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NASA GPSApplications for Scientific
Investigations
NASA GPSNASA GPSApplications for Scientific Applications for Scientific
InvestigationsInvestigations
Frank H. Bauer1, Ruth Neilan2
NASA Headquarters1, NASA Jet Propulsion Laboratory2
First Meeting of the International Committee on GNSS (ICG)United Nations Office of Outer Space Affairs
Vienna, Austria
December 1, 2005
ANAS
2
Space Applications of GPS: Probing the Earth
IONOSPHEREIONOSPHEREOCEANSOCEANS SOLID EARTHSOLID EARTH
ATMOSPHEREATMOSPHERE
Significantwave heightSignificant
wave height
Ocean geoid andglobal circulationOcean geoid andglobal circulation
Surface windsand sea state
Surface windsand sea state
Short-term eddyscale circulationShort-term eddyscale circulation
OCEANSOCEANS
High resolution 3Dionospheric imagingHigh resolution 3D
ionospheric imaging
Ionospheric struc-ture & dynamics
Ionospheric struc-ture & dynamics
Iono/thermo/atmo-spheric interactionsIono/thermo/atmo-
spheric interactions
Onset, evolution& prediction ofSpace storms
Onset, evolution& prediction ofSpace storms
TIDs and globalenergy transportTIDs and globalenergy transport
Precise ion cal forOD, SAR, altimetryPrecise ion cal forOD, SAR, altimetry
IONOSPHEREIONOSPHERE
Climate change &weather modelingClimate change &weather modeling
Global profiles of atmosdensity, pressure, temp,and geopotential height
Global profiles of atmosdensity, pressure, temp,and geopotential height
Structure, evolutionof the tropopause
Structure, evolutionof the tropopause
Atmospheric winds,waves & turbulenceAtmospheric winds,waves & turbulence
Tropospheric watervapor distribution
Tropospheric watervapor distribution
Structure & evolutionof surface/atmosphere
boundary layer
Structure & evolutionof surface/atmosphere
boundary layer
ATMOSPHEREATMOSPHERE
Earth rotationPolar motion
Earth rotationPolar motion
Deformation of thecrust & lithosphereDeformation of thecrust & lithosphere
Location & motionof the geocenter
Location & motionof the geocenter
Gross massdistributionGross massdistribution
Structure, evolution of the deep interior
Structure, evolution of the deep interior
Shape of the earthShape of the earth
SOLID EARTHSOLID EARTH
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Space Applications of GPS: Space Applications of GPS: Atmosphere & Ionosphere Atmosphere & Ionosphere Science InvestigationsScience Investigations
GPS Occultation Techniques• GPS Receivers in Low-Earth Orbit• High-resolution soundings of atmospheric
properties (e.g., water vapor, temperature, pressure), new observations important for weather and climate studies
• Ionospheric tomography - structure and irregularities, interest for scientific research and space weather applications
Occulting �LEO
Occulting GPS
Calibrating GPS
Ground receiver
Ionosphere
Neutral atmosphere
EarthOcculted �Signal
Ionospheric Remote Sensing
• Developed real-time software for GPS orbits, clocks, and ionosphere maps - technology transfer for aviation (US WAAS)
• Enhanced ionosphere capability ⇒ improved safety/availability algorithms and input to advanced space weather models
• Improved space weather research
GPS Satellite Occultation Techniques
International GNSS ServiceFormerly the International GPS Service
The IGS is a voluntary federation of more than 200 worldwide agencies that pool resources and permanent GNSS station data to generate precise GNSS products.
Over 350 permanent, geodetic GNSS stations operated by more than 100 worldwide agencies comprise the IGS network. Currently the IGS supports two GNSS: GPS and the Russian GLONASS.
NASA funds two centers, JPL and GSFC, to support IGS: Day-to-day management and coordination by IGS Central Bureau; responsibility and management of NASA's global GPS network that contributes to the IGS Network; an IGS Analysis Center (one of eight) for GPS orbits, clocks, and reference frame products; and an IGS Global Data Center where full access to data and products is provided.
IGS is a key component contributing to the ITRF and enabling its densification. IGS fosters unique application projects and working groups.
Graph courtesy Analysis Coordinator
G. Gendt, GFZ Potsdam
IGS Projects & Working GroupsIGS Reference Frame
Precise Time & Frequency TransferGLONASS Pilot Service Project
Low Earth Orbiters ProjectIonosphere WGAtmosphere WG
Sea Level - TIGA ProjectReal-Time WG
Data Center WGGNSS WG
GNSS: Global Navigation Satellite System
IGS products are formed by combining independent results from each of several Analysis Centers. Improvements in signals and computations have brought the centers’ consistency in the Final GPS satellite orbit calculation to ~ 2cm.
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NASA Supports the IGSNASA Supports the IGS
The IGS is an international science consortium involving over 200 organizations from nearly 100 countriesand is stronglysupported byNASA since 1992.
NASA Key Contribution Areas
~70/380+
NASA/JPL 1/8
JPL
NASA/GSFC 1/3
NASA Representatives
NASA/JPL
ANAS
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IGS Tracking Network 2005IGS Tracking Network 2005(GPS + GLONASS)(GPS + GLONASS)
http://igscb.jpl.nasa.gov/network/netindex.html
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GLONASS Network GLONASS Network (GLONASS/GPS Receivers)(GLONASS/GPS Receivers)
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NASANASA’’s Vision for Space Exploration s Vision for Space Exploration Supporting Infrastructure: Extend GPS?Supporting Infrastructure: Extend GPS?
Seamless reference and timing based on GPS technology, from the Earth to the Moon and beyond
Example: Mars Network -• Integrated Navigation and Telecommunications• Develop an in situ navigation capability to enable more precise targeting and location
information on approach and at Mars - GPS-like system at Mars
*
(*) concept architecture
BackupsBackups
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The Vision for Space ExplorationThe Vision for Space Exploration : Mandate: Mandate•• On January 14 2004, the US President announced a new vision for On January 14 2004, the US President announced a new vision for
NASANASA–– Implement a sustained and affordable human and robotic program tImplement a sustained and affordable human and robotic program to explore the o explore the
solar system and beyond;solar system and beyond;
–– Extend human presence across the solar system, starting with a hExtend human presence across the solar system, starting with a human return to the uman return to the Moon by the year 2020, in preparation for human exploration of MMoon by the year 2020, in preparation for human exploration of Mars and other ars and other destinations;destinations;
–– Develop the innovative technologies, knowledge, and infrastructuDevelop the innovative technologies, knowledge, and infrastructures both to explore res both to explore and to support decisions about the destinations for human explorand to support decisions about the destinations for human exploration; andation; and
–– Promote international and commercial participation in exploratioPromote international and commercial participation in exploration to further U.S. n to further U.S. scientific, security, and economic interests.scientific, security, and economic interests.
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NASA GPS Space Receivers NASA GPS Space Receivers –– OverviewOverviewUnprecedented Accuracy & Vehicle Security for NASAUnprecedented Accuracy & Vehicle Security for NASA’’ss
Demanding Space MissionsDemanding Space Missions
Blackjack Family (JPL)
Pivot / Navigator & Low Power Transceiver (GSFC)
MAGR-S / SIGI (JSC)
Ultra-precise: 2-cm orbit accuracy10-psec relative timing
Secure Capability for Shuttle
Attitude & Navigation for ISS
Weak Signal Detection & Fast
Acquisitionfor High Earth
Orbits
Reconfigurable Software Defined
Receiver
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Space Applications of GPS: Space Applications of GPS: Geodesy & Geodesy & Oceanography Science Investigations Oceanography Science Investigations
Gravity Field Measurements• GRACE dual-satellite mission • JPL GPS Receiver with integrated camera
and K-band spacecraft to spacecraft tracking
• 1-micron accuracy measurement• Improve knowledge of the Earth’s gravity
field by several orders of magnitude
Bi-Static Ocean Reflectrometry• Using reflected GPS signals, measure sea-surface
height and winds• Macro (Global) view of Ocean dynamics through
spaceborne techniques expected to improve weather prediction and provide Tsunami detection
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