手持裝置行人追蹤系統

Abstract

為了改進全球定位系統的缺點，例如：定位準確度、室內訊號不良，近年來個人導航系統成為了一個熱門的研究題目。大部份的個人導航系統均以計步器為基礎並利用微機電系統實作，藉由在使用者身上黏貼微機電系統來收集、分析資料，來計算使用者行走的步數、距離及方向，以便追蹤使用者的移動路徑。微機電系統黏貼的位置可分為：腳或腳踝、腰間、手持…等，由於使用者的手會產生不規則的抖動或振動，因此實作手持裝置定位的難度，相較於其他黏貼位置來得更加困難。 在本研究中，利用微機電系統實作了手持裝置行人追蹤系統，所使用的裝置包括加速度計及磁力計；此系統包含了三個模組：計步模組、步距模組及方向模組。計步模組藉由檢查加速度資訊並抓取步行樣本，來偵測使用者是否有走路的行為，同時濾除使用者手部的振動對裝置造成的雜訊；步距模組利用計步模組所抓取的步行樣本來估算此樣本所對應的步距；方向模組則利用磁力強度和加速度資訊來計算手持裝置的歐拉角和手持角度。 藉由整合上述三個模組的輸出資訊，我們實作了行人追蹤系統。使用者只需手持此系統的硬體裝置（約一般手持裝置大小），系統即可追蹤使用者的移動軌跡並輸出；此系統可應用在各種手持裝置上，進行室內及室外的個人定位；未來將會與全球定位系統整合，以改善全球定位系統之缺點，對於都市、室內及室外的個人導航都相當有幫助，同時也可應用於提供行動定位服務與家庭看護上。

The Personal Navigation System (PNS) becomes a popular research topic recently because people want to improve the shortcomings of Global Positioning System (GPS) such as accuracy and indoor usability. A lot of such systems are pedometer-based system which could be implemented using Micro Electro-Mechanical Systems (MEMS) and attached to different positions on a human body. The handheld pedometer is less than other locations such as foot and waist because the device held by one's hand has more noises and it is more difficult to model the human walking pattern. In this paper, a Pedestrian Tracking System (PTS) is designed for handheld devices and implemented using accelerometers and magnetometers. It is composed of three modules: stepping module, stride module and direction module. The stepping module detects a step occurrence of user through pattern matching in acceleration and filters the noises like shaking and vibrations. The stride module acquires the parameters of a step pattern from stepping module, and calculate the corresponding stride length of the step pattern. The direction module uses magnetic intensity and accelerations to evaluate the Euler angles and holding angles of a device. By integrating the outputs of stepping module, stride module and direction module, the Pedestrian Tracking System is implemented. This system, which can be embedded into cellphones or PDAs easily, is feasible for indoor or outdoor personal positioning with a given initial position. In the future, the PTS could be integrated with the GPS for improving the positioning accuracy of both. It is very helpful for personal navigation in urban areas, indoor and outdoor environments and could be applied in providing location based services and home healthcare, etc.