Incoherent scatter radar directional pattern using radio astronomical observations

The Irkutsk Incoherent Scatter (IS) radar is a unique facility in Russia, designed for geophysical and radio- probing investigations of the upper atmosphere. The range of problems tackled using the radar is quite extensive. Having a high potential and investigative capability, the radar represents an extremely sophisticated engineering facility. A maximum possible knowledge of all performance data of this instrument is necessary for conducting accurate measurements of space environment parameters and for scientific experiments. Of particular interest in this regard is the radar's antenna system. The spatial distribution of the radiation power (directional pattern) of the antenna system is as yet imperfectly understood. Because of the complexity and the unconventional nature of the antenna design, a mathematical simulation and calculation of the directional pattern involves a highly cumbersome task, and the reliability of such calculations is low. The overall worldwide practice shows that the most powerful tool for obtaining the directional pattern characteristics is to measure the variations of the noise power level when various cosmic radio sources traverse the beam. The advancement of digital technology in the present state of the art makes it possible to record large amounts of information needed to construct an accurate spatial distribution of the power received and radiated by the antenna. Results, thus obtained, are useful for correctly selecting the IS radar operation modes.