St. Petersburg State University of Aerospace Instrumentation has patented a method for forming phase-modulated signals for a multi-position system of airborne radar stations. Patent RU 2 870 893 C1 was published by Rospatent on September 29, 2026.
The development is designed for a situation where several radars simultaneously emit signals, and the stations are in different positions and operate as part of a single group. The method is based on complex M-sequences - a special type of signal-code constructions used for forming and processing radio signals.
The problem is that traditional M-sequences, built on polynomials of the same order, are not orthogonal. In multi-position mode, this can lead to mutual interference of signals in a common radar channel. It is this problem that the developers propose to solve by changing the code sequences.
The method allows unambiguous identification of modulated signals upon reception in a common radar channel - with simultaneous emission from several positions of airborne radars, spatially separated and combined into a single group. This eliminates mutual interference and increases the system's resistance to distortions.
In the new scheme, the values of the original binary alphabet are replaced by complex values associated with the phases of elementary pulses. For the obtained sequences, autocorrelation and cross-correlation characteristics are calculated, after which such phase values are selected at which the side lobes of the autocorrelation function become minimal, and the cross-correlation remains below a given level.
As a result, phase-modulated signals are formed that can be distinguished when simultaneously received in a common radar channel. The patent directly links this result to a multi-position system of airborne radars, spatially separated and combined into one group.
The authors indicate that the obtained signals have lower side lobes of the normalized autocorrelation function compared to traditional M-sequences. At the same time, the cross-correlation characteristics remain sufficiently low for use in multi-position airborne radars.
The development was created as part of research work on new methods for forming and processing radar frame streams for spatially distributed technical vision systems and group interaction of unmanned aerial vehicles.