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

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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