Optimized clock synchronization method based on two-way message exchange in FANET

Flying Ad hoc Network (FANET) comprises swarms of flying nodes, typically Unmanned Aerial Vehicles (UAVs), and has been widely used in disaster rescue and military reconnaissance. However, the clock synchronization performance becomes very poor due to asymmetric link delay caused by rapid node movement and random delay in message transmission. To improve clock synchronization performance, this paper proposes an optimized clock synchronization method based on two-way message exchange. Specifically, two follow-up messages are added to the conventional two-way message exchange mechanism in order to estimate the clock offset and link delay variation rate. Then, a Kalman filter is designed to track the clock offset, which can increase the stability of the synchronization and eliminate the influence of random delay noise. Finally, simulation results validate the performance of our proposal and show that the optimized clock synchronization method outperforms the conventional method.