Due to the multivariable and strong coupling flying-wing UAV model with strong-nonlinearity and uncertainty,an attitude control law based on block backstepping for flying-wing UAV is designed.The linear extension state observer of active disturbance rejection control theory is used to estimate the uncertainties. For avoiding the influence of nonlinear effect of drag rudder and time-delay of actuator on system dynamic properties,the function fitting is used to calculate the control signle of the drag rudder,...