V.V. Chapurskiy1, G.P. Slukin2, M.I. Noniashvili3, I.V. Kryuchkov4

1-4 NIIRET, Bauman Moscow State Technical University (Moscow, Russia)

For a non-cooperative system of spaced radars with phased array antennas consisting of one active radar and several radars operating only for reception, an analytical expression is obtained for the generalized correlation integral of coherent space-time processing under the influence of interference reflections from the earth's surface. The coordinated survey of space by the beams of the phased array antennas of different radars, when they are directed to a common reference point scanning a given area of space, the shape of the sounding signals of the LFM type spectrum with a large base and the complex coefficients of the local reflection of the sounding signals from the surface are taken into account.

An example of a numerical analysis of the generalized correlation integral module for a system of three radars spaced along the runway in the presence of reflections from the earth's surface for the situation of observing the aircraft on the takeoff-landing glide path is considered in detail. With a reflection coefficient from the earth's surface consists  0.9, the following results were obtained.

1. During the flight of the aircraft in the regular control points of the glide path in the approach zone to the runway, there is generally a correct measurement of the height (elevation angle) of the aircraft in the presence of reflections from the earth's surface.

2. Reflections with a reflection coefficient of  0.9, compared with their absence ( 0), lead to a very slight shift in the estimate of the height of the aircraft according to the maximum of the generalized correlation integral module, equal to no more than units of meters, amounting to about 2% of the width of the main lobe of the generalized correlation integral module at the level of 0.5.

3. For two models of the phased array pattern of the three radars spaced system, it was found that an increase in the level of the first side lobe from -17.7 dB to -13.3 dB, even with a high reflection coefficient from the surface of  0.9, does not lead to a noticeable effect on the measurement of the aircraft flight altitude at the control points of the runway glide path.

4. The main reason for the smallness of the influence of reflections in the system of spaced radars with phased array is to use a coordinated overview of the of space area above the earth's surface using a system of narrow beams of phased array antennas aimed at a common reference point, which, when viewed, changes its coordinates in a given area of space above the earth's surface.

Chapurskiy V.V., Slukin G.P., Noniashvili M.I., Kryuchkov I.V. Analysis the influence of reflections from the Earth's surface in a system of spaced radars with phased array antennas. Radiotekhnika. 2022. V. 86. № 5. P. 121−134. DOI: https://doi.org/10.18127/j00338486-202205-15 (In Russian)

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