合成孔径雷达(SAR)作为一种主动式的对地微波遥感技术,具有全天候、全天时和远距离的特点。通过发射大带宽信号,获得距离向的高分辨。通过平台相对静止场景的运动形成合成孔径,获得方位向的高分辨,SAR 平台的运动是成像的基本条件。对于机载SAR,由于载机在大气中飞行时受到大气湍流等因素的影响,不可能保持理想的运动状态,必然会产生运动误差,运动误差会导致相位误差和包络移动,从而导致图像散焦等问题。如何对SAR 进行运动补偿是实现成像的关键。基于惯导数据的运动补偿是实现高分辨成像的重要手段之一。根据惯导数据的特点,结合卡尔曼滤波原理和SAR 成像的几何模型,提出了一种基于卡尔曼滤波的惯导数据滤波和重采样方法。该方法可以有效剔除运动参数野值,精确地获得雷达平台的运动参数。文中所提出的运动补偿方法能和SAR 成像算法很好的结合,实测数据的成像结果验证了该方法的准确性和有效性。

As an active microwave remote sensing technology for earth surface observation, synthetic aperture radar (SAR) has the characteristic of long distance illuminating under all-weather conditions day and night. By transmitting large bandwidth signals, high resolution in the range direction is obtained. The motion of the SAR platform is the basic condition for imaging, which forms a synthetic aperture through the relative motion of the platform in a stationary scene to obtain high-resolution azimuth. For airborne SAR, due to the influence of atmospheric turbulence and other factors on the image during flight, it is impossible to maintain an ideal motion state, which inevitably leads to motion errors. Motion errors can cause phase errors and envelope movement, resulting in image defocusing. The motion compensation based on INS data is one of the important means to achieve high-resolution imaging. According to the characteristics of INS data, combined with the Kalman filtering principle and the geometric model of SAR imaging, an INS data filtering and resampling method based on Kalman filtering is proposed. This method can effectively eliminate the error value of motion parameters and obtain the motion parameters of the radar platform accurately. The motion compensation method proposed in this article can be well combined with SAR imaging algorithms, and the accuracy and effectiveness of the method are verified by the imaging result of measured data.

TN927