资源一号02D卫星在轨辐射定标精度验证与分析

On-orbit Radiometric Calibration and Validation of ZY-1-02D Satellite

资源一号02D卫星搭载了9谱段可见近红外相机(VNIC)和166谱段高光谱相机(AHSI),主推光谱分辨率,定位于中等分辨率、大幅宽观测和定量化遥感任务,可提供丰富的地物光谱信息,对复杂地物具有精确的探测与分类能力,高精度的辐射定标对于资源一号02D卫星数据应用至关重要。文章提出了一种基于内蒙古包头辐射定标场的在轨绝对辐射定标精度验证方法,利用2020年4月在内蒙古包头辐射定标场开展的星地同步观测试验,采用反射率基法对可见近红外相机和高光谱相机进行在轨场地绝对辐射定标精度验证,对载荷的外场绝对辐射定标系数的精度进行验证分析,检验定标系数的精度。试验结果表明:资源一号02D卫星的可见近红外相机和高光谱相机在轨辐射性能良好且稳定,能够有效支持后续定量化应用需求,由于其载荷的辐射定标精度直接制约卫星应用精度,在后续应用工作中,为充分发挥卫星效能,需要继续深入开展辐射定标精度监测工作。

ZY-1-02D satellite,carrying a 9-band visible near infrared camera(VNIC)and a 166-band hyperspectral imager(AHSI),was successfully launched on 12 September 2019.As a replacement of ZY-1-02C satellite,ZY-1-02D provides more accurate and spectrally dependent radiometric characterization of earth’s surface for natural resources applications.Radiometric characteristics quantification of ZY-1-02D satellite data is a very essential step that enables further quantitative study and application of the data.This paper describes the method of on-orbit reflectance-based vicarious calibration and validation based on the Baotou calibration site.A vicarious calibration and validation campaign that was conducted in April 2020 at the Baotou calibration site in Inner Mongolia Province of China,we use data from this campaign to get a comprehensive understanding of ZY-1-02D satellite radiometric calibration accuracy.The results show the accuracy of ZY-1-02D satellite sensors(VNIC and AHSI)calibration coefficients is within 7%.ZY-1-02D VNIC and AHSI have good and stable on-orbit radiometric performances and ZY-1-02D satellite data are highly reliable and can be used in quantitative natural resources applications.The accuracy of ZY-1-02D satellite sensors calibration coefficients determines the accuracy of satellite quantitative applications and long-term stability of satellite radiometric calibrations should be monitored in the future.