Differential Global Positioning System (DGPS)


[inline:cntplot.jpg=right]We do field surveys using a Differential Global Positioning System (DGPS) to measure the morphology of the intertidal beach to understand the short- to long-term behaviour of bar and rip patterns.

DGPS system

A DGPS measures the bathymetry with a high accuracy. It consists of two GPS receivers. The first GPS receiver (the base) is placed at a known position. The second GPS receiver (the rover) measures the coordinates of the unknown points. The base GPS receiver can calculate the error of a normal GPS measurement, because its position is already known. The difference between the measured and known position is the correction and the correction is transmitted by a radio to the rover. The correction is applied on the GPS measurement of the rover. The accuracy of the DGPS measurement is in a range of 2.5 centimetres horizontal and 4 centimetres vertical.

Beach map

DGPS measurements are kriged to a regular grid based on a anisotropic spherical variogram model. We use Surfer, Matlab or GMap (GStat) to do this.


The Coastal Research group provides dGPS monitoring services. We do beach monitoring projects for local and national authorities. Academic research monitoring is done at low costs. Please contact the laboratory for physical geography for rates.


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Laboratory for physical geography
Att. Ing. M. Maarseveen
P.O.Box 80.115
3508 TC Utrecht
phone: + 31 30 253 2785
phone: + 31 30 253 2749 (secretary)
E-mail: m.vanmaarseveen@geo.uu.nl