机载SAR静止场景成像及运动目标检测研究

针对真实飞行条件下飞机运动和定位误差导致多普勒中心频率和多普勒调频斜率误差,从而使图像出现大的变形的特点,提出了真实飞行条件下估计接收数据多普勒中心频率和多普勒调频斜率的新方法。该方法设置飞机速率和脉冲重复频率比为常数,保证方位向接收信号均匀空间取样,使用实时最小二乘拟合算法,增加了和距离相对应的多普勒中心频率曲线估计的精确性。给出了应用该方法的具体步骤,并通过此方法同时实现了实时对地物背景成像以及地面多个运动目标的检测。最后用试验结果验证了该方法的有效性。

Research on imaging of scenario and moving targets detection by airborne synthetic aperture radar

Errors caused by the aircraft motion and orientation lead to the errors of the Doppler centroid and Doppler rate,thus some significant distortions appear in images.A new method to estimate Doppler centroid and Doppler rate applicable to real flight condition is proposed.This method makes the ratio of aircraft horizontal velocity to pulse repetition frequency be constant;ensures the uniform space sampling for received signals in the azimuth direction;and uses the real-time least-mean-square fitting algorithm to increase the accuracy of the centroid curve.Through this method can realize the imaging of scenario and many moving targets detection in the real-time operation.The result of measurement shows that the method is valid.