N.Yu. Babanov1, V.I. Esipenko2, V.I. Irkhin3

1,2 Nizhny Novgorod State Technical University named after R.E. Alekseev (Nizhny Novgorod, Russia)

3 UTA Protection Group (Moscow, Russia)

Nonlinear radar has been taking an increasingly important place in Russia and abroad for the last 70 years. There are very few publications on this topic abroad, which can be explained by the importance of the results obtained in the field of expanding and deepening the theoretical and practical capabilities of radar research.

The paper analyzes the effect of electromagnetic wave diffraction on the characteristics of a nonlinear radar, the detection of targets at small angles of location at long distances is significantly degraded, since it is based on the radiation interpretation of radio wave propagation. The effect of shortening of the azimuth beam compared to the azimuth beam width has been experimentally detected, which limits the use of the interference region for calculating target detection zones. This circumstance is explained by the partial influence of electromagnetic waves reflected with a 180-degree rotation of the phase from individual elements of the Earth's surface (facets), i.e. the formation of the so-called “background” aperture takes place. It is shown that the target detection characteristics for these conditions can be improved if the influence of this background aperture is properly taken into account. This circumstance makes it possible to increase the energy potential of a nonlinear radar and optimize the processing of received signals in the azimuth sector of its real aperture of the antenna system. The difference between the propagation of electromagnetic waves in the real aperture of the antenna system compared with the background aperture is noted. Experimental data indicate that the power flux density from the Fresnel zone does not depend on the range. An estimate of the interference zone is obtained, which does not depend on the wavelength, but is determined only by the height of the antenna system and the probability coefficient of the appearance of abnormally large facets. The parameters of the optimal probing signal for excitation of the background aperture are selected. The energy potential of the background aperture is estimated. The coefficient of increasing the incident power on the target is determined, taking into account the effect of the background aperture. The coefficient of increasing the detection range of search objects located on the surface of the Earth's surface is found. The range resolution is estimated.

Babanov N.Yu., Esipenko V.I., Irhin V.I. The influence of the diffraction of electromagnetic waves on the characteristics of NRL. Nonlinear World. 2023. V. 21. № 1. P. 38-46. DOI: https://doi.org/10.18127/j20700970-202301-03 (In Russian)

1. Shtejnshleger V.B. Nelinejnoe rassejanie radiovoln metallicheskimi ob’ktami. Uspehi fizicheskih nauk. 1984. T. 142. Vyp. 1. S. 131-145 (In Russian).
2. Gorbachev A.A., Larcov S.V., Tarakankov S.P., Chigin E.P. Amplitudnye harakteristiki nelinejnyh rasseivatelej. Radiotehnika i jelektronika. 1996. T. 41. № 5. S. 558-562 (In Russian).
3. Vernigorov N.S. Princip obnaruzhenija ob’ektov nelinejnym radiolokatorom. Konfident. 1998. № 5 (In Russian).
4. Finkel'shtejn M.I. Osnovy radiolokacii. M.: Radio i svjaz'. 1983. 536 s. (In Russian).
5. Esipenko V.I., Rodionov Ja.G. Radiodal'nomer s chastotnoj moduljaciej dlja izmerenija rasstojanija do ob’эektov s nelinejnymi rasseivateljami. Nelinejnaja radiolokacija. 2007. № 3. S. 97-101 (In Russian).
6. Bol'shoj jenciklopedicheskij slovar' (In Russian).
7. Radiolokacionnye metody issledovanija Zemli. Pod red. Ju.A. Mel'nika. M.: Sovetskoe radio. 1980. 264 s. (In Russian).
8. Spravochnik po radiolokacii. Pod red. M. Skolnika. M.: Sovetskoe radio. 1976. 456 s. (In Russian).
9. Sovremennaja radiolokacija. Pod red. Ju.B. Kobzareva. M. Sovetskoe radio. 1969. 704 s. (In Russian).
10. Lozhkarev I.A., Parfencev I.V., Zvezhinskij S.S. Dal'nodejstvujushhij nelinejnyj radiolokator dlja prizemnogo monitoringa territorij i ob’ektov. Radiotehnika. 2022. T. 86. № 1. S. 49−54. DOI: https://doi.org/10.18127/j00338486-202201-08 (In Russian).