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  • Research Article
  • Open Access

Autonomous Positioning Techniques Based on Cramér-Rao Lower Bound Analysis

  • Mats Rydström1Email author,
  • Andreu Urruela2,
  • Erik G. Ström1 and
  • Arne Svensson1
EURASIP Journal on Advances in Signal Processing20062006:093043

Received: 31 May 2005

Accepted: 11 October 2005

Published: 12 March 2006


We consider the problem of autonomously locating a number of asynchronous sensor nodes in a wireless network. A strong focus lies on reducing the processing resources needed to solve the relative positioning problem, an issue of great interest in resource-constrained wireless sensor networks. In the first part of the paper, based on a well-known derivation of the Cramér-Rao lower bound for the asynchronous sensor positioning problem, we are able to construct optimal preprocessing methods for sensor clock-offset cancellation. A cancellation of unknown clock-offsets from the asynchronous positioning problem reduces processing requirements, and, under certain reasonable assumptions, allows for statistically efficient distributed positioning algorithms. Cramér-Rao lower bound theory may also be used for estimating the performance of a positioning algorithm. In the second part of this paper, we exploit this property in developing a distributed algorithm, where the global positioning problem is solved suboptimally, using a divide-and-conquer approach of low complexity. The performance of this suboptimal algorithm is evaluated through computer simulation, and compared to previously published algorithms.


Information TechnologyComputer SimulationSensor NetworkSensor NodeRelative Position


Authors’ Affiliations

Department of Signal Theory and Communications, Universitat Politècnica de Catalunya, Barcelona, Spain
Department of Signals and Systems, Chalmers University of Technology, Göteborg, Sweden


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© Rydström et al. 2006