DECAMETER BAND RADIO MONITORING

Abstract

Relevance and Problem Statement. The success of military operations critically depends on the effectiveness of Radio-Electronic Reconnaissance (RRTR), particularly within the Decameter (3–30 MHz) band used for long-distance communication. The core challenge for tactical RR is critical spectrum congestion and the dominance of far-zone RE (due to ionospheric reflection) over near-zone target RE by several orders of magnitude. Existing radio monitoring methods, which rely on manual or visual-instrumental analysis of signal parameters (fading, bearing stability), exhibit excessively low speed, rendering the detection of short-duration target emissions nearly impossible. Objective. To develop and substantiate automated approaches for the selection of target RE and increasing the speed of RRTR systems in the decameter band, especially when using small-sized receiving antennas. Achieving this objective necessitates the efficient use of a priori information. Research Methods. The proposed methodology is based on sequential band scanning with flow thinning (reduction) of the RE flux submitted for recognition. Thinning is performed using two primary a priori features: 1) frequency channels where target RE are confirmed absent; 2) the source location zone (automated discrimination of far-zone RE). The task of detecting and recognizing target RE in a frequency channel is reduced to multi-alternative detection of random signals under conditions of increased a priori uncertainty (specifically, unknown statistical characteristics of interference). Main Results and Practical Significance. Analysis demonstrates that applying thinning based on the source location zone (near/far) enables a several dozen-fold reduction in the RE flow submitted for detailed analysis. This significantly shortens the scanning time across the entire band and increases the probability of detecting short-duration emissions, which is critical for tactical RR. The proposed approach allows for the development of a radio monitoring complex that satisfies the conflicting constraints on operational speed and hardware costs. Further research is needed to increase the probability of correct detection of new RE, which currently stands at only $P_D \approx 0.3-0.4$ when using the energy principle.