Suppress Target Height Induced False Alarm in CSAR Moving Target Detection

Circular Synthetic Aperture Radar(CSAR)is a new SAR imaging mode, which has the advantages of long-time observation and multi-aspect observation. Based on these advantages, our team have proposed a single channel moving target detection method entitled logarithmic background subtraction(LBS). This method utilizes the target signal motion in sub-aperture image sequence. However, in-depth study shows that target with height will project a circular defocus, which also have motion when in sub-aperture image sequence. Thus, causing misdetection and false-alarm rate increasing. In this paper, the formula between defocus radius and point target height is derived and analyzed. Based on analysis, a false-alarm suppression method for moving target detection is proposed. It uses trajectory difference between moving target and defocus signal to remove the false-alarm caused by defocus signal and reduce the false-alarm rate. The proposed false-alarm suppression method is verified by W-band video SAR data.