FY-3B/VIRR真空红外定标辐射响应度一致性校正

Uniformity correction of radiance responsivity in vacuum infrared calibration for FY-3B/VIRR

在真空红外定标过程中,扫描辐射计系统响应度常受到试验污染及探测头部温度非一致性等因素影响,导致各通道获取定标系数及铂电阻转换系数不准确。为校正系统响应度的不一致性,可基于黑体辐射源恒温模式下的辐射稳定性和红外探测系统通道单一定标状态下响应度不变性,利用红外定标中的面源黑体及星上黑体变温数据,构建内外黑体红外通道响应一致性传递算法。针对FY-3B可见光红外扫描辐射计(VIRR)发射前定标数据,将定标过程中的系统响应度进行一致性校正。结果表明,面源黑体变温阶段面源黑体校正码值在升温和降温间的一致性优于0.7 DN,辐射传递过程中基准工况下星上黑体校正码值一致性优于0.3 DN,并分析了校正方法和其他传统方法在计算星上黑体变温阶段等效黑体温度的差异性。因此,该算法保证了空间辐射基准到红外探测系统以及星上黑体辐射传递过程的辐射准确性,为有效提高真空红外辐射定标精度提供技术保障。

In vacuum infrared calibration,factors,such as test contamination and non-uniformity of instrument temperature,cause response changes for scanning radiometer system,resulting in inaccurate calibration coefficients and platinum resistance conversion coefficients for each channel.The non-uniformity of the responsivity is corrected using the stability of the blackbody as a reference source in the constant temperature mode and the responsivity invariance in the single calibration state for the infrared detection system.The transfer algorithm of the consistent response from the internal to external blackbody measurement for the infrared channels is established by the data of variable temperature test for the surface blackbody and on-board blackbody in the infrared calibration.For the prelaunch calibration data of FY-3B visible infrared radiometer(VIRR),the non-uniformity of system responsivity is corrected during the calibration.At the temperature change stage,the uniformity of the correction signal for the surface blackbody between the heating-up and cooling-down stages is better than 0.7 digital number.In the radiance transfer stage,the uniformity of the correction signal for the on-board blackbody is better than 0.3 digital number in the reference condition.The difference between the correction method and other traditional methods in calculating the equivalent blackbody temperature of the on-board blackbody is analyzed.This algorithm ensures the transfer accuracy from the space-based radiance standard to the infrared detection system and on-board blackbody,and the technical support is provided to effectively improve the accuracy of vacuum infrared calibration.