M.B. Ryzhikov1, A.R. Bestugin2, Y.A. Novikova3, I.A. Kirshina4

1−4 Saint-Petersburg State University of Aerospace Instrumentation (Saint-Petersburg, Russia)

The tasks of conducting search and rescue operations or moving cargo from the developed territories, including over the arctic seas and deserts, can be realized with the help of unmanned aerial vehicles. At the same time, the task arises of automatically choosing a route to ensure flight safety in difficult weather conditions. To do this, you can use an on-board radar. At the same time, there is a problem of working in the presence of input signals reflected from weather formations that have a large range of power changes depending on the range. If no mechanisms are provided for controlling the gain control in the receiving path, then distortions occur both when evaluating radar reflectivity and when evaluating the width of the spectrum of wind flows, which negatively affects the correctness of the hazard assessment for the flight of the probed air areas.

This article presents a justification for the selection of initial data that meet the requirements for international standards for weather locators on the one hand, but on the other hand, they say that these requirements cannot be extended to the polar latitudes, where clouds have their characteristic radar reflectivity and geometric dimensions. For antennas with a symmetrical round shape of the main beam, the conclusion of those mathematical relations is given to obtain the final dependences of the required set attenuation on attenuators in the receiver in times or in decibels from the range or from the range secret number and its size. Based on the analysis carried out, it can be said that in the case of detecting a standard thunderstorm cell and in the case of sounding an arctic cloud, there are two laws for adjusting the gain at different ranges. At short ranges, they are identical in mathematical notation, but differ in the parameters characterizing the Arctic cloud and the standard thunderstorm cell, at the second range they differ in the form of mathematical notation.

The presented studies suggest the absence of re-reflections from the Earth's surface, since it is assumed that the level of the side lobes of the radiation pattern in the weather radar is better than the minimum recommended level in international standards. The obtained ratios and the results of theoretical analysis can be used in the development of weather radar software to improve the detection conditions and increase the accuracy of assessing the danger of dangerous weather phenomena for flight.

Ryzhikov M.B., Bestugin A.R., Novikova Y.A., Kirshina I.A. Temporary automatic gain control in a weather radar when a signal is reflected from a standard thunderstorm cell or from an arctic layered-rain cloud. Electromagnetic waves and electronic systems. 2023. V. 28. № 2. P. 21−28. DOI: https://doi.org/10.18127/j15604128-202302-03 (in Russian)

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