Boost-skipping trajectory optimization for air-breathing hypersonic missile

To improve the range and penetration ability, a boost-skipping trajectory is proposed for the air-breathing hypersonic missile, with its scramjet ignited in break cycle mode. The longitudinal plane motion equations are established including the thrust term of lateral jets, and constraints on path parameters and terminal conditions are modeled. Using hp-adaptive Gauss pseudospectral method, the optimal control problem is transformed into a nonlinear programming problem with a series of algebraic constraints. And then adopting the sequential quadratic programming algorithm, the optimal trajectory is obtained satisfying the constraints. Several simulations and comparative cases are carried out, simulation results illustrate the proposed hp-adaptive pseudospectral method is superior to conventional optimization method on both computing efficiency and accuracy. The range of the missile is significantly enhanced in this optimized boost-skipping trajectory, which is 3.81 times longer compared with the existing level flight trajectory.