Wireless Subnanosecond Time Synchronization for Moving Platforms

Time synchronization refers to the process of achieving and maintaining coordination among independent clocks via the exchange of local and remote time information. It is of great significance for the stable operation of key infrastructures such as communication, electricity, and transportation. However, existing high-accuracy time synchronization technologies, such as fiber-optic time synchronization, are mainly applicable to static scenarios and are difficult to meet the requirements of dynamic scenarios. In dynamic scenarios, varying multipath error and antenna group delay are the main factors affecting the accuracy of time synchronization. Here, we demonstrate a wireless time synchronization system suitable for dynamic scenarios. The system adopts a signal structure integrating time-pulsed and direct spread spectrum to overcome the near/far problem. Moreover, it utilizes a time-division multiplexing concentric transceiver antenna and a synchronous two-way measurements differential (STWMD) method to eliminate geometrical path delay, thereby not relying on the coordinates and velocities of the transceiver antennas. More interestingly, in experiments, we found that this method can eliminate the impact of multipath error and antenna group delay variation (GDV) on time synchronization, bringing the accuracy of time synchronization in dynamic scenarios into the subnanosecond era for the first time. This work holds great significance and potential in fields such as airborne or shipborne distributed radar and unmanned formation.