Dynamic Guidance of Gliders in Planetary Atmospheres

Abstract

Using dynamical systems techniques, a new algorithm to direct the trajectory of gliders to a preassigned target point is proposed. The algorithm is applicable to any unpowered lift-enabled vehicle (glider) traveling in planetary atmospheres, locally determining the shortest path to the target point. The guidance commands are chosen taking into account the drag and lift coefficients of the glider, with a parameterization based on wind tunnel data. As a proof of concept, the new algorithm has been applied to the guidance of the Space Shuttle during its return flight to Earth. Numerical simulations over a wide range of parameter values have shown that the algorithm is resilient to changes in both the initial conditions and the atmospheric conditions. For a typical gliding flight in the Earth’s atmosphere, from an altitude of 30 km down to 3 km, the margin of error for reaching the target ranges from 20 to 80 m.