解释了由目标运动引起的各项方位多普勒频移量的物理含义,利用驻定相位定理推导出目标运动对机载正侧视条带SAR图像方位向位置和目标初始位置、速度、加速度的解析关系;对由运动引起的方位向二次相位项、三次相位项以及四次相位项的影响给出了对应的偏移量和展宽量的理论表达式;通过分离各相位调制项的方法,实验验证了理论推导的正确性。该分析结果有助于深刻理解运动目标的SAR图像变化。
The physical meaning of each Doppler frequency shift items in azimuth direction caused by target motion is explained firstly. The analytical relationship between the peak position of the moving target' s strip image for airborne side-looking mode SAR in azimuth direction and the initial position, velocity and acceleration are obtained using stationary phase principle. The theoretical expressions of the offsets and spreading cross range of each phase modulation items, such as quadratic phase factor, cubic phase factor, and quartic phase factor, are derived. Through separation of the phase modulation items and motion parameters, the theoretical derivations are verified by the simulation experiments. The research resuhs are useful to understand the change of moving target' s SAR images.