Method for acquiring thermal radiation noise of gradient temperature gas medium in infrared imaging guidance

Abstract

The invention discloses a method for acquiring thermal radiation noise of a gradient temperature gas medium in infrared imaging guidance, comprising the following steps of: 1, establishing a finite-element analysis environment for a discrete medium; 2, carrying out ray tracing and searching an LOS (Line Of Sight) path; 3, acquiring thermal radiation intensity of a spectral band through iteration by adopting a discrete transfer method; and 4, acquiring the thermal radiation noise. The method for acquiring the thermal radiation noise, disclosed by the invention, and can overcome the dependence of radiation energy on space direction and ensure that the high-temperature gas radiation problem for a specific research purpose can be numerically solved; the introduced LOS path is an effective integral path for calculating the thermal radiation effect of the gradient and temperature medium, which forms disturbance to infrared imaging; a ray trace equation and a radiation trace equation, including temperature functions, are realized through developing an accurate ray tracing model based on a CFD (Computational Fluid Dynamics) grid in the temperature gradient field; and the method for acquiring the thermal radiation effect of a high-temperature gas can be obtained by utilizing the radiation discrete transfer method.

Description

technical field [0001] The invention relates to a method for acquiring thermal radiation noise of a gradient-temperature gas medium in infrared imaging guidance, and belongs to the technical field of infrared terminal guidance for high-speed aircraft. Background technique [0002] When a missile with an infrared imaging guidance system flies in the atmosphere at high speed, there is a high-temperature shock layer around its optical hood. The density, temperature, and composition of the gas in the shock layer are highly uneven, and generate strong infrared radiation, causing thermal radiation noise interference to the detector imaging, which seriously degrades the target image, which is called the aerodynamic thermal radiation effect. [0003] The aero-optical thermal radiation effect is a key issue that restricts the high-speed air-to-air missiles from using infrared imaging guidance technology to achieve high-precision hitting targets, and it is necessary to conduct in-dept...

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Problems solved by technology

[0005] For the research on the effect of aero-optical thermal radiation, most scholars in the industry study the mechanism of atmospheric thermal radiation from the perspective of molecular thermal motion. Without combining optical transmission, they cannot quantitatively obtain the specific wavefront distortion caused by high-temperature shock waves to infrared target imaging; Scholars who solve the radiative transfer equation to study this problem mostly use statistical methods (Monte Carlo) to solve the problem of radiative integral path, which requires a large number of samples and consumes a huge amount of calculation, and assumes that characteristic rays in different directions are emitted to this node The weight of the radiation intensity contribution of the spectral bands is the same, and the integral path dedicated to the calculation of the radiation intensity when analyzing the infrared imaging noise cannot be determined

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