Improved trajectory generation algorithm for terminal area energy management phase

Improve trajectory generation Algorithm of the vehicle in the terminal area energy management flight phase. Height is the independent variable of the 3DOF equation, and dynamic pressure schedule is determined by the ground track length and lateral maneuverability. Subsequently, longitudinal command is computed by propagated algorithm substituted for iterative algorithm under series of fixed roll angles. Finally, the flyable trajectory and its commands are generated by turning ground track into three steps, in order to eliminate the error of heading angle, crossrange and downrange. 3DOF simulation shows that: the algorithm can generate the trajectory and compatible commands, because it is considered of the coupling between longitudinal and lateral characteristics. Furthermore, the fly-back area can be adjusted by changing the dynamic pressure schedule, which can adapt for different initial conditions.