Simulation For Infrared Radiation Characteristic Of Special Vehicles And The Emissivity Measurement

With the widely application of advanced technologies in the military field,such as optical precision-guided tracking, optical stealth and anti-stealth, and opto-electronic countermeasure technology, the need of infrared radiance characters dataof the target and environmental background gradually increased. Nowadays, theacquisition of the infrared radiation data is usually through the way of outfieldtesting or theoretical analysis and numerical simulation. But the cost of outfieldtesting is very high and it is difficult to get the infrared radiation characteristic dataof the foreign military’s important military targets. Therefore, the establishment oftargets infrared radiation theory model and the calculation of the targets infraredradiation characteristic data through numerical simulation methods are importantresearch directions in the field of target infrared radiation.The infrared radiation theory model based on the finite element method isestablished in this paper. Combining with the GID pre-post processing software, acalculation program which can be used to simulate the infrared radiationcharacteristic of special vehicles automatically is compiled. For special vehicles,the3-D temperature filed, the infrared characters and the variation of the directionalspectral radiant exitance in the given detection direction within the band of3-5μmare calculated. The results show that the output infrared radiation of the target ismainly influenced by the reflected solar radiation within the band of3-5μm.However, within the band of8-14μm, its own radiation becomes the main influencefactor. And furthermore, in all the reflected solar radiation only very few of them isindirect reflected. On this basis, the principles of selecting the surface coatingmaterials which can enhance the infrared stealth effect are proposed.To obtain the material emissivity data which are needed in the calculation ofvehicles infrared radiation characteristic, the measurement methods of the materialemissivity are studied. The experimental platforms of emissivity measurementwhich are based on infrared thermometer and FTIR are established respectively. Thetwo platforms are used to measure the spectra normal emissivity of two familiarmental materials within the wave band of8-14μm and2.5-25μm. It can be seen thatthe data which are obtain by the two method match each other very well. At last, theerror analysis of the emissivity measurement base on infrared thermometer isstudied and the optimal emissivity setting value of the infrared thermometer whichminimizes the absolute value of the emissivity measurement error is carried out.