Performance of IEEE 802 11 Indoor Positioning System utilizing Kriging Algorithm for Database

Abstract

For the past few years indoor positioning technology has become an important topic in the development of navigation and position systems Indoor positioning services currently can track the location of people or objects and provide more applications in buildings Because Wi-Fi (IEEE 802 11) Access points (APs) are commonly distributed in indoor environments and are the basic equipment in mobile devices Wi-Fi based positioning systems were developed With the rapidly gaining popularity of the IEEE 802 11 standard protocol the main IEEE 802 11-based implementation approaches for an indoor positioning system are either based on the received signal strength (RSS) or signal time-of-flight measurements This thesis utilizes the fingerprinting approach and the time of arrival approach to develop two indoor positioning systems The Department of Aeronautics and Astronautics building at National Cheng Kung University in Taiwan is used as an example to demonstrate the implementation of the IEEE 802 11-based indoor positioning system However to build a fingerprint database requires lots of time As the range of the indoor environment becomes larger labor is increased To provide better indoor positioning services and to reduce the labor required for the establishment of the positioning system at the same time an indoor positioning system with an appropriate spatial interpolation method is needed The advantage of RSS is that signal strength decays as the transmission distance increases and this signal propagation characteristic is used in an interpolated database with the Kriging algorithm in this thesis Using the distribution of Reference Points (RPs) at measured points the signal propagation model of the AP in the building can be built and expressed as a function The function as the spatial structure of the environment can create the RSS database quickly in different environments Thus in this thesis an IEEE 802 11 indoor positioning system based on Kriging fingerprinting method is developed As shown in the experiment results with a 72 2% probability the error of the extended database is under 3 dBm and improves the error of positioning results by 17 9% On the other hand the extended timing measure capability of IEEE 802 11v records the timestamps of the signal transmission and reception into the message frame The signal time-of-flight is evaluated with timestamps and the time synchronization is calculated The extended capability enables the direct use of the time of arrival (TOA) technique and reduces the complication of measuring the signal time-of-flight The TOA based on the IEEE 802 11v protocol standard with an AP-supported IEEE 802 11v is discussed in the thesis as well

Date of Award	2015 Jan 21
Original language	English
Supervisor	Shau-Shiun Jan (Supervisor)