The effect of satellite movement on two-way time synchronization performance

2012 ◽  
Author(s):  
Li Wei ◽  
Xu Yongliang ◽  
Yuan Haibo
Keyword(s):  
Time Synchronization ◽  
Synchronization Performance

scholarly journals Finite-Time Synchronization of Complex Dynamical Networks with Time-Varying Delays and Nonidentical Nodes

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Ahmadjan Muhammadhaji ◽  
Abdujelil Abdurahman ◽  
Haijun Jiang
Keyword(s):  
Complex Networks ◽  
Finite Time ◽  
Time Synchronization ◽  
Sufficient Conditions ◽  
Time Stability ◽  
Finite Time Stability ◽  
Uniformly Smooth ◽  
Nonidentical Nodes ◽  
Smooth State ◽  
Synchronization Performance

In this paper, we investigated the finite-time synchronization (FTS) problem for a class of time-delayed complex networks with nonidentical nodes onto any uniformly smooth state. By employing the finite-time stability theorem and designing two types of novel controllers, we obtained some simple sufficient conditions for the FTS of addressed complex networks. Furthermore, we also analyzed the effects of control variables on synchronization performance. Finally, we showed the effectiveness and feasibility of our methods by giving two numerical examples.

scholarly journals An Analysis of Error Factors for Software Based Pseudolite Time Synchronization Performance Evaluation

2014 ◽  
Vol 18 (5) ◽  
pp. 429-436
Author(s):  
Ju Hyun Lee ◽  
Sun Yong Lee ◽  
Soyoung Hwang ◽  
Dong-Hui Yu ◽  
Chansik Park ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Time Synchronization ◽  
Analysis Of Error ◽  
Synchronization Performance

scholarly journals A High-Precision Energy-Efficient GPS Time-Sync Method for High-Density Seismic Surveys

2020 ◽  
Vol 10 (11) ◽  
pp. 3768
Author(s):  
Ruyun Tian ◽  
Junjie Zhang ◽  
Shuai Zhang ◽  
Longxu Wang ◽  
Hongyuan Yang ◽  
...  
Keyword(s):  
High Precision ◽  
Seismic Data ◽  
Energy Efficient ◽  
Time Synchronization ◽  
High Density ◽  
Seismic Survey ◽  
Data Synchronization ◽  
Synchronization Method ◽  
Synchronization Accuracy ◽  
Synchronization Performance

Large numbers of seismic channels and high-density energy-efficient acquisition systems are the development trend of seismic instruments and have attracted high R&D interests in recent years. The combination of remote sensing and wireless sensor network technology provides superior observation capabilities for high-density seismic exploration. However, large-scale and multi-node acquisition methods place higher requirements on time synchronization performance. Seismic data with poor time synchronization will cause considerable errors in the interpretation of seismic data and even have no practical significance. Thus, the strict time synchronization performance is the prerequisite and basis for the application of cable-less storage seismograph in high-density seismic array applications. The existing time synchronization methods have high power consumption and poor time synchronization accuracy, which is not suitable for the long-time task. In addition, these methods are affected by the number of nodes and the distance. This paper presents an energy-efficient time-sharing indexed interpolation intercept method for the seismic data synchronization. The time synchronization method uses the high-precision TCXO as the main clock and records GPS time in the SD card at intervals to achieve the high-precision time-stamp for the seismic data. Then the seismic data is intercepted intermittently based on precise time stamps, which achieves the strict seismic data synchronization. Performance analysis shows that the time synchronization accuracy of the proposed method is 0.6 μs and saves 73% energy of the time-sync periods compared to the common GPS timing method. The field measurement results indicate that the time synchronization accuracy is not associated with the working time and the distance between nodes so that the proposed synchronization method is suitable for the high-density seismic survey.

scholarly journals Comparison Study of Time Synchronization in NC-OFDM Systems Based on Symmetric Correlator

2019 ◽  
Vol 19 (2) ◽  
pp. 57
Author(s):  
Tajul Miftahushudur ◽  
Suyoto Suyoto
Keyword(s):  
Cognitive Radio ◽  
Time Synchronization ◽  
Mean Squared Error ◽  
Test Method ◽  
Multipath Channel ◽  
Ratio Test ◽  
Ofdm Systems ◽  
Cognitive Radio Systems ◽  
Radio Systems ◽  
Synchronization Performance

NC-OFDM as one of the candidates for the Cognitive Radio (CR) system has many challenges in the synchronizing time. This is due to the frequency sharing which can cause Narrowband Interference (NBI), which causes a very significant time synchronization error. Large errors in time synchronization can reduce overall NCOFDM system performance. In this study, we evaluate the time synchronization performance of NC-OFDM systems on the multipath channel in the present of NBI. We provide an evaluation of the time synchronization performance by comparing the time synchronization algorithm that has a timing metric such as an impulse-like (Symmetric correlator). Here, we present three algorithms that use the symbol training to calculate the arrival time of the NC-OFDM symbol. The simulation conducted by considering the effects of multipath channel, Signal to Noise Ratio (SNR), Carrier Frequency Offset (CFO), and SIR (Signal to Interference Ratio). SIR is modeled with NBI. Algorithm performance is measured by MAE (Mean Absolute Error) and MSE (Mean Squared Error). Simulation results show that the autocorrelation-based method has very poor performance in MAE and MSE tests, so it is not suitable for NC-OFDMbased Cognitive Radio systems. The GLRT (Generalized Likelihood Ratio Test) method and Iterative Normalization method perform well in case the NC-OFDM Cognitive Radio systems.

scholarly journals Randomized and Efficient Time Synchronization in Dynamic Wireless Sensor Networks: A Gossip-Consensus-Based Approach

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Nan Xiong ◽  
Minrui Fei ◽  
Taicheng Yang ◽  
Yu-Chu Tian
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Time Synchronization ◽  
Negative Impact ◽  
Wireless Sensor ◽  
Drift Estimation ◽  
Time Calibration ◽  
Topology Changes ◽  
Dynamic Topology ◽  
Synchronization Performance

This paper proposes novel randomized gossip-consensus-based sync (RGCS) algorithms to realize efficient time calibration in dynamic wireless sensor networks (WSNs). First, the unreliable links are described by stochastic connections, reflecting the characteristic of changing connectivity gleaned from dynamic WSNs. Secondly, based on the mutual drift estimation, each pair of activated nodes fully adjusts clock rate and offset to achieve network-wide time synchronization by drawing upon the gossip consensus approach. The converge-to-max criterion is introduced to achieve a much faster convergence speed. The theoretical results on the probabilistic synchronization performance of the RGCS are presented. Thirdly, a Revised-RGCS is developed to counteract the negative impact of bounded delays, because the uncertain delays are always present in practice and would lead to a large deterioration of algorithm performances. Finally, extensive simulations are performed on the MATLAB and OMNeT++ platform for performance evaluation. Simulation results demonstrate that the proposed algorithms are not only efficient for synchronization issues required for dynamic topology changes but also give a better performance in terms of converging speed, collision rate, and the robustness of resisting delay, and outperform other existing protocols.

Improving IEEE 1588v2 time synchronization performance with phase locked loop

2014 ◽  
Author(s):  
Rico Hartono Jahja ◽  
Saurav Dahal ◽  
Hwang Suk-seung ◽  
Kwon Goo-Rak ◽  
Jae-young Pyun ◽  
...  
Keyword(s):  
Time Synchronization ◽  
Phase Locked Loop ◽  
Synchronization Performance
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