自校准多通道红外辐射计的设计与性能测试

为满足遥感器热红外波段自动化观测定标的需求，研制了具有自动化观测能力的自校准多通道红外辐射计。该设备需具有以下特色功能:1）采用电机驱动镀金反射镜的设计，实现0°～90°仰角的大气下行辐射和地表辐亮度的测量，为消除大气下行辐射对反演地表温度的影响提供了技术手段；2）采用滤光轮分光的方法实现了6个光谱通道的自动设置，结合多通道温度与发射率分离算法可以实现场地温度与发射率的分离，为卫星遥感器热红外波段绝对辐射定标提供了2个关键因子；3）采用内置2个控温精度分别优于0.04 K和0.05 K、发射率均高于0.994，稳定性均优于0.0014的黑体实现内部探测器的实时辐射定标，有效地消除了内部背景辐射对辐射测量的影响，定标不确定度小于0.167%。等效测温不确定度为0.2 K（@303 K, 11 μm），为遥感器热红外波段场地自动化定标应用的开展奠定了基础。

Design and performance test of self-calibration multichannel infrared radiometer

In order to meet the needs of automated observation calibration for remote sensor thermal infrared band, a self-calibration multichannel infrared radiometer with automated observation capability was developed. The equipment has the following features: 1) the design of motor-driven gold-plated reflector was used to achieve the measurement of downward atmospheric radiation and surface radiance at an elevation angle of 0°~90°, which provided the technical means to eliminate the influence of downward atmospheric radiation on inversion surface temperature; 2) the filter wheel spectrometry was used to realize the automatic setting of 6 spectral channels, and combined with the multichannel temperature and emissivity separation algorithm, the separation of site temperature and emissivity could be achieved, which provided 2 key factors for the absolute radiometric calibration of satellite remote sensor thermal infrared band; 3) a black body with two built-in temperature control accuracy better than 0.04 K and 0.05 K, emissivity higher than 0.994, stability better than 0.001 4 was used to achieve the real-time radiometric calibration of the internal detector, which effectively eliminated the influence of internal background radiation on radiation measurement. The calibration uncertainty is less than 0.167%, and the equivalent temperature measurement uncertainty is 0.2 K (@303 K, 11 μm), which lays the foundation for the application of site automated calibration for remote sensor thermal infrared band.