Principles of Restoration and Modernization of the Radio Telescope Utr-2

Subject and Purpose. Restoring the world-largest decameter-wavelength radio telescope UTR-2 after the destruction inflictedby the full-scale Russian invasion requires significant efforts for mobilizing financial and organizational resources. In view of this, it is advisable to simultaneously repair the damaged systems and effectuate modernization of the instrument, which should significantly expand its functionality and increase the efficiency of its use. The present work is aimed at familiarizing the scientific community with basic principles underlying modernization of the UTR-2 radio telescope, and with the related expectations as to a significant increase in the information content of the future radio astronomical research projects performed with the facility. Methods and Methodology. Resorting to the expertise gained through half a century work on developing and operating unique radio astronomical equipment (ranging from antennas to data processing complexes) we are able to analyze possibilities for improving parameters of the radio telescope, as well as techniques of its large-scale modernization. The scientific approaches and technical solutions developed at the Institute of Radio Astronomy of the NAS of Ukraine allow expanding the field of view of the radio telescope, increasing the number of pattern beams usable simultaneously, and expanding the operating range towards both lower and higher frequencies. Results. Basic technical solutions have been suggested for modernizing the UTR-2 radio telescope through implementation of a hybrid phasing system for its antenna array. It has been decided to divide the existing array into 68 subsections, with each involving 30 elemental antennas inside. These are phased in an analog way, while phasing between the subsections is performed digitally, which should permit a more efficient use of the entire antenna field. Accordingly, it should be possible to simultaneously use up to 1000 antenna beams of the radio telescope for mapping the celestial sphere. Also, it is planned to increase the operating frequency range of the radio telescope from 8...3 3 MHz to 5...40 MHz. Conclusion. The modernization of the radio telescope UTR-2 opens up new opportunities for radio astronomical observations, ensuring a significant increase in the informative capacity of the radio astronomical research. The novel hybridized phasing system is beneficial for inclusion of the UTR-2 in the network of European low-frequency radio telescopes.