| The spatial heterodyne spectrometer combines the traditional interference spectroscopy technology with the grating technology.It has the advantages of high-throughput,high-spectral resolution,small volume,and no moving parts.Within a certain spectral range,high-precision spectra can be obtained.In addition,it is suitable for satellite platform mounting and widely used in high resolution remote sensing spectrum detection.However,at present,the domestic research on the spatial heterodyne spectrometer is still in its infancy.Due to the shortage of understanding the whole link and modulation process of the spatial heterodyne spectrometer and the lack of a complete forward model and instrument model,the application and development of the spatial heterodyne spectrometer is limited.Therefore,this paper focuses on the instrument model in the forward process of spatial heterodyne spectrum detection,and simulates linear spectrum and continuous spectrum based on the instrument model.The feasibility of the model is verified by comparing the simulation results with the measured data.According to the experimental conditions,potassium resonance double line spectrum and CO2 spectrum data are selected as the research objects respectively.First of all,Simulation of linear spectrum based on instrument model of spatial heterodyne spectrometer is carried out,and the potassium resonance double line spectrum is taken as the object of study,and the state of its transmission in the atmosphere is discussed,which provides a theoretical basis for the outdoor experiment of the spatial heterodyne spectrometer with the potassium resonance double line spectrum.Taking the potassium line spectrum as the analog signal,the instrument model of the spatial heterodyne spectrometer is simulated by using MATLAB and ZEMAX software.Combined with the results of outdoor experiment of potassium resonance double line spectrum of spatial heterodyne spectrometer,the obtained interferograms are processed to extract the target.The results of the MATLAB simulation and the ZEMAX simulation are compared with the measured data.The results show that the three lines are basically consistent,and the feasibility of establishing the instrument model of spatial heterodyne spectrometer is verified.Then,based on the instrument model of spatial heterodyne spectrometer,the simulation of continuous spectrum is carried out.The CO2 spectrum is selected as the research object.Because ZEMAX has limited setting of the incident spectrum,it is not possible to set complex spectra.Therefore,the continuous spectrum simulation is performed only on the basis of the model constructed by MATLAB.The input signal of the model is CO2 spectrum data which is simulated by SCIATRAN model.The effects of interference factors such as phase error,grating angle error,system vibration and offset error and noise on the model output are analyzed,and the final simulated spectrum are compared with the measured data of CO2.The results show that the difference between the simulated data and the measured data is mostly less than 0.2.On the whole,their spectral shapes are quite similar,and the trend of change is roughly the same.This verifies the feasibility of establishing a spatial heterodyne spectrometer instrument model and numerical modeling of the interference modulation process. |
