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Robotics-Based Location Sensing using Wireless Ethernet,” in (2002)

by A M Ladd
Venue:Proc. MOBICOM,
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Localization for Mobile Sensor Networks

by Lingxuan Hu, David Evans - Proc. MobiCom , 2004
"... Many sensor network applications require location awareness, but it is often too expensive to include a GPS receiver in a sensor network node. Hence, localization schemes for sensor networks typically use a small number of seed nodes that know their location and protocols whereby other nodes estimat ..."
Abstract - Cited by 287 (0 self) - Add to MetaCart
Many sensor network applications require location awareness, but it is often too expensive to include a GPS receiver in a sensor network node. Hence, localization schemes for sensor networks typically use a small number of seed nodes that know their location and protocols whereby other nodes estimate their location from the messages they receive. Several such localization techniques have been proposed, but none of them consider mobile nodes and seeds. Although mobility would appear to make localization more difficult, in this paper we introduce the sequential Monte Carlo Localization method and argue that it can exploit mobility to improve the accuracy and precision of localization. Our approach does not require additional hardware on the nodes and works even when the movement of seeds and nodes is uncontrollable. We analyze the properties of our technique and report experimental results from simulations. Our scheme outperforms the best known static localization schemes under a wide range of conditions.
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...tion. Ladd et al. used a robotics localization approach to achieve accurate localization for wireless networks by using learned variation in RF signal strengths received using standard Ethernet cards =-=[29, 30]-=-. Their approach performs well for indoor localization in fixed environments, but assumes fixed seed locations and requires a learning phase, so is not well suited to mobile sensor network application...

Practical robust localization over large-scale 802.11 wireless networks

by Andreas Haeberlen, Algis Rudys, Eliot Flannery, Dan S. Wallach, Andrew M. Ladd, Lydia E. Kavraki - in Proceedings of the 10th Annual International Conference on Mobile Computing and Networking (MOBICOM
"... We demonstrate a system built using probabilistic techniques that allows for remarkably accurate localization across our entire office building using nothing more than the built-in signal intensity meter supplied by standard 802.11 cards. While prior systems have required significant investments of ..."
Abstract - Cited by 189 (2 self) - Add to MetaCart
We demonstrate a system built using probabilistic techniques that allows for remarkably accurate localization across our entire office building using nothing more than the built-in signal intensity meter supplied by standard 802.11 cards. While prior systems have required significant investments of human labor to build a detailed signal map, we can train our system by spending less than one minute per office or region, walking around with a laptop and recording the observed signal intensities of our building’s unmodified base stations. We actually collected over two minutes of data per office or region, about 28 man-hours of effort. Using less than half of this data to train the localizer, we can localize a user to the precise, correct location in over 95 % of our attempts, across the entire building. Even in the most pathological cases, we almost never localize a user any more distant than to the neighboring office. A user can obtain this level of accuracy with only two or three signal intensity measurements, allowing for a high frame rate of localization results. Furthermore, with a brief calibration period, our system can be adapted to work with previously unknown user hardware. We present results demonstrating the robustness of our system against a variety of untrained time-varying phenomena, including the presence or absence of people in the building across the day. Our system is sufficiently robust to enable a variety of locationaware applications without requiring special-purpose hardware or complicated training and calibration procedures.
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...hniques for sensing a device’s location. Nibble [9], one of the first systems of this generation, used a neural network to estimate a device’s location. In our first work on wireless location sensing =-=[31]-=-, we developed a grid-based Bayesian location-sensing system over a small region of our office building, achieving localization and tracking to within 1.5 meters over 50% of the time. Roos et al. [43]...

WLAN Location Determination via Clustering and Probability Distributions

by Moustafa Youssef, Ashok Agrawala, A. Udaya Shankar - In IEEE PerCom 2003 , 2003
"... We present a WLAN location determination technique, the Joint Clustering technique, that uses (1) signal strength probability distributions to address the noisy wireless channel, and (2) clustering of locations to reduce the computational cost of searching the radio map. The Joint Clustering techniq ..."
Abstract - Cited by 175 (6 self) - Add to MetaCart
We present a WLAN location determination technique, the Joint Clustering technique, that uses (1) signal strength probability distributions to address the noisy wireless channel, and (2) clustering of locations to reduce the computational cost of searching the radio map. The Joint Clustering technique reduces computational cost by more than an order of magnitude, compared to the current state of the art techniques, allowing non-centralized implementation on mobile clients. Results from 802.11-equipped iPAQ implementations show that the new technique gives user location to within 7 feet with over 90% accuracy.
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... cellular-based systems [16], infrared-based systems [18, 3], ultrasonic-based systems [12], various computer vision systems [9], physical contact systems [11], and radio frequency (RF) based systems =-=[4, 20, 14, 5, 13, 10, 8]-=-. Of these, the class of RF-based systems that use an underlying wireless data network [4, 20, 14, 5, 13, 10], such as 802.11, to estimate user location has gained attention recently, especially for i...

Accuracy characterization for metropolitan-scale wi-fi localization

by Yu-chung Cheng, Yatin Chawathe, Anthony Lamarca, John Krumm - In Proceedings of Mobisys 2005 , 2005
"... Location systems have long been identified as an important component of emerging mobile applications. Most research on location systems has focused on precise location in indoor environments. However, many location applications (for example, location-aware web search) become interesting only when th ..."
Abstract - Cited by 143 (6 self) - Add to MetaCart
Location systems have long been identified as an important component of emerging mobile applications. Most research on location systems has focused on precise location in indoor environments. However, many location applications (for example, location-aware web search) become interesting only when the underlying location system is available ubiquitously and is not limited to a single office environment. Unfortunately, the installation and calibration overhead involved for most of the existing research systems is too prohibitive to imagine deploying them across, say, an entire city. In this work, we evaluate the feasibility of building a wide-area 802.11 Wi-Fi-based positioning system. We compare a suite of wireless-radio-based positioning algorithms to understand how they can be adapted for such ubiquitous deployment with minimal calibration. In particular, we study the impact of this limited calibration on the accuracy of the positioning algorithms. Our experiments show that we can estimate a user’s position with a median positioning error of 13–40 meters (depending upon the characteristics of the environment). Although this accuracy is lower than existing positioning systems, it requires substantially lower calibration overhead and provides easy deployment and coverage across large metropolitan areas. 1

Enhancing Location Privacy in Wireless LAN Through Disposable Interface Identifiers: A Quantitative Analysis

by Marco Gruteser , Dirk Grunwald - Mobile Networks and Applications
"... Abstract. The recent proliferation of wireless local area networks (WLAN) has introduced new location privacy risks. An adversary controlling several access points could triangulate a client's position. In addition, interface identifiers uniquely identify each client, allowing tracking of loca ..."
Abstract - Cited by 129 (4 self) - Add to MetaCart
Abstract. The recent proliferation of wireless local area networks (WLAN) has introduced new location privacy risks. An adversary controlling several access points could triangulate a client's position. In addition, interface identifiers uniquely identify each client, allowing tracking of location over time. We enhance location privacy through frequent disposal of a client's interface identifier. While not preventing triangulation per se, it protects against an adversary following a user's movements over time. Design challenges include selecting new interface identifiers, detecting address collisions at the MAC layer, and timing identifier switches to balance network disruptions against privacy protection. Using a modified authentication protocol, network operators can still control access to their network. An analysis of a public WLAN usage trace shows that disposing addresses before reassociation already yields significant privacy improvements.
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...ollecting Signal-to-Noise-Ratio (SNR) measurements from multiple access points 1 and by applying signal processing algorithms that take into account the propagation characteristics of the environment =-=[3, 10, 22, 32]-=-. While some researchers have proposed systems for controlling the dissemination of location information, the challenge of protecting WLAN users against untrustworthy access point operators has, to ou...

Localization of Wireless Sensor Networks with a Mobile Beacon

by Mihail L. Sichitiu, Vaidyanathan Ramadurai , 2004
"... Wireless sensor networks have the potential to become the pervasive sensing (and actuating) technology of the future. For many applications, a large number of inexpensive sensors is preferable to a few expensive ones. The large number of sensors in a sensor network and most application scenarios pre ..."
Abstract - Cited by 115 (2 self) - Add to MetaCart
Wireless sensor networks have the potential to become the pervasive sensing (and actuating) technology of the future. For many applications, a large number of inexpensive sensors is preferable to a few expensive ones. The large number of sensors in a sensor network and most application scenarios preclude hand placement of the sensors. Determining the physical location of the sensors after they have been deployed is known as the problem of localization. In this paper, we present a localization technique based on a single mobile beacon aware of its position (e.g. by being equipped with a GPS receiver). Sensor nodes receiving beacon packets infer proximity constraints to the mobile beacon and use them to construct and maintain position estimates. The proposed scheme is radio-frequency based, and thus no extra hardware is necessary. The accuracy (on the order of a few meters in most cases) is sufficient for most applications. An implementation is used to evaluate the performance of the proposed approach.

Towards Mobility as a Network Control Primitive

by David K. Goldenberg, Jie Lin, A. Stephen Morse, Brad E. Rosen, Y. Richard Yang - In MobiHoc ’04: Proceedings of the 5th ACM international symposium on Mobile ad hoc networking and computing , 2004
"... In the near future, the advent of large-scale networks of mobile agents autonomously performing long-term sensing and communication tasks will be upon us. However, using controlled node mobility to improve communication performance is a capability that the mobile networking community has not yet inv ..."
Abstract - Cited by 106 (1 self) - Add to MetaCart
In the near future, the advent of large-scale networks of mobile agents autonomously performing long-term sensing and communication tasks will be upon us. However, using controlled node mobility to improve communication performance is a capability that the mobile networking community has not yet investigated. In this paper, we study mobility as a network control primitive. More specifically, we present the first mobility control scheme for improving communication performance in such networks. Our scheme is completely distributed, requiring each node to possess only local information. Our scheme is self-adaptive, being able to transparently encompass several modes of operation, each respectively improving power efficiency for one unicast flow, multiple unicast flows, and many-to-one concast flows. We provide extensive evaluations on the feasibility of mobility control, showing that controlled mobility can improve network performance in many scenarios. This work constitutes a novel application of distributed control to networking in which underlying network communication serves as input to local control rules that guide the system toward a global objective.
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...ms. The focus of these studies, however, is not on network communications. For example, in [6], Cortes et al. have shown that mobility can be purposefully controlled to implement network coverage; in =-=[18], -=-Ladd et al. have shown that mobility can be used to improve the accuracy of network localization; in DARPA’s self-healing minefield project [8], mobility is used to improve and maintain network cove...

Modeling of Indoor Positioning Systems Based on Location Fingerprinting

by Kamol Kaemarungsi, Prashant Krishnamurthy , 2004
"... In recent years, positioning systems for indoor areas using the existing wireless local area network infrastructure have been suggested. Such systems make use of location fingerprinting rather than time or direction of arrival techniques for determining the location of mobile stations. While experim ..."
Abstract - Cited by 105 (2 self) - Add to MetaCart
In recent years, positioning systems for indoor areas using the existing wireless local area network infrastructure have been suggested. Such systems make use of location fingerprinting rather than time or direction of arrival techniques for determining the location of mobile stations. While experimental results related to such positioning systems have been presented, there is a lack of analytical models that can be used as a framework for designing and deploying the positioning systems. In this paper, we present an analytical model for analyzing such positioning systems. We develop the framework for analyzing a simple positioning system that employs the Euclidean distance between a sample signal vector and the location fingerprints of an area stored in a database. We analyze the effect of the number of access points that are visible and radio propagation parameters on the performance of the positioning system and provide some preliminary guidelines on its design.
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...t (on-line phase). After a number of empirical and feasibility studies such as in [13, 31], recent development has been focused on improvement of location estimation algorithms and system performance =-=[8, 23, 22, 18]-=-. Popular machine learning techniques such as neural network and support vector machines (SVMs) have been introduced to improve the performance with RSS fingerprinting. The following discussion is div...

Bayesian indoor positioning systems

by Eiman Elnahrawy, Richard P. Martin, Wen-hua Ju, P. Krishnan, David Madigan - In Infocom , 2005
"... Abstract — In this paper, we introduce a new approach to location estimation where, instead of locating a single client, we simultaneously locate a set of wireless clients. We present a Bayesian hierarchical model for indoor location estimation in wireless networks. We demonstrate that our model ach ..."
Abstract - Cited by 102 (15 self) - Add to MetaCart
Abstract — In this paper, we introduce a new approach to location estimation where, instead of locating a single client, we simultaneously locate a set of wireless clients. We present a Bayesian hierarchical model for indoor location estimation in wireless networks. We demonstrate that our model achieves accuracy that is similar to other published models and algorithms. By harnessing prior knowledge, our model eliminates the requirement for training data as compared with existing approaches, thereby introducing the notion of a fully adaptive zero profiling approach to location estimation. Index Terms — Experimentation with real networks/Testbed, Statistics, WLAN, localization,

GSM indoor localization

by Alex Varshavsky , Eyal de Lara , Jeffrey Hightower , Anthony LaMarca , Veljo Otsason , 2007
"... ..."
Abstract - Cited by 101 (7 self) - Add to MetaCart
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