Direction Finding for Radio Transmitters With Mini Interferometric Network

In this paper, we present the design and deployment of a broadband interferometric mini array. The network with five electromagnetic signal detectors deployed over an area about 1 km2 is applied here to record 20‐ to 70‐kHz vertical electric fields emitted by radio transmitters in very low frequency/low‐frequency band. Furthermore, interferometric imaging algorithm is employed to evaluate the elevation angles and azimuth angles of the electromagnetic radiation source. It is found that the deviation between expected azimuth and the mean value of calculated azimuth is less than 0.2° with standard deviation of 3.55°. The experiment results indicate that the mini array may provide benefits in determining the precise locations of electromagnetic radiation sources. Plain Language Summary The design and deployment of a broadband interferometric mini array is addressed. Working in very low frequency/low‐frequency band, the array utilizes interferometric imaging algorithm to find out the elevation angles and azimuth angles of the electromagnetic radiation source. The results showing the deviation azimuth between expected azimuth and calculated azimuth is less than 0.2° with standard deviation of 3.55°, which indicates that the mini array may provide benefits in determining the precise locations of electromagnetic radiation sources or describing the developing process of lightning. Key Points Interferometric imaging algorithm is applied for low‐frequency radio waves Azimuths for radio transmitters are calculated The deviation azimuth is less than 0.2°