使用被動式射頻識別反射訊號之車輛定位方法

Abstract

摘要 本篇論文實驗了以無線射頻辨識的技術與設備應用在精準化自身車輛定位的方法。無線射頻辨識的技術已被廣泛運用在生活中，穩定且可靠，例如悠遊卡以及國道收費系統等。本篇論文中使用的是被動式無線射頻標籤，台灣國道收費系統使用的標籤所利用的頻率是922MHz-928MHz。我們在避免影響現有設備運行的考量下，使用的頻率為910MHz。無線射頻標籤與讀取器的互動方式為，先由讀取器發出一段時間的訊號，標籤端以這些訊號為電容充電後，再透過反射讀取器所發出一段平穩的訊號回應讀取器的讀取請求。我們的系統利用此段訊號進行分析，以進行定位。透過分析被動式標籤反射回來的訊號資訊，計算被動式標籤相對於讀取器天線陣列的角度，在這篇論文中我們僅使用了一支讀取器天線來模擬MUSIC演算法中所需要的天線陣列。 在我們的情景中，假設讀取器的天線裝設在公共汽車，透過路邊停車空間的資料庫，我們可以藉由公車汽車行進過程中讀取路邊停車空間內汽車的e-tag資訊，經過計算後取得路邊車輛與公共汽車的相對關係，而行駛中的公共汽車本身具有其自身GPS、速度資訊還有路邊停車空間的位置資料，透過這些資訊的計算，我們理論上可以精準化公共汽車自身的GPS資訊。

Abstract This is a thesis that verified a method to optimize the precision of self-positioning of cars with RFID technology. In our daily life, RFID has already been in use for years. Such as EasyCard and Taiwan High Way Charge System, they’re stable and reliable. We used passive tags in our experiment. The frequency of Taiwan HighWay Charge System is from 922MHz to 928MHz. To avoid interference, our working frequency was set at 910MHz.RFID System works as follows, first, reader sends queries, then tag will charge itself with the power of queries’ signal. And the reader sends a constant wave for the tag to reflex to respond to the queries, which is the signal as data to analysis for positioning in our system. And in this thesis, we use only one antenna to simulate an array of antennas by moving it along the road. We assume the antenna of the reader was put on a bus. And with the database of roadside parking space, we could continuously query the tags on cars that stop in the parking space. With our method, we will get the angles of cars relative to our bus. And our bus has its gps, speed, the position of parking space information. With the information, we theoretically could optimize the gps information of our bus.