V.I. Evseev1, I.O. Kolachev2

1,2 Baltic State Technical University “VOENMEH” named after D.F. Ustinov (Saint-Petersburg, Russia)

1 v.evseev43@mail.ru; 2 kolachev_io@voenmeh.ru

Problem statement. Modern high-resolution radar systems are an integral part of modern information-measuring and control system for remote sensing of the Earth. Radars, as well as any elements of the measuring system, require calibration, a promising means of which is the use of a transponder (active repeater), since it can replace a full-fledged calibration range. This is due to the fact that the repeater allows you to form a set of virtual objects on the radar image by changing the phase structure of the retransmitted signal. However, due to the imperfection of the transponder control algorithms used, images of virtual objects are defocused.  
Goal. Select the characteristics of the radar image of the virtual object, which determines the possibility of its use as a reference for calibration of high-resolution radars, and justify the choice made.
Results. Computer modeling has shown that radar characteristics such as range and azimuth resolution are not effective in assessing the suitability of virtual objects for high-resolution radar calibration. It is established that instead of them, the cross-sectional area of the image of the formed object or the relative level of the first side maximum should be used.
Practical significance. The selected indicators can be used to improve and evaluate the effectiveness of control algorithms and digital signal processing of transponders to expand the permissible range of virtual object removal in which it can be considered acceptable for calibration.

Evseev V.I., Kolachev I.O. Radar images characteristics of virtual objects in transponder as an information-measuring and control system. Radiotekhnika. 2026. V. 90. № 2. P. 129−140. DOI: https://doi.org/10.18127/j00338486-202602-14 (In Russian)

1. Evseev V.I., Kolachev I.O. Tendencii i perspektivy razvitija radiolokacionnyh sistem s sintezirovannoj aperturoj kosmicheskogo bazirovanija. Vestnik obrazovanija i razvitija nauki Rossijskoj akademii estestvennyh nauk. 2022. № 1. S. 28-32. DOI: 10.26163/RAEN.2022.50.41.003 (in Russian).
2. Freeman A. SAR calibration: an overview. IEEE Transactions on Geoscience and Remote Sensing. 1992. V. 30. № 6. P. 1107-1121. DOI: 10.1109/36.193786.
3. Atroshenko L.M., Gorobec N.N., Krasnogorskij M.G., Maljukov V.M. Opyt sozdanija poligonno-kalibrovochnogo kompleksa dlja radiolokatora s sintezirovannoj aperturoj kosmicheskogo bazirovanija. Vestnik Sibirskogo gosudarstvennogo ajerokosmicheskogo universiteta im. akademika M.F. Reshetneva. 2013. № 5(51). S. 30-32 (in Russian).
4. Alekseeva A.M., Lepehina T.A., Nikolaev V.I. Sozdanie i osnashhenie radiolokacionnyh podsputnikovyh poligonov dlja letnyh ispytanij, kalibrovki i validacii kosmicheskih RSA. Radiotehnicheskie i telekommunikacionnye sistemy. 2024. № 4(56). S. 56-66. DOI: 10.24412/2221-2574-2024-4-56-66 (in Russian).
5. Xi M., Feng Y., Lei Z., et al. Geometric calibration of large-scale SAR images using wind turbines as ground control points. International Journal of Digital Earth. 2024. V. 17. № 1. P. 1-22. DOI: 10.1080/17538947.2024.2385080.
6. Evseev V.I., Titov K.I., Kolachev I.O. Voprosy obespechenija kalibrovki radiolokacionnyh stancij v sistemah distancionnogo zondirovanija Zemli. Informacija i kosmos. 2023. № 4. S. 12-24 (in Russian).
7. Evseev V.I., Kolachev I.O. Model' transpondera dlja kalibrovki radara v informacionno-izmeritel'noj i upravljajushhej sisteme distancionnogo zondirovanija Zemli. Radiotehnika. 2025. T. 89. № 12. S. 135–146. DOI: https://doi.org/10.18127/j00338486-202512-15 (in Russian).
8. Shimada M., Oaku H., Nakai M. SAR calibration using frequency-tunable active radar calibrators. IEEE Transactions on Geoscience and Remote Sensing. 1999. V. 37. № 1. P. 564-573. DOI: 10.1109/36.739116
9. Gruzdov V.V., Kolkovskij Ju.V., Krishtopov A.V., Kudrja A.I. Novye tehnologii distancionnogo zondirovanija Zemli iz kosmosa. M.: Tehnosfera. 2019. 482 s. (in Russian).
10. Oppengejm A., Shafer R. Cifrovaja obrabotka signalov. M.: Tehnosfera. 2006. 856 s. (in Russian).