Trajectory Design in Boost Phase of Air-Launched Rocket Based on the Effective Specific Impulse

A new trajectory design method of the air-launched rocket is presented in this paper. A dynamic model of the air-launched rocket is built. In order to make efficient use of aerodynamic force in the acceleration process, a new effective specific impulse is presented to analyze the flight characters of the air-launched rocket, by studying the mechanical energy. And the effective specific impulse is researched to analyze the regularity in the accelerated climbing. The results of analysis are used to guide the design of the trajectory. And then, the trajectory design problem is transformed into an optimal problem of single variable. Simulations are provided to demonstrate the effectiveness of the designed method.