Global Navigation Satellite System (GNSS) IGS Real-Time Combination Solution Summary of Real-Time Analysis Center (AC) Submissions from NASA CDDIS

The real-time observation data from a global permanent network of ground-based receivers are transmitted from the CDDIS in 1 to multi-second intervals in raw receiver or RTCM (Radio Technical Commission for Maritime Services) format. These real-time data are utilized to generate near real-time product streams. The real-time products consist of GNSS satellite orbit and clock corrections to the broadcast ephemeris.

These correction streams are formatted according to the RTCM SSR standard for State Space Representation and are broadcast using the NTRIP protocol. IGS analysis centers (ACs) access GNSS real-time data streams to generate near real-time product streams. The real-time products consist of GNSS satellite orbit and clock corrections to the broadcast ephemeris.

These correction streams are formatted according to the RTCM SSR standard for State Space Representation and are broadcast using the NTRIP protocol. The product streams are combination solutions generated by processing individual real-time solutions from participating IGS Real-time ACs. The IGS Real-Time Analysis Center Coordinator (RTACC) uses these individual AC solutions to generate this real-time IGS combined satellite and receiver clock product.

The effect of combining the different AC solutions is a more reliable and stable performance than that of any single AC's product. The solution summary files consist of reports on the combination analysis and the comparison with the IGS rapid solution product. This combination summary is a daily file available approximately one to three days after the end of the previous UTC day.