Vertical Reference Systems

The Symposium on Vertical Reference Systems (VeReS) was initiated on the occasion of the XXII General Assembly of the International Union of Geodesy and Geophysics (IUGG), Birmingham 1999, by Professor Dr. Wolfgang Torge, Past President of the International Association of Geodesy (lAG) and representative of lAG to the Pan-American Institute of Geography and History (PAIGH). The idea was to organise another joint symposium of lAG and PAIGH like the previous one held during the XX IUGG General Assembly at Vienna, Austria, in 1991. Good reasons for such a joint symposium were the great success and the ongoing activities of the Project on the South American Geocentric Reference System (Sistema de Referencia Geocentrico para America del Sur, SIRGAS) being sponsored by lAG and PAIGH since 1993. The SIR GAS Project (Working Group I) had presented a continental South American reference frame of 58 stations during the lAG Scientific Assembly at Rio de Janeiro, in 1997. This reference frame was already adopted by several South American countries as the basis for their new national horizontal geodetic datums (SIRGAS Working Group II). To overcome the problems of the heterogeneous vertical (height) datums between the individual countries, SIRGAS had installed its Working Group III "Vertical Datum" in 1997. As the discussion on the unification of vertical reference systems is also going on in lAG and other bodies of science and practice, it was decided to dedicate the symposium to this topic.

The cooperation between IAG and PAIGH.- Velocity estimates of IGS RNAAC SIRGAS stations.- The vertical reference system in the Argentine Republic.- Improvements in the ellipsoidal heights of the Argentine reference frame.- Brazilian first order levelling network.- The vertical geodetic network in Chile.- Approach to the new vertical reference system for Colombia.- Vertical control networks in Indonesia.- Current status of vertical control network in Peninsular Malaysia and plans for adjustment.- Vertical geodetic network of Mexico.- The new height system in Switzerland.- Subsidence of the permanent GPS station Bogotá.- Time series analysis of the daily solutions of the AGRS.NL reference stations.- Vertical motions from geodetic and geological data: a critical discussion of the results.- Central European vertical and kinematic systems.- Advances in the calculation of a height transformation model in Buenos Aires Province.- Estimation of station heights with GPS.- Contribution of individual space techniques to the realization of vertical reference systems.- Analysis of time series of GPS height estimates with regard to atmospheric pressure loading.- The impact of antenna radomes on height estimates in regional GPS networks.- Influence of tropospheric zenith delays obtained by GPS and VLBI on station heights.- A study on the effects of data accuracy and datum inconsistencies on relative GPS levelling.- Employing the strict kinematic model for the maintenance of a height reference frame based on conventional levellings.- Minimising the error budget in the third precise levelling of Sweden.- The influence of gravity variations on leveled heights.- Motorised levelling — the ultimate tool for production of classic national height networks.- New results in the determination of the geoid model in Argentina.- Data collecting and processing for quasi-geoid determination in Brazil.- Improving the quasigeoid model in Colombia.- Isostatic anomaly maps for Colombia.- Project to refine the geoidal solution in the Mexican area.- The vertical datum and local geoid models in Uruguay.- One approach to determine the geoid local trend at Montevideo area.- Current status of geoid calculation in Venezuela.- Geoidal undulations from GPS measurements in Venezuela.- Geoid study in Tierra del Fuego.- Preliminary geoid model for Tierra del Fuego.- Using a “GPS/MSL geoid” to test geoid models in the UK.- Online and postprocessed GPS-heighting based on the concept of a digital height reference surface (DFHRS).- General scheme for the computation of regional geoid undulations using spherical wavelets.- Predicting free-air gravity anomaly using artificial neural network.- Local geoid models — practical considerations.- The sea surface topography and its impact to global height system definition.- Correlation between multi-mission altimeter time series and tide gauge registrations in the Caribbean sea.- The EVAMARIA project: Identification and verification of sea level anomalies in the North Atlantic.- Vertical crustal movements of tide gauges sites around the North Atlantic Ocean.- Caribbean sea level variability from TOPEX/Poseidon altimetry.- Monitoring tide gauges benchmarks in Argentina by GPS.- Mean sea level and sea surface variability of Indonesian waters from TOPEX/Poseidon.- Using GPS to separate crustal movements and sea level changes at tide gauges in the UK.- Towards a globally consistent nautical chart datum definition in France.- The 3-D coastline of the new millenium (managing datums in n-dimension space).- Geoid variations due to mean sea level variations.- World height system specified by geopotential at tide gauge stations.- Scientific foundations of the SIRGAS vertical reference system.- The vertical reference frame for the Americas — The SIRGAS 2000 GPS campaign.- Preliminary results of SIRGAS 2000 campaign — IBGE analysis center.- Processing of the SIRGAS 2000 GPS network at DGFI.- Associated problems to link South American vertical networks and possible approaches to face them.- Connection of the vertical control networks of Venezuela, Brazil and Colombia.- Attempts to unify the Australian height datum between the Mainland and Tasmania.- Towards the establishment of an Indonesian unified vertical datum.- Determination of a unified height reference system for the computation of a local geoid around the volcanoes Merapi and Merbabu, Java, Indonesia.- The vertical reference system for Europe.- Cartagena Statement on Vertical Reference Systems.