Multispectral Imaging Sensors for Asteroids Relative Navigation

TARGET GROUP: ASTEROID NAVIGATION

OBJECTIVES

• To assess the feasibility of exploiting current imaging sensors technologies for the purpose of multispectral-based asteroid relative navigation;

• To determine the mission scenarios in which the multispectral approach produces the most significant improvements.

SUMMARY

Spacecraft relative navigation techniques in proximity of asteroids largely rely on optical measurements taken from mono-cameras. In fact such sensors are passive and provide a wide operative range, generally required by the mission’s operations. On the other hand, the visible imaging requires an adequate surface illumination to get fruitful measurements, posing several constraints to the spacecraft trajectories and operations. The use of multispectral imaging today is present in particular ground applications, such as detection and tracking of targets in the agricultural and military fields. The most common combination of cameras for multispectral imaging is thermal and visual. Concerning relative navigation, thermal imaging is proposed as a method to overcome low-light conditions in visual odometry algorithms by means of non-uniformity correction techniques. Multispectral Visual Odometry (VO) for unmanned air vehicles has been presented and experimentally validated; while other works consider a multispectral SLAM (Simultaneous Localization And Mapping) approach for robot navigation, also confirming experimentally that the information added by the thermal camera improves the performance of the monocular SLAM approach (despite being used as independent, non-stereo sensors). Different techniques for exploiting the multispectral information exist, since the fusion can take place at different steps of the processing. An option consists also in leaving the measurements as separated inputs for the navigation filter, depending on the application.

REFERENCE

https://re.public.polimi.it/retrieve/handle/11311/1191261/672601/PICCM02-21.pdf