Computation of datum shift parameters between two navigation datasets

Abstract

Geophysical surveys require precise navigation data which is usually acquired through real-time kinematic GPS. The acquired data needs to be transformed from the GPS reference datum to the local datum, by computing datum shift parameters using control points in the survey area. Oil and gas industry archives contain data from seismic surveys, conducted over the years by various data acquisition crews using different datum shift parameters. Sometimes these parameters are not documented in the navigation data headers. This leads to geo-referencing problems when combining data from different surveys. This paper reviews the transformation models and presents a simple approach for computing Molodensky-based datum shift parameters, by identifying common points between two surveys on a map. A real example is included to show the successful implementation of this method.