Pattern compensation for DOA estimation by electromagnetic vector sensors

Vector sensors are made of electric dipoles and magnetic loops. A full six vector sensor can measure the complete six electric and magnetic field components at one point in the space. Vector sensor concept was proposed from signal processing community and associated direction of arrival (DOA) estimation algorithm was based on isotropic radiation model. This paper shows that the radiation pattern compensation of sensor element is necessary for practical DOA application with improved accuracy, from more than 12° to about 1° for a realistic signal of 10 dB SNR. As a useful example, we consider a simpler yet more popular low-grazing angle application with a reduced vector sensor of two magnetic loop sensor elements for DOA estimation of a low-grazing angle source with vertical polarization. The reduced vector sensor can greatly simplify the system design, fabrication, measurement, and data processing.