ESTIMATION OF METHODOLOGICAL ERROR OF THE HIGH-FREQUENCY METHOD FOR CALCULATING THE SECONDARY RADIATION OF ELECTRICALLY LARGE RADAR OBJECTS

The paper presents the results of estimating the methodological error of the asymptotic high-frequency method for calculating the secondary radiation of electrically large radar objects using the example of a perfectly conducting sphere with a radius of 1 m. To evaluate the accuracy of the high-frequency method, the results of calculating the secondary radiation of the object under study obtained by the strict and approximate methods were compared. Calculations were performed for a frequency of 10 GHz, which corresponds to a wavelength of 3 cm, and for a frequency of 3 GHz, which corresponds to a wavelength of 10 cm. In addition, the influence of the number of elementary sections (triangular flat facets [13]) of the modelling surface on the accuracy of the results was evaluated. As a result of the study, it was shown that the accuracy of the asymptotic high-frequency method for calculating a perfectly conducting sphere with a radius of 1 m significantly depends on the number of facets per unit area λ×λ. By increasing the number of facets, it is possible to approximate the surface of the object of study with greater accuracy and achieve greater convergence of the results obtained by the approximate method with the rigorous one. However, an increase in the number of facets leads to a significant increase in the time required to calculate the characteristics of secondary radiation and develop a research model. In addition, as an example, the influence of the accuracy of calculating the secondary radiation of a perfectly conductive sphere with a radius of 1 m on the maximum radar detection range was assessed and the increase in the number of facets per unit area λ×λ was studied to achieve the required accuracy. It was found that increasing the number of facets for a metal sphere with a radius of 1 m from 80 000 to 1 280 000 in engineering calculations does not significantly affect the maximum radar detection range. Thus, the results obtained in this paper suggest that asymptotic high-frequency methods can be used to calculate smooth perfectly conductive objects of electrically large dimensions with the required accuracy.