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SENH Program Executive Review

SENH Program Executive Review. Geodetic Networks. "In all things it is a good idea to hang a question mark now and then on the things we have taken for granted." Bertrand Russell. NASA ESE Needs for Geodetic Networks.

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SENH Program Executive Review

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  1. SENH Program Executive Review Geodetic Networks "In all things it is a good idea to hang a question mark now and then on the things we have taken for granted." Bertrand Russell Geodetic Networks

  2. NASA ESE Needs for Geodetic Networks • Long term, systematic measurements of the Earth system require the availability of a terrestrial reference frame (TRF) that is stable over decades and independent of the technology used to define it. • The space geodetic networks provide the critical infrastructure necessary to develop and maintain the TRF and the needed terrestrial and space borne technology to support the Earth Science Enterprise goals and missions. • This infrastructure is composed of the:- Physical networks,- Technologies that compose them, and- Scientific models and model development that define a TRF. Geodetic Networks

  3. Geodetic Networks: • A stable and accurate TRF underlies Solid Earth and Climate roadmaps • SESWG report • Geodetic networks are one of seven observation strategies to address the fundamental solid Earth questions. • Maintenance of the global geodetic network, the TRF, and Earth Orientation Parameters is the “supporting framework”: an element of the fully realized solid Earth program. Geodetic Networks

  4. Geodetic Networks: Realization of TRF • TRF is a set of station positions and velocities • Networks of SLR, VLBI, and GPS ground systems enable TRF realization • Techniques have unique yet complementary capabilities • Allowing for evaluation of systematic error sources • Techniques are interdependent for TRF definition • Data and products are provided to the research community via international services of the IAG: IGS, ILRS, IVS. • Current consistency and accuracy of space geodetic systems • 1-3 cm positions, mm/yr velocities • 0.1 mas/day pole position • 3 µs UT1 • Sub-nanosecond timing distribution Geodetic Networks

  5. Geodetic Networks: 5-year outcome • TRF realized by coordinated multi-technique networks and analysis • Sub-centimeter consistency and accuracy globally • Improvement in the vertical component • Consistent and robust access to the improved TRF in real-time for all users • Improvement in network distributions, characteristics and efficiencies • Real-time GPS global sub-network, GNSS, GPS3 • eVLBI • SLR2000 • Analysis development and validation to optimize multi-technique methods • Improved data and product access interfaces via • Proposed collaborative project to implement state-of-the-art services aligned with SEEDS Geodetic Networks

  6. Geodetic Networks: NASA’s role among global collaborators • Networks, through the TRF, provide critical infrastructure to support flight projects. • This support is assumed by current and future missions to be provided yet is rarely budgeted or planned. • NASA leverages its resources by cooperating with international partners. • NASA supports and coordinates the geodetic services through central offices at JPL (IGS) and GSFC (ILRS and IVS). • This NASA coordination is a highly successful international activity endorsed by international organizations such as the IAG. • NASA’s space geodetic data sets are augmented by data contributed by other agencies to the international pool. • These activities are supported by the Crustal Dynamics Data Information System (CDDIS), a key data center supporting the IGS, ILRS, IVS, and IERS. • This results in access to greater and enhanced data sets and products. Geodetic Networks

  7. Geodetic Networks: Issues and Challenges • Maintaining and upgrading aging equipment and hardware • Transitioning new technology into the definition of the TRF • Developing new analysis techniques to address evolving requirements and new opportunities • Identifying a mechanism by which the support for this vital infrastructure can be shared by all users within NASA Geodetic Networks

  8. Introduction wrap-up • Geodetic networks support the TRF requirements of NASA ESE missions • Each of SLR, VLBI, GPS substantially and uniquely contributes to TRF determination • NASA’s SLR, VLBI, and GPS groups collaborate toward wide-ranging improvements in the next 5 years • NASA leverages considerable resources through its significant activity in international services • NASA faces certain challenges in continuing and advancing these activities Geodetic Networks

  9. Geodetic Networks: GPS Geodetic Networks

  10. Geodetic Networks: GPS Stations Map Geodetic Networks

  11. Geodetic Network: GPS Strengths • Relatively low cost • Hardware • Station operations • Analysis • Dense ground networks • High temporal resolution – 1 Hz • Universal access to TRF for ground stations and vehicles, aircraft, and spacecraft • Supports the objectives and goals of many users and agencies • Solid Earth Science ( e. g., NASA, NSF, USGS) • Climate Science (e. g., NASA, NSF, NOAA, USGS) • National security (DoD) • Space weather (NASA, USAF, NOAA) • Flight projects • POD (e. g., TOPEX, Jason, GRACE) • Opportunities for new and novel applications • Ocean reflections • Atmospheric occultations Geodetic Networks

  12. Geodetic Networks: GPS Technology Development TRF realization as a System Ground and flight hardware capabilities with analysis software • Ground stations • Continuous GPS Networks • Receiver tracking technology • Network Communications • Real-time Internet (RTNT) • Flight segment • Receiver development • Hardware deliveries to flight projects • Analysis • Computational efficiency ~ (Number of stations)3 • Optimal combinations • POD and positioning accuracy in real time and in post processing Geodetic Networks

  13. NASA’s Global Differential GPS System JPL processing center running IGDG NASA’s global real time network Internet Broadcast Internet Broadcast Revolutionary new capability: decimeter real time positioning, anywhere, anytime Remote user Running IGDG For more info see: http://gipsy.jpl.nasa.gov/igdg Geodetic Networks

  14. Special Value to NASA and Society • Autonomous operations in Earth orbit to enable smart sensor webs and reduce operational costs and communications bandwidth • Prototype GDGPS flight receiver being developed • Precise time transfer for interferometric SAR • Safe operations for NASA missions • RLV navigation payload based on GDGPS • Aviation safety and efficiency • Dryden plans to offer GDGPS services on all platforms • Timely monitoring and • response to natural hazards • NRT sea surface height • Many national security applications • GPS integrity monitoring • GPS enhancements • GPS capabilities to exceed Galileo’s Many commercial applications Geodetic Networks

  15. Geodetic Networks: IGS Structure International Association of Geodesy International Union of Geodesy and Geophysics Federation of Astronomical and Geophysical Data Service International Council for Science International GPS Service 200 Organizations in 80 Countries Analysis Coordinator • IGS Pilot Projects and Working Groups • Precise Time and Frequency Project (IGS/BIPM) • International GLONASS Service Pilot Project (IGLOS-PP) • LEO Pilot Project • Tide Gauge Benchmark Monitoring Project for Sea Level (TIGA) • Ionosphere Working Group • Atmosphere Working Group • IGS Reference Frame Working Group • Real-Time Working Group International Governing Board NASA Involvement: 4 of 27 IGS Reference Frame Coordinator Central Bureau Network Coordinator USERS Analysis Centers(8) Data Centers Associate Analysis Centers Global (3) Regional (5) Pilot Projects and Working Groups Network Stations(358) NASA Involvement: 72 Operational (23) Geodetic Networks Note: Red indicates NASA involvement

  16. Geodetic Networks: GPS Analysis • Geophysical models • Required to maintain TRF • Support mission enabling Precise Orbit Determination • Repeat Orbit Interferometry for InSAR • GRACE • TOPEX, Jason, other LEO’s • Formation Flying • Collateral science support • Solid Earth, such as - SCIGN (NASA, WM Keck, NSF, USGS) - Plate Boundary Observatory (NSF, USGS) - Post Glacial Rebound Studies • Atmospheric occultations Geodetic Networks

  17. optional 1553 Interface Board CPU & Memory Board Digital Signal Processing Board Host I/O Board Single Antenna RF Sampler Board, Diplexer & Amp Modules BlackJack is a Software Radio single antenna version (eg, Jason) • software-driven allows • mission-independent hardware • post-launch reconfigurability • mission-specific functionality • software-driven requires • mission-specific configuration & testing Geodetic Networks

  18. Current Missions with BlackJack Receivers GRACE (Mar 2002) • precise orbit • atmospheric remote sensing • gravity • ionospheric remote sensing • ocean surface reflections CHAMP (Jul 2000) • precise orbit • atmospheric remote sensing • gravity • ionospheric remote sensing FEDSat (Dec 2002) SAC-C (Nov 2000) • precise orbit (on-board, real-time) • atmospheric remote sensing • ionospheric remote sensing • ocean surface reflections • precise orbit • ionospheric remote sensing ICESat (Jan 2003) JASON-1 (Dec 2001) • precise orbit • precise orbit LEGEND • solid  full functionality • shaded  limited functionality Geodetic Networks

  19. Upcoming Missions with BlackJack Receivers C/NOFS (2003) OSTM (2007) • ionospheric remote sensing • precise orbit • precise orbit • atmospheric remote sensing • ionospheric remote sensing PARCS (2009) COSMIC (2005) • precise orbit and time Geodetic Networks

  20. Direct solid Earth science from the ground stations:How is the surface of the Earth changing? Geodetic Networks

  21. Geodetic Networks: GPS Issues and Challenges Current and pending issues (0-3 years): • Aging ground receivers • “Ownership” of the global network • Integration of new techniques, e. g. GALILEO • Communications infrastructure for real-time • Geophysical model development • International partnering Future issues (2-10 years): • Improved system redundancy • Verification and validation of TRF stability • Technology independence of the TRF • Integrated operation with the other techniques • Co-location • Smooth infusion of new technology Geodetic Networks

  22. Geodetic Networks: GPS 5-year Plan • New GPS signals • L2C (June 2004) • L5 (June 2005) • New GPS satellites • GPS III (2005) • New GNSS systems • Galileo (2004) • Network hardware • Replace aging and obsolete equipment (2003-2004) • Track new signals and satellites (2004-2007) • Increase number of real-time stations • Optimize station distribution and improve performance • Harden reference frame station subset • Upgrade analysis capability to support system evolution Geodetic Networks

  23. Geodetic Networks: SLR Geodetic Networks

  24. The SLR Technique Precise range measurements to satellites Passive space segment Near real-time global data availability Satellite orbit accuracy ~1-2 cm on LAGEOS Science and Applications Terrestrial Reference Frame 3-D coordinates and velocities of the ILRS tracking stations Time varying Earth Center of Mass and Scale (GM) Static and time-varying coefficients of the Earth's gravity field Earth Tides Measure of the total Earth mass Earth Orientation Parameters (EOP): polar motion, length of day Special Missions - Tether Dynamics, etc. Accurate satellite ephemerides: calibration, and validation of altimetry missions Backup precise orbit determination (POD) for other missions Geodetic Networks: SLR Unique Capabilities Geodetic Networks

  25. Geodetic Networks: Monitoring Temporal Gravity Changes Using SLR • +0.6 correlation between S2,2 time series and the SOI when S2,2 is shifted forward in time by 12 months. • Evidence of El Nino prediction? • Reported by Cox, Chao et al. (AGU, 2003) • Anomalistic behavior of J2 time series • First detection of large-scale unanticipated mass redistribution • Reported by Cox and Chao, (SCIENCE, 2002) Geodetic Networks

  26. Geodetic Networks: SLR Site Map Geodetic Networks

  27. Geodetic Networks: SLR Site Map (and co-locations) Geodetic Networks

  28. Geodetic Networks: Satellite Tracking List Geodetic Networks

  29. Geodetic Networks: ILRS Structure • NASA operates the ILRS Central Bureau • NASA actively participates in all ILRS entities (Governing Board, Working Groups, operational components) • ILRS supports NASA Missions and Programs • Over 70 organizations located in 27 countries participate in the ILRS Geodetic Networks

  30. Geodetic Networks: SLR Current Challenges SLR Cost Per Pass Down • Current NASA Systems have improved data quality and quantity over last 10 years • Decreased operating costs thru system improvements and automation • More satellite missions supported • Sub-centimeter performance • Performance limits have been reached with existing systems • Aging technology, very difficult to replace parts • Costly to operateand maintain • Chemical & HV Hazards • Further automation not cost effective Geodetic Networks

  31. Geodetic Networks: SLR 2000, the Future of SLR • Innovative hardware and intelligent computer systems • Fully automated, tracks 7/24 • Subcentimeter ranging accuracy • No ocular, chemical, or electrical hazards • Increased reliability • Lower replication and operating costs • Self-monitoring, low maintenance • SLR Network 5-Year Plan: • Integrate and checkout prototype by April 2004 • Replicate and deploy 12 NASA systems over the next 5 years, transitioning from existing system. • Possible use of SLR2000 as ground link in laser communications and transponder experiments. Geodetic Networks

  32. Geodetic Networks: SLR Backup Slides Geodetic Networks

  33. Geodetic Networks: SLR Technology Tall Poles Solved • Innovative hardware developed • New quadrant micro-channel plate pmt • Full aperture telescope use (eyesafe) • Passive 2 khz trans/rec switch • Risley prism point ahead • All sky thermal ir camera • 2 khz event timer/gate generator • Mtbf of several months • Tracking loop closed with qmcp-pmt Geodetic Networks

  34. Geodetic Networks: SLR Satellites Reflector Microsatellite Geodetic Networks

  35. Geodetic Networks: VLBI Geodetic Networks

  36. Geodetic Networks: VLBI Station Map Geodetic Networks

  37. Geodetic Networks: IVS Structure IVS has 73 permanent components, representing 37 institutions in 17 countries. NASA supports the IVS Coordinating Center, Network Coordinator, and 7 permanent components Geodetic Networks

  38. Geodetic Networks: VLBI Unique Capabilities • Celestial Reference Frame - quasars • Celestial pole • UT1-UTC • Differential navigation for spacecraft Geodetic Networks

  39. Geodetic Networks: VLBI Issues and Challenges • Improve temporal coverage from 3.5 days/week to full time. • Decrease processing delay from 15 days to near-real time. • Improve global configuration with more stations in the southern hemisphere. • Address serious RFI problem at S/X (2.2/8.4 GHz) by moving to higher RF bandwidths, e.g. K/Q (24/42 GHz). • Replace aging antennas. • Upgrade aging data acquisition equipment. • Establish fiber networks for electronic data transfer to remove the need to ship media from stations to correlator. Geodetic Networks

  40. Geodetic Networks: VLBI Technology Advances Mark 5 disk-based recording system • Media cost only $1.25/GB (half of tape) • Allows higher bandwidth recording • Enables automated/unattended operation • Allows electronic data transfer and near real time processing e-VLBI for data transfer • Gb/s data transfer demonstrated • Global experimental program for international transfer near Gb/s rates • New adaptive IP protocol studies Geodetic Networks

  41. Geodetic Networks: VLBI 5-year Plan • 2004 • Deploy and use Mark 5 at all correlators and stations • Establish e-VLBI for daily UT1 measurements • Study K/Q for using higher dual-frequency RF bands • 2005 • Begin replacement of Fairbanks antenna • Begin development of K/Q receivers • 2006 • Establish e-VLBI network of NASA stations with international partner stations • Begin replacement of data acquisition hardware with digital interfaces • 2007 • Fairbanks antenna complete • 2008 • e-VLBI networks in use for 3-4 days/week EOP and TRF measurements • Initial K/Q test installations Geodetic Networks

  42. Transition to integration slides Geodetic Networks

  43. Geodetic Networks: Integration Elements • Proposed activities • NGO proposal: National Geodetic Observatory • Focus US efforts in space geodesy to integrate techniques, attract new funding • INDIGO proposal: Inter-Service Data Integration for Geodetic Operations • Goal: to enable improved performance, accuracy, and efficiency in support of NASA’s Earth science and international user community by developing and providing uniform access to heterogeneous space geodetic data systems. • International organizations • IERS: International Earth rotation and Reference systems Service. • Compiles and distributes ITRF, ICRF, EOP time series • Pilot project on rigorous combination of data from all techniques • IAG: International Association of Geodesy • IGGOS: Integrated Global Geodetic Observing System, flagship project • IGGOS is expected to play a major role in geodesy community with integration of techniques at a very high level Geodetic Networks

  44. Geodetic Networks: Co-location Strategy • Importance of co-location • Co-location ties techniques together, enables combination for TRF • Local ties • accurate measurements of vectors between reference points for different techniques at a site • essential for combination of data from different techniques • limiting factor in closure of the networks • Approach and strategy • Improve local tie measurements. • Understand different solution results for each technique at a site. • Improve the co-location network. • Investigate new technology approaches to measuring local ties. Geodetic Networks

  45. Geodetic Networks: Next Steps Toward Integration • Global networks are NASA ‘critical infrastructure’ and strategic US assets. • Meeting challenges together for mutual strength • Continue and extend cross-technique coordination. • The goal of integration is the most stable and accurate reference frame and tracking capabilities. • The three techniques plan to jointly assess the structure and budget for the NASA networks and recommend an approach for integration. • An integrated program should achieve • appropriate balance of measurements, scientific needs and resources in the mix of SLR, VLBI and GPS. • appropriate balance of resources for scientific research and applications with the demanding requirements of the TRF and the geodetic networks infrastructure. Geodetic Networks

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