Improved Method for Calculating Exact Geodetic Latitude and Altitude Revisited

Sofair (1997) derived exact, singularity-free expressions for the geodetic latitude and altitude of an arbitrary point in space. Recently, a numerical problem was detected in the equations at points on and near the Equator when q becomes very large. In this paper, the equations are modified to neutralize the effect of large q, thus yielding equivalent, exact, singularity-free expressions that are also numerically stable everywhere and just as elegant. The revised algorithm is given. (AIAA)