Key Technology Research Of Polarization Crossfire Aviation Verification

The direct and indirect effects of atmospheric aerosols are recognized as major causes of global radiation balance and climate change.Due to the strong polarization and weak light intensity of atmospheric particles,polarization detection technology has been widely used in the field of aerosol remote sensing.The "Polarization crossfire" has obvious advantages in the detection and inversion of atmospheric aerosol comprehensive parameters by using dual polarization instruments on the same platform.Before the launch of the spaceborne remote sensor,an aerial flight verification experiment is carried out to effectively verify the key technologies of the polarization crossfire,which is of great significance to promote the realization of the polarization crossfire technology in orbit.In this paper,the key technologies of aviation verification are studied.including error sensitivity analysis of spaceborne polarization crossfire scheme,geolocation and correction method of dual polarization instrument on the same platform,and polarization cross calibration method.Specifically,firstly,according to the measurement principle and technical characteristics of the spaceborne polarization crossfire scheme,the error sensitivity is systematically analyzed.Combined with the difference between airborne and spaceborne,the configuration scheme of aviation and flight experiment is formulated and the aviation verification system is built.The attitude random effect of airborne platform is eliminated by the time synchronization method of aviation verification system.In addition,the geololocation and correction methods of dual polarization instrument on same platform are studied.The corresponding models of observation pixel and geographical spatial position are established by coordinate transformation,meanwhile,the geolocation result is corrected by the digital elevation model and the instrument misalignment correction.In addition,the error sources that affect the accuracy of geolocation are analyzed,based on which,an error statistical model based on Monte Carlo method is established for simulation calculation.The results show that the positioning accuracy of POSP and SIPC is about 25m at a flying altitude of 5000m.Finally,the experimental verification of the dual polarization instrument is carried out.The polarization and radiometric calibration coefficients of the dual polarization instrument are obtained under laboratory conditions.The field comparison experiments of POSP and CE318N are completed under natural target detection.The experimental results show that the two instruments have a good consistency,and the consistency deviation of radiance and polarization less than 4%and 0.005,respectively.The accuracy on laboratory calibration is verified.The results of flight test data show that after polarization cross-calibration,the root mean square deviation of the radiance of the land surface SIPC relative to the POSP is 2.54%,and the root mean square deviation of the polarization degree is 0.013,in addition,the root mean square deviation of the radiance of the ocean surface SIPC relative to the POSP is 9.28%,and the root mean square of the polarization deviation is 0.043,which verifies the feasibility of cross calibration between dual polarization instruments.The research in this paper has completed the preliminary verification of some key technologies of polarization crossfire,which are important link from polarization crossfire theory to on orbit practical application.and provides support for the expected evaluation of on orbit application effect after launch of spaceborne instruments.