ESA GNC Conference Papers Repository

Altimeter for planetary lander
C.P. Costa Pinto, A.M. Marques, O.D.M. Dubois-Matra
Presented at:
Salzburg 2017
Full paper:

This paper abstract is aiming the topic EXPLORATION MISSIONS. The need for landing control is getting more and more required as long as space bodies are being explored. While the best would be to get an image and react upon it, as these require heavy computation, it is faster hence more reliable to use approach sensors such as altimeters. RADAR altimeter and LIDAR altimeter are two of the approach sensors that can be used while landing in celestial bodies. The task of central computing units is made easier by using distributed computing with microcontrollers. They allow for direct information regarding range or speed. They allow processing information such as averaging and filtering absurd data. They allow for alarm generation or direct triggering events. Microcontrollers also can perform embedded activities that otherwise would need hardware that imply additional volume, mass and power consumption. This paper will describe a two altimeter solutions aiming a MARS mission based on a RADAR FMCW principle and another using ToF LIDAR making use of microcontroller capabilities. A best mix of functions, with the usage of hardware in the front-end and letting the base-band in the 'hands' of the microcontroller is the example of the above. The most interesting part of the RADAR approach is the adaptive solution defined as servo. This solution allows for RF hardware simplification, hence saving volume, mass and power, which are demands always present. The LIDAR solution is presented as an alternative that is expected to be more effective in certain regions of a mission.