| 摘要: | 隨著全球衛星定位系統（GPS）與全球導航衛星系統（GLONASS）逐步增加新的頻段和更新衛星，以及伽利略（Galileo）、北斗二號（CNSS）、準天頂衛星系統（QZSS）與歐洲同步衛星導航覆蓋服務（EGNOS）等新興衛星導航的建置，全球導航衛星系統技術已日趨成熟。近幾年來全球導航衛星系統的存在也更為人所知，並已經逐漸成為全球最重要的導航系統。由於全球導航衛星系統接收器的成本大幅降低，其應用領域也越來越廣泛，也同樣刺激手機內建全球導航衛星系統接收器和定位服務的需求。如個人導航裝置(PND)及手機等產品都將全球衛星定位系統功能納入其中，希望能提供個人用戶多樣的行動定位服務(LBS)。 然而，當在建築物密集的都市範圍、室內區域或是存在非直視性傳輸 ( NLoS ) 的環境，因為任何一種衛星系統存著直視性傳輸 ( Line of Sight, LoS ) 限制，導致定位技術結果會嚴重降低定位的精準度。由於都會區無線區域網路基地台日益普及，過去已有諸多文獻採用廣為應用發展的無線區域網路 ( WLAN ) ，目前文獻的室內定位技術主要有無線區域網路(Wi-Fi)、藍芽(Bluetooth)、無線射頻辨識系統(RFID)、超音波以及超寬頻(UWB)等數種無線技術，這些技術均具可於非直視(NLoS)的條件下運作的特性，因此不會有室內接收不到訊號的問題。而本論文利用IEEE 802.11作為位置評估的解決方式。不幸地，不穩定的訊號強度，導致無線網路定位技術無法提供高精準度的結果，因此影響了實際定位用途，使得定位的設備或是用戶屢次引導錯誤的結果，而無法提供設備或是用戶所在的位置。為了解決這個問題，本論文以一個新穎的室內定位解決方式，提供高精準度的非即時位置的評估。 本論文針對不需要即時性定位的應用，例如儀器設備監控、固定家庭自動化感測器等，提出利用長時間量測之無線區域網路訊號來解決訊號強度的不穩定性並獲得精準定位資訊。With frequency channel expansion, device renovation of global positioning system (GPS) and global navigation satellite system (GLONASS), and the deployment of new satellite navigation such as global navigation satellite system (CNSS), quasi-zenith satellite system (QZSS) and European geostationary navigation overlay service (EGNOS), the outdoor positioning technology has become the well-known navigation system in the world. In recent years, GPS has become the most important navigation system in the world. Moreover, it stimulates the need of cell phone with build-in GPS module. Because the GPS technique is designed for personal navigation device (PND), cell phone and electronic products, and it can provide various kinds of location-based service (LBS) for users. However, the accuracy of satellite-based positioning significantly degrades when the receiver is located in the urban area, i.e., the non-line-of-sight (NLoS) environment, or inside the building. In order to solve this problem, the widely deployed wireless network becomes a potential solution. There are many wireless technologies (e.g., Wi-Fi, Bluetooth, RFID and Ultra-wide-band) could support indoor positioning. This paper chooses IEEE 802.11 wireless local area network (WLAN) technology as the position estimating solution. Unfortunately, the WLAN-based positioning technology usually cannot provide accurate positioning results due to sophisticated environment. Hence the users are frequently misguided and unable to reach the place they want to get. In order to resolve this issue, we propose an indoor-positioning solution to obtain precisely estimated position, which is particularly used for non-real-time applications such as invaluable equipment property monitoring, fixed wireless measuring sensors and so on. This paper proposes the methodology using long-term wireless measurement to prevent the issue of time variance of signal strengths. Therefore, the precise locations of monitored devices could be acquired. |
