【作者】 杨丹；

【导师】 李真芳；

【作者基本信息】 西安电子科技大学 ， 信号与信息处理， 2011， 硕士

【摘要】 在机载干涉SAR(InSAR)系统中,由于气流等不稳定因素的影响,载机飞行过程中会发生位置偏移和姿态变化,载机位置偏移和姿态变化引起的运动误差影响雷达天线相位中心位置和雷达波束指向,从而影响SAR成像质量和InSAR高程反演精度。因而,对其进行运动补偿是保证成像质量和高程测量精度的关键。本文结合仿真和实测数据对机载InSAR运动补偿进行了系统的分析和总结。本文首先分析了位置偏移和姿态变化对SAR成像质量和InSAR高程反演精度的影响,接着研究了基于定位定向系统(POS)测量数据和基于回波数据的运动补偿方法。在基于POS的运动补偿方法中,利用高精度的POS测量数据获得位置偏移和姿态变化,将位置偏移和姿态变化统一等效为天线相位中心的位置变化,再按理想参考轨迹进行包络和相位补偿,并考虑地形起伏、方位空变、距离空变的影响,从而实现基于高精度POS测量数据的精确运动补偿。实际中,考虑到POS测量精度的限制,我们进一步研究基于回波数据的运动补偿方法。由于运动误差必然会反映在雷达接收的回波数据中,从回波数据中可以估计得到多普勒参数,进而获得载机运动参数,利用估计的运动参数完成SAR运动补偿;对于InSAR基线变化引起的干涉相位误差,我们利用方位配准偏移量来估计基线沿视线方向的线性变化量和利用谱分割子孔径方法进行时变基线误差估计,从而完成InSAR的运动补偿。更多还原

【Abstract】 Subject to unstable disturbances, such as atmospheric turbulence, an airborne SAR interferometry (InSAR) platform may deviate from a nominal, straight-line track with its attitude variance. The unstable movements of an airborne InSAR platform lead to defocused radar images and degraded Digital Elevation Model (DEM) accuracy. Therefore, it is necessary to compensate the motion errors. The focus of this dissertation is on analyzing the motion compensation of airborne InSAR using simulation and practical data.In this dissertation, the effects of position and attitude errors on the SAR image quality and DEM accuracy are first analyzed, and then two strategies based on the accurate POS data and the echo data are investigated to compensate the motion errors.For the method based on the POS data, the location and attitude variations are equivalent to the position deviation of the antenna phase centre (APC) from the ideal straight-line track, and then the envelope and the phase are compensated to the ideal reference track, taking account of the effects of the topography, azimuth and range dependence.In practical case, considering the limitation of POS accuracy, the compensation based on the echo data is investigated. The motion parameters can be estimated from the received echo data by using the Doppler parameter estimation techniques, and the motion compensation is then carried out. For the interferometric phase errors caused by the time-varying baseline, two methods based on the registration error and the spectral diversity are investigated to compensate the InSAR motion compensation.更多还原