Uniform Circular Array Beamforming Technology And Simulation

In passive location system, it needs to separate the weak target scattering signal fromthe strong direct wave signal and to obtain the final target positioning information, andthus it needs to use the combination of the space-time domain signal processing methods.Uniform circular array (UCA) antenna are valued and used widely in passive positioningsystem due to its two-dimensional scan and360°horizontal direction all-round coverage.This paper takes passive positioning system as the background, studies the separation ofthe weak target scattering signal from the strong direct wave signal with digitalbeamforming signal processing methods in the condition of uniform circular array.With uniform circular array digital beamforming (DBF) technology, the antennapattern has high sidelobe level, which restricts its ability to inhibit the interference signal.In order to improve the anti-jamming performance of uniform circular array, the paperstudies low sidelobe beam forming algorithms with uniform circular array. Windowingfunction method, virtual interference method, optimization constraints static synthesismethod and reference function method are analyzed and simulated. The results show thatthe virtual interference method and optimization constraints static synthesis method canobtain-30dB sidelobe level.In addition, to extract the weak scattering signal by suppressing the direct wavesignal, it is necessary to realize wide nulling in beam patterns. As the narrow nulling widthwith uniform circular array conventional nulling algorithms, the paper studies thealgorithms to widen the nulling to ensure the effectiveness of restricting the stronginterference signal. Multi-angle nulling algorithm, optimization constraints static synthesisnulling algorithm and covariance matrix weighting nulling algorithm are analyzed andsimulated based on uniform linear array and uniform circular array. The results show thatthe multi-angle nulling algorithm is simple to use with excellent depth and width, thewidth of10°or more can be achieved at the depth of-100dB. It’s suitable for the occasionthat the orientation of the scattered wave is unknown. Optimization constraints static beamcontrol method can obtain the ideal nulling width at-80dB, and maintain the main lobe unchanged, it’s suitable for the occasion that suppressing strong interference and enhancethe desired signal with known direction.