A Low-Cost Attitude Determination and Control System and Hardware-in-the-Loop Testbed for CubeSats

Abstract

Since their initial development in the late 1990s, CubeSats have quickly grown popular due to their relatively low cost and short development period. However, CubeSat launches are prone to failure, with less than half of CubeSats completely fulfilling their mission objectives. To improve mission success, we present a low-cost attitude determination and control system (ADCS) that scales to 1U CubeSats and other small satellites. The ADCS is necessary to point satellite antennae and solar panels effectively and to orient on-board payloads to the target locations, all of which are crucial to a mission’s success.

Modern methods for attitude determination and control rely on sophisticated actuators and sensors, such as reaction wheels and star trackers, that are often unable to be used on CubeSats due to weight, volume, and cost restrictions. Our proposed system relies on simple consumer-grade magnetometers, gyroscopes, and sun sensors to estimate the attitude of the satellite, long with a set of magnetic torque coils for actuation. Additionally, we provide a new method for calibrating on-board sensors that requires less storage space and allows for all parameters to be time-varying. By combining these low-cost sensors and actuators with sophisticated calibration, estimation, motion planning, and control software, we achieve full three-axis attitude determination and control. The system is also completely solid-state, with no moving parts or consumable propellant, greatly reducing the chance of hardware failure.

To further improve the development cycle, we have developed an open-source hardware-in-the-loop simulator to enable rapid testing of ADCS algorithms and other flight software. The result is a robust, open-source development suite for CubeSats that is low cost, easy to program, and reliable.