G.N. Tkachev1, V.A. Novobranets2, E.V. Kuznecov3, A.V. Chestnyh4

1–3JSC “Research and Production Complex” Research Institute of Long-Range Radio Communications” («NPK «NIIDAR») (Moscow, Russia)
4 Moscow State University of Technology and Management G.K. Razumovsky, (Moscow, Russia)
 

Radars for over-the-horizon detection (OTHR) are used to assess the air situation on the distant approaches to the national borders of the state. The most important characteristics of the air situation is the flight speed and altitude of observed air objects. Unfortunately, one of these parameters (flight altitude) is not measured in operating OTHR. In existing radars, only the distance (along the beam) to an air object, “Doppler velocity” and azimuth to an air object are measured.

Objective – to analyze the possibilities of estimating the flight altitude of an air object at large (over-the-horizon) ranges when implementing a new generation of elevation angle measurements (the angle of arrival of the echo signal at the receiving antenna) on the OTHR and retrofitting the OTHR with means of operational diagnostics of ionospheric parameters at the top of the first skip.

A technique for estimating the altitude of an air object flight for the simplest scheme of over-the-horizon radar has been developed: combined receiving and transmitting positions of the OTHR, a single-layer spherically layered ionosphere, and a vertical ionospheric sounding station is located in the area of the first skip. The requirements for the accuracy of measuring the parameters necessary for estimating the flight altitude of the air object are estimated: the range (along the beam) to the air object, the elevation angle (the angle of arrival of the echo signal at the receiving antenna), the height of the point of reflection of the radar signal from the ionosphere.

The results of the study open up additional possibilities for a new generation of OTHR for classifying air objects by flight altitude at distant approaches to a national border.

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