異質網路環境之行動搜尋關鍵技術-子計畫四---以感測系統為基礎之整合式室內及室外定位系統

Abstract

摘要：現代人希望能隨時隨地得到充足的周圍環境資訊，例如：道路、店家、氣候、景點等， 由於網路資訊發達，各地的環境資訊，皆可透過網際網路查詢取得大量相關的資訊，但這些資訊 卻不一定是使用者所需要的資料，大量的資訊反而造成使用者的困惑。在許多的應用中，資訊的 價值基本上會和使用者或資訊所在的地點有強烈的相關性，因此定位系統在這些的應用中就顯得 十分重要，而定位系統的準確性及可獲得性即為當中的關鍵性技術。 目前的定位技術，大略可分為室外及室內系統。室外系統以全球定位系統（GPS）為主流，透 過與圖資的整合，可提供使用者路徑規劃及即時道路況等資訊，目前已大量應用在汽車等的導航 系統上，但在室內或隧道中因無法接收到衛星訊號，而無法提供有效的定位資訊。室內系統則以 量測無線頻譜訊號的強度來做為估算量測點與訊號源之間距離為主要依據來進行定位，但由於無 線訊號的多路徑傳輸特性，常造成定位上的誤差。 目前商品化的GPS 設備，其精確度約在三十公尺，雖然在車輛導航系統上，可透過圖資及行 進位移來加以修正，但卻也無法有效的進行平面及立體的車道判斷，此外，若要應用在個人的步 行導航系上，因行人的位移不夠快，無法有效彌補GPS 精確度不足的問題。因此，我們希望透過 整合在個人手持數位設備（如：PDA、GPS）或車載數位系統上的微型感測元件，來分析行人或車 輛的移動，用以提升現有室外之GPS 定位系統及室內無線感測網路定位系統的精準度；此外，利 用無線網路通訊技術，使用者間可以互相交換資訊，讓使用者能夠知道一定範圍內其他使用者的 所在位置及收集相關資訊，我們希望透過資訊的交換可以發展出團隊導航的功能，此項功能可應 用在觀光導覽、車隊路線協調及自動化路況判斷等應用上。 我們主要使用的感測元件有：加速度計、角速度計、電子陀螺儀及磁力計等，希望透過分析 微型感測元件的量測資料及配合現有的定位系統能達成下列四個研究成果：(1)以低廉的成本達到 改善全球定位系統的精確度；（2）提升室內定位系統的精確度；(3)利用無線網路通訊技術，發展 團隊導航功能；(4)以個人定位系統為基礎，開發可還原汽車運動軌跡之車輛行進記錄器。

Abstract: Due to the convenience of Internet, people eager to grab information available to them. But on the contrary, too many unimportant data decrease the value of information and even confuse people. In many applications, the value of information usually strongly relates to the location of users, and position systems are a key technology for those applications. The accuracy of location information would be the most important issue. Positioning systems can be categorized into two types, indoor systems and outdoor systems. The main technology for outdoor systems is the Global Positioning System (GPS). It is widely used for car navigation systems. But the inaccuracy of the commercial GPS is about 30 meters. Although the inaccuracy can be corrected by the car navigation software, it is not acceptable for personal navigation systems. The indoor positioning systems usually are based on measuring the strength of radio frequency signals. But this approach suffers for the multipath progression problems of radio frequency signals. We can improve the accuracy of indoor and outdoor positioning systems by utilizing embedded tiny sensors in hand held devices. By analyzing data collected from various sensors, we can know the movement of users (or cars), and according to the displacement and direction information, we can reconstruct the walking paths of users or moving tracks of cars. Applying those tracking information, we can improve the accuracy of positioning systems. In this proposal, we would like to use embedded sensors like accelerometers, gyroscopes, magnetometers, etc., to collect movement information. By combining the analysis results of sensor readings and indoor or outdoor positioning systems, we would like to achieve the following four objectives: (1) Improve the accuracy of GPS by applying low cost sensors; (2) Improve the accuracy of indoor positioning systems; (3) Utilize the wireless sensor network technology, we would like to develop group navigation systems. (4) Based on the technology developed for personal navigation systems, we would like to develop equipments that can record sensor readings such that we can reconstruct the movement history of cars from these data.