摘要
無線感測網路是近年來重要的科技之一，可以應用在戰爭、環境、醫療等方面。ZigBee是無線感測網路的一種，主要是用在工業及醫療應用，利用ZigBee可以傳送人體生理資訊如血壓、心跳、脈搏等，讓醫療人員可以節省繁複的手續；對病人來說可以不用總是待在病房等待著醫療人員來定時檢查。但不是所有病人都是不良於行，只能等待醫護人員檢查，但是若隨意亂跑反而會造成醫護人員的麻煩與負擔。因此在這裡我們提出一個室內定位的方案來讓病人有多一點自由，也讓醫療人員不需陷入找不到病人的情況。 我們測量環境與人體對接收訊號強度的RSSI值所造成的影響，發現到RSSI值容易受環境的多重路徑效應所影響，使將接收到的RSSI值直接轉換成距離時會有很大的誤差。因此我們將接收的RSSI值加權調整以利訊號強度與距離的換算，再加入前次定位點運算來減少人體造成RSSI值的變動。 我們實作定位系統在一個室內環境裡，裡面佈置的參考節點大都只能接收到兩個參考節點的訊號，這是在定位時能得出結果的最低數目，而我們在實際測量後得到了平均誤差約為1.88公尺的成果。
並列摘要
ZigBee is an important technology of wireless sensor network in the era of an aging population and the shortness of medical care workers. ZigBee’s application can reduce burden of medical workers, on measure blood pressure, temperature, and heartbeat. In hospital, patients usually wait workers for regular check, or medical staff not fined the patient lead to delay other patients’ times. In this paper we propose an indoor location system use ZigBee. That patient can get a certain degree of freedom. Let patients not only in the room to wait for checking, but also not worried about patient’s place for medical staff. In our measurements, RSSI values usually effect by environment, like the wall, floor, and human, called the multipath effect. Human body can strengthen RSSI values; this will reduce the accuracy of location. The received RSSI value need using RSSI propagation model convert to distance. But let RSSI values immediately convert to the distance is difficult, because our measurements show RSSI value affected by multipath effect, so we can’t get an accuracy distance. In order to improve the accuracy of using RSSI value, we take human body into consideration to find a set of weighted RSSI values and previous position to get the regulate location point. Our experiment in an indoor environment and set the reference nodes let mobile node usually only two reference nodes signal can receive. Experiment result show the average error is 1.88 meters.