E.G. Borisov1, I. I. Gotsko2, O.G. Petkau3, G.L. Pavlov4, V.B. Suchkov5

1-3 JSC “Scientific Research Institute “Vector” (St. Petersburg, Russia)

4,5 Bauman Moscow State Technical University (Moscow, Russia)

1 begspb1967@mail.ru; 2goiw@ya.ru; 3 petkau-oleg@mail.ru; 4 pavlov_503@bmstu.ru; 5 vbs-2014@bmstu.ru

Statement of the problem. Determining the angular coordinates (azimuth and elevation) of ground-based radio sources from various types of aerial vehicles, including those with receiving stations located on loitering unmanned aerial vehicles (UAVs), is a pressing issue. The use of amplitude or phase methods in onboard radio monitoring systems for wide-band ground-based radio sources frequencies necessitates the deployment of complex antenna arrays with large dimensions and weight onboard UAVs. Using the amplitude method, it is difficult to achieve high direction-finding sensitivity over a wide frequency range and achieve high direction-finding accuracy. Therefore, it is necessary to develop a method for determining the azimuth and elevation angles of the radio-frequency emission sources that minimizes the weight, size, and cost requirements for the antenna system of the onboard radio-monitoring system's receiving path, while still ensuring operation over a wide range of frequencies.

Purpose. Development of a mathematical model for assessing the potential accuracy of measuring the azimuth angles and location of a ground source of radio emission by an onboard radio monitoring system located on two loitering UAVs.

Results. This article addresses the problem of determining the azimuth and position angles of a ground-based radio source by a pair of loitering UAVs performing coordinated flight in a circle around a selected center. A mathematical model is developed and new analytical expressions are derived for estimating the potential accuracy of angle measurements using the Cramer-Rao bound. It has been demonstrated that the integrated use of time and frequency parameters can, in some cases, significantly reduce the data accumulation time required to reliably determine the RES elevation angle. The results of numerical simulations for various conditions, including the high-frequency microwave range, are presented, demonstrating the possibility of achieving sub-degree accuracy using weakly directional antenna systems.

Practical significance. The results of estimation the potential accuracy of ground-based radio sources angle measurements can be used in the design of advanced passive radio direction-finding and radio monitoring systems based on small-sized airborne systems. It is shown that ground-based radio source azimuth and elevation angles can be determined using the least-squares method by measuring distance differences and Doppler frequency differences.

Borisov E.G., Gotsko I.I., Petkau O.G., Pavlov G.L., Suchkov V.B. Analysis of the accuracy of determining the angular coordinates of the radio emission source by loitering UAVs using difference-range and difference-Doppler methods // Radiotekhnika. 2026. V. 90. № 8.
P. 104−117. DOI: https://doi.org/10.18127/j00338486-202608-10

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