多光谱遥感器在轨运行期间，受化学分子污染、发射振动、宇宙辐射等因素的影响，其光谱响应特性会发生变化，使目标物理量的测量值产生偏差，且不能用辐射定标进行校正，影响数据产品序列的一致性。提出了一种基于光谱靶标的光谱响应退化特性在轨评估方法，通过建立响应函数退化模型，并利用光谱靶标反射率在检测波段内呈非线性变化的特性来实现对光谱响应函数退化情况的定量化评估。模拟仿真与外场实验结果初步验证了本文方法的有效性，该方法在提高辐射定标精度和优化遥感器设计等方面有重要意义。

When the multispectral remote sensor is working in the space, it will be affected by the contamination of chemical molecules, vibration during launch, radiation from space and etc. Its spectral characteristic will be degraded by time. As a result, bias will show in the physical measurement and cannot be rectifiec by radiometric calibration, which will affect the constancy of the data products. An on-orbit degradation assessment method is proposed, which is based on spectral targets. By establishing the degradation model of response function and using the nonlinear reflectance of spectral targets, quantitative assessment of the degradation can be achieved. The results of the simulation experiment and in-flight experiment verify the effectiveness of this method. The method has great significance in improving the accuracy of radiometric calibration, optimizing the camera design and other aspects of remote sensing.