Ranging and Positioning Accuracy of Indoor Locating System Using Wi-Fi

• Main Authors: Hui-Chi Chen, 陳惠琪
• Other Authors: 張嘉強
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/62543127410919650849

碩士 === 清雲科技大學 === 空間資訊與防災研究所 === 98 === In recent years, the wide distribution of wireless networks and the rapid development of mobile computing devices have made great contribution to the wireless-based positioning services. Based on the most popular of 802.11 standard, the existed wireless network environment can be effectively applied to build the positioning systems and provide the location services. This study is aimed at enhancing the accuracy of indoor locating to provide more accurate trajectory information services. It is designed by using Wi-Fi wireless networks to measure its signal strength and establish an optimal range estimation and correction model for high accuracy indoor positioning. This study collected the received signal strength (RSS) values from each mobile Wi-Fi access point (AP), and determined the signal path attenuation index for 1.7 in the test environment. Through the regression function, a ranging correction model was proposed to transform the RSS values to the range estimates with an effective error reduction from 10.1 m to 1.1 m. The positioning accuracy made at the test sites revealed that the 2D coordinate accuracy is 5.70 m under the probability of 95%, and shows a better performance than a reference accuracy of 9 m. The tests of success rate made along four selected paths also appeared an average of 59% and a best of 89% for Wi-Fi based indoor locating system. However, there is still room for locating using differential operation and non- line of sight observation as their positioning performance is not well as expected.