QUALIFICATION AND REFINEMENT OF THE IRANIAN GRAVITY DATABASE

Since 1986 several gravimetric geoid models were published in the Iran region. Based on primary investigation on these gravimetric geoid models, it is found that their relative and absolute accuracies versus GPS/levelling are more or less the same or in some cases worse than the current available global geopotential models (Kiamehr 1997,2003 ,2001a , 2003b, 2004 and Kiamehr and Sjöberg 2004). Regardless the effect of choosing proper computational method in determination of any geoid models, the quantity and quality of the gravity anomaly database plays a major rule in the final result of them. The main aim of this research is the creation of a more complete and also refined new gravity database for Iran. For this purpose different dataset from different sources are gathered and combined in a single database. Then we start to refine it from possible outliers by using Least Squares Collocation (LSC) approach. A special method used for the interpolation scheme of free-air gravity anomalies in order to take into account the effect of topography. The final grid file was creates based on the Kriging method with 80" * 90" resolution. The overall accuracy for the current database is estimated to near 10 mGal.