GPS World, September 2018

THE INTERNATIONAL GNSS SERVICE 25 Years on the Path to Multi GNSS 50 GPS WORLD WWW GPSWORLD COM SEPTEMBER 2018 WITH RICHARD B LANGLEY F or going on 25 years the International GNSS Service IGS has carried out its mission to advocate for and provide freely and openly available highprecision GNSS data as well as derived operational data products including satellite ephemerides Earth rotation parameters station coordinates and clock information The IGS is a self governed voluntary federation of more than 300 contributing organizations from more than 100 countries around the world that collectively operate a global infrastructure of tracking stations data centers and analysis centers to provide high quality GNSS data products The IGS products are provided openly for the benefit of all scientific educational and commercial users The IGS was first approved by its parent organization the International Association of Geodesy IAG at a scientific meeting in Beijing China in August 1993 A quarter of a century later the IGS community gathers for a workshop in Wuhan China this November to blaze a path to multi GNSS through global collaboration As a key component of the IAGs global geodetic infrastructure the IGS contributes to extends and densifies the International Terrestrial Reference Frame ITRF of the International Earth Rotation and Reference Systems Service IERS The ITRF provides an accurate and consistent spatial frame for referencing positions at different times and in different locations around the world In addition IGS products enable the use of GNSS technologies for scientific applications such as the monitoring of solid Earth deformations monitoring of Earth rotation and variations in the liquid Earth and for scientific satellite orbit determinations precise timing ionosphere monitoring and water vapor measurements IGS products are also considered critical by surveying geomatics and geo information users around the world who rely on them on a daily basis to improve efficiency Many applications that require reliable accurate GNSS positioning in construction agriculture mining exploration and transportation also benefit from the IGS COMMUNITY COLLABORATION At the heart of the IGS is a strong culture of sharing expertise infrastructure and other resources for the purpose of IGS Network 2017 GPS GPS GLONASS Multi GNSS encouraging global best practices for developing and delivering GNSS data and products all over the world The collaborative nature of the IGS community leverages this diversity to integrate and make full use of all available GNSS technologies while promoting further innovation More than 15000 geodetic community members some of whom comprise the backbone of the worldwide geodetic community ensure that new technologies and systems are integrated into operational IGS products Responsive to this innovation the IGS develops and publicly releases standards guidelines and conventions for the collection and use of GNSS data and the aforementioned products The IGS strives to maintain an international federation with committed contributions from its members Participation of individuals and organizations is often driven by user needs a key characteristic of the inclusive culture within the IGS STRUCTURE OF THE IGS The IGS consists of a central bureau a global network of GNSS stations data and analysis centers and a number of working groups all coordinated and overseen by a governing board Central Bureau The IGS Central Bureau CB functions as the secretariat of the IGS providing continuous management and technology to sustain the multifaceted efforts of the IGS in perpetuity The CB responds to the directives and decisions of the IGS governing board It coordinates the IGS tracking network and operates the CB information system the principal information portal where the IGS web FTP and BY Allison Craddock and Gary Johnston FIGURE 1 The extent of the IGS network in 2017 showing the locations of stations monitoring just GPS GPS and GLONASS and GPS and GLONASS plus at least one other constellation