State Key Laboratory of Experimental Physics and Computational Mathematics

Beijing, China

State Key Laboratory of Experimental Physics and Computational Mathematics

Beijing, China
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Qi Z.,State Key Laboratory of Experimental Physics and Computational Mathematics | Xiao L.,State Key Laboratory of Experimental Physics and Computational Mathematics | Fu S.,National University of Defense Technology | Li T.,National University of Defense Technology | And 2 more authors.
Applied Optics | Year: 2012

Given the rapid convergence characteristic of the stochastic parallel gradient descent (SPGD) algorithm, this study proposes a method that applies the algorithm to a two-step camera calibration method to resolve the frequent iteration and long calibration time deficiencies that exist under the traditional two-step camera calibration method, thereby achieving rapid calibration. The method first uses image coordinates obtained with subpixel positioning technology as initial values of control variables, in addition to positive disturbances produced on a two-dimensional plane, then uses two-step theory to calculate the average value of aberrations. Based on the same rationale, negative disturbances are then produced and the average value of the aberrations is calculated. Finally if, after assessing whether to continue with further iterations based on the difference in these values, continued iterations confirm new control variables based on the SPGD algorithm iteration formula, a new cycle is started until the results satisfy requirements. Theoretical analysis and experimental results show that the proposed rapid calibration method using the SPGD algorithm in the two-step camera calibration method is 3-4 times faster than the traditional two-step calibration method, and that it has significant potential value for use in certain time-constrained projects. © 2012 Optical Society of America.


Jiang T.,China Aerodynamics Research And Development Center | Ding M.-S.,China Aerodynamics Research And Development Center | Gao T.-S.,China Aerodynamics Research And Development Center | Dong W.-Z.,China Aerodynamics Research And Development Center | And 2 more authors.
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2013

Aero-optic effect induced by the flow-field outside the IR seeker optical window is one of the problems needed to be solved in designing a high-speed interceptor. When IR signatures form the target throughout the high-speed flow-field, the IR image on the seeker will be shifting, blurring and even jittering. These effects bring errors of position-setting, and degrade the intercepting precision. Based on the thermochemical non-equilibrium Navier-Stoke equations, the high-speed flow-field is simulated numerically. The Ray-tracing and physical-optic methods are used to get the OPD and PSF, which can describe the shifting and blurring of IR image. The affect factors of IR image shift and attenuation are considered, including Mach number, attack angle, altitude, incidence angle and IR wavelength. As a result, the aero-optical effects under 30km altitude have obvious influence on IR imaging, and increasing the incidence wavelength can reduce the attenuation of IR image intensity.


Jiang T.,China Aerodynamics Research And Development Center | Ding M.,China Aerodynamics Research And Development Center | Gao T.,China Aerodynamics Research And Development Center | Dong W.,China Aerodynamics Research And Development Center | And 2 more authors.
Guangxue Xuebao/Acta Optica Sinica | Year: 2012

Study on the bore-sight error (BSE) induced by high-speed flow-field is important for the hit precision of a hit-to-kill interceptor with infrared ray (IR) terminal homing system. Based on the flow-field by solving the thermal-chemistry non-equilibrium Navier-Stokes (N-S) equation, the ray-tracing method is used to calculate the BSE of ray transmission through the flow field outside the optical window. The impact factors of BSE are considered, including incidence angle, Mach number, attack angle, altitude and the IR seeker shape.


Wang-Xiaofei,State Key Laboratory of Experimental Physics and Computational Mathematics | Wang-Hui,State Key Laboratory of Experimental Physics and Computational Mathematics | Wang-Suixue,State Key Laboratory of Experimental Physics and Computational Mathematics | Haoxin K.,State Key Laboratory of Experimental Physics and Computational Mathematics
Proceedings of the International Astronautical Congress, IAC | Year: 2013

According to the thick dielectric material layer boundary, this paper designed a new broadband L-band omnidirectional antenna. Based on the combination of Antenna design and Radome design, the antenna achieved omnidirectional pattern and high gain In the wide frequency range. It could meet the high demand of carrier transmissing electromagnetic waves in the horizontal direction. Through modeling and simulation, a reasonable design size was obtained. Antenna product was tested and the results satisfied the design requirements. ©2013 by the International Astronautical Federation. All rights reserved.

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