radon-IAA) to deal with the problems of irregular range cell migration (RCM) and the irregular phase fluctuations among different pulses introduced by the irregular PRI. In our method, the irregular RCM is compensated by searching through the motion parameters, and the irregular phase fluctuations can be resolved by an IAA-based spectral analysis method. The effectiveness of the proposed method is verified by simulation experiments.
Aircraft recognition is of great theoretical and practical significance in fields like remote sensing, navigation and traffic monitoring. It seems difficult to recognize aircraft in low-resolution SAR imagery because of difference between real image and simulated template induced by poor image quality and inherent simulation error. Aiming at this problem, an aircraft recognition method using peak feature matching is proposed. Firstly, the scattering centers of detected target are extracted in low-resolution SAR imagery using an adaptive threshold. Secondly, the extracted peak features are used to estimate the aircraft azimuth angle, which can be used to reduce the searching space in template database dramatically. Finally, a novel peak feature matching method using spatial distribution information of entire peak set is proposed to measure the similarity between detected target and simulated template. Experimental results demonstrate the good performance of the proposed method on a variety of low-resolution SAR imageries.