結合Wi-Fi測距與GPS軌道資訊之室內定位技術

目前較為廣泛使用的定位系統，當屬全球定位系統(Global Positioning System, GPS)，其主要是以接收環繞地球上空的衛星信號進行定位，但其特性上最大的不足點，即為衛星信號的易遮蔽，導致衛星與定位接收器之間的直接信號傳遞出現阻斷，使其在密集的城市建築區內以及室內空間中的定位的表現能力上仍有明顯不足之處。近年來由於無線區域網路(Wireless Local Area Network，WLAN)廣泛的分布與行動運算裝置的快速發展，很多場所都漸以無線區域網路作為其網路架設的解決方案，故利用無線網路來發展定位技術的可行性及需求性也大為提高。本研究以GPS導航定位解算模式為基礎，感測單一Wi-Fi訊號發射裝置（AP）與行動裝置之間的距離，加上透過IGS網站上所取得的4顆GPS衛星資料，產生定位所需之4組觀測量，來達到組合式之WiFi/GPS室內定位作業實驗結果顯示，利用此一組合方式所測試的定位平均成功率可達到83%以上，另可使平面平均定位誤差約3公尺，高程平均定位誤差可小於1公尺。

關鍵字

Wi-Fi ； GPS衛星軌道；距離估測；室內定位

並列摘要

GPS(Global Positioning System) is regarded as an positioning system which is most widely applied. The main function is the process of positioning performed by receiving signals from satellites around Earth. However, the greatest weakness of its features is the insufficient performance in intensive buildings and indoor because the satellite signals between the satellites and the positioning receivers are easily terminated in the signal obstructed area. Because of the worldwide distribution of the technology of WLAN(Wireless Local Area Network) and rapid development of mobile devices in recently years, the possibility of the usage of WLAN in positioning has been increased significantly. WLAN has been gradually regarded as the solution of network establishment in many places so the accessibility and demand for the application of the development of positioning technology has been enhanced significantly. This research is based on the computation model of GPS navigation positioning. The obstructed are calculated by the distance between single WiFi access point(AP) and mobile device and the orbit information of four selected GPS satellite through the IGS(International GNSS Service). The results of the experiment show the average successful rate of positioning is over 83 percents. The average of horizontal positioning error is about 3 meters, and the average of vertical positioning error is less than 1 meter.