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Book ChapterDOI

TAIL: Two-level Approach for Indoor Localization

24 Sep 2007-pp 167-178
TL;DR: This paper presents a novel localization method for indoor environments using Wi-Fi infrastructure, which simplifies the development of location-aware applications and reduces the need for manually finding the location of the user.
Abstract: Popularity of ubiquitous computing increases the importance of location-aware applications, which increases the need for finding location of the user In this paper, we present a novel localization method for indoor environments using Wi-Fi infrastructure

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References
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Proceedings ArticleDOI
26 Mar 2000
TL;DR: RADAR is presented, a radio-frequency (RF)-based system for locating and tracking users inside buildings that combines empirical measurements with signal propagation modeling to determine user location and thereby enable location-aware services and applications.
Abstract: The proliferation of mobile computing devices and local-area wireless networks has fostered a growing interest in location-aware systems and services. In this paper we present RADAR, a radio-frequency (RF)-based system for locating and tracking users inside buildings. RADAR operates by recording and processing signal strength information at multiple base stations positioned to provide overlapping coverage in the area of interest. It combines empirical measurements with signal propagation modeling to determine user location and thereby enable location-aware services and applications. We present experimental results that demonstrate the ability of RADAR to estimate user location with a high degree of accuracy.

8,667 citations


"TAIL: Two-level Approach for Indoor..." refers methods in this paper

  • ...To overcome the difficulty of predicting signal propagation, radio map technique RADAR [4] has been proposed which works in two phases - offline and online....

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Journal ArticleDOI
TL;DR: A novel system for the location of people in an office environment is described, where members of staff wear badges that transmit signals providing information about their location to a centralized location service, through a network of sensors.
Abstract: A novel system for the location of people in an office environment is described. Members of staff wear badges that transmit signals providing information about their location to a centralized location service, through a network of sensors. The paper also examines alternative location techniques, system design issues and applications, particularly relating to telephone call routing. Location systems raise concerns about the privacy of an individual and these issues are also addressed.

4,315 citations


"TAIL: Two-level Approach for Indoor..." refers background in this paper

  • ...Cricket [1], Active Badge [2] and APS [3] fall into range-based category....

    [...]

Proceedings ArticleDOI
01 Aug 2000
TL;DR: The randomized algorithm used by beacons to transmit information, the use of concurrent radio and ultrasonic signals to infer distance, the listener inference algorithms to overcome multipath and interference, and practical beacon configuration and positioning techniques that improve accuracy are described.
Abstract: This paper presents the design, implementation, and evaluation of Cricket, a location-support system for in-building, mobile, location-dependent applications. It allows applications running on mobile and static nodes to learn their physical location by using listeners that hear and analyze information from beacons spread throughout the building. Cricket is the result of several design goals, including user privacy, decentralized administration, network heterogeneity, and low cost. Rather than explicitly tracking user location, Cricket helps devices learn where they are and lets them decide whom to advertise this information to; it does not rely on any centralized management or control and there is no explicit coordination between beacons; it provides information to devices regardless of their type of network connectivity; and each Cricket device is made from off-the-shelf components and costs less than U.S. $10. We describe the randomized algorithm used by beacons to transmit information, the use of concurrent radio and ultrasonic signals to infer distance, the listener inference algorithms to overcome multipath and interference, and practical beacon configuration and positioning techniques that improve accuracy. Our experience with Cricket shows that several location-dependent applications such as in-building active maps and device control can be developed with little effort or manual configuration.

4,123 citations

Journal ArticleDOI
TL;DR: This work reviews localization techniques and evaluates the effectiveness of a very simple connectivity metric method for localization in outdoor environments that makes use of the inherent RF communications capabilities of these devices.
Abstract: Instrumenting the physical world through large networks of wireless sensor nodes, particularly for applications like environmental monitoring of water and soil, requires that these nodes be very small, lightweight, untethered, and unobtrusive. The problem of localization, that is, determining where a given node is physically located in a network, is a challenging one, and yet extremely crucial for many of these applications. Practical considerations such as the small size, form factor, cost and power constraints of nodes preclude the reliance on GPS of all nodes in these networks. We review localization techniques and evaluate the effectiveness of a very simple connectivity metric method for localization in outdoor environments that makes use of the inherent RF communications capabilities of these devices. A fixed number of reference points in the network with overlapping regions of coverage transmit periodic beacon signals. Nodes use a simple connectivity metric, which is more robust to environmental vagaries, to infer proximity to a given subset of these reference points. Nodes localize themselves to the centroid of their proximate reference points. The accuracy of localization is then dependent on the separation distance between two-adjacent reference points and the transmission range of these reference points. Initial experimental results show that the accuracy for 90 percent of our data points is within one-third of the separation distance. However, future work is needed to extend the technique to more cluttered environments.

3,723 citations


"TAIL: Two-level Approach for Indoor..." refers methods in this paper

  • ...Proposals based on range-free techniques are described in [5], [6], [7] and [9]....

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  • ...Range-free technique uses the overlapping coverage region of reference nodes to estimate the required area [7]....

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01 Jan 2003
TL;DR: This paper presents APIT, a novel localization algorithm that is range-free, and shows that the APIT scheme performs best when an irregular radio pattern and random node placement are considered, and low communication overhead is desired.
Abstract: Sensor Networks have been proposed for a multitude of location-dependent applications. For such systems, the cost and limitations of the hardware on sensing nodes prevent the use of range-based localization schemes that depend on absolute point- to-point distance estimates. Because coarse accuracy is sufficient for most sensor network applications, solutions in range-free localization are being pursued as a cost-effective alternative to more expensive range-based approaches. In this paper, we present APIT, a novel localization algorithm that is range-free. We show that our APIT scheme performs best when an irregular radio pattern and random node placement are considered, and low communication overhead is desired. We compare our work via extensive simulation, with three state-of-the-art range-free localization schemes to identify the preferable system configurations of each. In addition, we study the effect of location error on routing and tracking performance. We show that routing performance and tracking accuracy are not significantly affected by localization error when the error is less than 0.4 times the communication radio radius.

2,515 citations


"TAIL: Two-level Approach for Indoor..." refers background or methods in this paper

  • ...Proposals based on range-free techniques are described in [5], [6], [7] and [9]....

    [...]

  • ...Appreciable accuracy of range-free localization techniques can be achieved only when the density of reference nodes is more or when reference nodes are distributed uniformly, or when the number of neighboring user nodes is more [9]....

    [...]