Before revision: A history of the subject, and more detailed equations for g can be found in Khan.NASA case file On the equilibrium figure of the earth by Mohammad A. Khan (1968) Somigliana equation The above expression for g has been supplanted by the Somigliana equation (after Carlo Somigliana) : where, is the spheroid's eccentricity, squared; is the defined gravity at the equator and poles, respectively; (formula constant); For Earth, = 9.7803253359 ms−2; = 9.8321849378 ms−2; k = 0.00193185265241 ; e2 = 0.00669437999013:Department of Defense World Geodetic System 1984 ― Its Definition and Relationships with Local Geodetic Systems, NIMA TR8350.2, 3rd ed., Tbl.
After revision: A history of the subject, and more detailed equations for g can be found in Khan.NASA case file On the equilibrium figure of the earth by Mohammad A. Khan (1968) The above expression for g has been supplanted by the Somigliana equation (after Carlo Somigliana)  For Earth, = 9.7803253359 ms−2; = 9.8321849378 ms−2; k = 0.00193185265241 ; e2 = 0.00669437999013:Department of Defense World Geodetic System 1984 ― Its Definition and Relationships with Local Geodetic Systems, NIMA TR8350.2, 3rd ed., Tbl.