中国科学院机构知识库网格系统: 检索

High-Precision Orbit Determination of the Small TJU-1 Satellite Using GPS, GLONASS, and BDS 期刊论文 OAI收割
IEEE SENSORS JOURNAL, 2023, 卷号: 23, 期号: 12, 页码: 13340-13350
作者: Gong, Xuewen; Li, Xingxing; Wang, Pengcheng; Wang, Qingyun; Wang, Fuhong

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收藏 | 浏览/下载：22/0 | 提交时间：2023/12/13

Global navigation satellite system (GNSS) data quality multi-GNSS fusion precise orbit determination (POD) precision and accuracy Tianjin University-1 (TJU-1)

Performance of snow density measurement systems in snow stratigraphies 期刊论文 OAI收割
HYDROLOGY RESEARCH, 2021, 页码: 13
作者: Jiansheng, Hao; Mind'je, Richard; Ting, Feng; Lanhai, Li

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收藏 | 浏览/下载：26/0 | 提交时间：2021/08/19

dielectric permittivity measuring systems gravimetric measuring systems precision and accuracy snow density snow stratigraphies

Performance of snow density measurement systems in snow stratigraphies 期刊论文 OAI收割
HYDROLOGY RESEARCH, 2021, 页码: 13
作者: Jiansheng, Hao; Mind'je, Richard; Ting, Feng; Lanhai, Li

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收藏 | 浏览/下载：15/0 | 提交时间：2021/08/19

dielectric permittivity measuring systems gravimetric measuring systems precision and accuracy snow density snow stratigraphies

A re-assessment of nickel-doping method in iron isotope analysis on rock samples using multi-collector inductively coupled plasma mass spectrometry CNKI期刊论文 OAI收割
2020
作者: Hongmei Gong; Pengyuan Guo; Shuo Chen; Meng Duan; Pu Sun

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收藏 | 浏览/下载：6/0 | 提交时间：2024/12/18

Fe isotope Ni-doping Stable isotope Precision and accuracy Mass bias correction Pseudo-high mass resolution

LABTM control system based on FPGA (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Mechatronics and Applied Mechanics, ICMAM 2012, December 8, 2012 - December 9, 2012, Taiwan
作者: Wang Y.; Yu P.; Yu P.; Wang Y.; Wang Y.

收藏 | 浏览/下载：151/0 | 提交时间：2013/03/25

This paper presents the digital PI control method for design and simulation of a high precision limited angle brushless torque motor control system in Field Programmable Gate Array device (FPGA). The direct drive structures which are widely applied in many servo control fields. Matlab Xilinx System GeneratorR toolbox based on Fixed-Point Arithmetic is used to design the digital PI controller using DSP architecture plot the responses of the control system and generate the VHDL source code. The control system model consists of a digital PI a real LABTM and a real absolute Inductosyn encoder to rpm and position blocks. Through loading generated codes in process of the simulation that built by the digital discrete model it is verified that the rising time of current loop is only 1.2ms and rate loop is 8ms overshoot is rarely 4.2%. Finally the comprehensive positioning accuracy of system can reach up to 5 arc sec and the rate jitter achieves 5% with the 4 arc sec accuracy absolute Inductosyn. (2013) Trans Tech Publications Switzerland.

Design of the real-time autofocusing system for collimator with long focus length and large aperture (EI CONFERENCE) 会议论文 OAI收割
2011 International Academic Conference on Numbers, Intelligence, Manufacturing Technology and Machinery Automation, MAMT 2011, December 24, 2011 - December 25, 2011, Wuhan, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：39/0 | 提交时间：2013/03/25

Large aperture collimator which has been widely used for calibrating and testing various optical devices plays an essential role in correlative laboratories. As being the basic testing and calibration equipment the large aperture collimator's accuracy should be much higher than the device under testing in order to ensure the accuracy of the measurement. However the process of adjusting the collimator is extremely complicated due to the collimator's large aperture and long focal length. So it is difficult to ensure the measurement's quality and easy to cause the system being vulnerable to the surrounding environment. One of the most common problems is defocus. In order to solve the problem above this issue presents a new type of autocollimator autofocusing system which uses pentaprism instead of using large-aperture plane mirror semiconductor lasers as light source and CCD sensor as receiver. The system is smaller lighter and more convenient when using. The computer simulation shows that the autofocusing system's resolution could reach the accuracy of 40m. If we use the relevant algorithms to execute the sub-pixel scanning the resolution could reach the accuracy of 10m. It shows that the system could satisfy the required testing precision of testing large aperture optical device.

Comparison of radiation temperature measurement precision between middlewave and longwave thermal-imaging systems (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Optoelectronics and Microelectronics, ICOM 2012, August 23, 2012 - August 25, 2012, Changchun, China
作者: Sun Z.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

A comparison study on temperature measurement precision between middlewave 3-5m and longwave 8-12m measuring thermal imaging systems has been conducted. The study was limited to systems working in indoor conditions and the target's temperature is in the range of 270K900K. First the Disturb Resisting Function (DRF) of infrared systems is deduced. On the base of DRF curve we find that the middlewave infrared system get the smaller influences under the same size disturb compared with the longwave system. A theory of the influence of target's physical characteristic and measurement conditions on the accuracy of temperature measurements has been developed. On the basis of the developed formulas an analysis of the influence of signal disturbances (because of incorrectly assumed emissivity limited transmittance of the atmosphere radiation reflected by the object and shift of optics radiation) on the accuracy of temperature measurement has been made. It has been found that the middlewave systems in typical temperature range offer generally better accuracy in temperature measurement than the longwave ones do. 2012 IEEE.

Design and experimental research of a new type focus mechanism used in space-based telescope (EI CONFERENCE) 会议论文 OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
作者: Wang D.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

The position of focal plane will be changed because of temperature fluctuation and vacuum environment. In order to make the telescope work well positioning accuracy of the mechanism is 0.008mm. The performance satisfies the need of precision a focusing mechanism is needed. To majority of large space-based telescopes and the scheme design is reasonable and practicable. 2012 IEEE. the general way to do this would be to use a reflector which was located in the backfocal distance. One of typical schemes of this mechanism was introduced however because of the big axial size the mechanism can't be used when the size of the enclosure was limited. A new type of focusing mechanism was introduced which has such advantages of small size high accuracy and low mass. The design and test methods had been discussed. According to the results the repeatability positioning accuracy is 0.0025mm

An accuracy requirement analysis for LED brightness and color correction system (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Transportation, Mechanical, and Electrical Engineering, TMEE 2011, December 16, 2011 - December 18, 2011, Changchun, China
作者: Wang R.

收藏 | 浏览/下载：62/0 | 提交时间：2013/03/25

Brightness and color correction system is working for the color uniform problem of LED display. The correction system can improve LED display's quality greatly. The accuracy of the LED system must consider the accuracy requirements of the color correction system. This paper analyze the accuracy requirements from two aspects. One is that the accuracy requirements should consider the chromatic tolerance for the human eyes the other one is that the accuracy requirements should be associated with the precision of measuring equipment. This paper discuss the accuracy requirement with the CIE1976LUV as a color space to meet the chromatic tolerance of the human eyes and also give an explanation on how the accuracy of the measuring equipment affect the the correction system. Then this paper give a method to ensure the accuracy requirement for the correction system of a LED display. 2011 IEEE.

Study on sub-pixel techniques for accurate image measurement of displacement (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Advanced Measurement and Test, AMT 2011, June 24, 2011 - June 26, 2011, Nanchang, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：16/0 | 提交时间：2013/03/25

The high resolving power camera was often used to improve the precision of measuring system although its price is high because the accuracy of image measure was limited by the pixel resolving ability of camera. A method of one dimension gray level quadrature sub-pixel to detect edge was presented. This method was applied to measure the displacement of measuring head on 3-coordinate measuring machine. The data of test was shown that this system can distinguish displacement 0.001mm. it is higher accuracy than pixel level. So this method is convenient and fast fit to track and measure the moving object. It is obvious that this method can save the cost of hardware.