About the possibility of using AMATERAS data to check the detection of dangerous asteroids

Asteroids approaching the Earth from the direction of the Sun and may pose a danger to the Earth are detected either too late or are not detected at all by optical observations. They can be detected using passive radar, using the radio emission of the Sun as a probing signal [2,3]. It is most convenient to use Venus, Mercury and the Moon as calibration objects when working out the method of detecting small celestial bodies, since their position relative to the Sun is easy to calculate, and their sizes are well known. If the control bodies deviate from the direction of the Sun by 2 degrees, the delay of the signals reflected from Mercury, Venus and the Moon will be 484, 118 and 0.2 ms, respectively. Due to the relatively small delay values of the reflected signals, it is impossible to use most of the available solar radio telescopes with an integration time of 1 to 10 seconds to implement this method. The radio telescope of the AMATERAS project [1], capable of receiving signals of less than 0.7 SFU with an integration time of 10 ms, is suitable for receiving and isolating reflected signals. The beam width of the radiation pattern of the AMATERAS radio spectropolarimeter is about 4 degrees at a frequency of 150 MHz, which allows receiving signals simultaneously directly from the Sun and reflected from the Moon during periods of solar eclipses. With the passive location of Mercury and Venus, it is most expedient to use type I radio flashes with a duration of less than 1 second as a probing signal. When locating the Moon, it is more convenient to use type III radio flashes, during which the radiation frequency changes at a speed of up to 20 MHz/ s (2 kHz in 10 ms). For ten years of observations of the Sun, a large amount of data has been accumulated on the AMATERAS system, including during solar eclipses, which allows us to work out algorithms for direction finding of small celestial bodies approaching the Earth from the Sun in the post-processing mode.

References

[1] Iwai K., Tsuchiya F., Morioka A., Misawa H. IPRT/AMATERAS: A new metric spectrum observation system for solar radio bursts // Solar Phys. 2012. V. 277. P. 447–457. DOI: 10.1007/s11207-011-9919-y.

[2] Vassilyev I., Zhumabayev B. On the possibility of using the Orbita radio polygon for radar detection of asteroids // Satellite monitoring of geodynamic processes and space weather. – Almaty, 2020 – pp. 133-138.

[3] Pavelyev A., Gubenko V., Matyugov S., Zakharov A., Yakovlev O. Perspectives of the bistatic radar and occultation studying of the Venus and planetary atmospheres and surfaces EGU General Assembly 2013 EGU2013-10289, 07-10 April 2013.