测量了自发参量下转换的宽光谱分布和时间相关性，搭建了基于自发参量下转换定标的辐射计.在自发参量下转换定标探测效率的基础上推导了光子计数模式的辐亮度测量方程，根据定标原理辐射计可以实时监测和校正仪器的光电衰变.通过插入光学衰减片和更换探测器模拟了辐射计在光路衰变和电路衰变情况下能够修正自身衰变对观测结果的影响，观测辐亮度的一致性优于0.38%.测量结果为自发参量下转换定标技术应用在未来的气候观测星上定标器等空间平台提供实验依据.

The spectral distribution and time correlation of spontaneous parametric down-conversion were measured, and a radiometer based on spontaneous parametric down-conversion calibration was established. Based on the detection efficiency of spontaneous parametric down-conversion calibration, a radiance measurement scheme in terms of photon count was proposed, the radiometer can correct the degradation of its own response and observe the radiance of the target in real time. By using the experimental technique of inserting optical attenuator and changing detectors, the radiometer can correct its own degradation if observed radiance measurement results under the condition of optical degradation and electronics degradation. The results show that the consistency of observed radiance can meet 0.4%.The measurement results provide experimental basis for the application of spontaneous parametric down-conversion calibration to space platforms.