A detailed Study of the Earth tide effects on the GPS kinematic/static posi
tioning is presented in this paper by using theoretical Earth tide computat
ion and practical GPS data processing. Tidal effects could reach up to 30 c
m in Denmark and Greenland depending on the measuring time and the position
of reference station. With a baseline less than 80 km, the difference of t
he Earth tide effects could reach more than 5 mm. So, in precise applicatio
ns of GPS positioning, the Earth tide effect has to be taken into account e
ven for a relative small local GPS network. Several examples are given for
demonstrating that the Earth tide effects can be viewed by GPS surveying. T
hey are given through static GPS data static processing, static GPS data ki
nematic processing, and airborne kinematic GPS data processing. In these ca
ses, the Earth tide effects can be subtracted from the GPS results. The det
ermination of tidal parameter through static GPS data kinematic processing
has also been tested, (C) 2000 Elsevier Science Ltd. All rights reserved.