Hybrid Navigation System for Spaceplanes, Launch and Re-Entry Vehicles

Abstract

In 2010 the German Aerospace Center (DLR) will conduct the second experiment of the DLR hypersonic SHarp Edge Flight EXperiment Program SHEFEX-2. The purpose is to investigate possible new shapes for future launcher or re-entry vehicles with faceted surfaces and sharp edges and to demonstrate key technologies for re-entry like hypersonic flight control using steerable canard �fins. Accurate control of the vehicle using the canards requires a highly accurate knowledge of the angle of attack and the side slip angle. Both angles can only be derived from the flight path and an attitude measurement. The �first can be achieved using GPS measurements. The second can be provided only by the most accurate Inertial Navigation Systems (INS) because drifts due to launch vibrations exceed the accuracy requirements. Therefore, a star tracker will be used to update the attitude information shortly before entry. The SHEFEX-2 mission describes an entry scenario which is applicable to other entry missions. There is a general need to develop a high accuracy integrated navigation system which can be used for multiple missions. This navigation system should combine the measurements from an inertial measurement unit (IMU), GPS receiver and star tracker with the option to include additional sensors. This paper will describe the concept of the integrated navigation system with a focus on integrating the star tracker into the SHEFEX-2 experiment.