Test Results of Rtk and Real-time Dgps Corrected Observations Based on Ntrip Protocol

For many years, real-time DGPS and RTK correction data distribution have been providing GPS users a means to accomplish their tasks with high accuracy positioning in real-time. Dial-up systems over phone line or local area network (LAN) enable users to download data from base stations at remote locations. Radio modems provides wireless communication links between a base station and a rover to enable surveyors to carry out real-time DGPS and RTK-surveys. While these techniques are still very much in use,the developments in telecommunication technology over the last decade or so has brought more services providing easier use, faster speed, and wider coverage of GNSS data distributions via Internet. NTRIP, or "Networked Transport of RTCM via Internet Protocol" developed by the Federal Agency for Cartography and Geodesy of Germany, enabling the DGPS or RTK correction data is streamed via Internet using GPRS or other future technologies. This paper discusses the technical basics of NTRIP and illustrates the test results of real-time DGPS and RTK observations based on NTRIP protocol. This study was carried out with three different GPS receivers; high, medium and low accurate, which classified according to the receiver accuracy performance and cost. It has been found that NTRIP is a cost effective, secure and reliable alternative to replace conventional RTK and real-time DGPS correction streaming techniques. * Corresponding author.