Fine Three-Dimensional VHF Lightning Mapping Using Waveform Cross-Correlation TOA Method

Abstract

Waveform cross-correlation approach was first applied to three-dimensional very high frequency (VHF) lightning mapping. A Hilbert transform of the original waveform and a three-step cross-correlation parsing process were employed to compute the time differences with a small 10-μs time window for the final time-of-arrival (TOA) positioning. The lightning channel continuity was significantly improved, and its fine structure, including the K process, was clearly distinguished with speeds of up to 1.1 × 107 m/s. The two overlapped K processes indicate the high location accuracy of the time-of-arrival, based on the waveform correlation method. The median (mean) values of the positioning precision with the proposed method were evaluated by duplicate located sources and estimated as σx = 20 m (26 m), σy = 19 m (28 m), and σz = 54 m (67 m).