Detection, Location and Imaging of Fast Moving Tarets using Multi-Freqnecy Anternna Array SAR

摘要

Detection, location and SAR imaging of moving targets in clutter have attracted much attentiion. Locations of moving targets in the SAR image are determined not only by their geometric loations but also by their velocities that cause their SAR imates de-focused, smeared, and mis-located in the szimuth dimension. Furthermore, the clutters may cause the detection of moving targets more difficult. Several antenna array based algorithms have been proposed to re-locate the moving targets in the SAR image. With a linear antenna array, the clutters may be suppressed using multiple phase centers. However, there are only two parameters involved in a linear antenna array, i.e., number of receiving antennas and the distance between two adjacent antennas. These two parameters physically limit the capability to detect the accurate locations of fast moving targets and such as vehicles, and only slowly moving targets, such as walking people, can be correctly re-located. In this paper, we propose an antenna array approach were transmitting single wavelength signals are generalized to transmitting multiple wavelength signals (called multi-frequency antenna array SAR). We show that, using multipfrequency antenna array SAR, not only the clutters can be suppressed but also locations of both slow and fast moving targets can be accurately estimated. For example, using two-frequency antenna array SAR system with wavelengths gamma _1 chemical bounds 0.03m and gamma _2 chemical bounds 0.05m, the maximal moving target velocity in the range direction is 15 m/s while using single frequency antenna array SAR system with wave length gamma _1 chemical bounds 0.03m or gamma _2 chemical bounds 0.05m, the maximal moving target velocity in the range direction are 3m/s or 5m/s, respectively. A robust Chinese Remainder Theorem (CRT) is developed anbd used for the location of fast and showly moving targets. Simulations of SAR imaging of ground moving targets are presented to illustrate the effectiveness of the multi-frequency antenna array SAR imaging algorithm.