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Báo cáo hóa học: " Systematic Errors and Location Accuracy in Wireless Networks"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Systematic Errors and Location Accuracy in Wireless Networks | Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing Volume 2006 Article ID 81787 Pages 1-9 DOI 10.1155 ASP 2006 81787 Systematic Errors and Location Accuracy in Wireless Networks Harri Saarnisaari and Timo Braysy Centre for Wireless Communications University of Oulu P.O. Box 4500 90014 Oulu Finland Received 13 May 2005 Revised 16 March 2006 Accepted 23 March 2006 Wireless systems already provide time delay and signal strength measurements and the future may see antenna arrays that provide directional information. All these maybe used for positioning. Although the statistical accuracy of different positioning methods is well studied the systematic error effects which arise for example from errors in sensor node location network synchronization or the path loss model are not. This study fills this gap providing a unified error-propagation-law-based tool to analyze measurement and systematic error effects. The considered positioning systems which are compared based on the developed framework are the hyperbolic time-delay-based direction finding DF received signal strength RSS and relative RSS RRSS location systems. The obtained analytical results verify our intuitive expectations the hyperbolic methods are sensitive to errors in network synchronization RRRS methods to channel modelling errors whereas DF methods are rather insensitive to systematic errors. However the bias of DF methods is at its largest if the sensor location error is perpendicular to the line joining the sensor and the source. If the methods are compared based on overall accuracy hyperbolic methods may be preferred in large sized networks whereas the DF and RRSS methods may provide better accuracy in small sized networks. However RRSS systems require a dense network in order to provide reliable results. Copyright 2006 H. Saarnisaari and T. Braysy. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use .