An alternative method of entry trajectory design for suborbital launch vehicle

Design of entry trajectory is primary for SLV's (Suborbital Launch Vehicle) return to the landing site in safety. Entry trajectory was divided into initial descent phase and transition phase according to the prominence of aerodynamics forces. At the initial descent phase, constant bank angle was employed. At the transition phase, desired height vs. velocity profile was built by a 4th order polynomial, and constraint boundaries were derived through denoting constraints to height vs. velocity space. Coefficients of the polynomial were obtained by meeting the constraints boundaries. Finally, the desired nominal trajectory was achieved after modulating range error to null.