Abstract: A distributed time-cooperative three-dimensional guidance method based on nonlinear extended state observer is proposed for the simultaneous attack of powerless flight vehicles with time-varying velocity. The complex leading angle of flight vehicle is defined to deduce the simplified relative motion equation，and the relative distances between flight vehicle and target and the approaching velocity are selected as the coordination variables. Considering the time-varying velocity of flight vehicle in practical situation, the modeling error of velocity change rate and the external interference are taken as the disturbance, which make up for the shortcomings of the existing methods that restrict the velocity strictly to a constant velocity. The nonlinear extended state observer is designed to estimate system disturbances, and the consensus control protocol with disturbance estimation is demonstrated to guarantee the bounded consensus of all flight vehicles' attack times. For an angle between the velocity direction and the line of sight direction always existing in the time-cooperative guidance law based on the control protocol, the time-cooperative guidance law is switched to the finite-time convergent guidance law to ensure the final guidance accuracy and attack effect when simultaneous attack is basically realized, and the fuzzy logic rules are used to achieve the smooth connection of the two guidance laws. The effectiveness and advantages of the proposed distributed time-cooperative guidance method are verified by using the simulated results. Key

Key words: multipleflightvehicles, time-varyingvelocity, time-cooperativeguidance, guidancemethod, consensus, distributedcommunicationtopology