Investigation into Star Tracker Algorithms using Smartphones with Application to High-Precision Pointing CubeSats

Abstract

For all common satellite attitude determination sensors, star trackers provide the most accurate measurement. However, these devices can be both large and expensive, and for some CubeSat applications it would not be suitable. Star trackers have in the past been successfully made for CubeSats. This paper investigates star tracker algorithms, implemented with a smartphone, so it may be used for testing attitude determination on a CubeSat. By testing through a proposed implementation, star centroids should be found by the moment method, stars should be identified by planar triangles, and QUEST should be used for attitude estimation. Smeared star images should be avoided and blurred images provide greater accuracy. Using these techniques, a star tracker using a smartphone may be constructed for attitude determination testing and software development, applied in the lost-in-space situation. This may be applied to QKD CubeSats, which require an attitude precision below 0.01°.

Autonomous and Earth-Independent Orbit Determination for a Lunar Navigation Satellite System

“…The star tracker is critical to any autonomous orbit determination architecture, and so will be briefly discussed. Given the high number of books and articles in the literature discussing star trackers [29][30][31], the reader is referred to them for further learning.…”

A Return to the Sextant—Maritime Navigation Using Celestial Bodies and the Horizon

“…Star tracker orientation determination for space applications has been well studied for the last 60 years since Apollo, and many models exist to estimate sensor pointing from a sequence of star measurements [ 19 , 20 , 21 , 22 , 23 ]. State-of-the-art systems can deliver attitude accuracies at 1 arc-sec, especially when combined with a gyroscope [ 20 ].…”

“…The estimated accuracy of the star tracker is simulated at approximately arc-sec, as has been demonstrated is obtainable from previous testing. This figure is a conservative estimate and considers the lower-end spectrum of sensors that employ commercial-off-the-shelf components [ 23 ].…”

Treatment of Extended Kalman Filter Implementations for the Gyroless Star Tracker

“…The star tracker is set to a square field of view of 20 • and a stellar magnitude maximum of 5.0. The attitude does not considerably improve with more than 8-10 stars [15,31], so a higher magnitude limit is not necessary.…”

“…The Calculated Reference of Stellar System (CROSS) star tracker is used as a test platform in this article. CROSS is a Wide Field of View (WFOV) star tracker being developed by the University of Sydney that seeks to be a high performing, versatile and competitive attitude determination unit for spacecraft designers [30][31][32].…”