Research on Background Electromagnetic Interference Suppression Method Based on MUSIC-LCMV Algorithm

Accurately extracting the electromagnetic radiation signal of the equipment to be tested from the environmental electromagnetic signal is one of the difficult problems that urgently need to be solved when conducting electromagnetic compatibility on-site testing. Virtual darkroom technology can accurately receive radiation information from the tested equipment in a noisy environment. However, there may be significant errors in the test results when there are strong interference signals. Based on the principle of spatial cancellation, this paper proposes a new method for suppressing background electromagnetic interference. This method combines the idea of simultaneously cancelling background noise in a virtual darkroom with the introduction of array signal processing, and uses beamforming as the operating mode to filter out background noise in on-site testing. This algorithm can overcome the shortcomings of traditional methods, that is, it does not need to assume that background noise is not related to the radiation signal of the tested equipment, the spatial distribution of background noise is uniform, and the signal-to-noise ratio is large. By providing less prior information or reference information of the on-site environment, good results can be achieved. Its core is high-precision direction of arrival estimation through multiple signal classification algorithm (MUSIC). After obtaining the direction of the signal, the Linear Constrained Least Variance (LCMV) algorithm is used to weight the signal received by each antenna. The weighted sum of each antenna suppresses background noise and preserves the radiation signal of the tested equipment intact. Finally, the correctness of this method was verified through an example.