GNSS

 

The Global Navigation Satellite System (GNSS) is a network of satellite-based systems for positioning and navigation on the ground, in the air or in orbit.  Apart from the space segment, each system also has a control segment, responsible for the system’s maintenance and quality control, and a ground segment consisting of ground-based tracking stations.  Currently GNSS comprises four systems:

• Global Positioning System (GPS), United States of America
• Global Orbiting Navigation Satellite System (GLONASS), Russian Federation
• Galileo, European Commission
• Beidou (translated as “Compass”), People’s Republic of China

 

 

IGS

The International GNSS Service (IGS), formerly the International GPS Service, is a voluntary federation of more than 200 worldwide agencies that pool resources and permanent GPS and GLONASS station data to generate precise GPS and GLONASS products. The IGS is committed to providing the highest quality data and products as the standard for Global Navigation Satellite Systems (GNSS) in support of Earth science research, multidisciplinary applications, and education. You can think of the IGS as the highest-precision international civilian GPS community. – Source: The International GNSS Service

 

 

The GNSS Project

 

The GNSS Project of HartRAO’s Space Geodesy Programme aims to densify the GNSS ground network in and around southern Africa and to promote the usefulness of GNSS data through research products and capacity building.

 

The GNSS Project is actively involved in capacity building in southern Africa:

• Post-graduate students undertake research in GNSS-related fields.
• Courses on the techniques of GNSS data processing and station installations are presented.

 

Research within the GNSS project focuses on the following topics:

·         The derivation of tropospheric precipitable water vapour content (PWV) and ionospheric total electron content (TEC) from the refraction of GNSS signals.

·         The geodynamics and crustal deformation of the African tectonic plates.

 

The GNSS Project, on behalf of HartRAO, serves as a regional data centre for IGS.  Responsibility for the maintenance and operation of the following GNSS stations are shared with our many collaborators:

• GOUG – Gough Island, Atlantic Ocean
• HRAO – Krugersdorp, South Africa
• MAIS – Marion Island, Indian Ocean
• MAUN – Maun, Botswana
• NMPL – Nampula, Mozambique
• RBAY – Richardsbay, South Africa
• RDRG – Port Mathurin, Rodrigues Island, Mauritius
• SIMO – Simonstown, South Africa
• STMP – São Tomé, Saõ Tomé and Príncipe
• SUTH – Sutherland, South Africa
• VESL – Vesleskarvet, Antarctica

 

The programme is also engaged in the following geodetic research, utilising GPS:

• Footprint, to determine local crustal and monument stability
• Collocation of different reference points and geodetic techniques
• Precise timing using GPS and a Hydrogen MASER
• Studying and eliminating short term site specific errors for GPS installations
• The measurement of short-term (~2 hours) small (mm/hr) motions
• Crustal deformation in southern Africa, using a regional network (see regional network map, adapted from the IGS Central Bureau world map), processed using GAMIT.

 

 

 

 This page was last updated on 2008/11/20 15:25 +0200 by Attie Combrink

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