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Study on the Extinction Characteristics of Smoke Jamming in Spacecraft
ZHANG Lei
Modern Defense Technology    2021, 49 (3): 80-85.   DOI: 10.3969/j.issn.1009-086x.2021.03.010
Abstract2973)      PDF (4593KB)(3118)       Save
Based on MIE scattering theory,the radiative transfer model of absorption,emission and scattering particle system in space environment is established.The change of total radiation in smoke diffusion process is studied,and the infrared stealth effect of particle optical properties,particle number density and smoke thickness on the whole smoke shielding is analyzed.The results show that the medium wave can provide a better stealth effect,and can mask up to 90% of the vehicle radiation.The refractive index of particles has little effect on the smoke stealth effect,and the absorption index has a greater effect on the smoke stealth effect;the particle size has a greater impact on the stealth effect,and there is an optimal particle size selection under the specific optical properties.The density of smoke has a saturation value,when the saturation value is exceeded,the stealth effect will not increase,and the thickness of smoke screen has no obvious improvement on the stealth effect.
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Effectiveness of Air Defense Missile Weapon System Based on Extension Theory
WANG Feng, ZHANG Lei
Modern Defense Technology    2018, 46 (3): 9-17.   DOI: 10.3969/j.issn.1009-086x.2018.03.002
Abstract310)      PDF (1600KB)(945)       Save
Based on the theory of extenics, the extension model of air defense missile weapon system was established. Using extended analysis principle and extension reasoning knowledge such as extension, divergence, and implication, the extensive analysis and modeling on firepower conversion, interception scheme generation and screening of air defense missile weapon system were carried out. The calculation on air defense efficiency was simulated. The simulation results conformed to the actual operational process, which made the intercepting scheme generation of the air defense missile weapon system more formal, more logical. It provided a new idea and a new method for calculating the efficiency of air defense missile weapon system. It laid a foundation for writing software programs to achieve intelligent processing.
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Fast Inertial Navigation Error Estimation Method for Airborne SAR
WANG Guan-yong, WANG Feng-fei, ZHANG Lei, HU Qing-rong
Modern Defense Technology    2018, 46 (1): 88-93.   DOI: 10.3969/j.issn.1009-086x.2018.01.014
Abstract210)            Save
To locate airborne synthetic aperture radar (SAR) image with high accuracy, a fast inertial navigation error estimation method is proposed by using advantage of sub image back projection (BP) imaging. The relationship between inertial navigation error in position, velocity and positioning error under BP imaging model is investigated. The observation equation of positioning error is obtained by approximating the relationship in linear. Estimations of inertial navigation error in position and velocity can be obtained by least square method. Monte Carlo tests are processed under Gauss observation errors with the same mean and variance. It is illustrated that the proposed method possesses a lesser error of mean square compared with the conventional range-Doppler (R-D) model based estimation method.
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