High altitude aero-optic imaging deviation prediction for a hypersonic flying vehicle

Aero-optic imaging deviation characterizes the image position displacement on an imaging plane induced by the nonuniform flow field surrounding a high-speed flying vehicle. It is a kind of aero-optic effect that all the airborne imaging systems will encounter. This paper studies the imaging deviation at high altitudes from 40 to 60 km, with a step length of 5 km. CFD computations are completed by the Reynolds-averaged Navier-Stokes method. Optics calculations are performed by solving a ray equation using the Runge-Kutta algorithm. The dependence of imaging deviation on altitude in 40-60 km is given. The imaging deviation slopes are also calculated and analyzed. The results show that as altitude increases from 40 to 60 km, the imaging deviations decrease. At smaller altitudes, the imaging deviation is relatively sensitive; whereas, at larger altitudes, the imaging deviation slopes approach zero from a negative value.