On-board radar complex for high-precision direction finding of radio sources for autonomous guidance of winged UAVs

Abstract

The subject of this article is the design of a cheap, simple, and highly accurate on-board radar system for determining the angular position of radio-signal emission stations, which can be used to guide UAVs to a specified area of space. The aim of this study is to develop high-precision functioning algorithms, practical recommendations for implementation, and experimental measurements of the main parameters of the onboard radio direction finders of radio radiation sources placed on winged UAVs. Objectives of the research: 1) analysis of the statistical theory of optimization of signal processing algorithms in radar systems; 2) synthesis of direction-finding algorithms for radio measurement sources capable of performing measurements with high accuracy and in a wide range of unambiguous measurement angles; 3) synthesis of the radio direction finder structural scheme and its simulation modelling; 4) design of radio direction finder receiving antennas capable of operating separately and in a complex; 5) justification of the choice of components for the input paths of receivers, parameters of ADC and microcomputers that make up the main components of the radar complex; 6) manufacturing of a working model of the radar complex; 7) experimental measurements in the laboratory. The methods for solving the tasks are based on the statistical theory of optimization of radio engineering systems for remote sensing and radar, existing software tools for simulation modelling, and the theory of radio measurements. The main idea behind creating a cheap, simple, and highly accurate on-board radar system for radio emitter direction finding is to combine the results of angular position measurements from several amplitude and phase meters. This approach allows us to create an easy-to-implement radio system with the advantages of different measuring instruments. The following results were obtained: 1) theoretical studies and simulation modelling confirmed that by combining measurements from a two-antenna amplitude direction finder with narrow diagrams, a two-antenna direction finder with wide diagrams, and a two-antenna phase finder, it is possible to achieve both high accuracy and a wide range of unambiguous measurements; 2) a radar system based on a cheap and commonly available element base was developed; 3) antennas were developed that can be easily installed under the wings of UAVs; 4) experimental studies confirmed the performance of complex signal processing in an on-board six-antenna radio direction finder. The material of this work forms the basis for further experimental development of radio-direction finders for various purposes, opens up opportunities for overcoming the contradiction between accuracy and range of unambiguous measurements, and highlights an additional direction for increasing the autonomy of winged UAVs.