G.G. Vertogradov1, V.G. Vertogradov2, V.Yu. Nesterov3

1,3 Southern Federal University (Rostov-on-Don, Russia)

2 FSUE “Rostov-on-Don Research Institute of Radio Communication” (Rostov-on-Don, Russia)

1 vertogradovgg@gmail.com; 2 v.vitaly.g@yandex.ru; 3 vadnesterov@sfedu.ru

A multichannel wide-aperture HF LFM radio direction finder is used to solve the problem of passive coherent radar to determine the location when an object moving in the Earth's atmosphere is illuminated by LFM signals from a transmitter remote at a distance of about 1400 km. As a result, it becomes possible to detect the object and evaluate the characteristics of the scattered wave: group delay, amplitude and two-dimensional arrival angles.

A scattering model has been developed that makes it possible, based on solving the optimization problem, to perform spatial localization of a moving object in the Earth's atmosphere, to estimate its height and geographical coordinates. It is shown that the solution of the multiparametric problem of estimating the spatial coordinates of an object moving in the Earth's atmosphere by the method of least squares makes it possible to coordinate the measured values of the arrival angles and the relative group delay for the propagation of the scattered field. The article also shows that using the developed approach, it is possible to obtain the characteristics of a moving object at different points in time: geographical coordinates and altitude of the object. The construction of the spatial trajectory of an object provides an estimate of its full velocity vector.

Experiments conducted from 2011 to 2020 show that with the help of an LFM radio direction finder, it is possible to detect and track an object at distances up to 200 km by its scattered radiation.

Based on the simulation results, the spatial positioning of unknown objects in the Earth's troposphere was performed. It turned out that traces of moving objects according to the results of inclined sounding are detected in the conditions of the developed Es layer of the ionosphere. It turned out that traces of moving objects according to the results of inclined sounding are detected only in the conditions of the developed Es layer of the ionosphere. It is established that the cases when the delay of the scattered signal significantly exceeds the delay for the direct Es signal correspond to the illumination of the object by a wave propagating along the section of the transmitter-object route in two hops. Situations where the delay of the scattered signal is less than that of the direct reflected from the Es layer of the ionosphere, the wave illuminating the object propagates in a single hop mode.

It is shown that in some sessions objects move at speeds significantly exceeding the speed of sound.

Vertogradov G.G., Vertogradov V.G., Nesterov V.Yu. Of the LFM radio direction finder of the HF wave to assess the parameters of the use objects moving in the Earth's atmosphere. Radiotekhnika. 2023. V. 87. № 12. P. 32−40. DOI: https://doi.org/10.18127/j00338486-202312-04 (In Russian)

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