International GNSS Service (IGS) Experiments and Pilot Projects supported by the CDDIS

The CDDIS has supported the IGS as a global data center since its inception in 1992, including active participation in several IGS Working Groups, Experiments, and Pilot Projects. These experiments and projects include:

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IGS Multi-GNSS Experiment (MGEX) (2012-present)

The IGS established the GNSS Working Group in 2003 to explore and promote the use of new navigation signals and constellations within the IGS. In August 2011, the IGS issued a Call for Participation in the IGS Multi-GNSS Experiment (IGS M-GEX), an experiment to track, collect, and analyze signals available from multiple GNSS. MGEX comprises the build-up of a new network of sensor stations, the characterization of the user equipment and space segment, the development of new concepts and data processing tools, and, finally, the generation of early data products for Galileo, QZSS, BeiDou and other emerging navigation systems. The experiment includes signals from the BeiDou, Galileo, and the QZSS Quasi-Zenith Satellite System systems, as well as from modernized GPS and GLONASS satellites, and space-based augmentation system (SBAS) of interest. Analysis centers will attempt to estimate inter-system calibration biases, compare equipment performance and further develop processing software capable of handling multiple GNSS observation data.

The goals of the IGS Multi-GNSS Experiment are:

  • Bring knowledge about the developments of GPS, GLONASS, Galileo, COMPASS which might help to improve or at least contribute to IGS products to the attention of the various participating elements of the IGS through reports and dedicated sessions in IGS workshops.
  • Prepare and conduct the IGS Multi-GNSS tracking experiment (M-GEX) focusing on tracking new signals and constellations by deployed multi-GNSS receivers (hard- and software receivers).
  • In the framework of the M-GEX experiment involve receiver manufacturers to set up a test bed for various receiver and antenna types as a prototype receiver validation facility.
  • Establish suitable interfaces to organizations already or soon operating multi-GNSS networks.
  • Prepare a consolidated feedback to GNSS system engineering based on relevant IGS experience of providing highest accuracy products for the existing systems.
  • Prepare a strategy for IGS participation in the mid- and longer term exploitation of the next generation of GNSS.
  • Coordinate closely with, and seek inputs from IGS Analysis Centers and other IGS WG's as appropriate.

To achieve these goals, the Multi-GNSS Working Group interacts closely with other IGS working groups (e.g., RINEX WG, the Antenna WG, the Data Center WG) as well as the IGS Infrastructure Committee. The Multi-GNSS Working Group helps to develop and implement new standards for multi-GNSS-related work within the IGS.

(Source: IGS MGEX website, July 2013)


Real-Time Pilot Project (RTPP) (2001-present)

The IGS Real-Time Pilot Project (RTPP) will provide an opportunity for the IGS to further expand and refine its existing real-time infrastructure, and upon successful completion, potentially initiate an official real-time service. The pilot project will gather and distribute real-time data and products associated with GNSS satellite constellations. The primary products envisioned for the project are multi-frequency observation data and precise satellite clocks and orbits made available in real-time. These products will be freely available to participants for any purpose in accordance with the IGS open data policy. An important theme of the pilot project will be to support and promote the development of real-time applications. The pilot project will operate for a period of up to 3 years. Annual reviews will be conducted by the IGS Governing Board for the purpose of assessing the project's progress towards achieving its goals and objectives:

  • Manage and maintain a global IGS real-time GNSS tracking network.
  • Enhance and improve selected IGS products.
  • Generate real-time products.
  • Investigate standards and formats for real-time data collection, data dissemination and delivery of derived products.
  • Monitor the integrity of IGU predicted orbits and GNSS status.
  • Distribute real-time observations and derived products to real-time users.
  • Support network DGPS/RTK
  • Encourage cooperation among real-time activities, particularly in IGS densification areas.

(From: IGS RTPP website, July 2013)

GPS Tide Gauge Benchmark Monitoring Pilot Project (TIGA-PP) (2001-2010)

The GPS Tide Gauge Benchmark Monitoring - Pilot Project (TIGA-PP) is a pilot study of the International GPS Service (IGS) for establishing a service to analyze GPS data from stations at or near tide gauges (TG) on a continuous basis (CGPS @ TG). The primary product of the service is time series of coordinates for analyzing vertical motions of Tide Gauges and Tide Gauge Benchmarks (TGBM). All products are made public to support and encourage other applications, e.g. sea level studies. In particular, the products of the service facilitate the distinction between absolute and relative sea level changes by accounting for the vertical uplift of the station, and are, therefore, an important contribution to climate change studies. The service may further contribute to the calibration of satellite altimeters and other oceanographic activities. The pilot project will operate for a period up to three years, from 2001 to 2004. After this period the IGS Governing Board will evaluate the project and decide whether or not this activity should become a regular IGS service function.

The goals of the TIGA-PP are identified as follows:

  • Establish, maintain and expand a global CGPS @ TG network
  • Contribute to the procedures in which IGS realizes a global reference frame in order to improve its utility for global vertical geodesy
  • Compute precise station coordinates and velocities for the CGPS @ TG stations using a processing stream that runs months behind real-time in order to include the largest possible number of stations.
  • Establish a secondary processing stream with much reduced latency in order to support operational activities that cannot tolerate large processing delays.
  • Monitor the stability of the network.

In December 2010, the IGS Governing Board accepted the change of the TIGA Pilot Project to the TIGA Working Group.

(From: TIGA-PP web site, June, 2001)

International GLONASS Service -- Pilot Project (IGLOS-PP) (2000-2005)

The International GLONASS Service - Pilot Project (IGLOS-PP) is a pilot service of the International GNSS Service (IGS) to track and analyze data from the Russian GLONASS satellite constellation. The primary products of the service are dual-frequency observations from the global tracking network and precise orbits computed for each satellite. These are made available to support and encourage other applications and studies. In particular, the products from the Service facilitate the use of combined GLONASS and GPS observations for scientific and engineering applications, and allow users to experiment with the combined systems as a prototype Global Navigation Satellite System. The pilot service will operate for a period of up to four years, from 2000-2003.

The goals and objectives of the IGLOS Pilot Service are as follows:

  • Establish and maintain a global GLONASS tracking network
    • Co-locate dual-frequency, combined GPS/GLONASS receivers with dual-frequency GPS receivers or upgrade existing dual-frequency GPS receivers to dual-frequency, combined GPS/GLONASS receivers at existing IGS sites and at new sites
    • Apply International GPS Service (IGS) network operations standards
    • Calibrate and evaluate combined GPS/GLONASS receivers and antennas
    • Produce precise (10-cm level) orbits, satellite clock estimates, and station coordinates
  • Evaluate microwave-derived orbits using SLR observations and orbits
    • Incorporate SLR observations in routine orbit processing
    • Obtain initial operational capability of 20-50 cm orbits at Analysis Centers
    • Receive independent orbit/clock/station solutions from Analysis Centers within three weeks of observations
    • Monitor and assess GLONASS system performance
  • Investigate the use of GLONASS to improve Earth Orientation Parameters
  • Improve atmospheric products of the IGS
  • Fully integrate GLONASS into IGS products, operations and programs.

(From: IGS IGLOS-PP web site, May 2000)