Feasibility Research Of Rocket Plume Detection Base On Spatial Heterodyne Spectroscopy

Potassium resonance doublet shape detection technology has important military significance.This paper studies potassium resonance double shape detection technology base on spatial heterodyne spectroscopy（SHS）.This paper,firstly,introduces the principle of the SHS and the source of potassium atom in rocket plume.At the same time,it analyzes the shape and the radiation mechanism of potassium atom in rocket plume.This provides theoretical basis for numerical simulation of potassium resonance double shape in rocket plume.Comparing to the merit and demerit of the plume flow field calculation method of simulation software Fluent and“ideal jet model and semi-empirical formula”,the result shows that“ideal jet model and semi-empirical formula”more easily combine with the algorithm of plume radiation model.The data of plume flow field are calculated by“ideal jet model and semi-empirical formula”,which is used as the data basis for numerical simulation of potassium resonance double shape in rocket plume.This paper uses C-G approximation to calculate radiation spectrum of potassium resonance double shape and analyzes radiation property with different position and different concentration of potassium.Secondly,the vertical distribution model of atmospheric temperature,pressure and density is established by American Standard Atmosphere.This paper uses the vertical distribution model of atmospheric temperature,pressure and density and HITRAN database to calculate the transmittance of oxygen‘A’absorption band by line by line integral method.The scattering characteristics of atmospheric particles are discussed by Mie scattering theory and calculated by empirical formula in engineering.So we can establish the atmospheric transmission of potassium resonance double shape that includes atmospheric molecules absorb and atmospheric scattering attenuation,which provides basis for the detected potassium resonance double shape.The article numerically calculates potassium resonance double shape that have attenuated by atmospheric absorb and scattering,the results show that the potassium resonance double shape can effectively through the atmosphere,and atmospheric scattering is the main factor of the attenuation of intensity.Oxygen’s absorb affects the fine structure of the spectral shapes,but it does not affect the results that the potassium resonance double shape are detected and discriminated by SHS.Through the analysis of the normalized spectral data of solar radiation,it shows that on the potassium line position the solar radiation intensity is weak,so there is weak background clutter on this position and the target signal can be extracted easily.Doppler shift of potassium resonance double shape from plume radiation is also studied,the result shows that the max Doppler shift is less than spectral resolution of SHS,so the Doppler shift don’t affect the result of the detection.Lastly,the detection experiment of K₂SO₄ flame is completed with SHS.By processing and analyzing the experimental data,we can clearly see that the SHS can effectively detect and discriminate potassium resonance doublet shape.Through the above analysis,it can be known that SHS can detect and discriminate the potassium resonance double shape from plume radiation in theory.This work will provide theoretical basis for establishing rocket plume detection system that use the SHS as the detection.