空间目标的地基红外辐射特性测量技术研究

Research on Technology of Ground-Based Infrared Radiation Feature Measurement for Space Target

提出了一种基于望远镜内部定标黑体与大气层外已知光谱特性的红外自然星体作为参照基准的地基大口径望远镜联合定标方法，在此基础上建立了相应的辐射度测量数学模型，以实现对空间目标的高精度红外辐射特性测量。内部定标黑体用于得到大口径望远镜后半光路系统对应探测器的各个像元响应度，外部标准红外自然星体用于估算大气层外目标附近大气与望远镜前半光路系统的等效透射率。在地基1．2m口径望远镜上对大量特性已知的红外自然星体辐射强度测量实验表明，当目标附近具有较强能量红外参考星情况下，如红外参考星在3～5μm波段大气层外辐照度高于1×10^16W／cm^2量级，目标红外辐射强度测量不确定度能够优于15％。该方法能够克服大气程辐射、消光及高质量大口径辐射定标源对大气层外目标红外辐射强度测量不确定度的影响，适合于地基大口径望远镜红外光电测量系统的辐射定标与大气层外空间目标红外辐射特性高精度测量。

In order to precisely measure infrared radiation characteristics of space target, a radiometric calibration method is presented based on the internal calibration blackbody and external natural star with known infrared spectral characteristics, and on the basis of the proposed method corresponding radiation measuring mathematical model is established. Internal calibration blackbody is used to measure the responsivity of each detector pixel involving the back half light path of the telescope, and the external natural star is used to estimate equivalent transmittance of the atmosphere near target region with the first half light path of the telescope. A large number of infrared radiation intensity measurement experiment show that the accuracy can be better than 15 % within 3-5 microns band on the 1.2-m ground based telescope when the target has strong infrared energy reference star and the exoatmosphere irradiance is higher than 1 × 10^16 W/cm2 order of magnitude. The method can overcome the effects of the atmospheric path radiation, extinction and large diameter radiation calibration source on the measurement precision about infrared radiation intensity of exoatmosphere space target, and it is suitable for calibrating of the ground based infrared radiation measurement system with large diameter and measuring of the infrared radiation characteristics of exoatmosphere space target with high precision.