The research interest of ultrawideband (UWB) discharge source location estimation has increased these years. In this paper, a direction of arrival (DOA) estimation method using multiple baseline wideband time-domain interferometry with Hilbert transform for UWB discharge source is proposed based on time-domain and frequency-domain characteristics of radiated RF electromagnetic pulses (EMPs) from discharge sources. Monte Carlo simulations are then carried out; the results indicate that, the proposed method provides a better performance in UWB discharge source DOA estimation than the traditional time-domain method, especially in low signal-to-noise ratio (SNR) conditions. Moreover, the influences of antenna array configurations and incident angles of radiated EMPs on the estimation precision are also studied. It has been shown that, the accuracy of both elevation angle and azimuth angle estimation improves with the increase of the antenna element number and baseline length. As for the influence of incident angles, the estimation accuracy of elevation angle enhances when real elevation angle increases, while that of azimuth angle tends to be opposite. Meanwhile, the real azimuth angle has little effect on the DOA estimation. Finally, an experimental setup for discharge source DOA estimation is introduced and the experiment results are illustrated.

RF electromagnetic pulses (EMPs) generated from gas discharge can not only cause serious interference or damage to electronic equipment but also be utilized in many new applications. In this paper, we establish an experimental platform for studying radiation characteristics of RF EMP from spark discharge plasma at atmospheric pressure. The influences of discharge voltage, electrode configuration, and storage capacitance on the amplitude-frequency characteristics of RF EMP are analyzed. A combined dipole-loop antenna model is proposed to describe the radiation process of EMP from spark discharge plasma. The results show that the frequency spectrum of RF EMP from spark discharge plasma mainly focuses on three intervals, namely, (0–50) MHz, (50–100) MHz, and (100–200) MHz. The radiated electric field intensity of EMP in all frequency bands enhances with the increase in discharge voltage or storage capacitance. Because of the polarization mismatch, the received field intensity in the ball-plate electrode configuration is the weakest compared to the plate-plate and ball-ball electrode. The whole radiation process of EMP from spark discharge plasma can be simulated by a combined dipole-loop antenna model well. The dipole antenna and loop antenna models are used to depict the radiation process of EMP during the discharge transient process and subsequently the energy releasing process, respectively. These results provide some fundamental knowledge for further study of RF EMP from gas discharge.

Apart from interfering in the communication system of an aircraft, electromagnetic pulses (EMPs) radiated from spark discharge plasma, which is generated during high-speed flight, can also be utilized in passive detection. In order to validate this idea, an experiment on direction of arrival (DOA) estimation of a spark discharge plasma target using its radiated EMPs is carried out in this paper. A combined time-domain antenna is designed based on the model of spark discharge process and is used to receive the radiated EMPs during the experiment. According to the experimental results, the DOA estimation system with combined antenna is able to obtain the direction information of a spark discharge plasma. Results also show that the estimation performance of elevation angle is better when the actual elevation angle of the discharge plasma target is higher, while the estimation performance of azimuth is opposite. The azimuth angle of a target has very little influence on the DOA estimation. Moreover, the estimation error can be reduced effectively by increasing the aperture size of receiving array. The previously mentioned results provide an approach to locate the discharge plasma source using radiated EMPs with passive detection techniques.