GNSS navigation system accuracy requirement for vehicle driving automation

Vehicle driving automation can be realized with a high precision navigation system. The major concern of such automation system is the safety. According to the tunnel concept and Required Navigation Performance (RNP), the safety risk is sum of accuracy, integrity and continuity risks of all components of the whole system. A vehicle automation system using high precision differential GNSS navigation system is subject to continuity and integrity risks caused by so called tunnel penetration events. This paper analyses navigation accuracy requirement that makes these tunnel event related integrity and continuity risks less than preset values. The parameters affecting these continuity and integrity risks are tunnel dimension, the vehicle driving control system error (CSE) and the navigation system error (NSE). The integrity and continuity risk results based on probability density functions of CSE and NSE show that there exists a combination of CSE and NSE accuracy which can guarantee tunnel event related integrity and continuity risks less than preset values