Yu.M. Meleshin1

1 MIET (Moscow, Zelenograd, Russia)

1 i@imym.ru

Modern radars built using multiple-input-multiple-output technology (hereinafter referred to as MIMO radars) are constructed using various signal-code structures and methods for ensuring the orthogonality of transmitting signals. The problems of controlling the spatial distribution of power for MIMO radar transmission while maintaining the orthogonality properties of transmitted signals are relevant, while an important direction in the development of MIMO radars is the transition to simple architectures using signals only with binary phase shift keying (BPSK) and quadratic keying (QPSK), such systems allow to abandon the use of digital-to-analog converters in transmitting channels and significantly simplify the implementation. This paper examines in detail the existing methods for controlling the power distribution for MIMO radars based on Zadoff-Chu sequences, which are constructed based on the synthesis of the alphabet of amplitude and phase values of both signals and the spatial precoding matrix. In this case, for the case with one direction, the problem is solved simply analytically, and for cases with several directions, the problem is solved by using optimization algorithms that change the extracted values from the alphabet and estimate the degree of divergence of the target distribution and the one obtained at each search iteration. Within the framework of this work, a replacement of the gradient descent optimization algorithm with a genetic algorithm is proposed, the operability of the proposed approaches is shown, and an increase in power in target directions from 3 to 7 dB is shown. A method for power control in MIMO radars with hardware limitations in terms of the phase values of transmitting element signals, in particular, only BPSK and QPSK, is proposed and investigated. As a result of modeling the proposed method, an increase in the radiated power in target directions from 2 to 3 dB for BPSK signals and from 2.2 to 3 dB (for 3 target directions) for QPSK signals is shown. It is shown that due to the specifics of the BPSK mode implementation, the final power distribution is always symmetrical, which indicates inefficient power distribution, however, even in this mode, the gain in radiated power towards target directions is considered a positive result. In the case of using QPSK signals, it is possible to achieve a significant gain even for 3 ... 5 spatial directions, while such signals can still be generated without using a digital-to-analog converter, using only two digital signals with two levels (for example, generated by FPGA) and a quadrature modulator in each transmitting channel. These results allow increasing the signal-to-noise ratio in operating modes with a priori information about target angular areas of interest, for example, in the additional search or target tracking mode.

Meleshin Yu.M. Algorithm for controlling spatial power distribution in MIMO-radars with BPSK- and QPSK-signals. Radiotekhnika. 2026. V. 90. № 1. P. 54−71. DOI: https://doi.org/10.18127/j00338486-202601-06 (In Russian)

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