Geomagnetic
// Specification of Object Reference Model (ORM)
SRM_FLOAT64 gm_radius // radius of the reference object;
// non-negative; in meters
// Origin of Coordinate System
// WGS84 Ellipsoid Origin (mass center)
// Coordinate System Orientation
SRM_UINT16 gm_epoch // epoch definition in year Common Era
SRM_FLOAT64 gm_latitude // degrees
SRM_FLOAT64 gm_longitude // degrees
SRM_FLOAT64 radius // distance from the mass-center of the
// reference object; non-negative; expressed
// in units of ORM/ERM radius