Z.F. Shaidulin1, I.V. Demichev2, D.A. Lukichev3, V.A. Ognev4

1−4Military university of Radio Electronics (Cherepovets, Russia)

Determination of the position parameter «range» in the theory of single-position determination of location (DoL) of radio emission sources (RES) of the high frequency range (HF) is inextricably linked with the description of the radio wave propagation (RWP) trajectory in the ionosphere. Ray representation is traditional, in which a ray at each point in space coincides with a vector that determines the direction of wave propagation and is perpendicular to the surface of constant phases of an electromagnetic wave (EMW). It is quite easy to estimate analytically the trajectory of the RWP and this way due to Smith's trajectory calculations based on the theorem on the equivalent path of a wave in the ionosphere. The equivalent trajectory makes it possible to determine the angles of the wave incidence on the ionosphere, the angles of elevation and arrival of the wave from the known values ​​of the effective heights. However, this approach is valid for an isotropic medium. In addition, the results of the experiment on reconstructing the height profile of the electron concentration indicate that the average modulus of the absolute error in determining the effective reflection height by various methods leads to unsatisfactory indicators of the accuracy of estimating the range to the RES. In the interests of the integrated development of single-position DoL systems of the HF range RES, to propose a method for reconstructing the RWP trajectory in a three-dimensionally inhomogeneous anisotropic ionosphere, which makes it possible to estimate the spatial parameters of the source.

The article considers a method for reconstructing the RWP trajectory on the basis of models of an arbitrarily polarized EMW, a flat-layered and anisotropic propagation medium using the algebra of quaternions has been developed, which makes it possible to determine the spatial-polarization parameters of the received HF radio wave at the entire stage of ionospheric propagation.

For a qualitative assessment of the method efficiency, simulation modeling of the accuracy of estimation of the RWP trajectory at various elevation angles and states of the ionosphere was carried out. The following have been determined: the regularity of the RWP trajectory estimation accuracy on the distance to the RES for various values ​​of the mean square error in measuring the reflection height; the gain in the accuracy of determining the range to the RES, provided by the developed method in comparison with the traditional one; requirements for the input data of the method to achieve optimal values ​​in the accuracy of estimation of the RWP trajectory. Due to a fundamentally new approach to measuring the parameters of the electromagnetic field in a three-dimensionally inhomogeneous anisotropic medium, based on the joint representation of the spatial-temporal dependences of changes in the parameters of radio wave polarization in hypercomplex space, a method has been developed for reconstructing the RWP trajectory in the ionosphere, the implementation of which makes it possible to potentially increase the accuracy of the HF range RES DoL.

Shaidulin Z.F., Demichev I.V., Lukichev D.A., Ognev V.A. Reconstruction of the radio wave trajectory in a three-dimensionally inhomogeneous anisotropic ionosphere based on the spatially polarization parameters. Electromagnetic waves and electronic systems. 2022. V. 27. № 2. P. 12−18. DOI: https://doi.org/10.18127/j15604128-202202-02 (in Russian)

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