中国科学院机构知识库网格系统: 检索

Modular aircraft simulation platform based on simulink (EI CONFERENCE) 会议论文 OAI收割
2010 IEEE International Conference on Mechatronics and Automation, ICMA 2010, August 4, 2010 - August 7, 2010, Xi'an, China
Chen C.-Q.; Ji Y.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

Aircraft simulation platform is the most important supporting technology in the aircraft development process. This simulation platform can be used for validating the design of subsystem and also it provides the necessary data for the Aircraft design. Wind has great impact on the flight parameter. In order to accurately simulate the wind model and calculate the flight parameters a simulation modeling method for flight parameter simulation platform under wind field environment is established. Firstly the various sub-systems which affecting flight parameters are analyzed some mathematical models of the flight parameter simulation platform is established. Secondly the atmospheric wind field is studied to analyze the impact on its trajectory. Then the model is built in the Simulink toolbox in the Matlab which is based on the principles of hierarchy and modularity using C MEX S-function for the complex kinetic equations. Finally when the models have been established encapsulating models for several subsystem and assembling them for the Aircraft simulation platform based on the unified interface. The simulation tests (including the performance test of a certain gliding Aircraft the wind influence test of a certain uncontrolled aircraft) prove the simulation capability of the platform and its calculating step can reach 1 ms. Comparing simulation with field test data of a certain uncontrolled aircraft it shows that the relative deviation of range is 0.47% the relative deviation of maximal altitude is 2.1%. Taking relevant standards as a reference standard it is demonstrated the platform is reliable meets the engineering accuracy requirements. 2010 IEEE.

Application of adaptive UKF in initial alignment of MINS/GPS integrated navigation system (EI CONFERENCE) 会议论文 OAI收割
2010 3rd International Conference on Advanced Computer Theory and Engineering, ICACTE 2010, August 20, 2010 - August 22, 2010, Chengdu, China
作者: Gao Q.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

In order to overcome the shortcomings of standard unscented Kalman filter (UKF) which are obviously influenced by the error of initial value and the model error of system adaptive UKF which is based on the adaptive principle is applied in initial alignment of the MINS/GPS integrated navigation system. Coarse alignment cannot be done by micro inertial measurement unit (MIMU) itself because of its low precision the method of using magnetometer to assist it with coarse alignment is presented. Simulation results show that the adaptive UKF can overcome the influences of initial values error and inaccurate system model and improve the convergence speed and alignment accuracy effectively. 2010 IEEE.

System identification of tracking error and evaluation of tracking performance using BP neural network (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2009: Advances in Infrared Imaging and Applications, June 17, 2009 - June 19, 2009, Beijing, China
Zhang N.; Shen X.-H.

收藏 | 浏览/下载：12/0 | 提交时间：2013/03/25

A novel approach for evaluating the tracking performance of optoelectronic theodolite is proposed. First an equivalent mathematic model of tracking error is established. Then the equivalent sine signal is inputted to the equivalent model and the outputs are sampled. The results of evaluating the tracking performance are obtained based on the statistical calculation of output produced by equivalent model. Equivalent model using the BP (Backprogration) neural network structure is identified. The training method of BP neural network adopts the LM (Levenberg-Marquardt) algorithm for the sake of speeding up training process. The BP neural network is trained and tested by using the training and testing samples gotten from the simulation model of optoelectronic theodolite tracking system under MATLAB/SIMULINK. The estimate errors of equivalent model including average error maximum error and standard error are 2.5872e-0060 2.8 and 1.9. The results show that the equivalent model identified based on BP neural network meets the needs of evaluating the tracking performance of optoelectronic theodolite. The accurate evaluation of tracking performance is achieved. 2009 SPIE.

Orientation error analysis of alt-alt photoelectric telescope (EI CONFERENCE) 会议论文 OAI收割
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, November 19, 2008 - November 21, 2008, Chengdu, China
作者: Wu X.-X.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

In order to ascertain the effects of main errors of alt-alt photoelectric telescope on measurement accuracy orientation error is analyzed.For analyzing optical mechanical and electrical errors from measured target to telescope picture we construct 7 coordinates such as:the earth's core coordinate alt-alt coordinate etc. carry through 21 times coordinate transformation form measuring equation with 26 variables. and we utilize Monte Carlo method to calculate the orientation error analyze the effects of errors upon pointing. The result indicates that the measuring error standard deviation of alt-alt telescope is minimum value about 10? at the zenith zone. and the deviation increases with the rotation angles of longitude and latitude axes. The model and the method not only can analyze and synthesize the main errors but also provide a reference to the whole design. 2009 SPIE.

Modeling diffractive optical elements in hybrid systems with the effect of the material dispersion (EI CONFERENCE) 会议论文 OAI收割
Current Developments in Lens Design and Optical Engineering IX, August 11, 2008 - August 12, 2008, San Diego, CA, United states
作者: Zhang H.; Liu H.; Liu H.; Liu H.; Zhang H.

收藏 | 浏览/下载：7/0 | 提交时间：2013/03/25

The diffractive optical element (DOE) is always modeled as an ideal pure diffractive element which neglects the refractive dispersion of the element's material. In this paper a new model of the diffractive optical element is proposed in which the effect of the refractive dispersion of the DOE's material is considered. The new model is explained and compared with standard diffraction-order expansion with the help of a hybrid system example. The analytical results show that the new model has an important meaning for the exact analysis of the hybrid refractive-diffractive optical system. 2008 Copyright SPIE - The International Society for Optical Engineering.

UV-VUV spectral irradiance responsivity calibration for space remote sensing spectroradiometer (EI CONFERENCE) 会议论文 OAI收割
Advanced Materials and Devices for Sensing and Imaging III, November 12, 2007 - November 14, 2007, Beijing, China
作者: Yu H.

收藏 | 浏览/下载：11/0 | 提交时间：2013/03/25

In order to overcome the irradiance responsivity calibration troubles caused by the weak response of most spectral radiometers in ultraviolet band and poor ratio of signal to noise and to meet special calibration condition for some remote sensing spectroradiometers in space a spectral irradiance responsivity calibration unit based on parallel light illumination mode is established it is composed of a 150W deuterium lamp and a spherical mirror. The calibration unit gets the output standard value of spectral irradiance by irradiance transfer this way avoids the spectral reflectance measurement difficulty of the spherical mirror. A flight spectral radiometer model used for space remote sense was calibrated in range from 160nm to 300nm the calibration error of spectral irradiance responsivity is 4.7%. Some factors which contribute to calibration uncertainties are discussed.

Real time tracking by LOPF algorithm with mixture model (EI CONFERENCE) 会议论文 OAI收割
MIPPR 2007: Automatic Target Recognition and Image Analysis; and Multispectral Image Acquisition, November 15, 2007 - November 17, 2007, Wuhan, China
Meng B.; Zhu M.; Han G.; Wu Z.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

A new particle filter-the Local Optimum Particle Filter (LOPF) algorithm is presented for tracking object accurately and steadily in visual sequences in real time which is a challenge task in computer vision field. In order to using the particles efficiently we first use Sobel algorithm to extract the profile of the object. Then we employ a new Local Optimum algorithm to auto-initialize some certain number of particles from these edge points as centre of the particles. The main advantage we do this in stead of selecting particles randomly in conventional particle filter is that we can pay more attentions on these more important optimum candidates and reduce the unnecessary calculation on those negligible ones in addition we can overcome the conventional degeneracy phenomenon in a way and decrease the computational costs. Otherwise the threshold is a key factor that affecting the results very much. So here we adapt an adaptive threshold choosing method to get the optimal Sobel result. The dissimilarities between the target model and the target candidates are expressed by a metric derived from the Bhattacharyya coefficient. Here we use both the counter cue to select the particles and the color cur to describe the targets as the mixture target model. The effectiveness of our scheme is demonstrated by real visual tracking experiments. Results from simulations and experiments with real video data show the improved performance of the proposed algorithm when compared with that of the standard particle filter. The superior performance is evident when the target encountering the occlusion in real video where the standard particle filter usually fails.

The application study on building materials with computer color quantification system (EI CONFERENCE) 会议论文 OAI收割
ICO20: Illumination, Radiation, and Color Technologies, August 21, 2005 - August 26, 2005, Changchun, China
作者: Yu H.; Li Z.; Li Z.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

The first impression of any building to a person is its exterior and decoration therefore at the same time and therefore the quality of decoration project shows the more important position in building project. A lot of projects produce quality problem because of the material color difference how to grasp and control the color change of building materials the color difference problem laying stone materials is also studied in this paper which exists universally at the common project and carry out color quantification and the solution scheme has been given using this system. and is often found at the high-grade decoration it has the very important meaning. According to the color theory a computer vision system used in color quantification measurement is established the standard illuminant A is selected as the light source. In order to realize the standardization of color evaluation the mutual conversion between RGB and XYZ color space is studied which is realized by the BP network. According to the colorimetry theory the computer program is compiled in order to establish the software system and realize the color quantitative appraisement in whole color gamut. LCH model is used at quantifying the color of building materials and L*a*V model is used at comparing the color change. If the wooden floor is selected and laid improperly during family fitment it is easy to present "flower face". The color also arises greater discrepancy using the laths of same tree. We can give the laying scheme using the color quantification system