A Simple Explicit Guidance Scheme Based on Velocities-to-be-Gained

In this paper, a closed-loop strategy in the vertical plane is derived in order to determine the thrust direction of a launch vehicle in terms of velocities-to-be-gained. the two velocities-to-be-gained are utilized, here, for a given altitude and zero vertical speed in a specied nal time the formulation is obtained for constant gravity assumption, but it works when the velocities
to-be-gained are obtained for a spherical-earth model via explicit or implicit relations