High Resolution Imaging Algorithm Of A Step Frequency Radar

A fundamental task of a conventional radar is to detect and localize radar targets. In recent years, more potential functions of radar are explored, such as a most importantone- radar imaging. Synthetic Aperture Radar (SAR)achieves a high azimuth resolution in virtue of the synthetic aperture principle and a high range resolution by transmitting wideband signal. Most of researches on radar imaging are based on linear frequency modulation (LFM) signals. In this work, how to image with a stepped frequency radarwill be studied. By transmitting a series of pulses with carrier frequencies linearly separated, a high bandwidth and a high range resolution can be achieved. In association with azimuthal synthesizing to achieve a high azimuthal resolution, synthetic aperture radar imaging can be finally achieved by a stepped frequency radar.The stepped frequency signal under consideration here transmits during flying a monochromatic narrowband pulse each time and then receives its echoed signals. All of the received signals are finally synthesized to obtain a radar image. Similar to radar imaging based on an LFM signal, radar imaging using an stepped frequency signal would perform azimuthal synthesis and range mitigation compensation. A difference is that echoed signals of different frequencies have different azimuthal displacements known a priori from reference locations, and a key point to image is to compensate the azimuthal displacements for echoed signals of different frequencies.In this paper, the process of range profile of stepped frequency radar is briefly introduced, including pulse synthesis technique,motion compensation algorithm and profile spelling methods. Subsequently, fundamentals of synthetic aperture radar (SAR) and typical SAR algorithms are studied. Finally, SAR based on the SFR is studied. Based on a fact that radar target response keeps the same in the azimuthal dimension, an efficient SF SAR algorithm is proposed.