Dr Muneendra Kumar
Consultant
Montgomery Village, MD, USA
Email: [email protected]
Dr. George A. Maul
Professor of Oceanography, Florida Institute of Technology, Melbourne
Email: [email protected]
Abstract
With the launching of Sputnik in 1957, the geodesy for the first time became really global. Just after three years, we got the first 3-D geocentric World Geodetic System (WGS) 1960 defined with a mean Earth ellipsoid. As the satellite systems improved, we can define and realize more accurate fundamental constants and Earth’s Terrestrial Reference Frames (TRFs). We have the most efficient and accurate GPS surveying technique, better models for tidal and temporal effects, and adjustment strategies. This has provided us the capability to achieve unprecedented positional accuracy, both absolute and relative.
During the 1980s, the International Hydrographic Organization (IHO) and Internal Civil Aviation Organization (ICAO) decided to adopt the WGS 84 for safe global navigation. In addition, as the WGS 84 was the only one available as a global coordinate system at that time, it also became a “universal” datum for all global mapping and charting.
However, it was also recognized that international navigation, mapping, and charting requirements at 1-2 m (1 sigma) level could be met with other national, regional, and/or continental 3-D geodetic geocentric systems. These days, with specially designed GPS survey projects, the geodetic systems can be easily defined and realized at accuracy level of ± 5 cm (1 sigma), which can then can support both the geodetic and mapping needs. Example of such systems are the Korean Geodetic System (KGS) 1995, European Reference (EUREF), and South American International Geodetic Reference System (SIRGAS) 2000.
In the West Asia and Middle East region to support all the development of mapping, charting, GIS, and urbanization, there is an immediate need to define and realize an accurate 3-D geocentric System. To achieve the best definition and accuracy, it is imperative that the recommendations of the International Association of Geodesy (IAG) and conventions of the International Earth Rotation Service (IERS) on tidal and temporal effects modeling and latest estimates of the fundamental constants are used.
This paper explains the merits of IAG recommendations and IERS conventions and proposes a new West Asia Geodetic System (WAGES) 2005 as a replacement for all the old datums of the region. By adopting the latest estimates of the fundamental constants, recommended tidal modeling, and correct temporal effects, we will be laying a solid foundation for all the planned developments in the region.
