High Precision Positioning and Accident Detection System for Vehicles in Traffic Tunnel

High-precision positioning of driving vehicle is an important problem in traffic tunnels where GNSS signal is not available. It becomes more and more urgent to solve the problem when ADAS or driverless cars goes into application gradually since the positions of cars are essential parameters for the algorithms of autonomous driving and safe driving in tunnels, where video and radar system of cars may encounter problems caused by weak light, obscured sight and strong reflected radar wave. As a solution to this problem, a high precision positioning system with IEEE 802.15.4-2011 UWB as air-interface was designed and implemented. Based on Decwave’s UWB chip, the system can provide centimeter level positioning precision. However, when utilizing the UWB chip in the tunnel positioning system, efficient solutions have to be found to overcome the limitation of the chip’s transmitting range in a scenario of long tunnel, and to enlarge the system capacity which might decrease seriously as the demand of high positioning rate in a scenario of vehicles with high speed. On the other hand, tunnels are prone to traffic accidents while there is usually lack of surveillance system in tunnels located in remote areas. Aiming at this application, the presented system also implements a functionality of accident detection. System overview, related design issues, key technologies and test results are presented in this paper.