本論文應用都卜勒效應於車與車之間通訊(V2V)，偵測可能與我們發生碰撞危險的車輛，運用都卜勒效應有快速得到對方車輛行為與訊息，且不需要視覺觀測。過去車輛在地導航目的地，是經由GPS來定位導航，收到當時的資訊已與實際情形有所差異，無法精確定位目標物位置，只能作為輔助功能，對於車輛本身安全，並沒有任何保障。而第五代行動通訊即將來臨，渴望克服許多問題，其中包含智慧控制系統和資料訊號時間延遲，將使精確定位技術進一步提升。如果車輛配備都卜勒雷達可預先評估與其他車輛碰撞情形，在發生碰撞前提出警訊給駕駛員，讓駕駛提前作出更明確安全的反應與決策。我們運用都卜勒雷達的原因是車輛之間能即時傳遞資訊，如:距離、相對速度、等…，所以本論文目的是在十字路口找出沒有剎車且將會與我們發生碰撞可能的車輛。 In this report, the Doppler Effect is applied to vehicle-to-vehicle (V2V) communication to identify the vehicle that may have the most dangerous impact on us by utilizing the results of Doppler effect to fast get other vehicles behavior and their sent messages without implementing any visual observations. In the past a vehicle navigates the location of its destination via GPS and at the time when we receive the information, sent from a moving object, to estimate the object’s location that would be different from the object actual location consequently we could not use GPS to precisely locate a moving object position but only to use it as an assistant apparatus to provide a secondary location information. Also the use of GPS could not provide and guarantee the safety of a vehicle. The emergence of fifth generation of mobile communications (5G) prompts people to eagerly exploit the new system to overcome many problems existing in the current communication systems such as the design of a wisdom control system and the data signal transmission time delay so as to enhance the positioning precision in current available positioning technology. If a vehicle is equipped with Doppler radar then it can assess in advance the possible collision situations incurred from other vehicles, and let the driver consider the situation to make proper decision. The reason to use the Doppler radar is that it enables, the information such as distance, relative speed and vehicle’s status etc. can be instantly transferred among vehicles. The main task of this report is to identify the vehicle at the crossroad that is still maintaining its speed without making de-acceleration that could possibly collide with us.