Real-time Software Verification Technique of Attitude Determination and Control System for CubeSat

This paper presents a real-time software verification technique for the attitude determination and control system (ADCS) of CubeSats. The on-board computer (OBC) of the CubeSat is equipped with a single core and limited redundancy, making it essential for reliable software to be installed. In consideration of cost, development time, resources, and manpower, an accessible software verification method is necessary. Based on this point of view, this paper first performs a model-in-the-loop simulation (MILS) using MATLAB, a commonly used software in educational institutions for ADCS design. Based on the designed model, software verification is performed by separating the space environment simulator, which provides dynamic models and sensor measurements, and the ADCS module. RS-232 communication is used for data input and output between these modules, and MATLAB-based software-in-the-loop simulation (SILS) and OBC-based processor-in-the-loop simulation (PILS), which is implemented in a real-time operating system (RTOS), are performed. The validity of the implemented software is verified by comparing the results. The proposed technique was validated by presenting the numerical errors of the SILS and PILS results of the SNUGLITE-II CubeSat ADCS.