The IGS will be embarking on a real-time pilot project in the summer of 2006. The start of the pilot project will mark the beginning of a transition of the existing IGS real-time prototype network into an expanded and more robust network. This future network is expected to provide a stable real-time infrastructure upon which to develop and make available real-time and near real-time IGS products including but not limited to, real-time raw-data streams, near real-time high rate data, real-time station-clock and satellite-clock information, and integrity information pertaining to IGS real-time products, in particular IGS predicted orbits. This session will focus on topics pertaining to the evolution of the IGS real-time prototype into a successful pilot phase and eventually a real-time service of the IGS. What real-time applications can the IGS support? What are the real-time products required by these applications? Will the IGS generate combined real-time products as is customary for IGS products? How will we deliver the products to the intended users? These questions will be addressed during this session. A position paper pertaining to the following topics will be presented: Management of the real-time network, the inclusion of Galileo and GLONASS, data formats including RTCM 3.0 and the distribution of IGS products where both the RTIGS and EUREF/NTRIP models will be discussed.

There is increasing demand for real-time GNSS data analysis and processing from a variety of different users with different applications worldwide. The exchange of GNSS data would benefit from a commonly accepted data format or standard.

The Radio Technical Commission for Maritime Services (RTCM) is an international non-profit scientific, professional and educational organization. RTCM members are organizations (not individuals) that are both non-government and government. Although started in 1947 as a U.S. government advisory committee, RTCM is now an independent organization supported by its members from all over the world.

RTCM Special Committees are chartered to address in-depth radio communication and radio navigation areas of concern to the RTCM membership. The output documents and reports prepared by these Committees are usually published as RTCM Recommended Standards.

The Special Committee (SC) 104 developed the RTCM Recommended Standards for Differential Global Navigation Satellite Systems (DGNSS). Version 2.x and the latest Version 3.0 provide broadcasted GNSS real-time differential corretions and raw data.

The RTCM standard supports the current GPS and GLONASS system and is also preparing the standard for the advent of Galileo. Service providers and vendors have worldwide adopted the standard and it is today the format used by GNSS receivers and by RTK network installations. Currently, new RTK network messages to support efficiently GNSS rovers are under discussion.

A comparison of the RTCM format Version 3.0 with other formats is presented focusing on raw data messages. Current properties of the messages, deficiencies and future extensions are discussed with respect to IGS applications.

The Real-Time IGS Working Group developed the RTIGS protocol for streaming GNSS data over the open Internet. The protocol makes use of the UPD transport protocol and is capable of transmitting any type of data or product. RTIGS GNSS data streams are available in a format that incorporates the JPL SOC format for data compression. Software packages including the RTIGS’s udpRelay, udpArchiver and MulticastReader have been in use for several years and have been proven to meet the demands for real-time GNSS product generation based on data from globally distributed reference stations.

At the same time, under the auspices of the "Radio Technical Commission for Maritime Services" (RTCM), GNSS vendors developed and finally agreed, in September 2004, on a new protocol for streaming GNSS data. The new protocol is called "Networked Transport of RTCM via Internet Protocol" (NTRIP) and it is also capable of streaming any kind of GNSS data. NTRIP has the potential to disseminate the upcoming RTIGS products over the Internet to stationary or mobile users worldwide. The NTRIP transport protocol provides an additional method for accessing global GNSS data in real-time and will thereby augment the existing RTIGS global network. Furthermore, RTCM's new Version 3 data format is being considered by the RTIGS to become the standard format for the transmission of real-time GNSS data.

Following a short introduction of NTRIP, the presentation describes the interface established as an IGS effort to merge today's real-time GNSS resources available through NTRIP and RTIGS. Conceptual details concerning the network of NTRIP Broadcasters necessary to share the workload with regard to bandwidth limitations, availability, and reliability are given. A brief overview on existing open source NTRIP software for stream collection, dissemination, and conversion closes the presentation.