Observations of VHF source radiated by lightning using short baseline technology

A new type lightning radiation locating system has been developed and tested which uses short baseline technique to investigate lightning discharges. The system uses broadband receiving system to detect direction of individual VHF electromagnetic impulses from lightning discharge processes. The differences of arrival time of pulses are used to measure the azimuth angle and the elevation angle from three of four horizontally spaced antennas. The phase difference method is improved using Fourier filtering method and a soft threshold wavelet denosing method. Radiation source direction and characteristics of electric field change have been analyzed for a multiple-stroke CG flash. Breakdown processes of stepped and dart leaders to ground are discussed, characteristics during and following return strokes are described. Analysis of these results reveals some details about lightning discharges and indicates that the system works well for close lightning discharges. According to the error estimation, the rule of errors and factors that influence accuracy of the network are analysed.