High Frequency Radio Surveillance System

Abstract

The radio system for high frequency spectrum monitoring and signal processing used in direction finding is presented in this paper. This main function is realized using 6-channel HF radio signal receiver. The high degree of flexibility is achieved by the application of antenna multicoupler unit which allows that signals from several antennas may be processed in the system. The system signal processing especially in the demodulator is based on the most modern components of software defined radio. The system is completely developed in the Institute IRITEL applying commercial components wherever such an approach may fulfill the expected performances. The realized development is highly multidisciplinary and specific, especially HF radio signal receiver and the structure of its modules (local oscillator, RF/IF receiver subsystem, demodulator and control block) which is presented in the paper in more details. User handling is simple over intuitive user interface and system functional parameters may be easily changed. Special attention in the paper is devoted to this interface and software control procedures. The designed electrical characteristics are verified by comprehensive set of measurements according to military specifications both for HF radio signal receiver and antenna multicoupler unit and these characteristics are illustrated by several examples. The system is approved for the application in real conditions.