High precision time synchronization between nodes under motion scenario of UAV platforms
Time synchronization is the foundation for transmission resource scheduling,cooperative localization and data fusion in UAV clusters.Two-way time synchronization is commonly used to synchronize time between nodes in scenarios with high synchronization accuracy requirements.However,the relative motion of the UAVs will cause the propagation delays of the two synchronization messages to be unequal,thereby causing time synchronization errors.To solve this problem,the causes of synchronization deviation are analyzed from the perspective of solving linear equations.A method is proposed to increase the number of equations by conducting two-way time synchronization twice,with the number of unknown quantities being reduced under the premise of the uniform motion of nodes.The solution formula for the clock deviation under uniform motion of nodes is derived,and the derivation results show that the clock deviation solution is independent of the speed of the nodes.Synchronization performance is compared with that of existing compensation methods under the additive Gaussian white noise channel.The effect of time stamp deviation and speed changing on the accuracy of the clock deviation solution is analyzed.Finally,the effectiveness of the dual-trigger two-way time synchronization is verified through field experiments.Simulation and experiment results show that,compared with conventional two-way time synchronization,the dual-trigger two-way time synchronization does not cause systematic deviations by the uniform motion of nodes.
unmanned aerial vehiclestwo-way time synchronizationasymmetric transmission delaylinear equations