Using representative synthetic data to analyze effects of filters when processing full waveform airborne TEM data

Abstract

Airborne time domain electromagnetic (ATEM) surveys have reached the stage where full waveform streamed data are recorded and delivered in addition to traditional survey products. One result of this advance in technology is that the line between the acquisition and processing phases has become more flexible and many parameters that used to be hardwired in acquisition can now be adapted during the processing phase. In order to make use of this opportunity the interpreter needs a clear description and understanding of the system specific corrections required to isolate geological responses as well as the effects of filters and other digital signal enhancement options that are available. Validating procedures on a synthetic data set is one way of ensuring that all geological responses falling within similar parameter ranges would be accurately presented after processing. In this study the effects of three time-series and four spatial filters were analyzed. Streamed full waveform data were simulated by adding measured high altitude data to synthetic models. The various filters were applied and the deviations from the true models compared with that of the unfiltered data. The results were evaluated based on whether the filtered results showed more or less deviation than the unfiltered data from the original noise-free models.