Evaluation of the impact of the time synchronization accuracy of multistatic radar positions on errors in determining the spatial coordinates of aerial objects

2013 ◽  
Vol 56 (4) ◽  
pp. 178-185
Author(s):  
Yu. N. Sedyshev ◽  
A. S. Dudush
Cybersecurity ◽  
2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Waleed Alghamdi ◽  
Michael Schukat

AbstractThe IEEE 1588 precision time protocol (PTP) is very important for many industrial sectors and applications that require time synchronization accuracy between computers down to microsecond and even nanosecond levels. Nevertheless, PTP and its underlying network infrastructure are vulnerable to cyber-attacks, which can stealthily reduce the time synchronization accuracy to unacceptable and even damage-causing levels for individual clocks or an entire network, leading to financial loss or even physical destruction. Existing security protocol extensions only partially address this problem. This paper provides a comprehensive analysis of strategies for advanced persistent threats to PTP infrastructure, possible attacker locations, and the impact on clock and network synchronization in the presence of security protocol extensions, infrastructure redundancy, and protocol redundancy. It distinguishes between attack strategies and attacker types as described in RFC7384, but further distinguishes between the spoofing and time source attack, the simple internal attack, and the advanced internal attack. Some experiments were conducted to demonstrate the impact of PTP attacks. Our analysis shows that a sophisticated attacker has a range of methodologies to compromise a PTP network. Moreover, all PTP infrastructure components can host an attacker, making the comprehensive protection of a PTP network against a malware infiltration, as for example exercised by Stuxnet, a very tedious task.


2014 ◽  
Vol 654 ◽  
pp. 370-373
Author(s):  
Bin Zhang ◽  
Bao Ren Chen ◽  
Yue Zhuo ◽  
Guang Cai Wang ◽  
Yi Jie Ding

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.


Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1367
Author(s):  
Jie Shen ◽  
Ming Yin ◽  
Ji-An Luo ◽  
Zhi-Bo Wang ◽  
Zhi Wang ◽  
...  

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.


Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-25
Author(s):  
Ying Liu ◽  
Fei Chen ◽  
Bin Yang ◽  
Xin Wang ◽  
Weiming Wang

In this paper, we investigate the finite-time synchronization control for a class of nonlinear coupled multiweighted complex networks (NCMWCNs) with Markovian switching and time-varying delay analytically and quantitatively. The value of this study lies in four aspects: First, it designs the finite-time synchronization controller to make the NCMWCNs with Markovian switching and time-varying delay achieve global synchronization in finite time. Second, it derives two kinds of finite-time estimation approaches by analyzing the impact of the nonlinearity of nonlinear coupled function on synchronization dynamics and synchronization convergence time. Third, it presents the relationship between Markovian switching parameters and synchronization problems of subsystems and the overall system. Fourth, it provides some numerical examples to demonstrate the effectiveness of the theoretical results.


2021 ◽  
pp. 2150165
Author(s):  
Chengye Zou ◽  
Xingyuan Wang ◽  
Haifeng Li

The finite time synchronization diffusion of uncertain networks with the switching topology is investigated in this paper. Spatiotemporal chaotic systems as nodes to construct the network, and the topology of network can jump from one construction to another to meet the actual demand. It is not like ordinary synchronization of network, our method can realize synchronization diffusion originated from boundary conditions, and the diffusion step can be determined by Taylor expand. The parameters are identified through proposed scheme against parameter uncertainties of system in practice. Numerical simulations are utilized to demonstrate the correctness and effectiveness of the finite time synchronization diffusion criteria. In the section of analysis and discussion, we have analyzed the impact of synchronization diffusion step and controller on the synchronization diffusion time.


2021 ◽  
Author(s):  
Songyu Yuan ◽  
Yuehua Li ◽  
Yong Chen ◽  
Chenghao Wang

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1398
Author(s):  
Waleed Alghamdi ◽  
Michael Schukat

The IEEE 1588 precision time protocol (PTP) is used by many time-sensitive applications and systems, as it achieves sub-microsecond time synchronization between computer clocks. However, a PTP network is vulnerable to cyber-attacks that can reduce the protocol accuracy to unacceptable levels for some or all clocks in a network with potentially devastating consequences. Of particular concern are advanced persistent threats (APT), where an actor infiltrates a network and operates stealthily and over extended periods of time before being discovered. This paper investigates the impact of the most important APT strategies on a PTP network, i.e., the delay attack, packet modification or transparent clock attack, and time reference attack, using a fully programable and customizable man in the middle device, thereby considering the two most popular PTP slave daemons PTPd and PTP4l. In doing so, it determines suitable attack patterns and parameters to compromise the time synchronization covertly.


2020 ◽  
Vol 10 (11) ◽  
pp. 3768
Author(s):  
Ruyun Tian ◽  
Junjie Zhang ◽  
Shuai Zhang ◽  
Longxu Wang ◽  
Hongyuan Yang ◽  
...  

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.


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