Spacecraft Attitude Determination System Using Nano-Optical Devices and Linux Software Libraries

Abstract

This paper presents a new spacecraft attitude determination system based on small optical devices and Linux-based software. This technology intends to support nanosatellite operations by providing low-cost, low-mass, low-volume, low-power, and redundant attitude determination capabilities with quick and straightforward onboard programmability for real-time spacecraft operations. The chosen commercial-off-the-shelf optical devices perform sensing and image processing on the same circuit board, and they are biologically inspired by insects’ vision systems, which measure optical flow and/or track objects while navigating the environment. The firmware on the devices is modified here to enable communication with PC/104 form-factor embedded computers running RealTime Application Interface for Linux. Algorithms are developed for operations using optical flow mode and point-tracking mode, and an application programming interface, along with Simulink® S-functions, is created. The performances of the proposed system, used in optical flow mode, point-tracking mode, and a combination of the two, are assessed using a spacecraft simulator at Rensselaer Polytechnic Institute, and they are compared with measurements from the PhaseSpace® motion-tracking system.