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Estimating the location of sensor nodes in wireless sensor networks is a fundamental problem, as sensor node locations play a critical role in a variety of applications. In many cases the area covered is very large making it impossible to localize all sensor nodes using single-hop localization techniques. A solution to this problem is to use a multi-hop localization technique to estimate sensor node...
We present a relative location estimation algorithm based on the coordinates inner product matrix-based maximum likelihood (CML) for determining the relative locations of sensor nodes in wireless sensor networks. We use the geodesic distance between each node to obtain the coordinates inner product matrix, then derive the maximum-likelihood estimator for coordinates inner product matrix to estimate...
In this paper algorithms for wireless sensor networks (WSN) localization and tracking are presented. They are optimized for the exploration of inaccessible environments with unknown shape and dynamics. The algorithms are based on semidefinite programming (SDP) and unscented Kalman filtering (UKF). The SDP approach is derived from a recent solution for WSN localization with anchor node uncertainty,...
This paper proposes methods for measuring size and distance of target objects by using mobile devices. For close-range measurement of a size of an object, users must hold the device close to the object and drag it along a desired direction. We develop a new approach for estimating a dragging distance of the device using acceleration signals retrieved from a three-axis accelerometer embedded on it...
The Distance Measuring Equipment (DME, DME/Normal) based navigation method known as DME/DME positioning has been proposed as one of the possible Alternative Position, Navigation, and Timing (APNT) services for aviation during the outage of the Global Navigation Satellite Systems. A DME interrogator measures the slant range to a DME transponder by means of the elapsed time in exchanging a pair of DME...
Wireless sensor networks (WSNs) are gaining more and more interest in the research community due to their unique characteristics. Besides energy consumption considerations, security has emerged as an equally important aspect in their network design. WSNs are vulnerable to various types of attacks, and as such, they require mechanisms to defend against them. Several anomaly detection algorithms have...
Ranging errors are inevitable in all local positioning systems, including those based on Time-of-Flight (ToF) technique. Results of experiments show that the major cause for these errors is a signal degradation from multipath propagation. This effect is especially critical in case of Non-Light-of-Sight (NLOS) conditions. This paper describes causes that affects ranging errors for nanoLOC™-TOF-technology...
Localization of wireless ad hoc and sensor networks has gained research attentions for several years. This paper proposes a hybrid localization scheme which exploits Received Signal Strength (RSS)-based ranging and Self Organizing Maps (SOM)-based range free localization methods to obtain the tradeoff between cost, power and location accuracy. By utilizing RSS-based distance estimation and connectivity...
Localization is one of the fundamental problems in wireless sensor networks (WSNs), since locations of the sensor nodes are critical to both network operations and to most of the application level tasks. There exists an extensive body of paper that aims at obtaining locations as well as spatial relations of nodes in WSNs without requiring specialized hardware and/or employing only a limited number...
In this paper, the data fusion algorithm for position estimation of the wireless sensor networks is investigated. A hybrid position scheme with both radio Based ranging measurement and time-Based ranging measurement is proposed. The position estimation performances of RSSI and TOF are compared and analyzed. A novel data fusion algorithm along with traditional Kalman filter is advanced to improve the...
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...
Practical low complexity time of arrival (TOA) estimation method with high accuracy is attractive in ultra wideband (UWB) ranging and localization. In this paper, a generalized maximum likelihood energy detection (GML-ED) ranging method is proposed and implemented. It offers low complexity and can be applied in various environments. An error model is firstly introduced for TOA accuracy evaluation,...
This paper proposed a new approach of 3D measurement using a home use 3D camera. Stereo image measurement is different from the other active measurement method like using a laser range finder or an ultra-sonic sensor. It is a passive method, which acquire the object as two images, and then calculate the distance information form the two images according to the principle of triangulation. Ordinarily,...
Wireless Sensor Networks (WSNs) are composed of nodes that gather metrics such as temperature, pollution or pressure from events generated by external entities. Localization in WSNs is paramount, given that the collected metrics must be related to the place of occurrence. This work presents an alternative way towards localization in randomly deployed WSNs based on the combination of individual position...
Self-localization using unsynchronized low-complexity anchors has a number of attractive features. Traditional self-localization techniques are not suitable to this scenario or have their applicability limitations. In this paper, a two-step hybrid self-localization technique using unsynchronized low-complexity anchors is proposed, which can achieve two-dimensional (2-D) instantaneous localization...
This paper presents a novel cognitive and cooperative tracking (CCT) approach based on extended Kalman filter (EKF) to localize mobile nodes in wireless networks. The proposed algorithm shows three important features: energy efficient, cognitive and cooperative. More specifically, the tracking algorithm adaptively adjusts the transmission power to optimize the energy consumption while meeting the...
The huge spread of wireless networks and the success of location-aware applications require novel indoor positioning mechanisms based on existing technologies such as IEEE 802.11. Taking inspiration from the RADAR, we propose WIDAR: a bistatic WI-fi Detection And Ranging system for off-the-shelf devices. WIDAR implementation is based on the USRP2 platform and is able to locate 802.11 stations while...
Localization of nodes is very important in wireless sensor network. A localization algorithm is proposed based on TOF (time of flight) ranging and Unscented Kalman Filtering (UKF). Firstly, TOF ranging was selected to measure the distance between beacon nodes and unknown nodes. With the TOF data, the distance measurement was obtained and optimized, and an node localization method was achieved by using...
Indoor WIFI localization is challenging especially when deployed over wireless device with limited system resource. Although GPS can give approximate position of the mobile users, it is usually limited indoor due to the degradation of signals by the building structures. While various alternative WIFI localization techniques have been proposed for indoor uses, accurate results are hard to achieve due...
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