Quasi-equilibrium glide auto-adaptive entry guidance based on ideology of predictor-corrector

A novel quasi-equilibrium glide auto-adaptive guidance algorithm based on ideology of predictor-corrector is proposed for high lifting entry vehicle. The quasi-equilibrium glide condition based on constant flight path angle is adopted. The vehicle heading is adjusted to firing plane using lateral guidance logic firstly, and then the range-to-go is calculated from the terminal position constraint. The needed flight path angle is calculated based on the range-to-go using the analytical relationship between range and flight path angle. The angle of attack is adjusted to control the trajectory to satisfy the quasi-equilibrium glide condition with the needed flight path angle. By the means, the quasi-equilibrium glide auto-adaptive guidance which meets the terminal position constraints is achieved. For the situation with terminal velocity constraint, the control variable bank angle is corrected according to the difference between the expected and predicted terminal velocity which is acquired analytically in each guidance period. The guidance algorithm is validated via a three-dimensional trajectory guidance simulation which results indicate that the quasi-equilibrium glide auto-adaptive guidance performs well.