CORC

浏览/检索结果: 共5条,第1-5条 帮助

限定条件                    
已选(0)清除 条数/页:   排序方式:
High accuracy star image locating and imaging calibration for star sensor technology (EI CONFERENCE) 会议论文
6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China
Zhang S.; Zhang Z.; Sun H.; Wang Y.
收藏  |  浏览/下载:12/0  |  提交时间:2013/03/25
Today aircraft attitude measurement technology plays an important role in an aircraft system because it can provide orientation for aircraft in action. Lately star sensor technology used in aircraft attitude measurement has become more and more popular because of its high accuracy  light weight  without attitude accumulation errors and other advantages. There are three main steps for star sensor to measure aircraft attitude  star image locating  star identification and attitude tracking. The latter two steps are based on the accuracy of star image locating. So it's critical to make efforts to advance the accuracy of star image locating. Some imaging errors  such as spherical aberration or coma aberration  also have negative effect on the accuracy of star image locating  of which the effect is necessarily reduced as well. At the beginning of this article  the structure of star sensor hardware is introduced. Secondly three methods for star image locating are described specifically  which are traditional centroid method  Gauss quadric fitting method and improved Gauss quadric fitting method. Subsequently an imaging calibration method is described for the purpose of reducing the effect of imaging errors. Finally the experiment shows that the accuracy of the star sensor is 2-arc-second. 2010 SPIE.  
Design of high precision star image locating method used in star sensor technology (EI CONFERENCE) 会议论文
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
Zhang S.; Sun H.; Wang Y.; Jia X.; Chen H.
收藏  |  浏览/下载:50/0  |  提交时间:2013/03/25
Nowadays star sensor technology used in aircraft attitude measurement has become more and more popular for its high precision  light weight  without attitude accumulation errors and other advantages. In order to enhance the accuracy of star sensor  it is critical to make efforts to promote the precision of star image locating. High precision star image locating method mentioned in this article includes two aspects. One is sub-pixel dividing algorithm used to acquire the coordinate of stars. The other one is imaging calibration method used to weaken the effect caused by imaging distortion. This method is finally realized in some type of star sensor system. Then an experiment is designed to verify the precision of the method. The result of the experiment shows that the precision of the method is 2" in the experimental environment. 2010 IEEE.  
The calibration of faint simulation star magnitude based on single photon count technique (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2009: Advances in Imaging Detectors and Applications, June 17, 2009 - June 19, 2009, Beijing, China
Gan X.-J.; Guo J.; Xu S.-Y.
收藏  |  浏览/下载:20/0  |  提交时间:2013/03/25
A calibration method of faint star magnitude of the star scene simulation device is proposed in this paper. In the research of simulation star magnitude  luminometers and CCD devices are the general calibration devices which are used to measure the illumination intensity and calibrate its magnitude. But if the simulation magnitude is only sixth magnitude  its illumination intensity is only 1.010-8 Lux. This illumination intensity level is the lowest illumination intensity that the commercial luminometer can detect. Hence the simulation star magnitude lower than six magnitude cannot be calibrated by luminoters. Likewise CCD devices also need an additive cooler in this case. When the single photon characteristic is presented due to the low luminosity of simulating light sources  the simulation star magnitude can be calibrated by detecting its photon flux of radiation with the method of single photon count. In this paper the detection principle of single photon based on a compact designed PMT detecting of the radiation level of simulation star magnitude is advanced. Especially a spectrum match method is proved theoretically to be an effective means for selecting PMT photosensitive type. In the case of the detection object of the simulation star in visible wavelength  a analysis indicates that the material of tri-alkali cathode materials its best choice after being compared the Signal-to-Noise of photon detector of several PMT photosensitive materials based on the different spectrum match ratio of different object light sources and different cathode materials. An experiment is employed to show the relationship of control voltage of PMT and its dark counter  the relationship of the environment temperature of PMT and its dark counter  which proves its only decades of CPS at room temperature. The so low dark counter avoids a bulky cooler and is convenient for installing it on the star scene simulation equipment. Finally in the experiment of calibrating the simulation star magnitudes the ability of its calibration is confirmed to reaches up to 12m  meanwhile its calibration error is within 0.2m. 2009 SPIE.  
Design of a scene simulator in land-based aerospace lab with the man-made light source system based on quantum theory (EI CONFERENCE) 会议论文
Optoelectronic Devices and Integration II, November 12, 2007 - November 15, 2007, Beijing, China
Zhu X.; Yi W.; Fang W.; Yi H.
收藏  |  浏览/下载:20/0  |  提交时间:2013/03/25
The paper presents a method with the technique of combination filtering of spectrum and the technique of DSP control for the simulation and recognition of the spontaneously lightening object and stellar map in the universe. The magnitude and the spectrum of a star can be simulated in a wide dynamic range. We established the mathematical models of the Vega's visible light spectrum and luminous flux density. Tungsten-halogen lamp as a light source is used to fit the linear light of the spontaneously lightening object in the universe. Through the experiment  it shows that the more sub-channels there are while filtering spectrum in the visible spectrum  and the more degrees the variable neutral density filters and the narrow-band attenuators have  more close to the actual spectrum the simulated spectrum is. It is proved that using the PID technique is beneficial to the output of the accurate and steady radiation from the light sources. The experiment shows that the using of this method can get perfect result in fitting and simulating the spectrum  magnitude and the stellar map of the spontaneously lightening object . The analysis of the consistent result and the experimental error is also discussed in detail in this paper.  
Study on integrated vehicle navigation system of "Beidou" double-star/DR (EI CONFERENCE) 会议论文
ICO20: Optical Devices and Instruments, August 21, 2005 - August 26, 2005, Changchun, China
Liu H.; Liu J.; Zhai L.; Xiu J.
收藏  |  浏览/下载:15/0  |  提交时间:2013/03/25
Vehicle navigation is the corn element of Intelligent Transport System. The integrated system of "Beidou" Double-star/DR is studied in this paper according to the present state of vehicle navigation in our country. "Beidou" Double-star navigation position system is one regional satellite position system built up by our country  which can provide rapidly not only highly precision position and brevity telegram service. However  when the vehicles go around the tall buildings  high mountain area  wayside trees and in the tunnels  all signal may not be received. If the satellite navigation position system is used only  the precision will be reduced. Therefore  this paper proposes a nonlinear self-adaptive Kalman filter model and its algorithm for a Double-star/DR integrated navigation system in land vehicles  and verifies effectively the algorithm and scheme through the means of simulation. Next  this paper introduces map match approach. The roads are segmented and character information is brought out. Then  proper search rules and map match algorithm are adopted. According to the current vehicle position information that Double-Star/DR system provides  the nearest road can be found in the map database. The vehicle position will be matched and displayed on the road. The result of the experiment shows that the Double-star/DR integrated algorithm and map match can improve reliability and the precision of vehicle navigation system efficiently.  


©版权所有 ©2017 CSpace - Powered by CSpace