APPROXIMATE ALTITUDE TRANSITIONS FOR HIGH-SPEED AIRCRAFT

In a previous paper, a near optimal guidance law for the ascent trajectory from Earth surface to Earth orbit of a hypersonic, dual-mode propulsion, lifting vehicle was derived. The energy-state approximation was used to determine the near-optimal flight path and the operation of the propulsion system. In this paper, the problem of the instantaneous attitude transitions that occur in energy-state approximation is addressed. The approach is to model the transitions as a sequence of two load factor-bounded paths (either climb-dive of dive-climb). The precise location of the transition is determined from analysis of the boundary layer equations associated with the energy-state dynamic model.