Table Of ContentInternational Association
of Geodesy Symposia
Klaus-Peter Schwarz, Series Editor
Springer
Berlin
Heidelberg
New York
Barcelona
Budapest
Hong Kong
London
Milan
Paris
Tokyo
International Association
of Geodesy Symposia
Klaus-Peter Schwarz, Series Editor
Symposium 101: Global and Regional Geodynamics
Symposium 102: Global Positioning System: An Overview
Symposium 103: Gravity, Gradiometry, and Gravimetry
Symposium 104: Sea Surface Topography and the Geoid
Symposium 105: Earth Rotation and Coordinate Reference Frames
Symposium 106: Determination of the Geoid: Present and Future
Symposium 107: Kinematic Systems in Geodesy, Surveying,
and Remote Sensing
Symposium 108: Applications of Geodesy to Engineering
Symposium 109: Permanent Satellite Tracking Networks for
Geodesy and Geodynamics
Symposium 110: From Mars to Greenland: Charting Gravity with
Space and Airborne Instruments
Symposium 111: Recent Geodetic and Gravimetric Research in Latin America
Symposium 112: Geodesy and Physics of the Earth: Geodetic Contributions
to Geodynamics
Symposium 113: Gravity and Geoid
Symposium 114: Geodetic Theory Today
Symposium 115: GPS Trends in Precise Terrestrial, Airborne,
and Spaceborne Applications
Symposium 116: Global Gravity Field and Its Temporal Variations
Symposium 117: Gravity, Geoid and Marine Geodesy
Symposium 118: Advances in Positioning and Reference Frames
Symposium 119: Geodesy on the Move
Geodesy on the Move
Gravity, Geoid, Geodynamics and Antarctica
lAG Scientific Assembly
Rio de Janeiro, Brazil, September 3-9, 1997
Convened and Edited by
Rene Forsberg, Martine Feissel
and Reinhard Dietrich
" Springer
Volume Editors Series Editor
Prof. Dr. Rene Forsberg Prof. Dr. Klaus-Peter Schwarz
Department of Geodynamics University of Calgary
Kort & Matrikelstyrelsen Department of Geomatics Engineering
Rentemestervej 8 2500 University Drive N. W.
DK-2400 Copenhagen NV Calgary, Alberta T2N IN4
Denmark Canada
Prof. Dr. Martine Feissel
Observatoire de Paris
61 Avenue de rObservatoire de Paris
F-75014 Paris
France
Prof. Dr. Reinhard Dietrich
Institut fur Planetare Geodasie
Technische Universitat Dresden
MommsenstraEe 13
D-Ol062 Dresden
Germany
Library of Congress Cataloging-in-Publication Data
Geodesy on the move: lAG Scientific Assembly, Rio de Janeiro, Brazil, September 3-9, 1997/ convened and edited
by Rene Forsberg, Martine Feissel and Reinhard Dietrich.
p. cm. --(International Association of Geodesy symposia; symposium 119)
Includes bibliographical references and index.
ISBN-13: 978-3-642-72247-9 e-ISBN-13: 978-3-642-72245-5
DOl: 10.1007/978-3-642-72245-5
1. Gravity-Measurement-Congresses. 2. Earth-Figure-Congresses. 3. Geodynamics-Congresses. 4. Geodesy
Antarctics-Congresses. I. Forsberg, Rene. II. Feissel, Martine. III. Dietrich, Reinhard, 1949- . IV. Scientific
Assembly of the International Association of Geodesy (1997: Rio de Janeiro, Brazil). V. Series.
QB330.G45 1998 526' .1-DC21 98-28910 CIP
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Dedication
This volume is dedicated to the late Professor Herman van Gysen, an outstanding geodesist from
South Africa, who as JAG Special Study Group president and co-convener took part in the
preparation oft he Rio Scientific Assembly. He had to cancel his participation in the meeting at short
notice due to the unexpected discovery of cancer, which claimed his life on February 19, 1998, at a
far too young age.
FOREWORD
Klaus-Peter Schwarz, lAG President
The University of Calgary
The Scientific Assembly of the International Association of Geodesy (lAG) was held
from September 3 to 9, 1997 in Rio de Janeiro, Brazil, in conjunction with the 18th
Brazilean Congress of Carthography. This was the first time that one ofthe major lAG
meetings took place in Brazil. It provided an opportunity to showcase the progress of
geodetic work in South America through campaigns such as SIRGAS. It also provided an
opportunity for a large group of international experts to present the state of the art in ge
odesy and geodynamis and to interact with their hosts on possibilities of future coopera
tion. For the lAG, it continued a trend, started in Beijing four years ago, to hold major
geodetic meetings outside of Europe and North America. The International Geoid School
which was held in Sao Paulo following this meeting showed another facet of this grow
ing internationalization of lAG activities and services.
The scientific program of the meeting consisted of three symposia and two special ses
sions, namely
Symposiuml: Advances in Positioning and Reference Frames
Symposium 2: Gravity and Geoid
Symposium 3: Geodynamics
Special Session 1: lAG Services
Special Session 2: Geodesy in Antartica.
Papers presented at the first symposium are published in volume 1 of these proceedings,
while papers of symposia 2 and 3 as well as special session 2 are contained in volume 2.
Papers presented at special session 1 will be published separately. More details on the
individual volumes are given in the prefaces written by the convenors.
The meeting was jointly organized by the lAG and the Brazilean Society of Cartography,
Geodesy, Photogrammetry and Remote Sensing. The two local organizing committees
worked closely together to economize on some of the organizational aspects and to guar
antee a smooth running of two conferences in the same place. Thanks go to our Brazilean
colleagues for their hard work and their warm hospitality. On the geodetic side, special
thanks go to Professor D. Blitzkov, the national representative of the lAG who chaired
the lAG Local Organizing Committee (LOC), and the dedicated group of individuals
working working with him. Similarly, Professor W. Torge, past president of the lAG,
who provided the liason between the LOC and the lAG Executive deserves a special vote
of thanks. Finally, the symposium and session convenors who not only organized the
scientific program but also took care of organizing the review rocess and editing these
proceedings, are thanked for their outstanding efforts.
PREFACE
The International Association of Geodesy (lAG) held its Scientific Assembly in Rio de
Janeiro, Brazil, 3-9 September 1997, in conjunction with the XVIII Brazilian Congress of
Carthography. It was organized by the Brazilian Society of Carthography, Geodesy, Pho
togrammetry and Remote Sensing, with Prof. D. Blitzkow as the lAG national organizer.
This was the first time the regular (4-year interval) lAG Scientific Assembly was held in
South America. The meeting was attended by approx. 250 participants from around the
world.
The meeting was difided into three main symposia: Advances in Positioning and Refer
ence Frames, Gravity and Geoid, and Geodynamics. In addition, special sessions were
scheduled on JAG services and Geodesy in Antarctica.
The present proceedings (Vol. 119) -cover the symposia Gravity and Geoid, Geodynam
ics, and the special session Geodesy in Antarctica. The title, Geodesy on the Move -Grav
ity, Geoid, Geodynamics and Antarctica, symbolizes the dynamics of geodesy, both in
terms of movement in the rapid scientific development of the field, the constant movement
of the Earth's crust, and the move in geodesy to cover the whole Earth geodetically -with
Antarctica as the last frontier.
The proceedings were peer-reviewed in accordance with lAG rules. For the Gravity and
Geoid symposium, the review process was organized by the session convenors: G. Boe
decker, M.G. Sideris, N.K. Pavlis, and P. Holota, in cooperation with the symposium
convenor (R. Forsberg). This is gratefully acknowledged.
The Gravity and Geoid symposium was divided into four sessions:
-Developments in static and kinematic gravimetry;
-Global gravity field from gravimetry and satellite altimetry;
-The geoid: theory and methods;
-Regional geoids and the gravity field in South and Central America;
These areas represent active areas of current research.
In the area of gravimetry, the presentations show constant development towards increased
accuracies at the 10-9 level, with new technological developments such as superconduct
ing and airborne gravimetry, which continue to improve. The global gravity field session
covers the ongoing developments of global spherical harmonic reference models, such as
the newest global gravity field model EGM96, including developments in recovering the
marine gravity field from satellite altimetry, and the prospects of future gravity field mis
sions to yield improved models. Within the theoretical and methodological developments
in geoid determination and gravity field modelling, new advances include presentations on
wavelets, cap sizes and modified kernels, and on terrain corrections and harmonic con
tinuation.
The Global Gravity Field session was a special occasion to thank Prof. (Emeritus) R.H.
Rapp, Ohio State University, who over the decades has been the pioneer and driving force
in developing high-resolution global spherical harmonic models, with the EGM96 model
being the crowning chievement, representing the combined efforts of space, military, and
university groups. R.H. Rapp was presented a special memorial gift during the session. He
gave an expanded overview of the topic, followed by presentations of many of his former
students.
The Geodynamics proceedings included:
-Earth rotation and variations of the geopotential;
-Reference frames and global deformations;
-Combination of space observations with other observations of deformations.
The symposium presented an excellent opportunity to survey the main results of more than
a decade of work in setting up global reference frames and organizing programs to moni
tor crustal deformations on a world wide or regional scale. During the 10 years of its
existence, the International Earth Rotation Service (IERS) has monitored and provided
access to the International Celestial and Terrestrial Reference Systems and to the Earth's
orientation with an overall consistency equivalent to 1 cm on the surface of the Earth. The
International Terrestrial Reference Frame (ITRF) provides positions and velocities for
about 300 sites worldwide. This continuing effort is based on the close cooperation of
laboratories and agencies making use of VLBI and satellite-geodetic techniques (laser
ranging, GPS, DORIS).
Several global site motions solutions based on a single technique or on a combination of
techniques were presented, showing that the motion of the major plates can be estimated
with a precision of a few millimeters per year, thus allowing the study of some of the
boundary zones. Plans or results were presented for a large number of crustal deformation
programs based on space geodesy that concern many parts of the world: Asia-Pacific,
Central Europe, the Middle-East, Egypt, the western Mediterranean Sea, the Andes, Cen
tral America. A number of contributions deal with deformation studies based on the inte
gration of space-geodetic observations (GPS) with other types of observations, such as
SAR interferometry, tide gauges, strainmeters/tiltmeters, and variations in the vertical or
geological data. Exciting results showing seasonal and longer term geopotential and geo
center variations in the atmosphere-hydrosphere-solid Earth system, based both on space
geodetic observations (SLR, DORIS) and atmospheric and oceanic data and models, were
also presented.
The Geodesy in Antarctica session was a special "interdisciplinary" geodesy session,
added to the program by the lAG executive committee, in order to stress the importance of
this continent in modem geodesy, and taking advantage of the location of the lAG Scien
tific Assembly in the southern hemisphere. The importance of Antarctica for geodesy is
increasing, as Antarctica holds the key to many challenging scientific questions regarding
global change and geodynamics. Antarctica is also the last major void of terrestrial gravity
x
field information on Earth, making an effort to collect additional data urgent in coming
years, in order to support future gravity field space missions (planned missions will leave
polar coverage gaps) and to improve global geopotential model development.
The Antarctica special session featured a broad spectrum of topics, ranging from over
views of global change and geodynamics, presentations relating to gravity field (geoid and
airborne gravity), to presentations of more localized efforts in geodynamics and funda
mental geodetic reference stations. Presentations on ice dynamics include measurements
by GPS methods and SAR interferometry.
May 1998 Rene FORSBERG
Martine FEISSEL
Reinhard DIETRICH
XI
CONTENTS
GRAVITY AND GEOID
Developments in static and kinematic gravimetry
Convenor: G. Boedecker
The changing role of gravity reference networks
W Torge
Improving accuracy and reliability of airborne gravimetry by multiple system
configurations 11
K P. Schwarz, C. Glennie, A. Bruton
Combining airborne and ground gravity using collocation 18
C. C. Tscherning, F. Rubek, R. Forsberg
Comparisons between absolute (AG) and superconducting (SG) gravimeters 24
M Amalvict, J. Hinderer, 0. Francis, J. Makinen
An airborne geoid mapping system for regional sea-surface topography:
application to the Skagerrak and Azores areas 30
L. Bastos, S. Cunha, R. Forsberg, A. Olesen, A. Gidskehaug, U Meyer, T. Boebel,
L. Timmen, G. Xu, M Nesemann, K. Hehl
The German gravity base net 1994 (DSGN 1994) 37
B. Richter, H Wilmes, A. Franke, E. Reinhart
SAR Interferometry for improved terrain corrections in surface and airborne gravimetry 45
S. Nielsen, R. Forsberg, S. Ekholm, J. J. Mohr
National gravimetric network of Uruguay 51
W Subiza, L. Timmen, W Torge
Global gravity field from gravimetry and satellite altimetry
Convenors: N. G. Pavlis and M. G. Sideris
Past and future developments in geopotential modelling 58
R.H Rapp
The world of gravity according to Rapp 79
C. Jekeli
