A Multi-Source Dynamic Determination Algorithm for Digital Synchronization Equipment

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.

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Transformer Differential Protection Using Process Bus According to IEC 61850-9-2 and Non-Conventional Instrument Transformers

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.799-800.1311 ◽

2015 ◽

Vol 799-800 ◽

pp. 1311-1315

Author(s):

G. Igarashi ◽

J.C. Santos

Keyword(s):

Time Synchronization ◽

Power Transformers ◽

Response Analysis ◽

Differential Protection ◽

Iec 61850 ◽

Instrument Transformers ◽

Synchronization Signal ◽

Conventional Instrument ◽

Transformer Differential Protection

Our aim is to show some impacts on the differential protection of power transformers when using Non-Conventional Instrument Transformers associated with the IEC 61850-9-2 process bus. Described herein are a model for simulating the samples in the process bus, a proposed algorithm for differential protection of power transformers adapted from conventional differential relays so that it works according to the IEC 61850-9-2 standard, and a response analysis of the protection algorithm with the loss of the time synchronization signal in the process bus. Suggestions on parameters to be followed for safer operation of the process bus in these circumstances are also offered.

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

Mathematical Problems in Engineering ◽

10.1155/2021/8860028 ◽

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.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.226-228.2050 ◽

2012 ◽

Vol 226-228 ◽

pp. 2050-2055 ◽

Cited By ~ 1

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.

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Weighted Average Instantaneous Frequency Extraction via Time-frequency Analysis

79th EAGE Conference and Exhibition 2017 ◽

10.3997/2214-4609.201700727 ◽

2017 ◽

Author(s):

N.H. Liu ◽

J.H. Gao ◽

Q. Wang

Keyword(s):

Frequency Analysis ◽

Instantaneous Frequency ◽

Weighted Average ◽

Time Frequency Analysis ◽

Time Frequency

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An Energy Efficient Synchronization Protocol for Target Tracking in Wireless Sensor Array Networks

Sensors ◽

10.3390/s19061367 ◽

2019 ◽

Vol 19 (6) ◽

pp. 1367

Author(s):

Jie Shen ◽

Ming Yin ◽

Ji-An Luo ◽

Zhi-Bo Wang ◽

Zhi Wang ◽

...

Keyword(s):

Target Tracking ◽

Energy Efficient ◽

Sensor Array ◽

Time Synchronization ◽

Wireless Sensor ◽

Guarantee System ◽

Network Maintenance ◽

Array Synchronization ◽

Synchronization Accuracy ◽

Synchronization Protocol

Time synchronization is an important middleware function that supports the Quality of Service (QoS) of systems in wireless sensor array networks. Instead of providing high synchronization accuracy for all application scenarios, we argue that synchronization protocols should be application specific. In this paper, we exploit the synchronization requirements of target-tracking systems in wireless sensor array networks and propose an energy-efficient Sensor Array Synchronization Protocol (SASP), which provides the required synchronization accuracy to guarantee the QoS. Specifically, when no target appears, to guarantee system lifetime, coarse synchronization is achieved with little overhead by piggybacking time information onto periodical network maintenance packets. Once targets appear, SASP achieves high inter-array and relatively higher intra-array synchronization accuracy rather than the traditional network-wide high accuracy on average. In this way, it guarantees reliable communication and accurate data fusion, while reducing energy consumption. Theoretical analysis and extensive evaluations show the effectiveness of the proposed protocol.

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Study on Aerospace Layering Time Synchronization Architecture and Time Synchronization Algorithm

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.546-547.1614 ◽

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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Low cost GNSS receivers in time synchronization systems

Bulletin of the Military University of Technology ◽

10.5604/01.3001.0011.8035 ◽

2018 ◽

Vol 67 (1) ◽

pp. 65-72

Author(s):

Grzegorz Czopik ◽

Tomasz Kraszewski

Keyword(s):

Time Synchronization ◽

Low Cost ◽

Global Navigation Satellite Systems ◽

Satellite Systems ◽

Time Frequency ◽

Delay Times ◽

Gnss Receivers ◽

Frequency Counter ◽

The One ◽

Global Navigation Satellite

The GNSS (GNSS — Global Navigation Satellite Systems) receivers can be utilized to obtain accurate time markers. The preliminary results of the cheap GNSS receivers’ tests are presented in the paper. The one receiver’s price (including antenna) does not exceed 30 $. The studies on the use of receivers in the time synchronization systems were executed. Three identical models of receiver modules were used. The 1PPS (1PPS — 1 Pulse Per Second) signals available on the receiver’s output were used. The 1PPS’s main time characteristics were described. Delay times between different receivers 1PPS signals were measured. Measurements were taken using 1 GHz oscilloscope and precise time/frequency counter T3200U. Keywords: time synchronization, 1PPS, GNSS, GPS time

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