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浏览/检索结果: 共8条,第1-8条 帮助

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A Multiwavelength Study of PSR J1119-6127 after 2016 Outburst 期刊论文  OAI收割
ASTROPHYSICAL JOURNAL, 2020, 卷号: 902, 期号: 2, 页码: 11
作者:  
Wang, H-H;  Lin, L. C-C;  Dai, S.;  Takata, J.;  Li, K. L.
  |  收藏  |  浏览/下载:46/0  |  提交时间:2020/11/30
The Feasibility of Ocean Surface Current Measurement Using Pencil-Beam Rotating Scatterometer 期刊论文  OAI收割
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING, 2015, 卷号: 8, 期号: 7, 页码: 3441-3451
作者:  
Bao, Qingliu;  Dong, Xiaolong;  Zhu, Di;  Lang, Shuyan;  Xu, Xingou
收藏  |  浏览/下载:28/0  |  提交时间:2015/09/28
Analyse the angular velocity estimation errors of -- filter based on high sampling rate (EI CONFERENCE) 会议论文  OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
作者:  
Zhang Y.
收藏  |  浏览/下载:31/0  |  提交时间:2013/03/25
In order to get angular velocity of stabilization servo mechanism from angular position sensors  -- filter based on high sampling rate was established  model and error characteristics were analyzed. With the hypothesis of constant acceleration  -- filter and its angular velocity transfer function were deduced. Combing with optimum parameters  the effects of and sample rate on the error characteristics were evaluated. According to the requirements of stabilization servo mechanism  the frequency characteristics of angular velocity transfer function are analyzed  and the filter parameters are designed. The experimental which filter tracked and smoothed sinusoidal signal  the results show that when the cutoff frequency of angular velocity loop is 44.9rad/s  sampling period and parameters are 0.08ms and 0.01279 respectively  the phase leading of angular position is 70. -- filter tracked sinusoidal signals with maximum angular velocity(30/s) and maximum angular acceleration(30/s2)  the error of angular velocity estimation was 0.053/s. In the engineering of electro-optical stabilization servo mechanism  -- filter can reduce noise effectively  and reached the requirement of platform angular velocity estimation. Also it is one of the effective methods to get angular velocity from angular position sensors. 2011 IEEE.  
High precision test method for dynamic imaging of space camera (EI CONFERENCE) 会议论文  OAI收割
2010 IEEE International Conference on Advanced Computer Control, ICACC 2010, March 27, 2010 - March 29, 2010, 445 Hoes Lane - P.O.Box 1331, Piscataway, NJ 08855-1331, United States
作者:  
Jin L.-X.;  Zhang K.;  Zhang K.;  Zhang K.;  Zhang K.
收藏  |  浏览/下载:31/0  |  提交时间:2013/03/25
A test method for dynamic imaging of space TDICCD (Time Delay and Integration Charge Coupled Devices) camera was presented in this paper. The test method adopted the PLL (Phase Locked Loop) technology and CMAC (Cerebella Model Articulation Controller) friction compensation as control strategy. Furthermore  According to this method  a test system for dynamic imaging of space TDICCD camera was designed and implemented. The system simulated the movement of the ground objects relative to the space aerocraft  to validate the capability of image speed match and the dynamic imaging quality of TDICCD camera. The design adopted a precision turntable and a drift turntable to simulate the movement around the earth and the drift motion in different latitude due to the rotation of earth  of the aerocraft. The turntables were drived by permanent magnet torque motor which was powered by PWM (Pulse Width Modulation). The system adopted DSP (Digital Signal Processor) as the control core and reached a very high performance. The experimental results showed that the steady speed error was better than 0.01 % and the instantaneous speed error reached 0.0267%. The precision of the test system designed met the requirement for dynamic imaging of TDICCD camera. 2010 IEEE.  
Phase error estimation with broadband white light by Phase Diversity (EI CONFERENCE) 会议论文  OAI收割
6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China
作者:  
Wang Z.;  Wang B.;  Zhang X.;  Zhang X.;  Zhang X.
收藏  |  浏览/下载:24/0  |  提交时间:2013/03/25
The technique of Phase Diversity (PD) is widely adopted to measure the wavefront error caused by atmosphere turbulence and system error. PD solves the Zernike coefficients of the wavefront by utilizing two images obtained with different defocus value. In this paper  we propose a method to restore the image and estimate the wavefront error of an imaging system. And we use present white noises to verify the robustness of the algorithm. We design an experiment system and implement it in our laboratory. The proposed algorithm is validated by computer simulations and experimental results. To use a broadband white object in experimental system a reasonable simplification for the system model is done. Our results show that the robustness against Gaussian white noises of the method is better then the case when the variance value is 0.03. The proposed method can be used as a wavefront sensor and restore the degradative images by photoelectric image system. 2010 SPIE.  
Micro assembled fourier transform spectrometer (EI CONFERENCE) 会议论文  OAI收割
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, November 19, 2008 - November 21, 2008, Chengdu, China
作者:  
Liang J.-Q.;  Zhang J.;  Zhang J.;  Zhang J.;  Wang B.
收藏  |  浏览/下载:30/0  |  提交时间:2013/03/25
With the trend of minimization of Fourier transform spectrometer (FTS) which is particularly pronounced in many applications  a model of a micro FTS with no moving parts is proposed and analyzed. During analyzng  the gradients which mainly introduce phase error are accounted. Based on these assumptions and the improved Mertz phase correcting method  the spectrum of signal is simulated with real extended light source. The resolution can be up to 3.43nm@800nm  with high signal-to-noise ratio (SNR) limiting resolving ability 6.8dB. In addition  the fabrication method of components are illuminated and demonstrated  which can not only make it bear some advantages over conventional micro dispersive spectrometers  but also afford some new concepts on the design of spectrometers with improved performance. 2009 SPIE.  
Annular sub-aperture stitching interferometry for testing of large asphreical surfaces (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging, ISPDI 2007: Optoelectronic System Design, Manufacturing, and Testings, September 9, 2007 - September 12, 2007, Beijing, China
作者:  
Zheng L.-G.;  Zhang X.-J.;  Deng W.-J.;  Wang X.-K.
收藏  |  浏览/下载:79/0  |  提交时间:2013/03/25
Annular subaperture stitching interferometric technology can test large-aperture  and the PV and RMS of residual error of the full aperture phase distribution is 0.027 and 0.0023  high numerical aperture aspheric surfaces with high resolution  the relative error of PV and RMS is -0.53% and -0.31%  respectively. The results conclude that this splicing model and algorithm are accurate and feasible. So it provides another quantitive measurement for test aspheric surfaces especially for large aperture aspheres besides null-compensation.  low cost and high efficiency without auxiliary null optics. In this paper  the basic principle and theory of the stitching method are introduced  the reasonable mathematical model and effective splicing algorithm are established based on simultaneous least-squares method and Zernike polynomial fitting. The translation errors are eliminated from each subaperture through the synthetical optimization stitching mode  it keeps the error from transmitting and accumulating. The numerical simulations have been carried on by this method. As results  the surface map of the full aperture after stitching is consistent to the input surface map  the difference of PV error and RMS error between them is -0.0074 and -0.00052 ( is 632.8nm)  respectively  
Effects of fabricated error on transmission performance of double screens cross loop slot FSS configuration (EI CONFERENCE) 会议论文  OAI收割
2006 7th International Symposium on Antennas, Propagation and EM Theory, ISAPE 2006, October 26, 2006 - October 29, 2006, Guilin, China
作者:  
He B.
收藏  |  浏览/下载:25/0  |  提交时间:2013/03/25
This paper proposes that the inter-layer separation distance (ISD) and the unit cell aligning error (UAE) are used as main variables to study the transmission performance attenuation of the double layer FSS configuration. The numerical analysis model for ISD and UAE was established and also was used to simulate the cross loop slot cell FSS transmission performance by the finite element and periodic moment method program. The double layer cross loop aperture FSS configuration designed was used as the numerical model. As a result of the numerical analysis  it is shown that both ISD and UAE produce insertion transmission loss (ITL) and insertion phase distortion (IPD) directly. Furthermore  ISD results in much loss of the amplitude of the transmitted signal for the FSS than UAE. It is significant for the designer for the multiplayer FSS to assign the fabricated error of the FSS dielectric layers. The UAE introduces the insertion phase variation badly.  
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