A Real-Time Operating System with GNSS-Based Tick Synchronization

The paper presents a real-time operating system (RTOS) with GNSS(Global Navigation Satellite Systems)-based tick synchronization for loosely coupled distributed cyber-physical systems (CPSs) such as distributed control systems connected with wireless networks or wide-area networks. In CPS, computations directly interact with the physical world with the universal physical time. A precisely synchronized system time is required for high performance control of the physical world. We have developed a RTOS that manages application tasks based on a system time, which is precisely synchronized with UTC (Coordinated Universal Time) provided by GNSS. The RTOS has mechanisms for tick rate compensation, tick phase compensation and system time compensation, which utilize GNSS receiver signals. Embedded computers with the RTOS can synchronously execute application tasks according to the precisely synchronized system time. The precise synchronous execution improves the performance of the control of the physical world.