Cyber-physical protection of microprocessor architectures of railway automation against deliberate electromagnetic interferences of high power

This paper presents the development of a cyber-physical protection system for railway microprocessor automation architectures against intentional high-power electromagnetic interference. The relevance of the study is determined by the increasing vulnerability of modern microprocessor interlocking systems to high-power microwave (HPM) radiation and ultra-wideband (UWB) electromagnetic pulses capable of causing failures of electronic components and compromising the safe control of railway traffic. The objective of the research is to develop an intelligent protection architecture that integrates structural electromagnetic shielding with an Edge Artificial Intelligence (Edge AI) module for rapid detection of hazardous electromagnetic events and initiation of protective actions. Short-Time Fourier Transform (STFT) is employed to process transient electromagnetic signals and generate phase-invariant spectrograms, while their classification is performed using a lightweight MobileNet convolutional neural network optimized for deployment on an STM32H7 microcontroller. The proposed approach incorporates mathematical models of electromagnetic field interaction, a Wald criterion-based decision-making algorithm, and a fail-safe architecture that automatically transfers the system to the SIL-4 safe state in the event of either a detected threat or an internal malfunction of the AI module. Experimental investigations conducted in a semi-anechoic chamber using calibrated measurement equipment confirmed the effectiveness of the proposed solution under electric field strengths up to 50 kV/m and an average detection-and-protection response time of approximately 3.1 ms. The scientific novelty of the research lies in the integrated application of spectral signal analysis, Edge AI technologies, and functional safety principles for protecting critical railway infrastructure against intentional electromagnetic attacks. The practical significance of the proposed solution consists in improving the resilience, operational reliability, and electromagnetic survivability of modern railway microprocessor interlocking systems while preserving deterministic fail-safe operation in accordance with railway safety requirements.