Aircraft Infrared Radiation Analysis And The Estimated Range Of Infrared Imaging System

Estimating the range of infrared imaging system is very good for raising system designing level, reducing cost, curtailing period of development and production. But there are many factors affect the range, such as: the characteristics of target, transmission in atmosphere, parameters of imaging system and so on. So the estimation of the range of infrared imaging system will be greatly difficult.This dissertation has analyzed aircraft infrared characteristics such as temperature and spectrum. Also has considered the radiation property of sky as the background. We get an expression between transmission rate and water vapor content and distance of atmospheric carbon dioxide, after fitting the data. According to the method of equivalent sea level, we can get equivalent water vapor content and equivalent distance of atmospheric carbon dioxide. Then we sum up out the law of absorptive, dispersive and total transmission rate with different distance in two atmosphere window 3 ~ 5μm and 8 ~ 13μm, and analyze it through calculating,.Also we have analyzed the impact of infrared imaging system performance on the ability of detection, and selected Catherine-GP type thermal imaging system carrying out the function valuation. MRTD is a main parameter of expressing the ability of imaging systemic temperature resolution. After considering the target form, detecting probability and SNR, we get more accurate relational expression between MRTD and space frequency variation. Formerly, people looked space frequency as a constant having nothing to do with distance. In fact, this brings about very big error. Because space frequency is the function of detecting range, we change MRTD into the function of detecting range therefore. MRTD which get from this method is more exactness and credibility.Using the parameters of Catherine-GP type thermal imaging system, we calculate the range of thermal imaging system to several kinds of representative targets under specially weather condition. Using this method, we estimate the range of tank and human body as point target. As well as estimate the range of laboratory standard target and battleplane as expend target. The calculated results accord with actual measurement results very well. Therefore said this method to estimate range of thermal imaging system is simply, practical and nicety.