基于中阶梯光栅的波长定标方法研究

波长定标是仪器遥感数据定量化的前提和基础。针对星载大气微量成分探测仪视场大、波长宽、空间分辨率和波长分辨率高的特点,建立了基于中阶梯衍射光栅的波长定标装置。中阶梯光栅因其较少的线密度和较大的闪耀角工作在较高的闪耀级次,光谱范围宽且具有较高的分辨率,可在工作波段内一次性输出多条分布较为均匀的谱线,克服了传统定标方式的缺点,提高了定标精度。本文首先介绍了波长定标装置的工作原理,接着利用该装置对高光谱大气微量成份探测仪进行波长定标,通过寻峰和回归分析给出载荷的波长定标方程,并利用标准汞灯谱线对定标结果进行检验。结果表明:高光谱大气微量成份探测仪的像元和波长近似满足线性分布规律,定标不确定度为0.025 8 nm,汞灯特征谱线的定标值和标准值偏差最大不超过0.043 5 nm,证明了定标结果的准确性。

Spectral calibration based on echelle

Spectral calibration is the premise of remote sensing data inversion. Considering the advantages of a large field, wide wavelength range, high spatial and spectral resolution, the spectral calibration equipment based on echelle is built. Working at a higher blazed order with a large blaze angle, the echelle is characterized by a wide spectrum range and high spectral resolution. It can output multiple spectral lines with uniform distribution in the detection band, which overcomes the shortcomings of the traditional calibration methods and improves the calibration accuracy. In our study, the working principle of the spectral calibration equipment is given first. Then using this equipment, the spectral calibration equation of the hyperspectral imaging spectrometer is given accurately by peak-searching and regression analysis. Finally, the calibration results are verified by using the unique characteristics of mercury spectral lines. The experiment results show that there is a approximate linear distribution between pixel and wavelength. The uncertainty of the wavelength calibration is 0.025 8 nm, and the maximum deviation of calibration values and standard deviation values of mercury spectral lines is less than 0.043 5 nm, which can prove the accuracy of the calibration results.