From Airbags to Wheels - The Evolution of GN&C for Entry, Descent, and Landing
No abstract provided
Martin, Alejandro San↗
Engineering topics
Martin, Alejandro San
Publications and source records attributed to Martin, Alejandro San.
Safe Landing on Uncertain Terrain - The Pillars of Europa Lander DDL
No abstract provided
Martin, Alejandro San↗
System for Estimating Horizontal Velocity During Descent
The descent image motion estimation system (DIMES) is a system of hardware and software, designed for original use in estimating the horizontal velocity of a spacecraft descending toward a landing on Mars. The estimated horizontal velocity is used in generating rocket-firing commands to reduce the horizontal velocity as part of an overall control scheme to minimize the landing impact. DIMES can also be used for estimating the horizontal velocity of a remotely controlled or autonomous aircraft for purposes of navigation and control.
Johnson, Andrew↗
Tracking Positions and Attitudes of Mars Rovers
The Surface Attitude Position and Pointing (SAPP) software, which runs on computers aboard the Mars Exploration Rovers, tracks the positions and attitudes of the rovers on the surface of Mars. Each rover acquires data on attitude from a combination of accelerometer readings and images of the Sun acquired autonomously, using a pointable camera to search the sky for the Sun. Depending on the nature of movement commanded remotely by operators on Earth, the software propagates attitude and position by use of either (1) accelerometer and gyroscope readings or (2) gyroscope readings and wheel odometry. Where necessary, visual odometry is performed on images to fine-tune the position updates, particularly on high-wheel-slip terrain. The attitude data are used by other software and ground-based personnel for pointing a high-gain antenna, planning and execution of driving, and positioning and aiming scientific instruments.
Ali, Khaled↗