ЦИФРОВАЯ ОБРАБОТКА СИГНАЛОВ В ПАССИВНОЙ МНОГОПОЗИЦИОННОЙ РЛС, СОЗДАННОЙ НА БАЗЕ ГРУППИРОВКИ БЛА

Abstract

The expediency of creating a passive multi-position radar based on a grouping of unmannedaerial vehicles is substantiated. The variant of building of such radar is proposed, the main technicalproblems of the sonar developing are evaluated and possible ways to overcome them areconsidered. It is shown that for detecting aerial targets and determining their coordinates fromthe radio emission of on-board equipment, the difference-rangefinder method is the most promisingas it does not depend on signal modulation and is potentially resistant to interference. Forsmall-sized UAV for transmitting information over open radio channels, the typical frequencyranges are 2.4 and 5.0 GHz. A block diagram of a passive multi-position radar has been developed,including digital shapers of the quadrature components of the received signal, blocks fordetecting and determining the coordinates of the target. The main parameters are calculated andanalytical expressions of digital signal processing algorithms for detecting and determining thecoordinates of the target are given. A stroboscopic effect is used in the digital quadrature componentshaper, which allows for bandpass signals to select the sampling frequency not by the upperboundary frequency of the spectrum, but by its width, which significantly reduces the requirementsfor the performance of the ADC and the DSP devices following it. The complex envelopes of thedetected signals are generated by the method of digital generation in the time domain using digitallow-frequency filters. The detection of signals is performed by an energy detector, the advantagesof which are simplicity of implementation and operability in the absence of a priori informationabout the received signal. To determine the coordinates of the radio source, signal delays arecalculated between pairs of signals received by three UAV from a multi-position radar, which aredetermined by the maximum modulo values of the mutual correlation functions of the signals inthese pairs. It is shown that the proposed algorithms are well adapted to the processing of possiblesources of radio emission on board small-sized UAV. It is established that the required performanceof the radar computer for real-time operation does not exceed 84.62 GFLOPS. The designof an on-board antenna module of a passive multi-position radar in the form of a microstrip reconfigurableantenna, tunable in frequency and polarization, is proposed.