Measurement of noise in airborne gravity data using even and odd grids

摘要

Gravity has been measured from aircraft in flight since the late 1950s (Thompson & LaCoste 1960). Recent improvements in GPS processing, and a new gravity instrument, the AIR Grav system (Argyle et al. 2000), have resulted in significantly reduced noise levels in airborne gravity data. In this paper we present a methodology to quantitatively calculate noise levels of airborne gravity data sets by dividing the flight lines into two equal data sets (the 'even' and 'odd' lines), gridding and filtering the separate data sets, and measuring the difference between the resultant grids. The data is low-pass filtered before the noise level is measured, and noise levels are calculated for specific filter lengths. We also present an example of this noise calculation performed on an AIR Grav data set from the foothills region of Alberta, Canada, along with an interpretation of the data (Peirce et al. 2002; Sander et al. submitted).