This illustrates the end-to-end data flow for the CICERO system. It begins with the collection of occultation data, which is sent to ground either directly or through a geosynchronous relay satellite (as depicted here). From there the data is sent to CDAAC for analysis, archiving, and distribution of final products. Data analysis also requires reference data from a GPS ground network. That data will be supplied by the International GPS Service (IGS) network consisting of hundreds of high-performance reference stations around the world.