WGS84 nach Topex Ellipsoid

double a_wgs84 = 6378137.0;
double f_wgs84 = 1 / 298.257223563;
double a_tp = 6378136.3;
double f_tp = 1 / 298.257;										
double r = (a_wgs84 - a_tp + (a_tp * f_tp - a_wgs84 * f_wgs84) * sin(lat_20Hz / 1000000.0)*sin(lat_20Hz / 1000000.0));

In Python:

WGS84 <-> Topex Ellipsoid

def wgs84_to_topex(lon,lat):
	lon = float(lon)
	lat = float(lat)
	a_wgs84 = 6378137.0;
	f_wgs84 = 1 / 298.257223563;
	a_tp = 6378136.3;
	f_tp = 1 / 298.257;										
	r = (a_wgs84 - a_tp + (a_tp * f_tp - a_wgs84 * f_wgs84) * np.sin(lat / 1000000.0)*np.sin(lat / 1000000.0))
	return r

 def topex_to_wgs84(lon,lat):
	lon = float(lon)
	lat = float(lat)
	a_wgs84 = 6378137.0;
	f_wgs84 = 1 / 298.257223563;
	a_tp = 6378136.3;
	f_tp = 1 / 298.257;										
	r = (a_tp - a_wgs84 + (a_wgs84 * f_wgs84- a_tp * f_tp) * np.sin(lat / 1000000.0)*np.sin(lat / 1000000.0))
	return r