平地假设与残余运动误差对机载重轨干涉SAR系统性能的影响分析

Performance Analysis of Flat Surface Assumption and Residual Motion Errors on Airborne Repeat-pass InSAR

对合成孔径时间长、方位空变误差大的重轨干涉SAR(InSAR)进行成像时,为简化时域算法模型而引入的平地假设和由导航系统精度而引入的残余运动误差会对成像及干涉测量产生影响。该文针对平地假设引入的高程误差和导航系统精度引入的残余运动误差进行了系统分析,对其在单次航过中引入的成像距离历程误差进行建模,从理论上分析了其对平面定位、干涉相位及DEM精度的影响,最后通过仿真及实测数据实验验证了理论分析的正确性。该文的分析结论为机载重轨干涉SAR系统设计和信号处理提供了理论依据。

When applied to the airborne repeat-pass Interferometric Synthetic Aperture Radar （InSAR）, which has a long synthetic aperture and large azimuth-dependent errors, the surface assumption used to simplify the time-domain algorithm model and the residual motion errors due to the precision of the navigation system affect the imaging result and the interferometrie measurement. This paper analyzes the altitude errors introduced by the surface assumption and residual motion caused by the precision of the navigation system. The range errors model is deduced during the single pass, and the effect of these errors on the plane location, interferometric phase, and DEM precision is analyzed. Further, the accuracy of the theoretical deduction is verified by simulation and real data. Finally, this research provides theoretical basis for the system design and signal processing of the airborne repeat-pass InSAR.