On-Orbit High-Precision spectral correction based on the Mie scattering

High-precision spectral calibration is crucial for ensuring the quality of spectral data in on-orbit spectrometer operations. While the detected light typically enters the spectrometer system at normal incidence, the calibration light source often enters at oblique angles, which can significantly affect calibration results. Experimental observations indicate that oblique incidence causes variations in the energy distribution at the spectrometer’s entrance pupil, with the non-uniformity of this distribution identified as the primary cause of spectral drift. However, modelling diffuser plates remains inherently challenging due to the randomness introduced during their fabrication process. To address this, the present study develops a spectral calibration model based on Mie scattering theory and analyses the causes of spectral drift. By systematically analysing the diffuser plates and optical structures within the calibration system, it is found that the oblique angles of the calibration light source and the particle sizes of the diffuser plates are critical factors influencing calibration accuracy. Additionally, the impact of wavelength on spectral drift is predicted, providing a method for correcting high-precision on-orbit spectral calibration. This study offers a robust theoretical foundation and practical approach to enhance the calibration accuracy of on-orbit spectrometers.