Research On Optical Detection Of Low Speed Targets In Near Space

Near space refers to the space with a height of20~100km. With its own particularity,this area neither belongs to the category of aviation nor belongs to the category ofspace. Study on near space has been enhanced by many countries. Nowadays there isstill no detection equipment and perfect optical detection theory that are fully appliedto near space target both at home and abroad. Firstly, this paper has carried out thesimulation of atmospheric radiative transfer and analyzed the optical properties ofnear space targets. Secondly, this paper further analyses the optical detection systemtheoretically for the low speed targets in near space. Thirdly, this paper providespractical detection work.This paper is made up with the following aspects:(1)On the basis of the atmospheric radiation transfer model, the sky background ofnear space is simulated. An atmospheric modeling tool, MODTRAN, is used to modelatmospheric transmission and the sky background brightness. The law of theatmospheric radiation transfer in near space is obtained, which provides the basis forthe optical detection theory to detect near space target.(2)The visible brightness characteristics of the low speed targets in near space isanalysed and simulated. Main researches are focused on the brightness characteristicsof low speed targets in near space on a variety of conditions, including differentazimuths and different ranges.(3)This paper analyses and simulates infrared radiation characteristic of low speedtargets in near space. Considering of the solar direct radiation, the solar radiationreflected by the ground, the infrared radiation of the earth and the atmosphere, thetemperature of near space target is calculated. Then the infrared radiationcharacteristic of the target is calculated.(4) The detect system for near space target is analysed theoretically. For visible waveband and near infrared wave band, we analyse the detect ability of a detector. For the middle infrared wave band and long infrared wave band, we estimate its detectionrange and parameters of the optical systems. The theoretical basis for optical detectionis provided for subsequent high-altitude weather balloon’s test.(5) The optical detection test of high-altitude weather balloon is given. This paperintroduces the image processing technology that is applied in the test, the test device,and the test results. The correctness of the detection scheme in visible waveband andnear infrared waveband is verified, which provides the basis for the follow-up work.