static const double a = 6378.137; /* semi-major axis (equatorial radius) of WGS84 ellipsoid */
static const double b = 6356.7523142; /* semi-minor axis referenced to the WGS84 ellipsoid */
static const double r_0 = 6371.2; /* standard Earth magnetic reference radius */
static const double a = 6378.137; /* semi-major axis (equatorial radius) of WGS84 ellipsoid */
static const double b = 6356.7523142; /* semi-minor axis referenced to the WGS84 ellipsoid */
static const double r_0 = 6371.2; /* standard Earth magnetic reference radius */