利用虛擬指紋建置法之智慧型天線系統實現精準室內定位技術

隨著無線通訊科技迅速發展，無線區域網路 (Wireless LAN, WLAN) 的終端裝置及無線接取點 (Access Point, AP) 裝置的普及化，WLAN技術已廣泛應用在商務區、學校、機場及其它公共區域，以定位為基礎的服務 (Location-Based Service, LBS) 在商業、公共安全的應用也漸漸地受到重視。室內定位技術之相關應用如：醫療照顧、人員追蹤、緊急救難系統及商場動線導引等，被廣泛提出並予以討論。關於室內定位的估測，許多智慧型定位技術早已被提出，並且可分為幾類。而特徵指紋辨識的定位方法是其中之一，其特點是在離線階段 (offline phase) 建立室內空間的無線訊號參考點 (（reference points, RPs）) 資料庫，並在上線階段 (online phase) 利用無線訊號RP資料庫來估算位置。然而，建置室內無線訊號資料庫是最關鍵的步驟，其中估測位置的準確度與RP的分佈和數量息息相關。一般情況下，收集接收的訊號強度(（received signal strengths, RSSs) ）所需要的時間與“真實的RP”之數量成正比。為減少離線階段整體過程的複雜性，本文提出一種有效率的改進方法，利用已知的訊號傳播模型，在RP的資料庫中，建構出“虛擬”的RP。利用RSS透過訊號傳播模型所計算出的虛擬RP，替代離線階段所收集的“真實”的RP 。本論文提出的方法，不僅可以縮短離線階段的整體收集時間，更能實現高精準度的室內定位成果。使用智慧型天線系統(（Smart Antenna System, SAS) ）的室內定位估測相較於一般的無線接取點 (access point)需要較長的時間，因為SAS經由多個天線組合來收集所有的RSS。透過本文提出的虛擬指紋建置法結合SAS，可以很容易地獲得足夠和有效的RSS，以更有效率的方式建置室內無線訊號的資料庫。實驗結果說明，運作於SAS上的虛擬指紋建置法可於室內無線訊號資料庫中減少33％“真實”的RP數量，並且達到高精準度的定位結果。

關鍵字

區域特徵指紋辨識法；室內定位；智慧型天線系統；位置評估；訊號強度；無線區域網路

並列摘要

Regarding indoor location estimation, many smart positioning techniques have been proposed and they could be classified into several categories. The fingerprinting is one of categories and its features are to build the indoor radio map during offline phase and to utilize the radio map to estimate the location during online phase. Creating indoor radio map is the most critical step, where the accuracy of location estimation depends on the distribution and number of reference points (RPs). Usually, the time required to collect received signal strengths (RSSs) is proportional to the number of ’real’ RPs. To reduce the complexity of offline process, this paper proposes an efficient scheme, which is based on the well-known signal propagation model, to construct ’virtual’ RPs in indoor radio map. The RSSs on virtual RPs are calculated and used to substitute for the training RSSs on ’real’ RPs collected during offline phase. The proposed scheme can not only shorten the collecting time but also achieve high accuracy for indoor positioning. The indoor location estimation using smart antenna system (SAS) also requires longer time to collect all RSS information because of multiple antennas. Combining this scheme with SAS, it can easily obtain enough and valid RSSs information to build the indoor radio map in a more efficient way. Experimental results showed that applying virtual fingerprint construction scheme on SAS can decrease 33% ’real’ RPs in indoor radio map without scarifying the positioning accuracy.

並列關鍵字

Fingerprint ； Indoor Positioning ； Smart Antenna System ； Location Estimation ； Receive Signal Strength ； WLAN

參考文獻

[1] P. Bahl and V. N. Padmanabhan, “RADAR: An In-Building RF-BASED User Location and Tracking System,” Proceedings of INFOCOM, vol. 2, pp. 775–784, April 2000.

[3] P. Prasithsangaree, P. Krishnamurthy, and P. K. Chrysanthis, “On Indoor Position Location with Wireless LANs,” Proceedings of IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC’02), Lisbon, Portugal, Sep. 2002.

[5] J. Hightower and G. Borriello, “Location systems for ubiquitous computing,” Proceedings of IEEE Computer Magazine, No. 34:57–66, 2001.

[6] K. Pahlavan, X. Li, and J. Makela, “Indoor geolocation science and technology,” Proceedings of IEEE Communications Magazine, No. 40:112–118, 2002.

[7] Y. Zhao, “Mobile phone location determination and its impact on intelligent transportation systems,” Proceedings of IEEE Transactions on Intelligent Transportation Systems, No. 1:55–64, 2000.

國際替代計量

利用虛擬指紋建置法之智慧型天線系統實現精準室內定位技術

未授權

主題瀏覽