tailieunhanh - Báo cáo hóa học: " A Constrained Least Squares Approach to Mobile Positioning: Algorithms and Optimality"

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: A Constrained Least Squares Approach to Mobile Positioning: Algorithms and Optimality | Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing Volume 2006 Article ID 20858 Pages 1-23 DOI ASP 2006 20858 A Constrained Least Squares Approach to Mobile Positioning Algorithms and Optimality K. W. Cheung 1 H. C. So 1 . Ma 2 and Y. T. Chan3 1 Department of Electronic Engineering City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong 2 Department of Electrical Engineering National TsingHua University Hsinchu 30013 Taiwan 3 Department of Electrical Computer Engineering Royal Military College of Canada Kingston ON Canada K7K 7B4 Received 20 May 2005 Revised 25 November 2005 Accepted 8 December 2005 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 . 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 Cramer-Rao lower bound approximately when measurement error variances are small. The asymptotic optimum performance is also confirmed by simulation results. Copyright 2006 Hindawi Publishing Corporation. All rights reserved. 1. INTRODUCTION Accurate positioning of a mobile station MS will be one of the essential features that assists third generation 3G wireless systems in gaining a wide acceptance and triggering a large number of innovative applications. Although the main driver of location services is the requirement of locating Emergency .