Optimal ascent guidance based on direct optimization method

In this paper, an optimal guidance algorithm is proposed for atmospheric ascent. The optimal guidance algorithm updates the reference trajectory to deal with the impact of disturbance by solving an optimal control problem on-board. For the strong nonlinear ascent dynamic, the optimal control problem is transformed into nonlinear programming problem by trajectory discretization. The direct optimization method is implemented for this nonlinear programming problem. Only a segment of the reference trajectory is updated by the optimal guidance algorithm. Due to the small amount of the discrete nodes and the initial guess solution which is close to the optimization solution, the direct optimization method is fast enough to generate a new reference trajectory. Numerical simulation for the Generic Hypersonic Vehicle model and scramjet engine is done for different cases of the aerodynamic coefficient bias. The results show the accuracy and the effectiveness of this optimal guidance algorithm.