Longitudinal Control System Design Using Gradient Method for a Suborbital Launcher

The aim of this paper is to present a design method for the guidance navigation and control system (GNC) of a suborbital launcher. In order to achieve a symmetric evolution in the vertical plane we start with the decoupled form of the equation of motion. Afterwards these equations are linearized and the extended stability and command matrices are constructed by adding some auxiliary equations. The linear control law is obtained and the control matrix containing the unknown coefficients is presented. The design of the control system is based on a modified gradient method. To illustrate the proposed method the synthesis of the control system in the specific case of the SLT ("Suborbital Launcher for Testing - SLT" financed thru „Programme for Research-Development-Innovation on Space Technology and Advanced Research – STAR”) is presented.