/*
 * STRUCT: SRM_GSM_3D_PARAMETERS
 *
 *   No parameters are needed to define the Geocentric Solar Magnetospheric
 *   (GSM) 3D Spatial Reference Frame (SRF), but a struct is declared for it
 *   anyway, to parallel the struct definitions of the other SRFs. The
 *   associated ORM/ERM is defined by the WGS-84 ellipsoid.
 */