Classification of geodetic networks, elevation of geodetic networks, permanent GPS station networks, functionality of GPS system, structure of GPS system, principles of positioning, GPS service classes, GPS signals, GPS data, reception of GPS signals, errors in GPS positioning, accuracy assessment for GPS receiver, expansion of GPS system, differential real-time DGPS, subsequent processing of differential measurements, inverted DGPS, monitoring the phases of GPS signal carrier, DGPS signal formats, source data and data after corrections, RTCM data format, RASANT data format, RINEX data format, NMEA data format, network RTK positioning, system architecture for network RTK positioning, error source characterisation, transfer format, cells, network corrections, message sending schedule, short message overview, examples of correction networks working in the emission regime, GNSMART solution of the company Geo, Leica Spider system, SAPOS system, EUPOS (European POSition Determination System) project, VRS systems, active reference geodetic GPS basis, components of active GPS basis, permanent stations, acquisition component, distribution component, user services, service classification, service application in geodetic terrain surveying.