A new accurate geoid - for a GNSS-based elevation-system

Abstract

A new geoid is on the way and it should be good enough for a new GNSS-based elevation system. The geoid will be determined by a combination of gravity measurements from satellites, aircraft and terrestrial measurements as well as GNSS measurements and terrestrial elevation measurements.

In recent years, DTU Space has carried out weight measurements on land, at sea and in the air; older gravitational networks have been checked with new accurate data, which has given an accuracy of 1-2 cm rms in the geoid compared to a global reference system.

In parallel, SDFE has performed GNSS measurements and precision terrestrial measurements continuously calculating more accurate elevations as a check of the fixed points.

To obtain a national geoid, the gravitational field-based "gravimetric geoid" is adapted to SDFE's 5D network, so that consistency is achieved at a level of 5 mm rms with the Danish Vertical Reference, DVR90.