定位技術於各種領域的應用主題已廣泛地研究與討論，近年來隨著無線行動技術與應用概念的加入，室內定位的相關議題也陸續被提出。
本研究的目的在於透過使用主動式 RFID 設備提升室內環境下定位的準確度，並設計一套定位效能上相較於現有主動式 RFID 定位法更為優異的定位法。本研究運用虛擬標籤與經驗法則提出適應性虛擬標籤定位法 (AVTL) 。其中虛擬中點標籤主要為避免參考標籤的佈置密度過高所造成的相互干擾問題進行設計，在不增加實體參考標籤佈置密度下有效提升定位準確度且在虛擬標籤的計算複雜度上相較於 VIRE 定位法來得更低。為了有效提升定位準確度，本研究亦設計歷史經驗輔助機制，藉由佈置於定位環境中的參考標籤之歷史 RSSI 資訊，穩定參考標籤的 RSSI 訊號與標籤異常狀況處理，以期能達到更精確的定位準確度表現。
本研究透過模擬平台與實際測量進行LANDMARC法與VIRE法以及本研究所提出的 AVTL 法進行效能比較，根據實驗結果，本研究所提出的適應性虛擬標籤定位法在定位準確度、定位成功率表現上相較現有定位法皆來得優異，而在定位回應時間上亦較VIRE 法明顯來得省時，為一可有效替代現有 RFID 室內定位法的改善方法。

Positioning systems are one of the key elements required by location-based services. In this paper we use the active Radio Frequency Identification (RFID) devices to enhance the positioning accuracy in indoor environment and propose a localization scheme which performs better than the existing approaches for location estimation.
This paper presents the design, implementation and analysis of a positioning system called AVTL which applies Virtual midpoint tags and Empirical scheme. Virtual midpoint tag is designed to avoid mutual signal interference effect from high density deployment of reference tags. Compared to the VIRE approach, this approach not only improves the positioning accuracy without adding physical reference tags but also performs less computational complexity than VIRE approach. To improve positioning accuracy effectively, we design empirical scheme. This scheme copes with the abnormal behaviors of reference tags and thus makes the RSSI signal become more stable and adaptable. Therefore, the empirical scheme can make the objects locating more accurate.
Finally, we compare the performance of the proposed AVTL, LANDMARC and VIRE through Simulation and Experiment. The results show that the proposed AVTL approach all performs better than the existing approaches in positioning accuracy and success rate significantly. Moreover, the response time of AVTL approach also performs better than VIRE. In this paper, the proposed AVTL approach is more competitive than the existing approaches and can achieve high positioning accuracy via simulation and experiment.

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