The Investigation On The AO Effect Ground Simulation Test And Instrumentation Of The High Speed Interceptor

To achieve superiority in today's high-tech regional war, great importance has been attached to the long-range strike and protection. With the new generation missiles/interceptors entering a period of rapid development, guidance by seeker is one of key technologies for these weapons, but the complicated disturbance caused by high speed missiles/interceptors traveling through the atmosphere will degrade the tracking & aiming sensor system of the seekers, even worse, will make the guidance system fail to function. This kind so-called aero-optical (AO) effect not only has become the bottleneck for development of high-speed interceptor, but also troubles China's development of high-speed missile technology and related equipment. It is also a difficult problem for the whole world. AO effect includes aerodynamic heat effect, aerodynamic heat radiation effect, optical transmission effect of the media in flow-field. The former two effects cause the temperature of the missile/interceptor nose and seeker to rise and decrease the S/N ratio of the seeker detecting the target, the latter effect decrease the seeker's tracking & aiming and identifying ability, thus making it a bottleneck for development of high-speed interceptor. To improve interceptor's tracking & aiming precision, it is necessary to make qualitative analyses and quantitative measurements about the AO effects related to the interceptor's seeker in the high speed real gas, and establish a set of ground simulation /test methods to test the AO effects and its calibration mechanism. This program is launched to solve a fundamental issue existed: the direct factor influencing the optical transmission - variation of refraction index of the media in flow-field, in other words, to use ground simulation equipment or facilities to investigate the AO effects when qualitatively visualizing and quantitatively measuring the interaction of high-temperature, turbulent or shock wave flow-field with optical beam propagatingthrough them, so that technology support can be provided for the high-speed interceptor development.This paper consists of seven chapters. Chapter one introduces the major issues and the progress in AO research both in China and abroad. Chapter two discusses the theoretical foundation and four engineering physics algorithm of AO. Chapter three provides the theoretical modeling and experimental verification of the index-of-refraction's variation with temperature, giving the correlation of AO effect with wavelength, and verifying it with experiments. Chapter four investigates mainly the holographic measurement of the index-of-refraction in 2-D flow-field. Chapter five investigates interferometric methods and data reconstruction for 3-D flow-field of the seeker. Chapter six introduces half-model test study of different parameters with AO effects utilizing the Shack-Hartman technology. Chapter seven investigates the simulation technology for AO, mainly in 2-D flow-field.This paper has a wide scope, ranging from theoretical foundation of AO to its engineering physics methods, from low temperature to high temperature that influence the index-of-refraction, from 2-D to 3-D (density field), from high speed to hyper-speed (interceptor's speed), from model test to numerical simulation (optical phase measurement). It preliminarily establishes a set of test theory and technical approach to wind tunnel test. Specifically speaking, it includes following work:(1) Theoretical analyses on key parameters of AO effect were made. From Maxwell equation, the computation formula for focusing intensity of ordered disturbance and the computation formula for pulse peak intensity were derived. The engineering algorithm (physics optical method) for numerical simulation of AO effect was also derived, the point-diffusion function obtained can be used to obtain sighting-axis deviation, blurring, jitter and Strehl ratio, so that the ground simulation of AO effect can be theoretically feasible. Four classes of ground simulation were introduced: distribution measurement...