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In this paper, we propose a positioning system using a time-synchronized wireless network that can achieve high positioning accuracy without being dependent on any global positioning system (GPS) devices with cm-level accuracy as the main goal and objective. The proposed system utilizes time of arrival (ToA) method to estimate the target's position. Based on the results, we can achieve time synchronization...
This paper aims at presenting an experimented low power Internet of Things architecture, that could be integrated to underwater monitoring systems like Autonomous Underwater Vehicles for wireless underwater sensing. The proposed hardware architecture of the sensor nodes is based on an ultra-low-power Flash Micro-controller that takes measurements from water sensors, and synchronizes the network by...
Underwater wireless sensor networks (UWSNs) provide a promising approach for ocean monitoring. Locating the sensor nodes (SNs) in UWSNs is critical for annotating data samples. However, the global positioning system (GPS) is not available underwater. The locations of SNs are usually interpreted from anchor nodes which are deployed at known locations on the seafloor or sea surface. Due to the characteristics...
Although a number of asynchronous physical-layer network coding (PNC) schemes have been proposed, synchronous PNC may still be preferred for its simplicity. In this paper we propose a new symbol-level synchronization scheme which reduces the misalignment to less than one hardware clock cycle period. In addition, we prototype the proposed scheme on the Universal Software Radio Peripheral (USRP) platform...
Localization of wireless networks has remained an active research topic for more than a decade, as it finds more and more applications in numerous scenarios, including environment surveillance, asset tracking, and healthcare monitoring, etc. In this paper, we consider the maximum likelihood localization of a network where some of the nodes are GPS-capable while the others attempt to achieve self localization...
We have proposed synchronized Spread-Spectrum Code-Division Multiple-Access (SS-CDMA) communication for location and short message communication system using Quasi-Zenith Satellite System (QZSS) as a safety confirmation system at the time of grade disaster. In this communication, the satellite reception timings of all uplink signals are synchronized using transmission timing control method in order...
After analyzing the shortcomings of existing synchronization methods based on GPS and the research status of synchronization for Crosswell Electromagnetic Imaging Logging Tool(CEMIT), a feasible synchronization method combined the actual conditions of CEMIT with the basis of existing research is proposed. First of all, GPS receiver provides a high accurate 1PPS, which received by Surface System, and...
Vehicular Ad Hoc Networks (VANET) are the fastchanging networks for connected vehicles, in which Vehicle- to-Vehicle and Vehicle-to-Infrastructure communication are the basis for technologies aiming at reducing accidents and improving operation. DSRC Safety Applications, designed to assist drivers in order to avoid accidents, might be subjected to malicious attacks, such as GPS time spoofing attacks,...
The uprising interest in multi-agent based networked system, and the numerous number of applications in the distributed control of the smart grid leads us to address the problem of time synchronization in the smart grid. Utility companies look for new packet based time synchronization solutions with Global Positioning System (GPS) level accuracies beyond traditional packet methods such as Network...
IEEE1588 (PTP: Precise Time Protocol), which aims for the sub-microsecond range of clock synchronization in a minimal network, is currently focused on highly precise clock synchronization. Boundary Clock (BC) and VLAN Priority are considered to be features that improve PTP accuracy. Although some papers addressed the accuracy, these evaluations were realized using different evaluation metrics and...
The use of animals, specially ovines, for controlling infesting species in crops is an ancient method that has several advantages with respect to the use of chemical and/or mechanical techniques. Shepherds required to supervise animals, are getting increasingly less available and are costly. Over the last years, technologies for automatic animal supervision have been investigated, typically including...
The i.Drive Lab has developed inter-disciplinary methodology for the analysis and modelling of behavioral and physiological responses related to the interaction between driver, vehicle, infrastructure, and virtual environment. The present research outlines the development of a validation study for the combination of virtual and real-life research methodologies. i.Drive driving simulator was set up...
The problem to rectify and optimize distance measures from satellites in GNSS devices has been thoroughly explored in many researches. Instead there is not much information on available procedures to replicate the observed errors. The replication of GNSS errors can, in fact, be useful in many traffic simulation scenarios to test for ITS performances. The purpose of this article is to present cases...
In this study, we investigate the feasibility of detecting small intruder aircraft through camera images obtained onboard a small unmanned aircraft. The research group (Small Unmanned Aerial Vehicle Laboratory) from NASA Langley Research Center flew a set of missions with their small UAS (sUAS) where one of those vehicles is outfitted with three 4K resolution cameras located at the tips of the wings...
The SyncBoard is a reconfigurable sensor timing board that accurately records the Time of Validity (TOV) from sensors, while acting as a protocol conversion tool. It is intended to be usable by people without expertise in hardware development. To allow accurate timing, the SyncBoard has a highperformance microcontroller with a 32-bit timer clock running at a maximum of 100 MHz. By capturing the TOV...
Recently, researchers found a new type of attacks, called time synchronization attack (TS attack), in cyber-physical systems. Instead of modifying the measurements from the system, this attack only changes the time stamps of the measurements. Studies show that these attacks are realistic and practical. However, existing detection techniques, e.g. bad data detection (BDD) and machine learning methods,...
Recent years, double-ended techniques for PD location in MV cables emerged in large numbers. Nevertheless, great majority of the methods face the challenge of the time-synchronization between the two cable terminals because of the satellite invisibility and atmospheric condition problems in the global positioning system (GPS) receiver. Conventional methods adopt free running 1PPS to synchronize system...
Graph Processing has been widely used to capture complex data dependency and uncover relationship insights. Due to the ever-growing graph scale and algorithm complexity, distributed graph processing has become more and more popular. In this paper, we investigate how to balance performance and cost for large scale graph processing on configurable virtual machines (VMs). We analyze the system architecture...
This paper describes an open source analogue to digital converter designed to meet the requirements of power system waveform measurement. In particular, attention is given to ensuring that waveforms are synchronously sampled to maintain the relationship between the various observed quantities, and the system is synchronized to the UTC time base by means of a GPS receiver, making a wide area comparison...
We present a real-time TDOA localization testbed utilizing software defined radio and GPS based synchronization. A distributed software stack enables the localization of unknown signals by transporting the recorded baseband samples of several sensors over a backhaul network for centralized signal processing in a fusion center. To overcome the relatively large drifts of synchronization signals provided...
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