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This article is part of the series Wireless Location Technologies and Applications.

Open Access Research Article

A Constrained Least Squares Approach to Mobile Positioning: Algorithms and Optimality

KW Cheung1*, HC So1, W-K Ma2 and YT Chan3

Author Affiliations

1 Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong

2 Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan

3 Department of Electrical & Computer Engineering, Royal Military College of Canada, Kingston, ON, Canada, K7K 7B4

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EURASIP Journal on Advances in Signal Processing 2006, 2006:020858  doi:10.1155/ASP/2006/20858

The electronic version of this article is the complete one and can be found online at: http://asp.eurasipjournals.com/content/2006/1/020858

Received:20 May 2005
Revisions received:25 November 2005
Accepted:8 December 2005
Published:20 April 2006

© 2006 Cheung et al.

The problem of locating a mobile terminal has received significant attention in the field of wireless communications. Time-of-arrival (TOA), received signal strength (RSS), time-difference-of-arrival (TDOA), and angle-of-arrival (AOA) are commonly used measurements for estimating the position of the mobile station. In this paper, we present a constrained weighted least squares (CWLS) mobile positioning approach that encompasses all the above described measurement cases. The advantages of CWLS include performance optimality and capability of extension to hybrid measurement cases (e.g., mobile positioning using TDOA and AOA measurements jointly). Assuming zero-mean uncorrelated measurement errors, we show by mean and variance analysis that all the developed CWLS location estimators achieve zero bias and the Cramér-Rao lower bound approximately when measurement error variances are small. The asymptotic optimum performance is also confirmed by simulation results.


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