Transformation of Cartesian to Geodetic Coordinates without Iterations

Abstract

A noniterative transformation of earth-centered, earth-fixed (ECEF) Cartesian coordinates to geodetic coordinates of a point is presented. The transformation is based on ellipsoidal coordinates. The ECEF Cartesian coordinates of a point are first transformed to the ellipsoidal coordinates by closed formulas. Second, the reduced latitude referred to the reference ellipsoid takes the approximation to the reduced latitude referred to a confocal ellipsoid. Third, the approximation can be improved by a correction for the purpose of higher accuracy. The accuracy of the transformation is analyzed in the paper and it is shown that the derived geodetic coordinates are sufficiently accurate for the most geodetic purposes.