一种横向机动弹道下SAR成像算法

针对横向机动弹道下SAR成像回波方位向和距离向严重耦合、弹载SAR平台实时性要求高的特点,提出了一种基于频谱分析的扩展SAR成像算法。首先,以初始距离相同的目标作为成像处理对象,建立了横向机动下弹载SAR成像模型,分析了回波相位和瞬时距离的泰勒展开;然后,采用包含水平面速度和偏航加速度参数的相位因子依次进行距离徙动校正、二次相位补偿和多普勒中心频率补偿,实现了SAR图像的精确聚焦。该算法处理流程简单、实时性高,适合横向机动弹道下的中等分辨率的大斜视成像,给出了算法流程,仿真验证了算法有效性。

A SAR Imaging Algorithm in Horizontal Maneuver Trajectory

In horizontal maneuver trajectory, missile-borne SAR imaging echo in range and in azimuth couples severely with each other and missile-borne SAR needs high real-time performance, so a SAR imaging algorithm based spectral analysis was proposed. Firstly, the target in same distance was set as an imaging object, missile-borne imaging geometric model in horizontal maneuver trajectory was established and echo phase as well as taylor expansion of instantaneous range was analyzed. Then phase factor including horizontal speed and yaw acceleration parameters was adapted to correct range migration, compensate quadratic phase, compensate doppler center frequency. After these processes, precise focus of the SAR images was acquired. This algorithm had the characteristic of simple process, high real-time performance and medium imaging resolution, which was suitable for missile-borne SAR imaging in horizontal maneuver trajectory. A flow chart was presented and simulation results showed the validity of this algorithm