Star-Tracker-Constrained Attitude MPC for CubeSats

TL;DR

This paper introduces a linear MPC framework for CubeSat attitude control that ensures star-tracker availability during ground-target tracking, offering computational efficiency and compatibility with aerospace software.

Contribution

The paper develops a linearized, quadratic-program-based MPC method for CubeSat attitude control that maintains star-tracker functionality and reduces online computational complexity.

Findings

The proposed MPC maintains star-tracker availability during maneuvers.

Simulation results show lower computational load compared to nonlinear MPC.

Performance is validated in high-fidelity nonlinear simulations with varying conditions.

Abstract

This paper presents an online linear model predictive control (MPC) framework for slew maneuvers that maintains star-tracker availability during ground-target tracking. The nonlinear rigid-body dynamics and geometric exclusion constraints are analytically linearized about the current state estimate at each control step, yielding a time-varying linear MPC formulation cast as a standard quadratic program (QP). This structure is compatible with established aerospace flight-software practices and offers a computational profile with lower online complexity than comparable nonlinear MPC schemes. The controller incorporates angular-rate, actuator, and star-tracker exclusion constraints over a receding horizon. Performance is assessed in high-fidelity nonlinear model-in-the-loop simulations using NASA's "42" spacecraft dynamics simulator, including a Monte Carlo campaign over varying target geometries and inertia perturbations.