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System Description - References

USER EXPERIENCE:

  • Development of a Real-Time Single-Frequency Precise Point Positioning System and Test Results
    Yang Gao and Kongzhe Chen
    The University of Calgary

    Describe the development of a real-time single-frequency PPP system
    using the ireal-time GPS orbit and clock products from the JPL GDGPS System.
    Report test results under road and marine conditions.
    ION GNSS 2006, Fort Worth, TX, USA, Sept.2005.

  • StarFire: A Global SBAS for Sub-Decimeter Precise Point Positioning
    Kevin Dixon
    Navcom Technology Inc.

    Describe the structure and performance of the Navcom differential system,
    which is based partially on JPL's Real Time GIPSY (RTG) software, and on
    the GDGPS tracking network.
    ION GNSS 2006, Fort Worth, TX, USA, Sept.2005.

  • Real-Time Precise Point Positioning (PPP) Using Single Frequency Data
    Kongzhe Chen and Yang Gao
    The University of Calgary

    Investigates PPP using single-frequency data and precise real-time
    orbits and clocks while comparing ionospheric correction methods:
    Klobuchar, GIM, GRAPHIC and ionospheric gradient estimation. Includes
    both static and kinematic airborne positioning results, contrasting
    the different modeling methods.
    ION GNSS 2005, Long Beach, CA, USA, Sept.2005.

  • Performance Evaluation of Global Differential GPS (GDGPS) for Single Frequency C/A Code Receivers
    Sundar Raman, and Lionel Garin
    SiRF Technology, Inc.

    Analyze the performance of GDGPS as a replacement for local differential GPS (LDGPS) for single-frequency users.
    ION GNSS 2005, Long Beach, CA, USA, Sept.2005.

  • Real-time Kinematic Positioning with NASA's Global Differential GPS System
    Kechine, M.O., C.C.J.M Tiberius, H. van der Marel
    University of Delft, The Netherlands

    Independent performance assessment of the GDGPS system for real-time
    kinematic positioning performed at University of Delft, The Netherlands.
    GNSS Conference, St. Petersburg, Russia, May 2004.


GDGPS SYSTEM DESCRIPTION AND PERFORMANCE ANALYSIS:

  • Enhanced Broadcast Ephemeris for High Accuracy Assisted GPS Positioning
    Yoaz Bar-Sever, Byron Iijima, Aldo Navarro, Larry Romans, Jan Weiss
    Jet Propulsion Laboratory, California Institute of Technology

    Enhanced broadcast ephemeris (e-BCE) is a novel A-GNSS product that uses the conventional RINEX broadcast ephemeris format to compensate for all key error sources in user positioning. It enables mobile wireless devices to obtain meter-level positioning without altering existing protocols or data interfaces anywhere along the A-GNSS communications chain.
    Presented at the ION GNSS 2012 meeting

  • Real-Time Sub-cm Differential Orbit Determination of Two Low-Earth Orbiters with GPS Bias Fixing
    Sien Wu and Yoaz Bar-Sever
    Jet Propulsion Laboratory, California Institute of Technology

    An effective technique for real-time differential orbit determination of two low Earth orbiters with GPS bias fixing is formulated. With this technique, only moderatequality GPS orbit and clock states (e.g., as available in real-time from the Global Differential GPS System with 1020 cm accuracy) are needed to seed the process.
    ION GNSS 2006, Fort Worth, TX, USA, Sept.2005.

  • The Global Differential GPS System (GDGPS) and The TDRSS Augmentation Service for Satellites (TASS)
    Yoaz Bar-Sever, Larry Young, Frank Stocklin, Paul Heffernan and John Rush
    Jet Propulsion Laboratory, California Institute of Technology

    Status of the NASA GDGPS System and the newly developed TDRSS
    Augmentation Service for Satellites (TASS), with focus on space applications.
    Presentation at the ESA 2nd Workshop on navigation equipment,
    Noordwijk, The Netherlands, December 2004.

  • Real-Time Point Positioning Performance Evaluation of Single-Frequency
    Receivers Using NASA's Global Differential GPS System

    Muellerschoen, R., B. Iijima, R. Meyer, Y. Bar-Sever, E. Accad
    Jet Propulsion Laboratory, California Institute of Technology

    Techniques for precise real time positioning of single frequency users.
    Accuracy assessment of real-time global ionospheric maps produced by
    the GDGPS System.
    ION GNSS Meeting, Long Beach, CA, September 2004.

  • Toward Decimeter-level Real-Time Orbit Determination:
    a Demonstration Using the SAC-C and CHAMP Spacecraft

    Reichert, A., T. Meehan, and T. Munson
    Jet Propulsion Laboratory, California Institute of Technology

    Demonstration of onboard, autonomous, real-time orbit determination
    with JPL's Real Time GIPSY (RTG) software and analysis of the
    orbit determination capabilities of the GDGPS System
    ION GPS Meeting, Portland OR, September, 2002.

  • Demonstration of Decimeter-level Real-time Positioning of an Airborne Platform
    M. Armatys, R. Muellerschoen, Y. Bar-Sever, R. Meyer
    Jet Propulsion Laboratory, California Institute of Technology

    Proceedings,ION NTM-2003, Anaheim, CA

  • Orbit Determination With NASA's High Accuracy Real-Time Global Differential GPS System
    R. J. Muellerschoen, A. Reichert, D. Kuang, M. Heflin, W. I. Bertiger and Y. E. Bar-Sever
    GPS orbits and clocks are computed in real-time with data from NASA's global GPS network. The accuracy of the GPS orbits and reference frame alignment to ITRF'97 is discussed. The dissemination of the global correction message is over the Internet, and a signal-in-space (SIS) is provided by America's Inmarsat satellite. The SIS will soon expand for global coverage with Inmarsat's ASPAC (Asia/Pacific) and EMEA (Europe/Africa) satellites yielding coverage over the entire globe between +/-75 degrees in latitude. The inherent latency in providing the corrections to the user through the geosynchronous satellites is shown to have little impact on true real-time positioning. Orbit determination, post-processed but filtered as if in real-time, of a low-Earth orbiter's GPS data using the real-time orbit and clock products will be presented. Anticipated plans call for uploading the code to a space-qualified receiver and performing orbit determination with the GPS differential global corrections as transmitted by the Inmarsat beams.
    Proceedings of ION GPS-2001, Salt Lake City, UT, September 2001.

  • Results of an Internet-Based Dual-Frequency Global Differential GPS System
    R. J. Muellerschoen, W. I. Bertiger and M. F. Lough
    Observables from a global network of 18 GPS receivers are returned in real-time to JPL over the open Internet. Global GPS orbits accurate to 30-40 cms RSS and precise dual-frequency GPS clocks are computed in real-time with JPL's Real-Time Gipsy (RTG) software. Corrections to the broadcast orbits and clocks are communicated to the user over the open Internet via a TCP server. Tests of user positioning show real-time RMS accuracy of 8 cms RMS in horizontal and 20 cms RMS in the vertical.
    Proceedings of IAIN World Congress, San Diego, CA, June 2000

  • An Internet-Based Global Differential GPS System, Initial Results
    R. J. Muellerschoen, W. I. Bertiger, M. F. Lough, D. Stowers, D. Dong
    Using a network of 15 global GPS receivers, GPS data is returning to JPL via the open Internet to determine the orbits and clocks of the GPS constellation in real-time. Corrections to the broadcast orbits and clocks are currently communicated in real-time to the user over the open Internet via a TCP server. Tests of user positioning show real-time RMS accuracy of ~10 cms RMS in horizontal and < 20 cms RMS in the vertical.
    ION National Technical Meeting, Anaheim, CA, Jan, 2000


THE EVOLUTION OF THE GDGPS SYSTEM:

  • RTGx is the next generation GDGPS orbit determination and positioning software
    RTGx is based on the navigation software for the Next Generation GPS Operational Control Segment (OCX) developed by JPL for the U.S. Air Force. Built to the exacting standards of the OCX Project, RTGx represents a significant improvement over RTG in quality and performance. This article, presented at the 2012 ION GNSS Meeting in Nashville, TN, describes the innovative design features of the software and its key quality attributes. RTGx will replace RTG as the GDGPS core orbit determination and positioning software in early 2013.

  • Flight Tests Demonstrate Sub 50 cms RMS Vertical WADGPS Positioning
    Wide Area Differential GPS (WADGPS) positioning is performed in real-time during NASA's DC-8 AirSAR flights. R. J. Muellerschoen, W. I. Bertiger and M. L. Whitehead
    The goal of the experiment is to demonstrate absolute positioning in earth-fixed coordinates to better than one meter in all components in real-time. Results show dual-frequency real-time RMS (root-mean-square) accuracy in the vertical to be 50-60 cms with an RMS horizontal accuracy of better than 40 cms.
    Proceedings of ION GPS-99, Nashville, Tenn., September 1999.

  • Incorporation of Orbital Dynamics to Improve Wide-Area Differential GPS
    J. Ceva, B. Parkinson, W. I. Bertiger, R. J. Muellerschoen, and T. P. Yunck
    Navigation, Summer 1997, Vol. 44, No. 2, pg. 171-180
    Invited Contribution to Institute of Navigation "Red Books," Global Positioning System: Papers Published in Navigation, Vol. IV, 1999.

  • A Real-Time Wide Area Differential GPS System
    W. I. Bertiger, Y. E. Bar-Sever, B. J. Haines, B. A. Iijima, S. M. Lichten, U. J. Lindqwister, A. J. Mannucci, R. J. Muellerschoen, T. N. Munson, A. W. Moore, L. J. Romans, B. D. Wilson, S. C. Wu, T. P. Yunck, G. Piesinger, and M. L. Whitehead
    Invited Contribution to Institute of Navigation "Red Books," Global Positioning System: Papers Published in Navigation, Vol. IV, 1999
    Navigation: Journal of the Institute of Navigation,  Vol. 44, No. 4, 1998, pgs. 433-447

  • A Close Look at Satloc's Real-Time WADGPS System GPS Solutions
    M. L. Whitehead, G. Penno, W. J. Feller, I. C. Messinger, W. I. Bertiger, R. J. Muellerschoen, and B. A. Iijima
    GPS Solutions, Vol 2, No. 2, John Wiley & Sons, Inc., 1998. Invited Paper

  • Precise Real-Time Positioning Using Wide Area Differential GPS, Field Tests
    W. I. Bertiger, Y. E. Bar-Sever, T. J. Borden, B. A. Iijima, R. J. Muellerschoen, T. N. Munson, A. W. Moore, L. J. Romans, S. C. Wu, M. L. Whitehead, W. Feller, G. Penno
    Proceedings of the ION National Tech. Meeting, Long Beach, CA, Jan. 1998

  • Concept for a Wide-Area GPS Navigation System
    W. I. Bertiger, S. M. Lichten, A. J. Mannucci, R. J. Muellerschoen, S. C. Wu, and T. P. Yunck
    NASA Tech Brief, NPO-19625, June, 1997.

  • A Prototype Real-Time Wide Area Differential GPS System
    W. I. Bertiger, Y. E. Bar-Sever, B. J. Haines, B. A. Iijima, S. M. Lichten, U. J. Lindqwister, A. J. Mannucci, R. J. Muellerschoen, T. N. Munson, A. W. Moore, L. J. Romans, B. D. Wilson, S. C. Wu, T. P. Yunck, G. Piesinger, and M. L. Whitehead
    Proceedings of the ION National Technical Meeting, Santa Monica, CA, Jan. 1997.

  • Orbit and Troposphere Results of a Real-Time Prototype WADGPS System
    R. J. Muellerschoen, W. I. Bertiger, and L. J. Romans,
    Proceedings of the ION National Tech. Meeting, Santa Monica, CA, Jan. 1997.

  • A Prototype WADGPS System for Real Time Sub-Meter Positioning Worldwide
    T. P. Yunck, Y. E. Bar-Sever, B. A. Iijima, S. M. Lichten, U. J. Lindqwister, A. J. Mannucci, R. J. Muellerschoen, T. N. Munson, L. J. Romans, S. C. Wu
    Proceedings of the 9th International Technical Meeting of The Institute of Navigation, Kansas City, MO, September 17-20, 1996.

  • soc format
    R. J. Muellerschoen

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