关键词: 光谱辐射定标, 光谱模拟, 凹柱面光栅, 辐射分光, 光学设计

Abstract:

Currently， ground calibration equipment for space remote sensing cameras lacks precise simulation of various spectral line distributions and cannot simultaneously perform both broadband and narrowband spectral radiometric calibration， resulting in low accuracy of ground radiometric calibration for space remote sensing cameras， a long and complex calibration process for both broadband and narrowband， and inability to conduct radiometric calibration tests across multiple spectral ranges. To address these challenges，a design method for a spectral radiometric calibration system based on a concave cylindrical grating with a pre-collimation and beam expansion system.Considering the field curvature characteristics of the concave cylindrical grating， a wedge-shaped field curvature compensation prism is designed. Additionally， the collimating and beam-expanding system is used to reduce the imaging field of view of the system， improving the spectral resolution of the concave cylindrical grating spectroscopic system. This enhancement doubles the spectral resolution of the entire system， from 5 nm to 2 nm. Finally， the system performance is tested. In the broadband mode， the system achieves color temperature simulations of 3 000 K， 6 400 K， and 9 000 K within the 500–900 nm spectral range， with a simulation error better than 5%. In the narrowband mode， the half-peak width of the system’s output beam is less than 3 nm. In the multispectral mode， the spectral simulation errors for equi-energy spectra are 1.1% in the 545–600 nm range， 2.5% in the 630–690 nm range， and 1.5% in the 680–725 nm range. This system meets the requirements for broadband and narrowband radiometric calibration and multifunctional testing and calibration of space cameras， attitude navigation systems， and remote sensing instruments.

Key words: spectral radiation calibration, spectral simulation, concave cylindrical grating, radiation spectroscopy, optical design