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IGS Real Time Pilot Project (RTPP) Data Access

Data Access

To receive the IGS real-time GNSS data streams, free Ntrip client software has been provided by BKG and is available for several platforms. The Ntrip software can be downloaded from here. After completion of the user registration the authorization (user-ID and password) will be provided by the institution which operates the IGS-IP Broadcaster. BKG operates the primary IGS Ntrip Broadcaster www.igs-ip.net to distribute streams carrying observations from the International GNSS Service (IGS) and data from other global resources.

In the BKG NTRIP infrastructure, the data sources (receivers) transmit their data to the broadcast servers using the NtripServer application. A number of NtripCasters serve data to users in different communities using the HTTP protocol. The IGS Caster serves as the RTIGS-NTRIP Interface for the IGS Pilot Project. It disseminates data for nearly 150 stations, mainly in RTCM3 and RTIGS formats. A small number of stations transmit in various flavours of RTCM2. Ntrip server and Ntrip client software for various operating systems is available under GPL.

NTRIP Tools: Open Source NTRIP software is available from the Subversion server software.rtcm-ntrip.org. This includes POSIX ntripclient/server programs, multi-stream BKG Ntrip Client/Server programs, a RTCMv3 encoder/decoder for observations and proposed State Space Representation messages, and a RTCMv3 to RINEX converter. A bug tracker system allows you to inform authors about software problems that you may detect.

 

Proposed RTIGS Data Distribution Models

Proposed Global Data Center Observation Distribution Model

The proposed Global Data Center (GDC) Observation Distribution Model is designed to provide a robust data collection and distribution network while minimizing the required network bandwidth. The ultimate goal is to have two independent streams from the data collection station to each Analysis and Global Data Center. However this strategy is not yet fully achievable. As an intermediate step, a geographical redundancy concept is proposed where data from two or more stations in a geographic region, is sourced from either two different regional data centres (operated by the same agency) or from a different regional data center. As an example, station data in eastern North America could be sourced from NRCan, UNB (from BKG Global DC), and NGS. If either regional data center (or any link in the chain) has a problem the RTAC would continue to function using a less redundant network.

 

Proposed Real-Time Analysis Center Data Collection Model

The proposed Real-Time Analysis Center (RTAC) Data Collection Model recommends that the analysis data centre operators access station data directly from Regional data centers rather than global data centers. This approach has two benefits; firstly it removes one layer of latency and secondly it removes one point of failure from the data collection path. At the Analysis center layer the operator has at least two ways of building robustness into the data collection model. Option one is to design in geographical data redundancy where for a given region, stations are selected from either different data providers or from two different regional data centers operated by the same agency. Another option would be to design your application to support both geographic and stream redundancy where two independent streams are available for each station.


Last modified: 2010-12-02