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Techniques to improve ground-based wireless location performance using a cellular telephone network.

機(jī)譯：使用蜂窩電話(huà)網(wǎng)絡(luò)提高地面無(wú)線定位性能的技術(shù)。

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摘要

The primary objective of this thesis is to seek a ground-based location scheme suitable for mobile positioning in cellular phone networks. To this end, several techniques are proposed to handle issues that may occur in a cellular network and which may deteriorate wireless location performance. These issues include the lack of signal availability due to co-channel interference, the inefficiency in mobile location calculations, and the significant Non-Line-of-Sight (NLOS) errors resulting from multipath propagation. With the IS-95 CDMA pilot signal as an example, signal availability---or hearability---is thoroughly analyzed. The analysis shows that hearability is poor for location purposes. To improve signal hearability, two methods that are known to be effective---the enhanced signal processing method and the idle period down link (lPDL) method---are fully discussed. Another promising solution in poor signal hearability environments is the combination of cellular network-based methods with other positioning methods. As an example, the integration of GPS and a cellular network is proposed. Better location performance can be obtained by epoch-by-epoch Least Squares (LS)-based integration schemes or by Kalman filter-based integration schemes. The position of a mobile handset is normally obtained by solving non-linear equations. However, it represents a high computational burden and may suffer from a convergence problem. To resolve these issues, an enhanced two-step LS solution is proposed for hybrid time difference of arrival (TDOA)/angle of arrival (AOA) wireless location schemes. This method can provide performance which is almost equivalent to that of Taylor-series-based solutions while imposing a low computational burden. Because NLOS errors within time of arrival (TOA), TDOA, and AOA measurements are very large compared to receiver noise, NLOS errors should be mitigated before the measurements are used in the position calculation. Two NLOS error mitigation methods are proposed. One is a distribution function-based method which depends on system redundancy and a high clear intersection density. The other is a channel estimation-based method which mitigates NLOS errors by using only the earliest signal from among all multipath replicas. The effectiveness of all of the proposed methods has been proved by simulation tests, verifying that these methods can be successfully applied in an actual wireless location system design.
機(jī)譯：本文的主要目的是尋求一種適用于蜂窩電話(huà)網(wǎng)絡(luò)中的移動(dòng)定位的基于地面的定位方案。為此，提出了幾種技術(shù)來(lái)處理可能發(fā)生在蜂窩網(wǎng)絡(luò)中并且可能惡化無(wú)線定位性能的問(wèn)題。這些問(wèn)題包括由于同頻道干擾而導(dǎo)致的信號(hào)可用性不足，移動(dòng)位置計(jì)算效率低下以及由于多徑傳播而導(dǎo)致的嚴(yán)重的非視線（NLOS）錯(cuò)誤。以IS-95 CDMA導(dǎo)頻信號(hào)為例，對(duì)信號(hào)可用性（或可聽(tīng)性）進(jìn)行了全面分析。分析表明，出于定位目的，可聽(tīng)性很差。為了提高信號(hào)的可聽(tīng)性，已全面討論了兩種有效的方法-增強(qiáng)信號(hào)處理方法和空閑周期下行鏈路（lPDL）方法。在信號(hào)可聽(tīng)性較差的環(huán)境中，另一個(gè)有希望的解決方案是將基于蜂窩網(wǎng)絡(luò)的方法與其他定位方法相結(jié)合。作為示例，提出了GPS和蜂窩網(wǎng)絡(luò)的集成。可以通過(guò)基于逐個(gè)最小二乘（LS）的集成方案或基于卡爾曼濾波器的集成方案獲得更好的定位性能。通常通過(guò)求解非線性方程來(lái)獲得手機(jī)的位置。然而，它代表了高計(jì)算負(fù)擔(dān)并且可能遭受收斂問(wèn)題。為了解決這些問(wèn)題，針對(duì)混合到達(dá)時(shí)間差（TDOA）/到達(dá)角（AOA）無(wú)線定位方案提出了一種增強(qiáng)的兩步LS解決方案。這種方法可以提供幾乎與基于泰勒級(jí)數(shù)的解決方案相同的性能，同時(shí)又可以減輕計(jì)算負(fù)擔(dān)。由于到達(dá)時(shí)間（TOA），TDOA和AOA測(cè)量中的NLOS誤差與接收器噪聲相比非常大，因此在位置測(cè)量中使用測(cè)量值之前應(yīng)減輕NLOS誤差。提出了兩種減輕NLOS誤差的方法。一種是基于分布函數(shù)的方法，該方法取決于系統(tǒng)冗余和高凈交集密度。另一種是基于信道估計(jì)的方法，該方法通過(guò)僅使用所有多徑副本中的最早信號(hào)來(lái)減輕NLOS錯(cuò)誤。通過(guò)仿真測(cè)試證明了所有提出的方法的有效性，驗(yàn)證了這些方法可以成功地應(yīng)用于實(shí)際的無(wú)線定位系統(tǒng)設(shè)計(jì)中。

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  • 作者

    Ma, Changlin.;

  • 作者單位

    University of Calgary (Canada).;

  • 授予單位 University of Calgary (Canada).;
  • 學(xué)科 Engineering Electronics and Electrical.
  • 學(xué)位 Ph.D.
  • 年度 2003
  • 頁(yè)碼 279 p.
  • 總頁(yè)數(shù) 279
  • 原文格式 PDF
  • 正文語(yǔ)種 eng
  • 中圖分類(lèi) 無(wú)線電電子學(xué)、電信技術(shù);
  • 關(guān)鍵詞

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