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.

Study on High Precision Disciplined Time-Frequency Transferring Experiments through Optical Fiber Link

2014 ◽  
Vol 34 (5) ◽  
pp. 0506004
Author(s):  
李晓亚 Li Xiaoya ◽  
朱勇 Zhu Yong ◽  
卢麟 Lu Lin ◽  
吴传信 Wu Chuanxin ◽  
经继松 Jing Jisong ◽  
...  
Keyword(s):  
Optical Fiber ◽  
High Precision ◽  
Time Frequency ◽  
Fiber Link

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

Investigation on GEO satellite orbit determination based on CEI measurements of short baselines

2019 ◽  
Vol 72 (06) ◽  
pp. 1585-1601
Author(s):  
Zejun Liu ◽  
Lan Du ◽  
Yongxing Zhu ◽  
Zhihan Qian ◽  
Jinqing Wang ◽  
...  
Keyword(s):  
Orbit Determination ◽  
Atomic Clock ◽  
Phase Delay ◽  
Integer Ambiguity ◽  
Small Scale ◽  
Time Service ◽  
Time Frequency ◽  
Time Operation ◽  
Geo Satellite ◽  
Phase Fitting

Connected-Element Interferometry (CEI) is a technique for measuring the phase delay of difference of Time Of Arrival (TOA) of a downlink radio signal to two antennae on a short baseline. This technique can use an atomic clock for time-frequency transmission and achieve intermediate accuracy angular tracking. Owing to the relatively short length of the baseline, the passive reception mode, and near real-time operation, CEI can be used to continuously monitor the orbit variations of both cooperative and non-cooperative satellites. In this paper, a small-scale CEI system of two orthogonal baselines (75 m × 35 m) is investigated to track a Geostationary Earth Orbit (GEO) Television (TV) satellite at 110·5°E. The phases are extracted from correlation results. The results show that the Root Mean Square (RMS) of the phase fitting residuals, if not calibrated, is within 2° at night and up to 10° in the daytime. After applying the calibration signal, the RMS of the phase fitting residuals in the daytime decreases to the same level at night. Comparing the phase delay with the a priori phase delay using Two-Line-Element (TLE) data, the integer ambiguity is successfully resolved. Finally, a batch algorithm is used to estimate the orbit of the GEO satellite, and the orbit determination accuracy is evaluated using the precise orbits provided by the China National Time Service Centre (NTSC). The results show that the accuracies in the radial direction and the cross-track direction are less than 1 km, and the Three-Dimensional (3D) position accuracy reaches the 2 km order of magnitude.

Design and Implementation of IEEE 1588 High Precision Clock Synchronization Based on GPS Time Service

2012 ◽  
Vol 532-533 ◽  
pp. 292-296 ◽  
Author(s):  
Kang Wang ◽  
Yong Hui Hu ◽  
Zai Min He ◽  
Hong Jiao Ma
Keyword(s):  
High Precision ◽  
Time Synchronization ◽  
Clock Synchronization ◽  
Time Service ◽  
Ieee 1588 ◽  
Design And Implementation ◽  
Nanosecond Range ◽  
Application Fields ◽  
Timing Requirement ◽  
Precision Clock

In view of PTP high precise timing requirement for many application fields, GPS time service is provided with the advantages of high precision and high stabilization. The principle and timescale of PTP based on GPS are analyzed and discussed. And then a PTP time synchronization platform with GPS-based UTC time is designed and implemented, the correlative key design flowchart is described as well. Finally, the paper gives the experiment results, which show the time synchronization accuracies can reach nanosecond range.

Theoretical and experimental study on ultra-long unrepeated optical fiber link based on bidirectional Raman amplifier

2020 ◽  
Vol 34 (23) ◽  
pp. 2050244
Author(s):  
Ronghua Chi ◽  
Tao Lu ◽  
Xiaohan Sun
Keyword(s):  
Optical Fiber ◽  
Signal Transmission ◽  
Power Budget ◽  
Long Distance ◽  
Theoretical Simulation ◽  
Raman Amplifier ◽  
Transmission Link ◽  
Fiber Link ◽  
Power Evolution ◽  
Good Agreement

In this paper, an ultra-long distance transmission fiber link based on bidirectional Raman amplifier is studied by theoretical simulation and experimental verification. The power evolution of pump and WDM signals in optical fiber in 355 km transmission link is simulated theoretically. The performance of the ultra-long distance system based on co-pump/counter-pump/bidirectional-pump Raman amplifier (CORA/CTRA/BiRA) are simulated. And the power budget is also predicted by simulation. The performance of 10*100 Gb/s signal transmission in 355 km fiber link based on bidirectional Raman amplifier are tested experimentally. The theoretical and experimental results are in good agreement.

Time Delay Measurement of Optical Fiber Link Using Time-Frequency Joint Transfer

2019 ◽  
Vol 39 (9) ◽  
pp. 0906003
Author(s):  
郭俊成 Juncheng Guo ◽  
卢麟 Lin Lu ◽  
吴传信 Chuanxin Wu ◽  
张宝富 Baofu Zhang ◽  
魏恒 Heng Wei ◽  
...  
Keyword(s):  
Time Delay ◽  
Optical Fiber ◽  
Time Frequency ◽  
Delay Measurement ◽  
Fiber Link ◽  
Time Delay Measurement
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