The quality of these data are validated by checking the number of observations, number of observed satellites, date and time of the first and last record in the file. To reduce electronic network traffic, the Regional Data Centers are used to collect data from several Operational Data Centers before transmitting them to the Global Data Centers. Data not used for global analyses are archived and available for online access at the Regional Data Centers. GDCs are tasked to provide an on-line archive of at least 100 days of GPS data in the common data format, including, at a minimum, the data from all global IGS sites. The three GDCs provide the IGS with a level of redundancy, thus preventing a single point of failure should a data center become unavailable.
Users can continue to reliably access data on a daily basis from one of the other two data centers.
Furthermore, three centers reduce the network traffic that could occur to a single geographical location. More detail concerning the IGS data flow can be found in the IGS Annual Reports, in the section on Data Centers. The IGS Analysis Centers retrieve the data sets from the Global Data Centers and produce GPS ephemerides, station coordinates, earth rotation parameters, etc. The Central Bureau is responsible for the overall coordination and management of the service. The success of the IGS is due to the voluntary and active participation of Associate Members and Contributing Organizations .