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This paper presents a novel range-free geo-localization algorithm in wireless networks. The algorithm does not require ranging devices. It uses node connectivity to estimate the location of unknown (location unaware) nodes based on two or more anchor (location aware) nodes. The algorithm works in two steps. In the first step, the True Intersection Points (TIPs) that constitute the vertices of the...
This paper describes a localization method for an IR-UWB (Impulse Radio Ultra Wideband) two-way ranging system developed for precise time-of-arrival measurements. The ranging system provides a time resolution of 275 ps, which allows precise indoor distance estimation with the accuracy of 4 cm. In this work, a two-way ranging algorithm has been extended into a localization algorithm without the need...
The accurate node location is necessary for wireless sensor network applications in both the military and civilian areas. In this paper, we use the Cramer-Rao Bound (CRB) to verify that node localization algorithms based on received signal strength (RSS) and time of arrival (TOA) are both reasonable. The varying number of blindfolded nodes as well as the hybrid of RSS and TOA ranging methods are used...
Centroid Algorithm Localization is to fix position using the wireless sensor connections, which has larger error. To increase the localization accuracy, based on the fact that the centroid algorithm is comparative stable under the changing environment, and the conveniences of RSSI, a revised and improved centroid algorithm based on RSSI is proposed in this paper. Combined with the advantages of the...
Impulse-Radio Ultra Wideband (IR-UWB) is a promising technology for indoor localization due to its robustness against multipath interference. In this paper, to deal with the synchronization requirement among anchors in traditional time-difference-of-arrival (TDOA) localization, which is difficult to achieve, an asynchronous time-difference-of-arrival (TDOA) localization method is proposed. The theoretical...
Localization is a major issue and a challenging task for underwater acoustic networks. The characteristics of underwater acoustic networks are fundamentally different from that of terrestrial networks. For example, it is not easy to get GPS into water and underwater acoustic networks often just have few anchors. Thus many of the localization schemes for terrestrial networks cannot be used directly...
Accurate localization in wireless sensor actuator networks (WSANs) is crucial since a primary purpose in their deployments is accomplishing tasks based on a spatial dimension in the environment — be it sensor data collection or actuation.
Cooperative positioning is suitable for applications where conventional positioning fails due to lack of connectivity with a sufficient number of reference nodes. In a dense network, as the number of cooperating devices increases, the number of packet exchanges also increases proportionally. This causes network congestion and increases packet collisions. In order to maintain the quality of positioning,...
Position or localization is an important and extensively studied problem in ad-hoc wireless sensor networks. Most schemes require some nodes functioned as anchors with positions configured manually which are error-prone. In this paper, an anchor-free localization scheme is proposed. High accurate TOA is acquired by means of measure the time difference between two simultaneously transmitted radio and...
In this paper, we explore the possibility of using directionality of free-space-optical (a.k.a. optical wireless) communications for solving the 3-D localization problem in ad-hoc networking environments. Range-based localization methods either require a higher node density (i.e., at least three other localized neighbours must exist) than required for assuring connectedness or a high-accuracy power-intensive...
In underwater sensor networks, localization is one of the most important issues because sensor nodes are considerably difficult to be deployed at determined locations. Since range-based schemes require additional device and precise time synchronization for measuring distances in underwater environments, range-free schemes are promising in the view point of energy consumption and implementation. Coarseness...
Cooperative positioning is an emerging topic in wireless sensor networks and navigation. It can improve the positioning accuracy and coverage in GPS-challenged conditions such as inside tunnels, in urban canyons, and indoors. Different algorithms have been proposed relying on iteratively exchanging and updating positional information. For the purpose of computational complexity, network traffic, and...
On the basis of ranged-based methods, in this paper, we will raise a ranging method of TOA (Time of Arrival) based on ultra-wideband (UWB) communication technology. UWB signal have many beneficial characteristics such as good confidentiality, strong penetrating ability, high positioning accuracy and low power consumption. However, for the application of the node localization, UWB direct signal is...
Wireless networks have boosted the interest of users and network operators on location due to the possible synergies between the cellular layout and location techniques. As a result, location methods have been proposed to provide this information in most wireless technologies. Evaluation of the performance of these and further techniques is initially achieved by means of simulation. It is essential...
Localization and tracking functionalities can benefit a number of applications. Despite the large number of algorithms and technologies that have been proposed in this context, the literature still lacks a widely accepted solution, capable of cutting a tradeoff between service quality (i.e., localization accuracy) and device/architecture cost and complexity. In this paper, we tackle the problem from...
In this paper, we exploit the concept of data fusion in UWB (ultra wide band) localization systems by using different location-dependent observables. We combine ToA (time of arrival) and RSS (received signal strength) in order to get accurate positioning algorithms.We assume that RSS observables are usually available and we study the effect of adding ToA observables on the positioning accuracy. The...
Wireless sensor network is the technology of future due to its potential to be applied in all kind of monitoring, automation and management applications. In wireless sensor networks localization has become very important because for any application which need information from a specific region of WSN deployment we need location information of the individual nodes. Localization may also help network...
The development of energy aware and precise localization algorithms is a challenging task in the development of wireless sensor networks (WSN). The achievable precision of the algorithms strongly depends on the accuracy of the measured observations (e.g. time of signal flight or received signal strength). In reality, observations are highly defective due to multiple effects (e.g. signal propagation)...
In this article, we present a content-based video search service for mobile device users. After taking a photograph, the user can upload it to our server, which will then return videos containing key frames that are similar to the uploaded picture. The proposed service demonstrates that the search application is feasible.
The accuracy issues in the location prediction system using active RFID tags is addressed in this paper. First we present the location prediction accuracy in different environmental conditions. Later on, we propose a new technique to improve the prediction accuracy. The proposed technique is validated with measured data obtained under different propagation environments.
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