Research Of The Operating Range Of The IR Imaging System Expressed By Atmospheric Transmittance Based On The MODTRAN

Performance characteristic and theoretical modeling is the hotspot and difficult points in researchof infrared imaging system evaluation nowadays. Operating range is one of the main tactical indexesof infrared imaging system, and it is main parameter for system performance evaluation. Itsestimation has great significance for design, develop and manufacture infrared thermal imagingsystem. Therefore, it remains the focus of our study.Formula of affect distance of infrared thermal imaging system is studied in this article. Infraredradiation feature of target and background, atmosphere absorption, scattering and attenuation wouldinfluence affect range of thermal imaging system. Based on background radiation character, this papersets the atmospheric parameter with software MODTRAN and takes into account the impact ofatmospheric density, horizontal and tilt direction of transfer of infrared radiation. Water vapor, carbondioxide, ozone and other trace gases in atmosphere, aerosol and different weather conditions alsoconsidered for study the atmosphere transmit ratio in different spectrum. Spectrum interval bisectionmethod was used to process the data from MODARAN. A database was built for simplify atmospheretransmission calculation. Then the paper use soft program calculating the system operating range indifferent altitude, different atmospheric concentration and different altitude by successiveapproximation method with joint of characters of Gatherine-GP thermography. Results show that thedatabase model built by spectral interval bisection method and successive approximationprogramming method are reliable. And it also makes the judgment of the point target range of infraredthermal imaging system more accurate and greatly reduces the judgment time.