Abstract

With the increased capacity of the Internet, applications that transfer continuous data streams by IP-packages, such as Internet Radio, have become well-established services. Compared to these applications, the bandwidth required for the transfer of real-time GPS data is relatively small. As a consequence, EUREF currently considers the use of the open Internet for real-time collection and exchange of GPS data, as well as for broadcasting derived products. Possible fields of geodetic application are the collection of raw or RINEX data from reference stations, and the distribution of RTCM corrections over the Internet for precise positioning and navigation purposes.
This presentation focuses on various aspects of the implementation of a EUREF-based DGPS/RTK service using the Internet. The current status of a trial system called EUREF-IP is described. It streams RTCM corrections over the Internet and connected GSM/GPRS cellular phone networks. Server and client software characteristics are outlined. Problem areas like latency and IP-Multicast are discussed. The achievable accuracy is demonstrated based on test measurements. Conclusions are drawn concerning the potential of DGPS/RTK over the Internet for establishing location-based services.