DRAG DERIVED ALTITUDE FOR IMPROVED NAVIGATION ACCURACY IN MARS ENTRY DESCENT AND LANDING SYSTEM

Precise on-board navigation accuracy is a key issue for Mars Entry Descent and Landing Systems. During the entry phase, a probe can rely on the Inertial Navigation System, whose performances are limited by: sensor accuracy, initialization at Mars Entry Interface, platform alignment, instability of vertical channel. The vertical channel stabilization is particularly important and drives the altitude navigation accuracy up to the main parachute deployment. This paper shows that the Drag Derived Altitude technique can be beneficially used in Mars entry scenario to stabilize navigation solution and provide an altitude estimation independently of the Entry Interface conditions.