Reactivity model of nanosatellite and UAVS embedded computing systems

Ihor Turkin, Oleksandr Liubimov, Lina Volobuieva

Abstract


The embedded computer is a key element of the avionics of both spacecraft and unmanned aerial vehicles (UAVs). Its reactivity determines the system’s ability to ensure that the reaction time to external events meets the specified real-time constraints. This study aims to investigate the reactivity of the microcontroller of the embedded computing system as a component of the overall technical efficiency of the hardware and software complex. The mathematical model of reactivity, as well as methods, tools, and technology for experimental research of the reactivity of a real-time operating system, are the subjects of this study. This study aims to develop and verify a model of the reactivity of embedded computer software for use in nanosatellites and unmanned aerial vehicles. This study substantiated the need to create a set-theoretic model of the reactivity of embedded avionics systems for small spacecraft and unmanned platforms. A constraint analysis (Worst-Case Execution Time, WCET) was performed for typical onboard computer tasks. The requirements for the model were formulated, and its mathematical description and software implementation were developed. Numerical modeling methods were used to verify the simulation results’ compliance in the actual processes in the system. Results. The proposed mathematical model of reactivity considers the stochastic characteristics of event flows and two-stage interrupt processing, allowing the probability of a timely system response to various types of events to be assessed. Experimental verification confirmed the model’s correctness and suitability for analyzing the Boryviter / Falco platform under the control of the FreeRTOS operating system. The scientific novelty lies in the development of a new concept for optimizing the work of the real-time operating system scheduler of UAV and nanosatellites OBC, which is based on a complex mathematical model of energy consumption, computational performance and reactivity of the OBC, which, unlike power consumption control mechanisms in processors with dynamic frequency or voltage regulation, is specifically focused on OBC microcontrollers, in which the frequency and voltage are fixed, and optimization is possible only through the correct choice of the policy for controlling energy-saving modes. Conclusions. The developed model can be used to assess and improve the reactivity of computing systems, including the university nanosatellite Khai-1KA and unmanned aviation systems. Further research is aimed at creating instrumental software for reactivity analysis to support software engineering of new generations of aerospace and unmanned platforms with a high level of autonomy, considering the implementation of AI/ML tools.

Keywords


Nanosatellite; UAV, Onboard Computer (OBC), Software; Reactivity; Reactivity Model

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DOI: https://doi.org/10.32620/aktt.2025.6.12