oa A new processing system for very early time SkyTEM101 data

Early times are of interest for near-surface surveys and are object of developments during the last decade both in the electronics and the processing domains. The new SkyTEM system, called SkyTEM101, has a very short turn-off of 3 μs which authorizes the use of gates between 3 and 10 μs, and to increase the vertical resolution of the near-surface. However, a reliable monitoring of the Coil Response (CR) is necessary to get these very early time gates usable. For this, a new Coil Response Correction (CRC) has been developed which allows removing the CR in the first early gates before the inversion process. Application of this CRC correction to high altitude and production measurements has shown its efficiency to reduce the CR to the noise level. A new adaptive data filtering has also been developed to maintain the best lateral resolution above different areas like open fields or forests above which the signal to noise ratio varies due to the change of the helicopter altitude. This improvement of the lateral resolution has a great value for environmental surveys where definition of local and shallow heterogeneities is a critical issue.