A Research of Improving Indoor Location System Practicability Based on Active RFID

• Main Authors: Pang-Wei Hsu, 徐邦維
• Other Authors: Woei-Chyn Chu
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/56216564320491773676

碩士 === 國立陽明大學 === 醫學工程研究所 === 96 === In recent years, mobile positioning technology accompanied by the progress and innovation of mobile communications and wireless network technologies advanced rapidly. Because signal conduction of the popular global positioning system (GPS) is influenced by the sheltering of the building, it led to bad positioning accuracy while applying GPS to indoor positioning. Many studies have been conducted in order to solve this problem, such as infrared, ultrasonic wave and wireless radio wave. Due to every technology has its physical characteristics and restrictions, there are merits and demerits respectively while applying. Among them, radio wave technology is the current mainstream. Owing to indoor positioning always being limited by the effect of spacing and environmental factors, they led to unsatisfying efficiency, in terms of lack of standard procedures and cost. It is still a long way from practical realization. Here we utilize the characteristic of rapid and large-quantity tag accessibility and the advantage of cost-efficiency of radio frequency identification (RFID) to explore the practicability of indoor positioning system. This research used active RFID to implement LANDMARC positioning method. LANDMARC utilized the concept of reference tags to demarcate the position of the tracking tags with good positioning accuracy. However there were many faults hide behind its working mechanism. In this study, we analyse the beforehand work of various positioning systems, and find out an optimal model. Besides, we propose a moving average filter method to improve the depletion of signal strength variation. Finally, we achieved using the least amount of tags to cover the largest positioning range, to achieve the cost-down goal and the best positioning efficiency simultaneously. Our results show when using four RF readers with inter- reference-tag distance of 3.2m, we can accurately locate the tracking tag with an average error and the largest error all one of 1.4m. We have improved the depletion of selecting wrong neighbors, and improved the positioning accuracy effectively.