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	Gimbal displacement error analysis on an electro-optical seeker (EI CONFERENCE) 会议论文 OAI收割 Optical Design and Testing IV, October 18, 2010 - October 20, 2010, Beijing, China 作者: Zhang X.; Zhang X.; Zhang X. 收藏 \| 浏览/下载：32/0 \| 提交时间：2013/03/25 It is essential to analyze the gimbal displacement errors for a seeker due to the importance for cueing of targets and tracking for the final approach. Otherwise for a seeker electro-driven with a concentric glass dome the large errors will decrease the picking pointing and tracking precision rooted from the displacement errors existing between the rotation center of the optical system and the gimbal. And the gimbaled camera system displacement errors are never eliminated but reduced due to the geometric errors consists of geometric tolerances of gimbal structure manufacture installation and vibration coming from working environment. In this paper the gimbal displacement errors in an electro-optically stabilized platform resulting from geometric errors and environment errors were analyzed and shown in detail. The mathematical modal of the gimbal displacement errors created based on multi-body dynamics demonstrated the connection between the gimbal displacement errors and the stabilized platform. Taking a visible light image seeker as a case the diameter is 120mm and the geometric tolerances came from the values of primary design and the vibration data came from the environmental vibration test on the pitch-yaw seeker and at the same time the errors resulting from installation were considered too. Based on calculating the maximum gimbal displacement error will reach to 0.2mm for pitching angle smaller than 40 and yawing angle smaller than 60. However the critical parts have been found out according to the probability theory and the reliability analysis successfully used in the paper and finally the maximum gimbal displacement error reduced to 0.1mm which is acceptable corresponding to the picking pointing and tracking precision for an optical imaging seeker. 2010 Copyright SPIE - The International Society for Optical Engineering.
	1D-KBA microscope using double-periodic multilayer (EI CONFERENCE) 会议论文 OAI收割 Advances in X-Ray/EUV Optics and Components IV, August 3, 2009 - August 5, 2009, San Diego, CA, United states 作者: Wang Z.; Wang X.; Wang X.; Wang X.; Wang Z. 收藏 \| 浏览/下载：11/0 \| 提交时间：2013/03/25 To study the action of shock wave in CH target one-dimensional grazing incidence KBA microscope for 4.75keV energy was set up. Because of strong absorption in air 4.75keV energy microscope can just work in vacuum. Accordingly the alignment and assemblage will be very complicated and difficult. A special multilayer method using double periodic multilayer was proposed to solve this problem. This multilayer has high reflectivity not only for 4.75keV X-rays but also for 8keV X-rays at the same grazing incidence angle. It means 1D-KBA microscope has the same light trace for different working energies. Therefore we can implement the alignment and assembly of 4.75keV system by the help of 8keV X-rays. Because 8keV X-rays is very easy produced by X-ray tube and has strong transmittability in air the alignment and assemblage process became relatively easy. By now we have finished the alignment experiment at 8keV and obtained imaging results. The performance is about 2-3m resolution in 250m field of view. It is coincide with the calculation. 2009 SPIE.
	Application of CMOS APS star tracker with large FOV in attitude and angular velocity determination (EI CONFERENCE) 会议论文 OAI收割 Advanced Sensor Systems and Applications III, November 12, 2007 - November 14, 2007, Beijing, China Lu D.; Guang J.; Shaoju W.; Tao C. 收藏 \| 浏览/下载：29/0 \| 提交时间：2013/03/25 The paper deals with the spacecraft attitude determination problem using a new kind of star tracker with large FOV based on CMOS APS. Star tracker has been developed since 1970s and proved to be the most accurate sensor ever used in the spacecraft attitude determination systems. But the traditional CCD star tracker also has some disadvantages such as small FOV high power consumption low sample rate and low working angular rate limit which prevent the use of CCD star tracker in attitude large angle maneuvering process. The new kind of star tracker based on CMOS APS has no such disadvantages and is more applicable on modern low-cost agile small satellites. Its higher sample rate and working angular rate limit over traditional CCD star tracker make it more adapt for spacecraft angular velocity determination. Because of the large FOV of the star tracker the mathematical model of traditional CCD star tracker with a small FOV is not appropriate. So a new mathematical model was quoted to fit the star tracker with a large FOV. An alternative adaptive algorithm was also introduced in the paper. It can help the EKF algorithm work lacking of accurate covariance of the observation noise. An optimal estimation algorithm was used to estimate the angular velocity directly from the star tracker measurements. Mathematic simulation results indicate the CMOS APS star tracker can give accurate attitude information and estimated angular rate. The method can be used as the chief attitude determination system design of low-cost satellite without gyros or be used as a backup strategy in the event of gyro failures to enhance the reliability of the attitude determination system.
	Research on selecting working angle in ball spinning 期刊论文 OAI收割 International Journal of Vehicle Design, 2005, 卷号: 39, 期号: 1-2, 页码: 73-79 M. S. Li; S. H. Zhang; D. C. Kang 收藏 \| 浏览/下载：14/0 \| 提交时间：2012/04/14 ball spinning working angle peeling diameter bulging axial feeding rate radial reduction ball diameter