基於幾何特性輔助的無線定位演算法

Abstract

近幾年來，無線定位估測吸引了許多領域的研究目光，而以網路架構為基礎，利用發送訊號來作為移動者和基地台間彼此的溝通方式，這種定位方式更被廣泛的應用。在以往的研究方式，二階最小平方定位法 (two-step Least Square Estimation)廣為大家所應用的一種，並提供了移動者有效的定位計算。但是此種演算法在不好的幾何環境下會使精準度產生偏差，利用兩種幾何的指標：幾何衰減效應(GDOP)和幾何量測優勢分析(GDOP MOM)，作為本篇論文的分析標準。在文章 中，我們建立了幾何輔助演算法(GALE)，藉由基地台和移動者間的幾何相關位置，來達到使GDOP 和MOM 這兩個幾何指標最小值的方式，藉由two-step LS 重新找出虛構的基地台群集。幾何輔助演算法(GALE)演算法尤其用在較差的幾何特性時能大大的提升了two-step LS 的定位精準度，並且節省了量測時間，在最後一章節的模擬分析中，可以發現GALE 在網路定位環境中的優越點。

In recent years, wireless location estimation has attracted a significant amount of attention in different areas. The network-based location estimation schemes have been widely adopted based on the radio signals between the mobile station (MS) and the base stations (BSs). The two-step Least Square (LS) method has been studied in related research to provide efficient location estimation of the MS. However, the algorithm results in inaccurate location estimation under the circumstances with poor geometry property such as two indexes, the geometric dilution of precision (GDOP) and the GDOP measure-of-merit (MOM). In this paper, the geometry-assisted location estimation (GALE) schemes are proposed by considering the geometric relationships between the MS and its associated BSs. According to the minimal GDOP and MOM criterion, the BSs are fictitiously repositioned and are served as a new set of BSs within the formulation of the two-step LS algorithm. The proposed GALE schemes can both preserve the computational efficiency from the two-step LS method and obtain precise location estimation under poor geometric environments. Comparing with other existing schemes, numerical results demonstrate that the proposed GALE algorithms can achieve better accuracy in wireless location estimation.