NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competencies and with regard for appropriate balance.
This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences.
The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. William A. Wulf is president of the National Academy of Engineering.
The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine.
The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. William A. Wulf are chairman and vice-chairman, respectively, of the National Research Council.
This study was supported by a grant from the National Science Foundation to the National Academy of Sciences. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the organizations or agencies that provided support for the project.
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Copyright 1997 by the National Academy of Sciences. All rights reserved.
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All Papers in Part II of this report are reprinted as they were received from the authors. They were not formatted or edited by the National Research Council.
STEERING COMMITTEE ON IMPROVING THE DIFFERENTIAL GPS INFRASTRUCTURE FOR EARTH AND ATMOSPHERIC SCIENCE APPLICATIONS
RANDOLPH H. WARE (chair),
University Navstar Consortium, Boulder, Colorado
E. ANN BERMAN,
Tri-Space, Inc., McLean, Virginia
Massachusetts Institute of Technology, Cambridge
RUTH E. NEILAN,
Jet Propulsion Laboratory, Pasadena, California
BENJAMIN W. REMONDI,
The XYZ's of GPS, Inc., Dickerson, Maryland
ROBERT J. SERAFIN (NAE),
National Center for Atmospheric Research, Boulder, Colorado
W. KENNETH STEWART,
Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
Aeronautics and Space Engineering Board Staff
David A. Turner, Study Director
George M. Levin, Board Director
Ted Morrison, Senior Project Assistant
AERONAUTICS AND SPACE ENGINEERING BOARD
JOHN D. WARNER (chair),
The Boeing Company, Seattle, Washington
Aerospace Corporation, Los Angeles, California
Federation of American Scientists, Washington, D.C.
GEORGE A. BEKEY,
University of Southern California, Los Angeles
GUION S. BLUFORD, JR.,
NYMA, Inc., Brook Park, Ohio
RAYMOND S. COLLADAY,
Lockheed-Martin Astronautics, Denver, Colorado
BARBARA C. CORN,
BC Consulting, Inc., Searcy, Arkansas
STEVEN D. DORFMAN,
Hughes Electronics Corporation, Los Angeles, California
DONALD C. FRASER,
Boston University, Boston, Massachusetts
International Technology Underwriters, Bethesda, Maryland
WILLIAM H. HEISER,
U.S. Air Force Academy, USAF Academy, Colorado
U.S. Air Force (retired), Williamsburg, Virginia
Huberman Consulting Group, Washington, D.C.
JAMES G. O'CONNOR,
GRACE M. ROBERTSON,
Boeing (formerly McDonnell Douglas Aerospace), Long Beach, California
Stanford University, Stanford, California
George M. Levin, Director
With support from the National Science Foundation and other federal agencies, the National Research Council established a steering committee, under the auspices of the Aeronautics and Space Engineering Board to design, organize, and conduct a workshop to discuss plans and objectives for Global Positioning System (GPS) reference station networks1 and to develop options for improving communications and coordination among GPS users in the Earth, oceanic, and atmospheric sciences and reference station network operators. The steering committee was asked to develop a workshop agenda that might include descriptions and discussions of the following: (1) GPS networks, their purposes, and the type and format of data they provide; (2) GPS scientific applications and their requirements; (3) potential modifications for maximizing the usefulness of GPS data for scientific applications; (4) commonalities between the requirements of various scientific applications; (5) options for improving coordination and communication among the scientific GPS users and network operators; and (6) benefits and costs associated with improved coordination and communication.2
The NRC Steering Committee on Improving the Differential GPS Infrastructure for Earth and Atmospheric Science Applications, hereinafter referred to as the Steering Committee, was formed in November 1995 and held its first meeting on December 20, 1995.3 At this meeting, the Steering Committee received briefings on civil GPS planning and policy making mechanisms within the federal government and on the current status of federally funded and operated GPS reference station networks.4 The Steering Committee also heard remarks from the workshop's sponsors and engaged in a roundtable discussion on the expectations for, and goals of, the workshop. This information was then used by the Steering Committee to plan the workshop agenda.
The workshop was held at the University Corporation for Atmospheric Research, Boulder, Colorado on March 11 and 12, 1996. Approximately 75 individuals from government, academia, and industry who either use, manage, operate, or supply equipment for GPS refernce station networks attended the workshop. The following items were included on the agenda:5
introduction to civilian GPS policy and management within the federal government
presentations from public sector network operators and service providers
poster papers on networks, data formats, and access to GPS-derived data via the World Wide Web
presentations on site, network, and data requirements for GPS applications in the earth, oceanic, and atmospheric sciences
three working groups sessions (GPS networks, data sources, and static positioning applications; dynamic positioning/navigation applications; and GPS-based remote sensing of the atmosphere) to discuss issues raised in the presentations relating to sources of error, user requirements, network
At a minimum, a GPS reference station consists of a GPS receiver and antenna temporarily or permanently located at a carefully surveyed geodetic control point. Equipment for storing data derived from the GPS signal and disseminating this data to users is often also associated with reference stations.
The benefits of improved coordination and communication among scientific GPS users and network operators are discussed in various places throughout Section I of this report. However, the costs of improved coordination and communication were not discussed at the workshop and, therefore, are not discussed in the report.
Appendix B contains brief biographies of the Steering Committee members
The status of the U.S. Air Force ground control network used to maintain the operational capability of the GPS satellites was not discussed at this meeting or at the workshop.
and data standardization, and user/operator coordination
plenary session for presentations by each working group and related discussions
The Steering Committee met once more on the day after the workshop to begin writing the summary portion of this report.
ORGANIZATION OF THE REPORT
This report, which represents the results of the workshop, is divided into two sections.6 Section I includes an executive summary, a chapter introducing the reader to GPS and its usefulness for Earth, oceanic, and atmospheric research, and four chapters summarizing the themes of the workshop presentations, poster papers, and working group discussions. Section II contains the proceedings of the workshop and is divided into five chapters corresponding to the five categories of invited papers written by workshop speakers and authors of poster papers. The appendices contain additional information about the workshop and the Steering Committee.
The Steering Committee thanks everyone who participated in the workshop for their thoughtful contributions.
This report does not claim to discuss or represent every GPS application in the geosciences or to represent every organization that uses GPS for these applications. In addition, it does not discuss or represent every orgainization that manages and operates a GPS reference station network. The report is limited to a summary and proceedings of the events that took place at the workshop.