Abstract: A multi-stage trajectory optimization method based on Gauss pseudospectral method (GPM) is proposed for optimizing the high-precision trajectory of tactical two-stage booster rockets under multiple constraints. According to the operating characteristic of the two-stage engine, the entire trajectory is divided into four flight phases, such as launching, climb, endurance and attack. In order to improve the accuracy of optimization trajectory near the no-fly zone and enemy fire coverage, the conception of quasi-contact point is introduced, and the trajectory is further subdivided. The connection points are used to ensure the smooth connection between adjacent phases. GPM is used to transform the trajectory optimization problem into a nonlinear programming problem. In order to further improve the computational efficiency and reduce the difficulty of setting the initial value, an iterative strategy based on the initial value generator is designed to achieve the optimization of multi-stage trajectory. Full consideration is given to the various flight characteristics and constraints of rocket in each phase, and the numerical examples are used to demonstrate the merits of the proposed algorithm. The simulated results show that the proposed algorithm has high effectiveness and can get the feasible optimal trajectory. Key

Key words: tacticalrocket, multi-stagetrajectoryoptimization, Gausspseudospectralmethod, quasi-contactpoint, complexconstraint, iterativestrategy