無線感測網路主要是利用許多感測節點散佈於環境中，並利用無線傳輸的方式依據每個不同的需求因而產生不同動作。感測節點可以感測資料亦或是傳送資料給資料收集點，由於感測節點再隨機散佈的情形下，大都需要仰賴硬體設備或接收到的封包訊息，來決定感測節點的位置資訊，需要花費額外的時間與成本，而估算的節點位置可能會產生與實際位置相差很大的情況。因此，感測節點的定位問題在無線感測網路中，是一項值得探討的議題。 本篇論文提出一個在無線感測網路的定位機制。我們利用一個移動的參考節點搭載了GPS, 透過所提出的移動方式、廣播方式；並提出環境中未知感測節點的接收方式、透過訊號強度的變換計算距離的方式 (Received signal strength indicator, RSSI)。利用一個移動的參考節點，來涵蓋整個網路環境，進而降低整個需求成本、提升定位的準確度。 Wireless sensor network applications are based on monitoring or managing the sensing area by using the location information with sensor nodes. These sensor nodes are random deployed, so they have to be aware to their location before starting their tasks. Most sensor nodes need hardware support or receive packets with location information to estimate their location, and needs lots of time or costs. It may have a huge error. In this thesis we present a localization mechanism in wireless sensor networks. This mechanism can cooperate with node localization algorithm and mobile reference node moving direction scheme. We use a mobile reference node with GPS to move to the whole environment, and we use RSSI and trilateration to estimate unknown nodes’ location. We can obtain more unknown nodes location by mobile reference node moving. It decreases the energy consumption and average location error.
