基於行動電信網路的車速量測之研究

Abstract

智能運輸系統(Intelligent Transportation Systems；ITS)可以利用一些感測器(sensors)或軟體測量道路車速。林、張及皇甫曾提出Lin-Chang-Huangfu(LCH)方法來計算細胞停留時間。它只需要使用行動交換中心(Mobile Switching Center；MSC)中標準計數器的值，而不需要對電信網路做任何修改。本論文藉由推導LCH方法計算出的細胞停留時間(cell residence times)的偏差(bias)來探討此方法的準確性。我們並藉由一些過濾和補償技術來擴充LCH方法應用於車速的估計，並且以台灣桃園縣龍潭鄉國道三號上的車輛偵測器(Vehicle Detector；VD)來驗證我們的方法。我們的研究結果指出LCH方法在車速的估計上是有效的。

Vehicle speeds of roads are often measured by the Intelligent Transportation Systems(ITS) through some sensors or software solutions. Our previous work proposed the Lin-Chang-Huangfu(LCH) scheme to compute the cell residence times by the standard counter values in the mobile telecommunications switches without any modification to the telecommunications network. In this paper, we investigate the accuracy of the LCH scheme by deriving the bias of the cell residence times computed in this scheme. Then we extend the LCH scheme with some filtering techniques for the vehicle speed estimation, and validate our approach with the vehicle detector measurements at National Highway 3, Longtan Township, Taoyuan County, Taiwan. Our study indicates that the LCH scheme is an effective approach for the vehicle speed estimation.