Possibility of Precise Positioning and Precise Inshore Navigation Using RTK and Internet

The practical need for GNSS positioning in real time led to the development of a medium for data transmission. DGPS correction data can be transmitted over an area of several hundred square kilometers using longwave radio frequencies. The RTK technique needs greater radio line throughput capacity as well as shorter distances between ground based reference stations. The RTK data from the reference stations can be transmitted through the DARC system by local stations using UHF channels, but the local stations in Poland are not interested in the propagation of RTCM data. The authors present test results of RTK and DGPS measurements using data transmission by Internet and mobile phones. The rover user is equipped with a GPRS (General Packet Radio System) modem in a GSM phone, which is connected to a laptop computer or receiver controller with special RTCM Client software that receives the RTCM data stream from the server via the TCP/IP protocol and transmits it via the serial port to the rover GPS receiver. The new Polish EUPOS-ASGPL active control network allows the use of the RTK technique with a practical range of ten nautical mile in Poland's inshore area.