全球衛星定位系統的完善建置使衛星導航系統得以普及於民用車輛中，駕駛人不必事先查詢交通路線即可輕鬆上路。然而存放道路資訊的資料庫其內涵數據量龐大，使用者通常每隔半年、甚至數年才對其更新。所以導航系統建議的駕駛路徑無法根據現有路況做出即時反應，也因此導致駕駛人可能被指引、駛上一條無法通行的道路。 即時路況資訊的收集與應用則被期望能解決此類問題而被廣泛的討論。在台灣政府與民間企業的投入後也開始出現一些相關的服務與產品實作。然而即時路況資訊卻受限於成本高昂、取得不易等不利因素，至今尚未成為普遍的解決方案。 本研究提出在極少量資訊下完成替代路徑的選擇，使得導航系統得以根據當前位置建議駕駛人駛離原先的導航路徑，快速繞離無法通行或不利行駛的道路的五種解決方案。除了僅需少量資訊外，此五種解決方案皆採用簡單啟蒙式策略，以期能快速銜接、適應於當今已普及、計算能力較低落的車載導航系統中，解決繞路導航的問題。在本論文的最後更以改自VanetMobiSim的逼真模擬器進行充分的實驗測試與分析探討。模擬的結果顯示本研究提出的五種方法皆能有效的改善車輛繞路所需的時間，並且同路探索是其中表現較為優異的一個。 The GPS navigation system has been widely adopted nowadays to help guide the driver on the road. Because of the large size of the road spatial database, the update frequency of the road database in the navigation system is low in general. As the result, the recommended path of the navigation system sometimes is not accurate. In addition, it is difficult for the navigation system to react to changes of road condition in real time. To resolve this issue, real time road traffic information has been discussed and collected/implemented by government agencies and industries. However, such a resolution is expensive and difficult to access by most people. So far, it is not a common practice. In this thesis, we propose to find alternative paths in the navigation system by means of very little information. Based on the current location, our algorithms are able to recommend the driver to detour to farther alternative paths and shorten the time of travel. The simplicity nature of our algorithms is suitable for low-end navigation devices, which have only limited computing capability. We analyze our algorithms by extended simulations conducted on top of a simulator developed from VanetMobiSim. The simulation results show that all of our proposed strategies can effectively reduce the amount of time for detouring.
