datum 
The problem of datum definition as a function of coordinate combinations is reviewed.


These measures are also invariant with respect to "datum" shifts and orientation, and practically invariant to changes in scale.


Improvements in height datum transfer expected from the GOCE mission


Using the GOCE error model, simulation studies were performed in order to estimate the accuracy of datum transfer in different areas of the Earth.


As an example, the accuracy of the vertical datum transfer from the tide gauge of Amsterdam to New York was estimated equal to 57?cm when the EGM96 error model was used, while in the case of GOCE error model this accuracy was increased to 6?cm.


Comparisons of AUSGeoid98 with GPS and Australian Height Datum (AHD) heights across the continent give an RMS agreement of ±0.364?m, although this apparently large value is attributed partly to distortions in the AHD.


The use of GPS for height control in an area with existing levelling data requires the determination of a local geoid and the bias between the local levelling datum and the one implicitly defined when computing the local geoid.


In the latter case two bias parameters had to be introduced to account for a possible levelling datum difference between the levelling on the dam and that on the adjacent roads.


National height datum, the GaussListing geoid level value w0 and its time variation 0 (Baltic Sea Level Project: epochs 1990.8,


Nonlinear analysis of the threedimensional datum transformation [conformal group ?7(3)]


The weighted Procrustes algorithm is presented as a very effective tool for solving the threedimensional datum transformation problem.


In particular, the weighted Procrustes algorithm does not require any initial datum parameters for linearization or any iteration procedure.


The extra gravity data did indeed improve the fit of the computed geoid to local GPS/Australian Height Datum (AHD) observations by 58% over the gravimetriconly AUSGeoid98.


On monitoring a vertical datum with satellite altimetry and waterlevel gauge data on large lakes


Using TOPEX satellite altimetry, waterlevelgauge data, and a geoid model, the geopotential, W0, of the International Great Lakes Datum of 1985 (IGLD85) is determined.


The two sets of data yield generally consistent results at the fewdecimeter level and both indicate a tilt of about 33 cm in the computed datum across the region.


The effects of these errors and those of datum shifts are assessed using three independent DEMs for a test region in South Africa.


Local datum definition and geodetic network positioning using global navigation satellite systems


The problem of datum definition as applied to localarea geodetic networks is investigated using data collected from global navigation satellite systems (GNSS).


Traditionally, datum definition has been accomplished by constraining one station to set coordinates.

