The IGS global system of satellite tracking stations, Data Centers, and Analysis
Centers puts high-quality GPS data and data products on line in near real time
to meet the objectives of a wide range of scientific and engineering
applications and studies. The IGS collects, archives, and distributes GPS
observation data sets of sufficient accuracy to satisfy the objectives of a wide
range of applications and experimentation. These data sets are used by the IGS
to generate the data products mentioned above which are made available to
interested users through the Internet. In particular, the accuracies of IGS
products are sufficient for the improvement and extension of the International
Terrestrial Reference Frame (ITRF), the monitoring of solid Earth deformations,
the monitoring of Earth rotation and variations in the liquid Earth (sea level,
ice-sheets, etc.), for scientific satellite orbit determinations, ionosphere
monitoring, and recovery of precipitable water vapor measurements.
The primary mission of the International GPS Service, as stated in the
organization's 2002-2007 Strategic Plan, is
The International GPS Service provides quality data and products as the standard for global navigation satellite systems (GNSS)
in support of Earth science research, multidisciplinary applications, and
education. These activities aim to advance scientific understanding of the Earth
system components and their interactions, as well as to facilitate other
applications benefiting society.
The IGS Terms of Reference (comparable to the by-laws of the organization)
describes in broad terms the goals and organization of the IGS. To accomplish
its mission, the IGS has a number of components: an international network of
over 350 continuously operating dual-frequency GPS stations, more than a dozen
regional and operational data centers, three global data centers, seven analysis
centers and a number of associate or regional analysis centers. The Central
Bureau for the service is located at the Jet Propulsion Laboratory, which
maintains the Central Bureau Information System (CBIS) and ensures access to IGS
products and information. An international Governing Board oversees all aspects
of the IGS. The IGS is an approved service of the International Association of
Geodesy since 1994 and is recognized as a member of the Federation of
Astronomical and Geophysical Data Analysis Services (FAGS) since 1996.
The IGS collects, archives, and distributes GPS observation data sets of
sufficient accuracy to meet the objectives of a wide range of scientific and
engineering applications and studies. These data sets are used to generate the
following products:

• GPS satellite ephemerides
• GLONASS satellite ephemerides
• Earth rotation parameters
• IGS tracking station coordinates and velocities
• GPS satellite and IGS tracking station clock information
• Zenith tropospheric path delay estimates
• Global ionospheric maps