Vol. 1, No. 1, 2002 JournalJournal ofof GlobalGlobal PositioningPositioning SystemsSystems ISSN 1446-3156 (Print Version) ISSN 1446-3164 (CD-ROM Version) International Association of Chinese Professionals in Global Positioning Systems (CPGPS) Journal of Global Positioning Systems Aims and Scope The Journal of Global Positioning Systems is a peer-reviewed international journal for the publication of new information, knowledge, scientific developments and applications of the global navigation satellite systems as well as other positioning, location and navigation technologies. The Journal will include original research papers, review articles and invited contributions. Short research and technical notes, book reviews, and commercial advertisements are also welcome. Specific questions about the suitability of prospective manuscripts may be directed to the Editor- in-Chief. Editor-in-Chief Jinling Wang The University of New South Wales, Sydney, Australia [email protected] Editorial Board Ruizhi Chen Changdon Kee Salah Sukkarieh Finnish Geodetic Institute, Finland Seoul National University, Korea The University of Sydney, Australia Wu Chen Hansjoerg Kutterer Todd Walter Hong Kong Polytechnic University, Hong Kong Deutsches Geodaetisches Forschungsinstitut, Stanford University, United States Dorota Grejner-Brzezinska Germany Lambert Wanninger Ohio State University, United States Jiancheng Li Ingenieurbuero Wanninger, Germany Ren Da Wuhan University, China Caijun Xu Bell Labs/Lucent Technologies, Inc., United States Esmond Mok Wuhan University, China C.D. de Jong Hong Kong Polytechnic University, Hong Kong Guochang Xu Delft University of Technology, The Netherlands J.F. Galera Monico GeoForschungsZentrum (GFZ) Potsdam, Hans-Jürgen Euler Departamento de Cartografia FCT/UNESP, Brazil Germany Leica Geo-systems, Switzerland Günther Retscher Ming Yang Yanming Feng Vienna University of Technology, Austria National Cheng Kung University, Taiwan Queensland University of Technology, Australia Gethin Roberts Kefei Zhang Yang Gao University of Nottingham, United Kingdom RMIT University, Australia University of Calgary, Canada Rock Santerre Guoqing Zhou Shaowei Han Laval University, Canada Old Dominion University, United States Thales Navigation, United States Bruno Scherzinger Applanix Corporation, Canada Editorial Advisory Board Junyong Chen Gerard Lachapelle Peter J.G. Teunissen National Bureau of Surveying and Mapping, China University of Calgary, Canada Delft University of Technology, The Netherlands Yongqi Chen Jingnan Liu Sien-Chong Wu Hong Kong Polytechnic University, Hong Kong Wuhan University, China Jet Propulsion Laboratory, NASA, United States Paul Cross Keith D. McDonald Yilin Zhao University College London, United Kingdom NavTech, United States Motorola, United States Guenter Hein Chris Rizos University FAF Munich, Germany The University of New South Wales, Australia IT Support Team Satellite Navigation & Positioning Group The University of New South Wales, Australia Publication and Copyright The Journal of Global Positioning Systems is an official publication of the International Association of Chinese Professionals in Global Positioning Systems (CPGPS). It is published twice a year, in June and December. The Journal will have both print version (ISSN 1446-3156) and CD-ROM version (ISSN 1446-3164), which can be accessed through the CPGPS website at http://www.cpgps.org/journal/journal.html. Whilst CPGPS owns all the copyright of all text material published in the Journal, the authors are responsible for the views and statement expressed in their papers and articles. Neither the authors, the editors nor CPGPS can accept any legal responsibility for the contents published in the journal. Subscriptions and Advertising Membership dues in the CPGPS include the subscription to the Journal CPGPS Logo Design: during the period of membership. Subscriptions from non-members Peng Fang University of California, San Diego, United States and advertising inquiries should be directed to: CPGPS Headquarters Cover Design and Layout: Department of Geomatics Engineering Satellite Navigation & Positioning Group The University of Calgary The University of New South Wales, Australia Calgary, Alberta, Canada T2N 1N4 Fax: +1(403) 284-1980 Printing: E-mail: [email protected] Wuhan University, China © CPGPS, 2002. All the rights reserved. Journal of Global Positioning Systems Vol. 1, No.1, 2002 Table of Contents The Modernization of GPS: Plans, New Capabilities and the Future Relationship to Galileo Keith D. McDonald .......................................................................................................................................................... 1 Precise Ionosphere Modeling Using Regional GPS Network Data Y. Gao and Z.Z. Liu ....................................................................................................................................................... 18 Multipath Mitigation for Bridge Deformation Monitoring G. W. Roberts, X. Meng, A. H. Dodson, E. Cosser........................................................................................................ 25 3D Multi-static SAR System for Terrain Imaging Based on Indirect GPS Signals Yonghong Li, Chris Rizos, Eugene Donskoi, John Homer, Bijan Mojarrabi................................................................. 34 Accuracy Performance of Virtual Reference Station (VRS) Networks Günther Retscher ............................................................................................................................................................ 40 Pseudolite Applications in Positioning and Navigation: Progress and Problems J. Wang........................................................................................................................................................................... 48 Experts Forum An Overview of Atmospheric Radio Occultation T. P. Yunck,.................................................................................................................................................................... 58 The Contribution of GPS Flight Receivers to Global Gravity Field Recovery Peter Schwintzer and Christoph Reigber, ....................................................................................................................... 61 Ocean Remote Sensing with GPS Cinzia Zuffada ................................................................................................................................................................ 64 GPS For Ionospheric Sensing: Space and Ground Based E. A. Essex ..................................................................................................................................................................... 66 Journal of Global Positioning Systems (2002) Vol. 1, No. 1: 1-17 The Modernization of GPS: Plans, New Capabilities and the Future Relationship to Galileo Keith D. McDonald Navtech Consulting, Alexandria, VA USA Received: 18 July 2002 / Accepted: 18 July 2002 Abstract. This paper reviews the development, status that could be implemented with new generations of GPS and current capabilities of GPS. The modernization replenishment and follow-on spacecraft. This paper improvements planned for GPS are then discussed addresses the concerns, options, issues and plans during and summarized, including brief descriptions of the the next fifteen years and beyond for improvements to additional features planned for the spacecraft, the GPS and the significant performance benefits that will be available to users. The European Community is planning control segment and the user equipment. A to deploy a navigation satellite system with similar discussion is presented of the impact of the system performance characteristics to GPS in the 2008 time modernization plans and activities in improving the frame. We will briefly investigate the benefits and performance of the four principal operating modes features of the combined capabilities of GPS and Galileo of GPS. The implications of the GPS modernization that may impact international users in the future. and enhancement activities and their relationship to GPS has become an essential part of the navigation, the analogous European Galileo program activities positioning, surveillance and timing aspects of ground, and other GNSS efforts are covered. Several marine, aviation and space applications. The current uses, technical, policy and implementation concerns with new ones, will continue to grow resulting in a need relating to the timely deployment of the for even more demanding capabilities. improvements to GPS are briefly addressed. 2 Background Key words: GPS, Modernization, GNSS, GALILEO 2.1 Development and Implementation The US Department of Defense (DOD) developed the 1 Introduction concept and general configuration for GPS in the early 1970's as a joint program involving all three military During the past three decades, the Global Positioning departments. The program was initially directed by the System (GPS) has grown from a navigation concept Joint Services Navigation Satellite Executive Steering through development and implementation to an Group (NAVSEG) formed in the Pentagon in 1968. This operational system of 28 spacecraft currently serving group was chartered to determine the feasibility and millions of users. Its use has increased such that over a practicality of a space-based navigation system for million GPS receivers a year have been produced since improving military navigation and positioning.