Geoid modeling in Saudi Arabia

 

 

 

By: Dr. Dafer A. Algarni

 

 

College of Engineering, King Saud University,

 

P.O.Box 800, Riyadh 11421, Saudi Arabia.

 

 

 

ABSTRACT

 

Determining the geoid in Saudi Arabia is not an easy matter, mainly because of the lack of necessary data at the present time. The global positioning system (GPS)  is being used extensively in the country and seems to have alleviated this problem. In the present study, ellipsoidal heights derived from GPS measurements at stations of known orthometric heights were used to determine  the geoid surface in the country by least-squares surface fitting. Orthometric heights of  test stations were then obtained on the basis of the derived ellipsoidal height (from GPS) and the value of the geoid undulation obtained from the derived geoid map. The accuracy of the computed orthometric heights were found to be in the order of a few decimeters. This level of accuracy is believed to be acceptable for some mapping purposes in the country. The derived  accuracy can further be improved if more data stations of accurate orthometric heights were used for deriving of the geoid on the basis of the proposed least-squares surface fitting technique.

 

 

Published in the ITC Journal, 1997, No. 2, pp. 114-120.