Sun, 06 Jul 2008 11:04:53 BST CiteULike: dcastros location http://www.citeulike.org/user/dcastro/tag/location CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/257569 <i>International Journal of Wireless Information Networks, Vol. 9, No. 3. (July 2002), pp. 155-164.</i> A Probabilistic Approach to WLAN User Location Estimation Teemu Roos Petri Myllymã¤ki Henry Tirri Pauli Misikangas Juha Sievã¤nen doi:10.1023/A:1016003126882 International Journal of Wireless Information Networks, Vol. 9, No. 3. (July 2002), pp. 155-164. 2005-07-16T07:16:49-00:00 2002 International Journal of Wireless Information Networks 9 3 155 164 estimation location wlan http://www.citeulike.org/user/dcastro/article/556628 <i>Sensor and Ad Hoc Communications and Networks, 2004. IEEE SECON 2004. 2004 First Annual IEEE Communications Society Conference on (2004), pp. 406-414.</i><br /><br />We characterize the fundamental limits of localization using signal strength in indoor environments. Signal strength approaches are attractive because they are widely applicable to wireless sensor networks and do not require additional localization hardware. We show that although a broad spectrum of algorithms can trade accuracy for precision, none has a significant advantage in localization performance. We found that using commodity 802.11 technology over a range of algorithms, approaches and environments, one can expect a median localization error of 10 ft and 97th percentile of 30 ft. We present strong evidence that these limitations are fundamental and that they are unlikely to transcend without a fundamentally more complex environmental models or additional localization infrastructure. The limits of localization using signal strength: a comparative study E Elnahrawy Xiaoyan Li RP Martin Sensor and Ad Hoc Communications and Networks, 2004. IEEE SECON 2004. 2004 First Annual IEEE Communications Society Conference on (2004), pp. 406-414. 2006-03-19T11:57:34-00:00 2004 Sensor and Ad Hoc Communications and Networks, 2004. IEEE SECON 2004. 2004 First Annual IEEE Communications Society Conference on 406 414 location power signal http://www.citeulike.org/user/dcastro/article/2883776 <i>Mobile Computing, IEEE Transactions on, Vol. 6, No. 3. (2007), pp. 311-321.</i><br /><br />Location estimation using the global system for mobile communication (GSM) is an emerging application that infers the location of the mobile receiver from multiple signals measurements. While geometrical and signal propagation models have been deployed to tackle this estimation problem, the terrain factors and power fluctuations have confined the accuracy of such estimation. Using support vector regression, we investigate the missing value location estimation problem by providing theoretical and empirical analysis on existing and novel kernels. A novel synthetic experiment is designed to compare the performances of different location estimation approaches. The proposed support vector regression approach shows promising performances, especially in terrains with local variations in environmental factors Location Estimation via Support Vector Regression Zhi-Li Wu Chun-Hung Li Joseph Ng Karl Leung doi:10.1109/TMC.2007.42 Mobile Computing, IEEE Transactions on, Vol. 6, No. 3. (2007), pp. 311-321. 2008-06-11T20:33:24-00:00 2007 Mobile Computing, IEEE Transactions on 6 3 311 321 estimation location svm http://www.citeulike.org/user/dcastro/article/1234005 <i>IEEE Transactions on Mobile Computing, Vol. 1, No. 1. (January 2002), pp. 59-69.</i> A Statistical Modeling Approach to Location Estimation Teemu Roos Petri Myllym&\#228;ki Henry Tirri doi:10.1109/TMC.2002.1011059 IEEE Transactions on Mobile Computing, Vol. 1, No. 1. (January 2002), pp. 59-69. 2007-04-18T12:53:52-00:00 2002 IEEE Transactions on Mobile Computing 1536-1233 1 1 59 69 IEEE Educational Activities Department estimation location statistical http://www.citeulike.org/user/dcastro/article/2802348 <i>Communications Magazine, IEEE, Vol. 36, No. 4. (1998), pp. 38-45.</i><br /><br />Applications for the location of subscribers of wireless services continue to expand. Consequently, location techniques for wireless technologies are being investigated. With code-division multiple access (CDMA) being deployed by a variety of cellular and PCS providers, developing an approach for location in CDMA networks is imperative. This article discusses the applications of location technology, the methods available for its implementation in CDMA networks, and the problems that are encountered when using CDMA networks for positioning Overview of radiolocation in CDMA cellular systems JJ Caffery GL Stuber doi:10.1109/35.667411 Communications Magazine, IEEE, Vol. 36, No. 4. (1998), pp. 38-45. 2008-05-15T18:37:44-00:00 1998 Communications Magazine, IEEE 36 4 38 45 cdma cellular location radio http://www.citeulike.org/user/dcastro/article/2776180 <i>Military Communications Conference Proceedings, 1999. MILCOM 1999. IEEE, Vol. 2 (1999), pp. 1328-1332 vol.2.</i><br /><br />This paper discusses an improved method for localization in a DS-CDMA based cellular-phone communication link. This method suggests an optimization for code synchronization, which allows for TDOA (time difference of arrival) estimations to be solved for the position of a mobile phone. It is known that the time delay of a received DS signal, derived from the classical DLL, may express severe timing errors due to multipath effects. A new anti multipath multi-tracking extended Kalman filter loop is shown to achieve far better results especially in the environment of specular multipath. Specifically, this new loop minimizes the errors due to multipath components by letting the EKF decide upon the best weights of its sub-chip processing branches, resulting in a RAKE-like tracking loop. This loop tracks not only the line of sight path, but also the other multipath components as well as their power and phase. It is shown that the implementation of this technique converges to the classical non-coherent code tracking DLL structure when no multipath is assumed, but results in a new and efficient tracking loop structure in the more realistic fading channel case. The application of this technique to the EIA IS-95 system is considered, where accurate location estimations as well as power management utilities are treated Anti multipath cellular radio location for DS/CDMA systems using a novel EKF subchip RAKE tracking loop E Fishler BZ Bobrovsky doi:10.1109/MILCOM.1999.821419 Military Communications Conference Proceedings, 1999. MILCOM 1999. IEEE, Vol. 2 (1999), pp. 1328-1332 vol.2. 2008-05-09T15:42:49-00:00 1999 Military Communications Conference Proceedings, 1999. MILCOM 1999. IEEE 2 1328 1332 vol.2 cdma kalman location loop mobile multipath radio rake tracking http://www.citeulike.org/user/dcastro/article/1591767 <i>Personal Communications, IEEE [see also IEEE Wireless Communications], Vol. 7, No. 5. (2000), pp. 28-34.</i><br /><br />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 GPS-less low-cost outdoor localization for very small devices N Bulusu J Heidemann D Estrin doi:10.1109/98.878533 Personal Communications, IEEE [see also IEEE Wireless Communications], Vol. 7, No. 5. (2000), pp. 28-34. 2007-08-25T07:37:52-00:00 2000 Personal Communications, IEEE [see also IEEE Wireless Communications] 7 5 28 34 gps location low outdoor small http://www.citeulike.org/user/dcastro/article/2067671 <i>Communications Magazine, IEEE, Vol. 45, No. 11. (2007), pp. 136-141.</i> A Scheme for Location-Based Internet Broadcasting and Its Applications J Oh ZJ Haas Communications Magazine, IEEE, Vol. 45, No. 11. (2007), pp. 136-141. 2007-12-06T16:52:00-00:00 2007 Communications Magazine, IEEE 45 11 136 141 location http://www.citeulike.org/user/dcastro/article/1236499 <i>Personal, Indoor and Mobile Radio Communications, 2002. The 13th IEEE International Symposium on, Vol. 2 (2002), pp. 720-724 vol.2.</i><br /><br />Location aware services are becoming attractive with the deployment of next generation wireless networks and broadband multimedia wireless networks especially in indoor and campus areas. To provide location aware services, obtaining the position of a user accurately is important. While it is possible to deploy additional infrastructure for this purpose, using existing communications infrastructure is preferred for cost reasons. Because of technical restrictions, location fingerprinting schemes are the most promising. In this paper we present a systematic study of the performance tradeoff and deployment issues. In this paper we present some experimental results towards such a systematic study and discuss some issues related to the indoor positioning problem. On indoor position location with wireless LANs P Prasithsangaree P Krishnamurthy P Chrysanthis Personal, Indoor and Mobile Radio Communications, 2002. The 13th IEEE International Symposium on, Vol. 2 (2002), pp. 720-724 vol.2. 2007-04-19T08:42:56-00:00 2002 Personal, Indoor and Mobile Radio Communications, 2002. The 13th IEEE International Symposium on 2 720 724 vol.2 indoor location position wireless wlan http://www.citeulike.org/user/dcastro/article/257573 <i>INFOCOM 2000. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings. IEEE, Vol. 2 (2000), pp. 775-784 vol.2.</i><br /><br />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 RADAR: an in-building RF-based user location and tracking system P Bahl VN Padmanabhan INFOCOM 2000. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings. IEEE, Vol. 2 (2000), pp. 775-784 vol.2. 2005-07-16T07:32:08-00:00 2000 INFOCOM 2000. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings. IEEE 2 775 784 vol.2 location system tracking http://www.citeulike.org/user/dcastro/article/1915462 <i>Communications Magazine, IEEE, Vol. 34, No. 10. (1996), pp. 33-41.</i><br /><br />With the advances in wireless communications and low-power electronics, accurate position location may now be accomplished by a number of techniques which involve commercial wireless services. Emerging position location systems, when used in conjunction with mobile communications services, will lead to enhanced public safety and revolutionary products and services. The fundamental technical challenges and business motivations behind wireless position location systems are described, and promising techniques for solving the practical position location problem are treated Position location using wireless communications on highways of the future TS Rappaport JH Reed BD Woerner Communications Magazine, IEEE, Vol. 34, No. 10. (1996), pp. 33-41. 2007-11-14T19:19:07-00:00 1996 Communications Magazine, IEEE 34 10 33 41 communications location wireless http://www.citeulike.org/user/dcastro/article/1915461 <i>Signal Processing, IEEE Transactions on [see also Acoustics, Speech, and Signal Processing, IEEE Transactions on], Vol. 39, No. 12. (1991), pp. 2593-2610.</i><br /><br />The Cramer-Rao lower bound for source localization is studied in the context of multipath stochastic sources, multipath propagation, and observations, in an array of sensors. A general expression is derived and then specialized to simpler configurations and related to results previously reported in the literature. The special case of a single stochastic source in a multipath environment is treated. The relative importance for source localization of the temporal (multipath) and spatial (array baseline) structures of the incoming wavefield is assessed. It is shown that for an array of <e1>K</e1> sensors the multipath contribution to the Fisher information matrix can be interpreted as the contribution of <e1>K</e1> independent arrays whose size depends on the number of spatially resolved replicas. The degradation due to unknown source spectra is analyzed. When the source spectrum is completely arbitrary, source location is not possible with a single sensor. If a parametric form of the source spectrum is available, the multipath structure can be used to locate the acoustic source Cramer-Rao bound for location systems in multipath environments MJD Rendas JMF Moura Signal Processing, IEEE Transactions on [see also Acoustics, Speech, and Signal Processing, IEEE Transactions on], Vol. 39, No. 12. (1991), pp. 2593-2610. 2007-11-14T19:18:44-00:00 1991 Signal Processing, IEEE Transactions on [see also Acoustics, Speech, and Signal Processing, IEEE Transactions on] 39 12 2593 2610 cramer-rao environment location multipath systems