A model-based parameter estimation of current distribution along lightning return stroke channel

A model-based parameter estimation (MBPE) technique is proposed to reduce the number of frequency-domain calculation points required for the evaluation of space-time current distribution along a lightning return stroke channel. In applying this technique to a rational function model for the channel current distribution, a uniform-like and a two-stage adaptive sampling strategies are investigated. To obtain height dependent current distribution at required frequency sampling points, the antenna theory model of lightning channel is used. The proposed technique is validated against the conventional inverse fast Fourier transform algorithm which uses a method of moment solution for all frequencies within the channel base current spectrum. It is shown that considerable computation efficiency is achieved in terms of CPU time without losing accuracy.