3DOF ascent phase trajectory optimization for aircraft based on adaptive Gauss Pseudospectral Method

3DOF ascent phase trajectory optimization problem for minimum fuel-to-climb is investigated in the research. The Gauss Pseudospectral Method (GPM) and adaptive strategy is proposed to transcribe the trajectory optimization problem into a Nonlinear Program Problem (NLP). Then, the Sequential Quadratic Programming (SQP) integrated in a sparse nonlinear program solver named SNOPT is used to solve the resulting NLP problem with a proper initial guess. The optimality of the ascent trajectory is also checked via Bellman's principle. The simulation results demonstrate that the method can generate a feasible 3DOF ascent trajectory with all constraints satisfied.