Ellipsoidal Earth Reference Model (ERM) Geometry & Notation
• Ellipsoids are standard in current geodesy practice.
• For SNE data modeling, spheres are often used to simplify dynamics equations.
• Geocentric coordinates (GCC) are defined by the point P(X, Y, Z).
• Geodetic coordinates (GDC) are defined by the point P(Ø, ?, h).