scholarly journals Highly Accurate Timestamping for Ethernet-Based Clock Synchronization

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Patrick Loschmidt ◽  
Reinhard Exel ◽  
Georg Gaderer
Keyword(s):  
Clock Synchronization ◽  
Theory And Practice ◽  
Major Influence ◽  
Network Time ◽  
Network Time Protocol ◽  
Precision Time ◽  
Distributed Measurement ◽  
Synchronization Accuracy ◽  
Coordinate Data

It is not only for test and measurement of great importance to synchronize clocks of networked devices to timely coordinate data acquisition. In this context the seek for high accuracy in Ethernet-based clock synchronization has been significantly supported by enhancements to the Network Time Protocol (NTP) and the introduction of the Precision Time Protocol (PTP). The latter was even applied to instrumentation and measurement applications through the introduction of LXI. These protocols are usually implemented in software; however, the synchronization accuracy can only substantially be improved by hardware which supports drawing of precise event timestamps. Especially, the quality of the timestamps for ingress and egress synchronization packets has a major influence on the achievable performance of a distributed measurement or control system. This paper analyzes the influence of jitter sources remaining despite hardware support and proposes enhanced methods for up to now unmatched timestamping accuracy in Ethernet-based synchronization protocols. The methods shown in this paper reach sub-nanosecond accuracy, which is proven in theory and practice.

scholarly journals Overview of Time Synchronization for IoT Deployments: Clock Discipline Algorithms and Protocols

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5928
Author(s):  
Hüseyin Yiğitler ◽  
Behnam Badihi ◽  
Riku Jäntti
Keyword(s):  
Time Synchronization ◽  
Clock Synchronization ◽  
Constrained Systems ◽  
Clock Model ◽  
Network Time ◽  
Expected Performance ◽  
The Everyday ◽  
Network Time Protocol ◽  
Synchronization Problems ◽  
Constrained Devices

Internet of Things (IoT) is expected to change the everyday life of its users by enabling data exchanges among pervasive things through the Internet. Such a broad aim, however, puts prohibitive constraints on applications demanding time-synchronized operation for the chronological ordering of information or synchronous execution of some tasks, since in general the networks are formed by entities of widely varying resources. On one hand, the existing contemporary solutions for time synchronization, such as Network Time Protocol, do not easily tailor to resource-constrained devices, and on the other, the available solutions for constrained systems do not extend well to heterogeneous deployments. In this article, the time synchronization problems for IoT deployments for applications requiring a coherent notion of time are studied. Detailed derivations of the clock model and various clock relation models are provided. The clock synchronization methods are also presented for different models, and their expected performance are derived and illustrated. A survey of time synchronization protocols is provided to aid the IoT practitioners to select appropriate components for a deployment. The clock discipline algorithms are presented in a tutorial format, while the time synchronization methods are summarized as a survey. Therefore, this paper is a holistic overview of the available time synchronization methods for IoT deployments.

Application of Precision Time Protocol on Networked Control Systems

2012 ◽  
Vol 203 ◽  
pp. 192-197 ◽  
Author(s):  
Chuan Shun Yang ◽  
Xiang Ying Kong
Keyword(s):  
Control Systems ◽  
Networked Control Systems ◽  
Clock Synchronization ◽  
Networked Control ◽  
Detection Methods ◽  
Test Results ◽  
Precision Time ◽  
Application Requirements ◽  
Synchronization Accuracy ◽  
Precision Time Protocol

In order to overcome the problem of the clock synchronization accuracy between scattered nodes was not high on traditional networked control systems, proposed a new method of using the IEEE 1588 standard for precision time protocol. First studied the principle and algorithm of precision time protocol, the best master clock algorithm and timestamp detection methods. Then presented the timestamp detection method with the use of software and hardware on networked control systems to improve clock synchronization accuracy, and analyzed the feasibility of the method in theory. Finally, tested accuracy of the clock synchronization, and the test results showed that synchronization accuracy can reach nanosecond, can meet the application requirements of the networked control systems.

scholarly journals Twist-n-Sync: Software Clock Synchronization with Microseconds Accuracy Using MEMS-Gyroscopes

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 68
Author(s):  
Marsel Faizullin ◽  
Anastasiia Kornilova ◽  
Azat Akhmetyanov ◽  
Gonzalo Ferrer
Keyword(s):  
Global Positioning System ◽  
Clock Synchronization ◽  
Bundle Adjustment ◽  
High Rate ◽  
Network Time ◽  
Global Positioning ◽  
Mems Gyroscopes ◽  
Network Time Protocol ◽  
Android App ◽  
High Degree

Sensor networks require a high degree of synchronization in order to produce a stream of data useful for further purposes. Examples of time misalignment manifest as undesired artifacts when doing multi-camera bundle-adjustment or global positioning system (GPS) geo-localization for mapping. Network Time Protocol (NTP) variants of clock synchronization can provide accurate results, though present high variance conditioned by the environment and the channel load. We propose a new precise technique for software clock synchronization over a network of rigidly attached devices using gyroscope data. Gyroscope sensors, or IMU, provide a high-rate measurements that can be processed efficiently. We use optimization tools over the correlation signal of IMU data from a network of gyroscope sensors. Our method provides stable microseconds accuracy, regardless of the number of sensors and the conditions of the network. In this paper, we show the performance of the gyroscope software synchronization in a controlled environment, and we evaluate the performance in a sensor network of smartphones by our open-source Android App, Twist-n-Sync, that is publicly available.

Design of Clock Synchronization Algorithm in Networked Control Systems

2012 ◽  
Vol 263-266 ◽  
pp. 1376-1381
Author(s):  
Yi Liu ◽  
Hai Ying Yang
Keyword(s):  
Control Systems ◽  
Networked Control Systems ◽  
Clock Synchronization ◽  
Propagation Delay ◽  
Linear Matrix ◽  
Fitting Algorithm ◽  
Time Drift ◽  
Precision Time ◽  
Synchronization Accuracy ◽  
Precision Clock

The key point of the existing Ethernet test and measurement is that the method needs to achieve precision clock synchronization between different terminals. In this paper, an improved method was proposed with consideration of the time drift and propagation delay, expressing master-slave synchronization as a linear relationship and inducting the line of least squares fitting algorithm that traded as linear matrix form. The precision time protocol (PTP) was also analyzed in this paper. The experiment results show that the synchronization accuracy reaches sub-microsecond grade, which is the same as the PTP.

Administrasi Hubungan Sekolah dan Masyarakat

2020 ◽  
Author(s):  
Fisma Janusuri
Keyword(s):  
Community Participation ◽  
Community Empowerment ◽  
Major Influence ◽  
Learning Achievement ◽  
Quality Of Learning ◽  
Good Schools ◽  
Education Process

Community empowerment in education is needed especially to support the implementation of good schools. The level of community participation in the education process in this school seems to have a major influence on the progress of the school, the quality of learning services in schools which will ultimately affect the progress and learning achievement of children in school.

scholarly journals Security Vulnerability Assessment of Google Home Connection with an Internet of Things Device

Proceedings ◽  
2021 ◽  
Vol 74 (1) ◽  
pp. 1
Author(s):  
Hilal Çepik ◽  
Ömer Aydın ◽  
Gökhan Dalkılıç
Keyword(s):  
Internet Of Things ◽  
Vulnerability Assessment ◽  
Smart Home ◽  
Human Life ◽  
Computer Systems ◽  
Security Vulnerability ◽  
Network Time ◽  
Network Time Protocol ◽  
Home Systems

With virtual assistants, both changes and serious conveniences are provided in human life. For this reason, the use of virtual assistants is increasing. The virtual assistant software has started to be produced as separate devices as well as working on phones, tablets, and computer systems. Google Home is one of these devices. Google Home can work integrated with smart home systems and various Internet of Things devices. The security of these systems is an important issue. As a result of attackers taking over these systems, very serious problems may occur. It is very important to take the necessary actions to detect these problems and to take the necessary measures to prevent possible attacks. The purpose of this study is to test whether an attack that attackers can make to these systems via network time protocol will be successful or not. Accordingly, it has been tried to attack the wireless connection established between Google Home and an Internet of Things device over the network time protocol. Attack results have been shared.

Sign in / Sign up

Export Citation Format

Share Document