A SYNTHESIS OF A SPATIAL METHOD FOR DETECTING ACTIVE AND SEMI-ACTIVE RADIO-BASED DEVICES FOLLOWED BY PROCESSING OF THE PROTECTED SIGNAL

Abstract

This paper addresses the problem of developing a spatial method for detecting active and semi-active radio-based devices, followed by adaptive processing of the protected signal under conditions of intense interference and a priori uncertainty regarding radio channel parameters. The relevance of this study stems from the constant increase in the number of specialized technical devices for covert information gathering that utilize broadband, noise-like, and low-observable signals, making them difficult to detect using traditional methods of radio monitoring and spectral analysis. An analysis was conducted of modern methods of spatial signal selection, adaptive interference suppression, and algorithms for estimating the direction of signal arrival in technical information protection systems.

A mathematical model of a two-channel spatial signal processing system based on directional and omnidirectional antennas is proposed. An algorithm for adaptive interference compensation using delayed and difference observations has been developed, which allows for the estimation of spatial selection coefficients and reduces the impact of interference components on the receiver output. Analytical expressions for estimating spatial processing coefficients have been derived, and the algorithm has been presented in vector-matrix form. A block diagram of a receiver with an adaptive spatial detection algorithm and subsequent processing of the protected signal has been developed.

Numerical simulations were performed to investigate the dependence of the signal-to-interference ratio on the angle of incidence of the interference signal. The simulation results confirmed the effectiveness of the proposed method and demonstrated the possibility of increasing the signal-to-interference ratio by up to 10 dB depending on the spatial position of the interference source. It was established that reliable detection of radio eavesdropping devices is ensured at signal-to-interference ratios ≥ (3–6) dB. It has been shown that the proposed method has relatively low computational complexity compared to classical MVDR and MUSIC algorithms, which paves the way for its practical application in information security systems, radio monitoring, and specialized telecommunications systems.

Keywords: signal processing, radio frequency devices, adaptive receiver, interference cancellation, antenna, information security, spatial detection.