97 feb 6

Geodetic Surveying 1997

Expect 1997 to be the most significant year in the history of surveying. Here are some components of this turning point:

GPS is now fully operational as a world-wide, U.S. sponsored system, guaranteed by the Presidential Decision Directive (PDD) for secure future use by Surveyors, who require differential procedures to overcome signal distortion.

GLONASS is now fully operational as a world-wide, Russia sponsored system providing similar satellite availability in which signal distortion is not applied. This enables 1m autonomous positioning and double satellite densification.

Practical dual-system receivers will be introduced in conjunction with advanced software enabling full geodetic computations with ranges from both systems, thus halving the dilution of precision (DOP).

Multipath will become less significant in contributing to overall error.

The nationwide CORS system is available to everyone with internet access providing increasingly accurate reference points by which to reduce the number of field rovers required for a campaign. Further densification of the CORS network, coupled with refinement of computed positions enables continuous refinement of HARN point locations.

Governments, constructing Geographic Information Systems, will discover the value in a globally common, primary coordinate database based on the International Terrestrial Reference Frame (ITRF) or equivalent, and begin to require such coordinates in land surveys.

Thus, geodesy becomes a central methodology to the practice of surveying.

The NCAD mission is to facilitate the world-wide adoption of a common coordinate system, independent of state boundaries, and to facilitate the practice of geodetic positioning in conjunction with surveying and GIS. A seminar series will be announced in March. Please watch our web site for details.