Near-optimal highly robust guidance for aeroassisted orbital transfer

One of the difficulties in aeroassisted orbital transfer vehicle design is the complexity of the guidance scheme, In present aeroassisted orbital transfer guidance schemes, the reference value of the bank angle or the climb rate is determined via a predictor-corrector algorithm so that the desired apogee can be reached after the vehicle exits the atmosphere. These guidance schemes are quite sensitive to parameter dispersion effects due to atmospheric density errors, system errors, navigation errors, and aerodynamic coefficient errors. An innovative guidance scheme, called safety zone guidance, is developed. In this highly robust guidance, the control is not determined by aiming only at the desired apogee; instead, for each altitude-velocity pair, a special value of the path inclination is determined by maximizing the control margin while aiming at the desired apogee during the atmospheric pass. This results in a robust and accurate guidance scheme as shown by extensive numerical tests.