基于极化有源定标器的高分三号SAR在轨测试分析

In-orbit Calibration of GF-3 SAR Using Quad-polarized Transponder

高分三号(GF-3)是我国第一部全极化星载合成孔径雷达,也是世界上最为先进的全极化星载合成孔径雷达之一,在轨测试和定标是其定量化和全极化应用的前提,卫星发射后,开展了为期三个月的在轨测试和定标.本文提出了一种新型全极化有源定标器设计方案,利用研制的新型全极化有源定标器获取的在轨测试数据,分析了SAR(Synthetic Aperture Radar)天线方向图、SAR发射脉冲特性以及SAR发射天线极化隔离度等指标,分析结果表明,高分三号SAR具有良好的性能指标.根据全极化成像结果对极化有源定标器指标进行了验证,验证结果表明,有源定标器可以提供不同的散射矩阵且具有良好的点目标特性和极化隔离度指标.

GF-3 is the first quad-polarized spaceborne SAR(Synthetic Aperture Radar)of China and it is one of the most advanced quad-polarized spaceborne SARs.In-orbit calibration is very essential for reliably and quantitatively measuring,and system calibration has been performed during the first three months since launch.A design concept of quad-polarized transponder is proposed.Based on the data obtained using the novel quad-polarized transponders developed for GF-3 during the calibration campaign,this paper analyzes some performances of GF-3 SAR such as the azimuth antenna pattern,the characteristic of SAR pulse and the polarization isolation in azimuth.The analysis result shows that the performances of GF-3 are quite well.Furthermore,the performances of the transponders are validated using the quad-polarized image result.It is proved that the transponders not only can provide various types of scattering matrix but also have a perfect performance of reference point target and the polarization isolation.