Objectives  Aiming at the formation control of multiple vessels in an intermittent communication environment, a coordinated formation control law based on the backstepping method is proposed, and sufficient conditions for formation given to ensure robustness.

  Methods  First, the backstepping method is used to design the control law of vessel formation in normal communication periods, and an error observer is added to eliminate errors caused by the external environment and ensure that the vessels form an ideal formation in normal communication periods. Then the control law is designed for the missing period of communication in an intermittent communication environment. In addition, during the initialization and maintenance of the vessel formation, communication duration must meet certain requirements. Therefore, sufficient conditions are given to realize formation in an intermittent communication environment. The stability of the formation control law is verified by the Lyapunov theory, and the reliability of the given sufficient conditions is proven.

  Results  The simulation results show that by using this control law and satisfying the given sufficient conditions, vessels can realize formation in an intermittent communication environment.

  Conclusions  In the case of intermittent communication or similar periodic communication absence, the results of this study have certain reference value for the design and research of vessel formation control.