Ground experimental simulation method of infrared radiation of high altitude aircraft’s surface

Abstract

It is difficult and costly to accurately measure the spectral and spatial distributions of the infrared radiation signature of a high altitude aircraft’s surface at relatively low temperatures. To reduce the experimental cost, simulated experimental measurement on the ground is usually made to measure its infrared signature. However, there are three main difficulties in the ground measurement: (1) it is difficult to simulate the temperature at high altitude which is much lower than the temperature near the ground; (2) it is difficult to accurately measure the infrared signature of a low temperature surface on the ground; and (3) it is difficult to measure the infrared signature of a prototype aircraft surface. To solve these problems, a ground experimental simulation method to obtain the infrared signature of a high altitude aircraft’s surface is developed, which makes it possible to use a scale model (scale factor M) at relatively higher temperature (n times the temperature of the aircraft’s surface) to experimentally simulate the infrared signature of the actual aircraft’s surface. The results show that the integrated radiation intensity in the wavelength band between λ₁ and λ₂ of an original flying aircraft’s surface at a temperature range from T₁ to T₂ is equal to $\frac{{\overline{\varepsilon }}_{{\lambda }_1-{\lambda }_2,T_1-T_2}}{{\overline{\varepsilon }}_{{\lambda }_1/n-{\lambda }_2/n,{\mathit{nT}}_1-{\mathit{nT}}_2}{M}^2{n}^4}$ times the integrated radiation intensity in the wavelength band between λ₁/n and λ₂/n of the scale test surface model on the ground at a temperature range from nT₁ to nT₂.