Integrated Inertial Navigation System/Global Positioning System (INS/GPS) for automatic space return vehicle

A digital GN&C system that automatically returns a space vehicle from orbit to a precision touchdown/landing is described. It is demonstrated that a capsule or lifting body manned return vehicle (MRV) with integrated INS/GPS (inertial navigation system/global positioning system) provides a highly autonomous and automatic deorbit, entry, and precision landing capability. Simulation results are used to demonstrate automatic MRV landing feasibility using absolute GPS for a vertically landing capsule vehicle and the feasibility of using integrated differential GPS/INS to provide the accuracy for a lifting body to perform a safe runway landing without needing TACAN (tactical air navigation) or microwave landing system (MLS) navigational aids. Testing of an advanced system using differential GPS/INS is expected to provide an extensive database on GPS/INS system accuracies and to demonstrate a lower cost alternative to TACAN, DME (distance measuring equipment), and MLS navigation aids