Technique for Automatic Profiling of Underlying Surface Electric Parameters on the Very Low Frequencies Radio Path

Abstract

Relevance. Information about the electrical characteristics of the underlying surface has a significant impact on the calculations results of the radio tracks energy parameters in the very low frequency band. Currently, various versions of developed digital maps can potentially improve the accuracy of calculations and simplify the operator's activities in the initial data input. However, the capabilities of digital cartography are not integrated into existing forecasting techniques. The purpose of the study is to reduce the number of manual operations during the forecasting of the radio tracks energy parameters in the very low frequency band by developing a technique that allows to automate the input of the underlying surface electrical parameters. Methods. In this study we used methods of mathematical statistics to choose the quantization levels of radio tracks electrical parameters rationally. We used an interpolation method with a given decimation coefficient to obtain an electrical characteristics profile that meets the requirements of the forecasting methodology. Result. We selected the levels and quantization intervals of the underlying surface electrical characteristics which are needed to obtain the horizontal profiles, using statistical estimates. Further, we performed interpolation with the «nearest neighbor» method with a given decimation coefficient to exclude areas with frequent changes in the profiling parameters values. The decimation coefficient relies on the condition that the smallest length of a homogeneous section should not be less than the wavelength. The developed technique is implemented in the Matlab modeling environment as a combination of scripts and auxiliary functions. We provided an example of the technique application as the forecasting the ground wave field strength on a heterogeneous track. The novelty lies in the development of an original technique that provides rational profiling of the underlying surface electrical conductivity and dielectric permittivity for the subsequent usage of the obtained data in the forecasting the radio tracks energy parameters in the very low frequency band. Practical significance. The developed technique makes it possible to reduce the operator load during the initial data input and increases the accuracy of presenting this data. The technique can be used in a wavehop method for the predicting the radio tracks energy parameters to determine the vector sum of spatial and ground waves at the receiver.