Available at: https://digitalcommons.calpoly.edu/theses/3046
Date of Award
6-2025
Degree Name
MS in Aerospace Engineering
Department/Program
Aerospace Engineering
College
College of Engineering
Advisor
Eric Mehiel
Advisor Department
Aerospace Engineering
Advisor College
College of Engineering
Abstract
This thesis presents the design, calibration, and validation of a low-cost star tracker system and hardware-in-the-loop testbed intended for small satellite applications. The system is composed entirely of commercial off-the-shelf components and integrates both a custom star tracker and a screen-based star field simulator for controlled, repeatable testing. An analytical modeling approach was used in the early design phase to predict system accuracy based on key optical and geometric parameters, informing the selection and configuration of components and guiding the development of calibration routines.
A simulation environment was developed to validate the star tracker software and assess the impact of noise and distortion on centroiding accuracy. Calibration techniques were implemented to estimate key intrinsic parameters, including focal length, principal point, and optical distortion. The testbed was then used to collect real measurements across a range of known attitudes, enabling detailed error analysis and characterization of measurement noise. The final system supports end-to-end validation of star tracker algorithms in both software and hardware and provides a foundation for future testing and integration with the Cal Poly Spacecraft Attitude Dynamics Simulator. After calibration and misalignment corrections, the system provides an improvement over the previous system and is able to perform attitude determination with a mean angular error of 750 arcseconds. An error characterization campaign and analysis conclude that the leading cause of error is uncorrected distortion caused by the screen and imaging optics of the system.