The different levels of authorization are used to protect the stored gravity data against unlicensed access. 

Beginners should use the First-Time Registration to log on to the system. Simultaneously they'll get the neccessary data for the Guest Account. 

Guest users only get information about the SG stations and the metadata of the gravity data in the Retrieval section, they don't have access to any datafiles neither within the Retrieval nor in the Download or Upload section. 

Each user of an explicit defined GGP Participant group inherits the Guest rights and additionally get access to all gravity data of his own goup only both in the Retrieval and in the Download section. Within the Upload section he is allowed to upload data files. 

The Administrator inherits all GGP Participant group rights. These rights are used only for GGP-ISDC management and service tasks.