V.V. Chapursky1, G.P. Slukin2, A.A. Filatov3, D.E. Koroteev4

1–4 NII RET Bauman Moscow State Technical University (Moscow, Russia)

The presented concept and theoretical analysis of virtual MIMO radars are of practical importance in the study and creation of MIMO radars with antenna systems (AS), consisting of transmitting and receiving elements remote from the points of processing radar signals. Four examples of virtual MIMO radars are considered with two variants of the original real short-range MIMO radars with a linear and non-linear arrangement of AS elements and with two types of their projections on linear virtual axes, spaced in coordinates, and on axes, spaced in coordinates and angles of inclination.

For specific parameters of probing signals in a short-range MIMO radar, a comparison of variants of virtual MIMO radars was carried out in terms of resolution. It was performed according to the shape of the main and side lobes of generalized uncertainty functions (GUF) in the range-azimuth coordinates in the case of a stationary point target with the emission of monopulse multifrequency signals are applied.

It is found that the original real MIMO radar with linear AS has a narrower range-azimuth GUF main lobe compared to MIMO radar with AS elements located somewhat randomly. In the case of three virtual MIMO radars with different coordinates, with a linear arrangement of their AS elements parallel to each other, the similarity in shape and width parameters of the GUF main lobe in the «range-azimuth» coordinates was established with slight differences in the levels of the first side lobes. This result is valid for a linear one-dimensional and two-dimensional arrangement of AS elements of a real MIMO radar. For three virtual MIMO radars spaced in coordinates and tilt angles, noticeable differences in the shape and width parameters of the GUF main lobes in the range-azimuth coordinates were found, with additional differences in the shape and levels of the first side lobes. In this case, the narrower main lobe corresponds to a virtual MIMO radar, the AS axis of which is parallel to the AS axis of the real radar.

The methods of combining GUF with orthogonal in time operation of 3 spatially separated virtual MIMO radars are considered: 1) with coherent combining interference is observed, caused by the summation of partial complex GUF which leads a narrow main lobe and the presence of the first interference lobes by about 6 dB less level; 2) with incoherent merging, the general GUF diagram completely coincides with the GUF of individual virtual MIMO radars; 3) multiplicative GUFI combining results in complete suppression of side lobes and strong narrowing of the GUF main lobe. Further analysis should be aimed at taking into account the phase synchronization system and the positioning accuracy of real and virtual MIMO radars.

Chapursky V.V., Slukin G.P., Filatov A.A., Koroteev D.E.  Virtual MIMO radars and their comparison based on generalized uncertainty functions. Achievements of modern radioelectronics. 2023. V. 77. № 5. P. 5–19. DOI: https://doi.org/10.18127/j20700784-202305-01
[in Russian]

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