Time Synchronization in Laser Ranging with Multi-Receiving Telescopes Based on Fiber-Time-Frequency Transfer

2019 ◽  
Vol 56 (1) ◽  
pp. 011204
Author(s):  
张海峰 Zhang Haifeng ◽  
邓华荣 Deng Huarong ◽  
龙明亮 Long Mingliang ◽  
程志恩 Cheng Zhien ◽  
张忠萍 Zhang Zhongping ◽  
...  
Keyword(s):  
Time Synchronization ◽  
Laser Ranging ◽  
Time Frequency ◽  
Frequency Transfer

scholarly journals Modeling and Performance Evaluation of Precise Positioning and Time-Frequency Transfer with Galileo Five-Frequency Observations

2021 ◽  
Vol 13 (15) ◽  
pp. 2972
Author(s):  
Wei Xu ◽  
Wen-Bin Shen ◽  
Cheng-Hui Cai ◽  
Li-Hong Li ◽  
Lei Wang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Satellite Orbit ◽  
Average Frequency ◽  
Satellite System ◽  
Observation Data ◽  
Navigation Satellite ◽  
Dual Frequency ◽  
Time Frequency ◽  
Combination Model ◽  
Frequency Transfer

The present Global Navigation Satellite System (GNSS) can provide at least double-frequency observations, and especially the Galileo Navigation Satellite System (Galileo) can provide five-frequency observations for all constellation satellites. In this contribution, precision point positioning (PPP) models with Galileo E1, E5a, E5b, E5 and E6 frequency observations are established, including a dual-frequency (DF) ionospheric-free (IF) combination model, triple-frequency (TF) IF combination model, quad-frequency (QF) IF combination model, four five-frequency (FF) IF com-bination models and an FF uncombined (UC) model. The observation data of five stations for seven days are selected from the multi-GNSS experiment (MGEX) network, forming four time-frequency links ranging from 454.6 km to 5991.2 km. The positioning and time-frequency transfer performances of Galileo multi-frequency PPP are compared and evaluated using GBM (which denotes precise satellite orbit and clock bias products provided by Geo Forschung Zentrum (GFZ)), WUM (which denotes precise satellite orbit and clock bias products provided by Wuhan University (WHU)) and GRG (which denotes precise satellite orbit and clock bias products provided by the Centre National d’Etudes Spatiales (CNES)) precise products. The results show that the performances of the DF, TF, QF and FF PPP models are basically the same, the frequency stabilities of most links can reach sub10−16 level at 120,000 s, and the average three-dimensional (3D) root mean square (RMS) of position and average frequency stability (120,000 s) can reach 1.82 cm and 1.18 × 10−15, respectively. The differences of 3D RMS among all models are within 0.17 cm, and the differences in frequency stabilities (in 120,000 s) among all models are within 0.08 × 10−15. Using the GRG precise product, the solution performance is slightly better than that of the GBM or WUM precise product, the average 3D RMS values obtained using the WUM and GRG precise products are 1.85 cm and 1.77 cm, respectively, and the average frequency stabilities at 120,000 s can reach 1.13 × 10−15 and 1.06 × 10−15, respectively.

A Multi-Source Dynamic Determination Algorithm for Digital Synchronization Equipment

2014 ◽  
Vol 654 ◽  
pp. 370-373
Author(s):  
Bin Zhang ◽  
Bao Ren Chen ◽  
Yue Zhuo ◽  
Guang Cai Wang ◽  
Yi Jie Ding
Keyword(s):  
Time Synchronization ◽  
Weighted Average ◽  
Reference Source ◽  
Time Frequency ◽  
Output Performance ◽  
Synchronization Signal ◽  
Dynamic Source ◽  
Security And Reliability ◽  
Multiple Reference ◽  
Synchronization Accuracy

In order to improve the security and reliability of digital synchronization network, digital synchronized equipment mostly uses reference source design and ensure the output performance in abnormal situation by redundancy back-up of multiple reference sources. The paper not only describes the concept of time-frequency equipment reference source and its judgment index, but also details a multi-source dynamic determination algorithm for digital synchronization equipment. A multi-component weighted average approach is designed the multi-source dynamic source selected processes by the study of several time sources of anomaly detection to improve the accuracy of the synchronization signal. The algorithm with simple structure can help keeping the high synchronization accuracy of multi-source time synchronization system.

scholarly journals Key technology of high-precision time frequency transfer via 200 km desert urban fiber link

2019 ◽  
Vol 68 (6) ◽  
pp. 060602
Author(s):  
Kang Ying ◽  
You-Zhen Gui ◽  
Yan-Guang Sun ◽  
Nan Cheng ◽  
Xiao-Feng Xiong ◽  
...  
Keyword(s):  
High Precision ◽  
Key Technology ◽  
Time Frequency ◽  
Precision Time ◽  
Fiber Link ◽  
Frequency Transfer

scholarly journals Long-Distance Time Transfer in Optical Fiber Networks Using a Cascaded Taming Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ding Chen ◽  
Jiangning Xu ◽  
Yifeng Liang ◽  
Shan Jiang ◽  
Hongyang He
Keyword(s):  
Optical Fiber ◽  
High Precision ◽  
Wavelength Division Multiplexing ◽  
Time Synchronization ◽  
Atomic Clock ◽  
Process Time ◽  
Long Distance ◽  
Time Service ◽  
Time Frequency ◽  
Fiber Link

In order to meet the time service needs of high-precision, long-distance, and multinode optical network, this paper proposes a new time synchronization solution, which combines the wavelength division multiplexing (WDM) technology with cascaded taming clock technology. The WDM technology is used for time synchronization between each pair of master-slave nodes. In the system, there are two wavelengths on the fiber link between the master node and the slave node for transmitting signals. 1 plus per second (PPS) signal, time code signal, and 10 MHz signal are, respectively, and successively, sent to the optical fiber link. By solving the one-way delay through analysis of error contribution and link characteristics of the time transmission process, time synchronization of the master-slave nodes pair is achieved. Furthermore, the authors adopt cascaded taming clock technology to ensure accurate time synchronization of each node. A 700 km long-distance time-frequency synchronization system is constructed in the laboratory. The system uses a cesium atomic clock as the reference clock source and transmits the signals through 8 small rubidium atomic clocks (RB clocks) hierarchically. Results from the experiment show that the long-term time stability is 47.5 ps/104 s. The system’s structural characteristics and the experiment results meet the requirements to allow practical use of high-precision time synchronization in networks. This proposed solution can be applied in various civil, commercial, and military fields.

Real-Time Measurement Method of Doppler Based on GPS Carrier Signals

2012 ◽  
Vol 226-228 ◽  
pp. 2050-2055 ◽  
Author(s):  
Shao Feng Dong ◽  
Bao Qiang Du ◽  
Wei Zhou
Keyword(s):  
Frequency Shift ◽  
Real Time ◽  
Measurement Method ◽  
Dynamic Range ◽  
Time Synchronization ◽  
Influencing Factor ◽  
Doppler Frequency ◽  
Time Measurement ◽  
Time Frequency ◽  
Real Time Measurement

According to Doppler effect of satellite on the time synchronization technology between satellite and the ground station, a real-time measurement method of Doppler is proposed based on GPS carrier signals. Using Doppler observations from GPS receiver, the method can real-timely measure Doppler frequency shift of GPS including dynamic Doppler and media Doppler whose error can be timely modified in the receiver end. Simulation results show that the frequency shift caused by dynamic Doppler, a main influencing factor in the course of transmission of time-frequency signal by GPS satellite, is between plus or minus several thousands Hz. Comparing to traditional measurement method of Doppler, the method makes it possible to fast track phase of signal in large dynamic range in synchronous technology.

Optical Two-Way Time-Frequency Transfer across a Three-Node Free-Space Network

2020 ◽  
Author(s):  
Martha I. Bodine ◽  
Jennifer L. Ellis ◽  
William C. Swann ◽  
Sarah A. Stevenson ◽  
Jean-Daniel Deschenes ◽  
...  
Keyword(s):  
Free Space ◽  
Time Frequency ◽  
Space Network ◽  
Frequency Transfer

Study on Aerospace Layering Time Synchronization Architecture and Time Synchronization Algorithm

2012 ◽  
Vol 546-547 ◽  
pp. 1614-1619
Author(s):  
Fei Jiang Huang ◽  
Xiao Chun Lu ◽  
Jun Yang ◽  
Qing Xiao Shan ◽  
Yong Bin Zhou
Keyword(s):  
Time Synchronization ◽  
Rapid Development ◽  
Frequency Standard ◽  
High Accuracy ◽  
Time Frequency ◽  
Aerospace Application ◽  
Visual Model ◽  
Application Systems ◽  
Synchronization Algorithm ◽  
Time And Frequency Standard

The rapid development of various kinds of aerospace application systems requires the appropriate high-accuracy time and frequency standard. This problem can be effectively solved by establishing suitable time and frequency standard in aerospace. Based on the establishment of aerospace satellite visual model, the simulation of satellite visual time on 3-layer constellation structure, including GEO satellite, IGSO satellites and MEO satellites, has been conducted. The visual features of this constellation have been gained. Combining with the major influencing factors of satellite clock correction error, aerospace time synchronization architecture on the basis of layering has been proposed. The time synchronization algorithm in line with this architecture has been researched. The results show that aerospace time frequency standard established based on this layering time synchronization architecture can meet the demand on high-accuracy time frequency of future aerospace application systems.

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