Airborne Gravity 2010 - Geoscience Australia

Airborne Gravity 2010
Post-processing software improvements
Several executable programs developed by Moscow State University (MSU) are used for postprocessing
of GT-1A and GT-2A data.
One program handles quality control issues such as checking of GPS and gravimeter data for missing
epochs or blocks, spikes, or other problems. Data is tagged accordingly so the processor can readily
determine problems before attempting to generate free-air gravity values.
The second program, called GT-Nav, is used to compute the differential solution from the GPS data,
whether using one or multiple base stations.
A third major program called GT-Grav brings the GPS and gravimeter data together and generates
free-air gravity values corrected for altitude, aircraft attitude, latitude, and speed.
Over the past several years, we have incorporated the GT-1A processing software seamlessly into a
Geosoft Oasis montaj menu-driven processing stream (Figure 19), whilst retaining the capability of
executing this software independently as an alternative. We continue to develop and make
refinements to additional Geosoft scripts and executables which are used for quality control of the
GPS and gravity data variables at different stages of the processing sequence.
In the past, it has been necessary to use third-party applications such as Waypoint GrafNav (NovAtel,
n.d.) to assist in isolating problems with GPS data. It is now possible to use advanced features within
GT-Nav processing to carry out this function.
Full documentation of the post-processing procedures is now very advanced and is used for training
processors new to the GT-1A or GT-2A gravimeters.
Figure 19. Post-processing functions, including QC, GPS processing, and free-air gravity
calculations, have been incorporated into the Geosoft Oasis montaj suite of programs. This
allows processors to quickly and easily produce in-field free-air maps and profiles for QC
purposes and for immediate client feed-back.
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