This volume contains most of the papers which were presented at the Interdisciplinary Symposium No. 4 "Geodetic Features of the Ocean Surface and their Implications" during the XVIII. General Assembly of the International Union of Geodesy and Geophysics (IUGG) in Hamburg, August 1983. The symposium was jointly sponsored by the International Associ ation of Geodesy (lAG) and the International Association for the Physi cal Sciences of the Ocean (IAPSO), and was as such one further step in animpQrtant line of international and interdisciplinary symposia, re lated to the field of Marine Geodesy. Originally the term "Marine Geodesy" was widely understood as "Geodesy in the Marine Environment" and dealt primarily with two as pects: precise position determination at sea and determination of a fine structured marine geoid. However, mainly with the impact of satel lite radar altimeter measurements, a new understanding began to develop: it became evident that the field of Marine Geodesy could not be treated adequately from geodesists alone but that it needed close cooperation with related disciplines such as oceanography and marine geophysics. Symposium No. 4 at Hamburg could demonstrate that this coopera tion has already become a lively reality. The "geodetic features of the ocean surface" don't only reflect oceanographical but also marine geo physical aspects. As such scientists from geodesy, oceanography, marine geology and geophysics came together to present their ideas and to dis cuss questions of mutual interest.

This book covers the entire field of satellite geodesy and is intended to serve as a textbook for advanced undergraduate and graduate students, as well as a reference for professionals and scientists in the fields of engineering and geosciences such as geodesy, surveying engineering, geomatics, geography, navigation, geophysics and oceanography. The text provides a systematic overview of fundamentals including reference systems, time, signal propagation and satellite orbits, together with observation methods such as satellite laser ranging, satellite altimetry, gravity field missions, very long baseline interferometry, Doppler techniques, and Global Navigation Satellite Systems (GNSS). Particular emphasis is given to positioning techniques, such as the NAVSTAR Global Positioning System (GPS), and to applications. Numerous examples are included which refer to recent results in the fields of global and regional control networks; gravity field modeling; Earth rotation and global reference frames; crustal motion monitoring; cadastral and engineering surveying; geoinformation systems; land, air, and marine navigation; marine and glacial geodesy; and photogrammetry and remote sensing. This book will be an indispensable source of information for all concerned with satellite geodesy and its applications, in particular for spatial referencing, geoinformation, navigation, geodynamics, and operational positioning.

Geodesy is the science of accurately measuring and understanding three fundamental properties of Earth: its geometric shape, its orientation in space, and its gravity field, as well as the changes of these properties with time. Over the past half century, the United States, in cooperation with international partners, has led the development of geodetic techniques and instrumentation. Geodetic observing systems provide a significant benefit to society in a wide array of military, research, civil, and commercial areas, including sea level change monitoring, autonomous navigation, tighter low flying routes for strategic aircraft, precision agriculture, civil surveying, earthquake monitoring, forest structural mapping and biomass estimation, and improved floodplain mapping. Recognizing the growing reliance of a wide range of scientific and societal endeavors on infrastructure for precise geodesy, and recognizing geodetic infrastructure as a shared national resource, this book provides an independent assessment of the benefits provided by geodetic observations and networks, as well as a plan for the future development and support of the infrastructure needed to meet the demand for increasingly greater precision. Precise Geodetic Infrastructure makes a series of focused recommendations for upgrading and improving specific elements of the infrastructure, for enhancing the role of the United States in international geodetic services, for evaluating the requirements for a geodetic workforce for the coming decades, and for providing national coordination and advocacy for the various agencies and organizations that contribute to the geodetic infrastructure.

This selection of papers emphasizes the advances in the field and covers a wide range of topics in geophysics, geodynamics, and oceanography to which modern geodesy is contributing.

It was in September 1906 that the predecessor of the IAG, the 'Internationale Erdmessung', th organized the 15 General Assembly at the Hungarian Academy of Sciences in Budapest. It was 95 years later, in September 2001, that the IAG returned to this beautiful city to hold its Scientific Assembly, IAG 2001, in the historical premises of the Academy. The meeting took place from September 2-7, 2001 and continued the tradition of Scientific Assemblies, started in Tokyo (1982) and continued in Edinburgh (1989), Beijing (1993) and Rio de Janeiro (1997). Held every four years at the midpoint between General Assemblies of the IAG, they focus on giving an integrated view of geodesy to a broad spectrum of researchers and practitioners in geodesy and geophysics. The convenient location of the main building of the Hungarian Academy in downtown Budapest and the superb efforts of the Local Organizing Committee contributed in a major way to the excellent atmosphere of the meeting. As at previous meetings, the scientific part of the program was organized as a series of symposia which, as a whole, gave a broad overview of actual geodetic research activities. To emphasize an integrated view of geodesy, the symposia did not follow the pattern of the IAG Sections, but focussed on current research topics to which several IAG Sections could contribute. Each symposium had 5 sessions with presented papers and poster sessions on two consecutive days.