Modeling And Simulation Of Infrared Signature Of Air Target

At present the infrared-guided weapon has been more widely applied in themilitary reconnaissance, target detection and tracking, owing to its superiority. A lotof tests are needed to be done in the development process of the infrared-guidedweapon, which were conducted by field tests previously and the cost is veryexpensive. Therefore, the infrared-guided weapon is much more expensive. With therapid development of the large scale integrated circuits, the computer runs fastersignificantly and becomes much cheaper. Computer simulation technology isincreasingly used in the development process of the infrared-guided weapon. Thedissertation aims to model and simulate the infrared signature of the air target, andprovides the theoretical foundation for the infrared scene image generation systemto set up the infrared radiation parameters.The thesis focuses on the infrared signature modeling and simulation of theskin and jet plume of an air target, which is specified an air-to-air missile as anexample.The surface temperature of an object is origin of its infrared signature. Thedissertation analyzes the main factors to affect the skin temperature of the air targetfirstly, and obtains the temperature distribution of the air target’s skin based onFLUENT6.2software. The effects of the flight mach number, the flight altitude andflight angle of attack on the air target’s skin temperature distribution are discussedsimultaneously. The infrared radiation characteristic of the air target’s skin nearby iscalculated based on the air target’s skin temperature distribution. Then thetransmission feature of the atmospheric to infrared radiation is studied, and thespectral transmittance which can characterize the attenuation effect of theatmospheric to infrared radiation is obtained based on the MODTRAN model underdifferent conditions. The mathematical model of the infrared detection device isestablished according to its operating principle, and the relationship between theinfrared radiation received by the infrared detection device and the infrared imagegenerated by the infrared detection device is established. Finally the air target’s skininfrared image in different flight states is simulated based on the above-mentionedparts. Combustion products of air target’s engine machine are released into the air byits tail jet. The gases of the high temperature and high pressure form the plume flowfield which is several times of its own size. The plume flow field is an importantsource of infrared radiation of the air target, which is belonged to high-temperaturenon-uniformity of gas radiation. The geometry model of plume flow field is builtfirstly. The temperature, pressure and other physical parameters distribution of theplume flow field are solved based on FLUENT6.2software. Then the Band modelC-G approximation is used to approximate the non-uniform gases as the uniformgases by cutting the non-uniform gases into several small pieces. The infraredradiation characteristic of any given line of sight direction is calculated, anddifferent flight states are analyzed at the same time.