scholarly journals Design of Tracking, Telemetry, Command (TT&C) and Data Transmission Integrated Signal in TDD Mode

2020 ◽  
Vol 12 (20) ◽  
pp. 3340
Author(s):  
Linshan Xue ◽  
Xue Li ◽  
Weiren Wu ◽  
Yikang Yang
Keyword(s):  
High Precision ◽  
Data Transmission ◽  
Measurement Technology ◽  
Complex Frequency ◽  
High Precision Measurement ◽  
Network Nodes ◽  
Time Frequency ◽  
Transmission Equipment ◽  
And Control ◽  
Extrapolation Error

For satellite or aircraft networks, tracking, telemetry, and control (TT&C) and data transmission between different nodes are necessary. Traditional measurement mostly adopts the frequency division duplex (FDD) mode and uses a continuous measurement system to achieve high-precision measurement. However, as the number of network nodes increases, the mode suffers from complex frequency domain allocation, and high-cost measurement and data transmission equipment is required. This paper proposes the integrated signal in time division duplex (TDD) mode to improve frequency utilization to address these circumstances. The proposed signal can transmit the TT&C and data at the same frequency. In addition, the high-precision time-frequency synchronization and relative measurement technology in the TDD mode for distributed spacecraft or aircraft networks are studied. The simulation results show that the signal can work normally when the Doppler extrapolation error is less than a quarter of the integration frequency. The distance extrapolation error should be less than a quarter of the length of a chip. The integrated signal reduces the frequency band occupation and realizes the integration of TT&C and data transmission. In addition, the measurement performance is reduced by only 2~3 dB compared with that of the traditional pure TT&C signal.

scholarly journals CPLD-Based Displacement Measurement System for Nanoscale Grating Ruler

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jiyuan Sun ◽  
Chunlin Tian
Keyword(s):  
High Precision ◽  
Measurement System ◽  
Measurement Accuracy ◽  
Displacement Measurement ◽  
Measurement Technology ◽  
Precision Manufacturing ◽  
High Precision Measurement ◽  
Measurement Control ◽  
High Measurement ◽  
The Times

With the continuous development of science and technology, industrial production has higher and higher requirements for precision. Many high-precision measurement technologies emerge as the times require, and nanoscale grating ruler displacement measurement technology is one of them. As a kind of precision sensor, nanoscale grating ruler has important application in displacement measurement system. CPLD has the advantages of high integration and fast programming speed, which is often used to control the displacement measurement system of nanoscale grating ruler. The purpose of this paper is to deeply explore the measurement effect and related application principle of nanoscale grating ruler displacement measurement system based on CPLD technology. A set of nanoscale grating ruler displacement measurement system is designed based on CPLD technology. The output signal of grating ruler is programmed by CPLD. The x-axis displacement of the experimental platform controlled by stepping motor is measured, and the measured data are recorded by carrying out analysis and research. The results show that compared with the traditional phase difference measurement system, the measurement accuracy of the system based on CPLD is improved by 24.7%, the robustness of the measurement system is improved by 18.6%, and the measurement speed is increased by 27.3%. Therefore, this kind of nanoscale measurement precision grating ruler displacement measurement control system based on CPLD has three characteristics: high measurement accuracy, strong anti-interference ability, and high measurement motion efficiency, which can effectively meet the requirements of grating ruler displacement measurement system for high-precision manufacturing technology.

scholarly journals Narrow-Linewidth Laser Linewidth Measurement Technology

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhenxu Bai ◽  
Zhongan Zhao ◽  
Yaoyao Qi ◽  
Jie Ding ◽  
Sensen Li ◽  
...  
Keyword(s):  
High Precision ◽  
Spectral Resolution ◽  
Dynamic Range ◽  
Rapid Development ◽  
Research Progress ◽  
Measurement Technology ◽  
Laser Linewidth ◽  
Narrow Linewidth ◽  
High Precision Measurement ◽  
Linewidth Measurement

A narrow-linewidth laser with excellent temporal coherence is an important light source for microphysics, space detection, and high-precision measurement. An ultranarrow-linewidth output with a linewidth as narrow as subhertz has been generated with a theoretical coherence length over millions of kilometers. Traditional grating spectrum measurement technology has a wide wavelength scanning range and an extended dynamic range, but the spectral resolution can only reach the gigahertz level. The spectral resolution of a high-precision Fabry–Pérot interferometer can only reach the megahertz level. With the continuous improvement of laser coherence, the requirements for laser linewidth measurement technology are increasing, which also promotes the rapid development of narrow-linewidth lasers and their applications. In this article, narrow-linewidth measurement methods and their research progress are reviewed to provide a reference for researchers engaged in the development, measurement, and applications of narrow-linewidth lasers.

High precision measurement of the SOS surface thickness in the rough phase

1991 ◽  
Vol 1 (12) ◽  
pp. 1669-1673 ◽  
Author(s):  
Hans Gerd Evertz ◽  
Martin Hasenbusch ◽  
Mihail Marcu ◽  
Klaus Pinn ◽  
Sorin Solomon
Keyword(s):  
High Precision ◽  
Precision Measurement ◽  
High Precision Measurement ◽  
Surface Thickness
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