To provide shared reference stations.

A reference station system is provided with a plurality of GPS reference stations dispersed at various locations throughout the world and capable of simultaneously collecting all the sets of GPS satellite calendars. The reference stations are each related to network servers connected to the Internet. Each network server posts orbit calendars, navigation data, and another information from the reference stations corresponding to clients and useful for the clients. All such network servers transmit the information to the other servers within the system. When data is transmitted, each server verifies and confirms the data. Each client is not allowed to make access to a complete database of the orbit calendars or another GPS system information until he is recognized as a subscriber.