U.S. Space-Based Positioning, Navigation, and Timing:

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U.S. Space-Based Positioning, Navigation, and
Timing  A Status and Policy Review
GNSS Korea 2006 Jeju, Korea October 18-20,
2006 Ms. Ruth Neilan Jet Propulsion Lab National
Aeronautics and Space Administration
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Overview

• Background
• U.S. Space-Based PNT Policy
• GPS Modernization Status
• International Cooperation

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Global Positioning System

• Baseline 24 satellite constellation in medium
  Earth orbit
• Global coverage, 24 hours a day, all weather
  conditions
• Satellites broadcast precise time and orbit
  information on L-band radio frequencies
• 3 dimensional position worldwide
• Two types of services
• Civil (free of direct user fees)
• Military (U.S. and Allied military)
• Three system elements
• Space
• Ground control
• User equipment

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GPS is a Global Public Service

• Free access to civilian signals
• One-way broadcast, like FM radio
• Public domain documentation
• Anyone can develop user equipment
• Worldwide utility providing consistent,
  predictable, dependable performance
• Critical component of global information
  infrastructure
• Owned and operated by the U.S. Government
• Paid for by U.S. taxpayers
• Guided at a national level as multi-use asset
• Acquired and operated by Air Force on behalf of
  USG

Available NowEmpowering the Future
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What is Space-Based PNT and GPS?

• Space-based positioning, navigation, and timing
  (PNT) includes the global navigation satellite
  systems (e.g. GPS, GLONASS, Galileo, etc.) and
  their augmentations
• GPS is a space-based radio-navigation system
• Satellites broadcast precise and synchronized
  time signals and data to allow users to estimate
  their position, velocity, and time
• Augmentations improve performance of space-based
  PNT systems such as GPS

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Current Constellation
29 Operational Satellites (Baseline
Constellation 24)

• 28 Block II/IIA/IIR satellites operational
• 1 Block IIR-M satellite operational
• Transmitting new second civil signal (L2C)
• Continuously assessing constellation health to
  determine launch need
• New IIR-M satellite launched Sep 06
• 6 remaining Block IIR-M satellites
• Next launch November 2006
• Global GPS civil service performance commitment
  met continuously since Dec 1993

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Recent Launches
Providing worldwide position, navigation timing
GPS IIR-1120 Mar 04 50th GPS Satellite
GPS IIR-12 23 Jun 04
GPS IIR-13 06 Nov 04
GPS IIR-14/15(M) 25 Sep 05 and 25 Sep
06 Modernized GPS Satellites
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U.S. Augmentations
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International Augmentations
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Overview

• Background
• U.S. Space-Based PNT Policy
• GPS Modernization Status
• International Cooperation

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U.S. 2004 Policy

• First U.S. national policy was titled
• U.S. GPS Policy 1996
• U.S. Space-Based Positioning, Navigation, and
  Timing (PNT) Policy
• Signed on December 8, 2004
• Recognized changing national and international
  scene since 1996
• Updated U.S. policy while retaining principles in
  previous policy

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2004 Policy Objectives

• Improve the performance of space-based PNT
• Ensure civil services exceed, or are at least
  equivalent to, those of foreign civil space-based
  PNT services
• Includes robust resistance to interference for
  civil, commercial, homeland security, and
  scientific users worldwide
• Provide space-based civil PNT services free of
  direct user fees on a continuous, worldwide basis
• Civil, commercial, homeland security and
  scientific use
• Provide uninterrupted access to U.S. space-based
  PNT services for U.S./allied national security
  purposes

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2004 Policy Objectives (contd)

• Provide open, free access to information
  necessary to use these civil services
• Improve capabilities to deny hostile use of any
  space-based PNT services
• Without unduly disrupting civil and commercial
  access
• Maintain the GPS as a component of multiple
  sectors of the U.S. Critical Infrastructure
• Ensure that foreign PNT systems are interoperable
  with GPS
• Or, at a minimum, are compatible

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2004 U.S. Policy Summary

• Demonstrates continued U.S. Government commitment
  to space-based PNT for all stakeholders
• Provides framework for public/private decision
  makers
• Improves ability to coordinate efforts across the
  various agencies of the U.S. Government
• Creates basis for meaningful dialogue between
  service providers and end users
• Promotes common standards for worldwide
  interoperability

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Policy Implementation

• Established a stronger National Space-Based PNT
  Executive Committee IGEB disestablished
• Chaired by Deputy Secretaries of Defense and
  Transportation
• Membership includes State, Commerce, Homeland
  Security, JCS, and NASA
• Supported by a new National Coordination Office
• National Coordination Office for Space-Based PNT
  was established on November 1, 2005
• Director, Deputy Director, and staff from the
  Departments and Agencies

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Organizational Structure
WHITE HOUSE
Defense
Transportation
NATIONALSPACE-BASED PNT EXECUTIVE
COMMITTEE Co-Chairs Defense, Transportation
State
ADVISORYBOARD Sponsor NASA
Commerce
Homeland Security
NASA
COORDINATIONOFFICE Host Commerce
Joint Chiefs of Staff
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National Coordination Office

• Facilitates information sharing, coordination,
  and issue resolution regarding space-based PNT
  across the U.S. Government
• Evaluates plans to modernize the U.S. space-based
  PNT infrastructure
• Conducts or oversees space-based PNT studies and
  analyses
• Represents the National Executive Committee
• As well as with the private sector and
  representatives of foreign governments

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Web-based Information

• PNT.gov established to disseminate information on
  the National Executive Committee
• Contains information on policy, ExCom Membership,
  Policy, the Advisory Board, frequently asked
  questions, and recent public presentations
• GPS.gov established to disseminate information on
  GPS applications
• Brochure on GPS applications available for
  download
• Copies available upon request
• Contains additional links to various other
  websites

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Overview

• Background
• U.S. Space-Based PNT Policy
• GPS Modernization Status
• International Cooperation

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GPS Modernization

• For all users
• System-wide improvements in accuracy,
  availability, integrity, and reliability
• Backward compatibility
• For civil users
• Higher standalone accuracy
• Robustness against interference
• Improved indoor, mobile, and urban use
• Interoperability with other GNSS constellations
• Maintains international competitiveness

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GPS Modernization (contd)
Increasing System Capabilities w Increasing
Defense / Civil Benefit
Block IIA/IIR
Block III
Block IIR-M, IIF

• Backward compatibility
• 4th civil signal (L1C)
• Increased accuracy
• Increased anti-jam power
• Assured availability
• Increased security
• System survivability

• IIR-M IIA/IIR capabilities plus
• 2nd civil signal (L2C)
• M-Code (L1M L2M)
• IIF IIR-M capability plus
• 3rd civil signal (L5)
• Anti-jam flex power

• Basic GPS
• Standard Service (16-24m SEP)
• Single frequency (L1)
• Coarse acquisition (C/A) code navigation
• Precise Service (16m SEP)
• Y-Code (L1Y L2Y)
• Y-Code navigation

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Second Civil Signal (L2C)

• Designed to meet commercial needs
• Freely available since Dec 2005
• Currently on 2 satellites
• Will be on all future satellites
• 24 satellites - 2014
• Expected to generate over 5 billion in user
  productivity benefits

Benefits existing professional receivers
Increases accuracyfor consumers
Supports miniaturization, possible indoor use
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Third Civil Signal (L5)

• Available on 1st IIF 2008
  24 satellites 2016
• Designed to meet demanding requirements for
  transport safety
• May also enable global, centimeter-level accuracy
  using new techniques
• Opportunity for international interoperability

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Fourth Civil Signal (L1C)

• Designed with international partners for
  interoperability
• Specifically for interoperability with the
  Galileo Open Service
• Modernized civil signal at L1 frequency
• Original signal retained for backward
  compatibility
• More robust navigation across a broad range of
  user applications
• Improved performance in challenged tracking
  environments

Under trees
Inside cities
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GPS III

• Next-generation satellites are needed to
  accommodate increasing capabilities
• First launch 2013 24 satellites 2021
• Civil benefits
• Delivers full operational capability for L2C and
  L5
• In combination with GPS IIR-M and IIF satellites
• Provides L1C for interoperability with Galileo,
  QZSS
• Significant increase in system accuracy
• Improved availability of accuracy with integrity
• Revised acquisition strategy
• Incremental development approach to reduce risk,
  increase flexibility
• Separate contracts for space and ground segments
  to ensure best technology and most efficient
  implementation

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GPS III Proposed Accuracy

• Horizontal Accuracy (95) 1.8 meters
• Vertical Accuracy (95) 3.19 meters
• Timing 5.2 nanoseconds
• Assumptions
• - Global Average
• - Dual frequency
• - SIS URE 0.25 meters
• - UEE 0.8 meters
• - SS-SYS-800 GPS III System Spec

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Overview

• Background
• U.S. Space-Based PNT Policy
• GPS Modernization Status
• International Cooperation

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Global Navigation Satellite Services (GNSS)
Expanding

• Sep 2005 2nd civil GPS signal
• Dec 2005 first Galileo test satellite
• Dec 2005 3 GLONASS satellites
• This year European EGNOS operational
• Japan preparing for MSAS ops in 2007 and QZSS
• India moving forward with GAGAN and IRNS
• China Beidou, Compass

Interoperability key to seamless global operations
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U.S. International Cooperation
Outlined in 2004 Presidential Policy on
Space-Based Positioning, Navigation, and Timing
(PNT)

• Provide civil GPS and augmentation services free
  of direct user fees on a continuous, worldwide
  basis
• Provide open, free access to information needed
  to develop equipment
• Improve performance of civil GPS and
  augmentations to meet or exceed that of
  international systems

• Encourage international development of PNT
  systems based on GPS
• Seek to ensure international systems are
  interoperable with civil GPS and augmentations
• Or at a minimum, are compatible
• Address mutual security concerns with
  international providers to prevent hostile use

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U.S. International Cooperation (contd)

• Ongoing cooperation with Europe, Japan, Russia
• Compatibility and interoperability
• National security
• Level playing field in global markets
• Seeking formal relations with Australia, India,
  Brazil
• Multilateral cooperation
• U.N. International Committee on GNSS
• ICAO, IMO, NATO

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GPS-Galileo Agreement

• In 2004, United States and European Community
  signed agreement on GPS-Galileo cooperation
• Recognizing importance of compatibility and
  interoperability for all parties
• Agreed to spectrally separate signals for
  military, civilian, and public regulated services
• Agreed to implement a common, open, civil signal
  on both Galileo and GPS III, free of direct user
  fees
• Working groups establishedto continue
  cooperation
• Compatibility and Interoperability
• Trade and Commercial Applications
• Next-Generation GNSS
• Security Issues

June 26, 2004, press conference at U.S.-EU Summit
in Ireland (U.S. Sec. of State Colin Powell,
Irish Foreign Minister Brian Cowen, EU
Vice-President Loyola De Palacio)
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Japan

• Worlds largest consumer of GPS technology
• U.S.-Japan cooperation began in 1998
• Initially focused on interoperability with MSAS,
  Japans GEO-based augmentation system
• Promotes common principles such as free market
  access
• Annual plenary meetings, technical working groups
• Current focus is on Quasi-Zenith Satellite System
  (QZSS)
• Regional system to complement, augment GPS over
  Japan
• Will improve performance in urban canyons and
  mountains
• Will freely broadcast GPS L1C, L2C, L5 signals
• GPS-QZSS interoperability achieved

MT-SAT used for MSAS
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Russia

• Cooperation started in 2004
• Working groups are pursuing GPS-GLONASS
  interoperability
• Enhanced PNT through combined service
• Combined search and rescue capabilities
• Currently pursuing formal cooperation agreement

GLONASS satellite
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International Committee on GNSS

• Multilateral group chartered through United
  Nations
• First meeting December 2005
• Next meeting November 2006

• Purpose Promote use of GNSS to improve
  efficiency and security of transport, search and
  rescue, geodesy, etc., particularly in developing
  countries
• Coordination among GNSS providers to ensure both
  compatibility and interoperability
• Assistance to developing countries in use of PNT
  services
• Focal point for international information
  exchange
• Forum for addressing future user needs

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Summary

• U.S. policy encourages and promotes worldwide use
  of civil GPS and augmentations
• International cooperation is a priority
• Supporting and promoting interoperability and
  compatibility with other GNSS systems to include
• Europes Galileo, Russias GLONASS, and Japans
  QZSS
• Opportunity for partnership with all nations
• GPS getting better and will continue to improve
• Augmentations enable high performance today
• New GPS signal (second civil signal) now
  available
• Many additional upgrades in the future

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Contact Information
Ms. Ruth E. Neilan Jet Propulsion Laboratory
(JPL) IGS Central Bureau M/S 238-540 4800 Oak
Grove Drive Pasadena, California 91109 Ph
818-354-8330 Fax [phone]
Ruth.Neilan_at_jpl.nasa.gov Presentation and other
GPS information available PNT.gov
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Contact Information
Michael E. Shaw Director U.S. National
Space-Based PNT Coordination Office 14th and
Constitution Ave, N.W. Washington, D.C. 20230
Ph [phone] Fax (202)
482-4429 Michael.Shaw_at_pnt.gov Presentation and
other GPS information available PNT.gov GPS.gov
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• Backups

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Baseline GPS and Galileo Signal Structures

• Civil GPS
• L5 BPSK-10 1176.45 MHz
• L2 BPSK-1 1227.6 MHz
• L1 BPSK-1 with a future
• BOC (1,1) 1575.42 MHz

• Galileo (as currently understood)
• E5A/E5B 2 x BPSK-10 or BOC (15,10)
• 1164-1214 MHz
• E6 BPSK-5 BOC (10,5) 1279 MHz
• E2/L1/E1 BOC (1,1) OS BOC (15,2.5)
• cosine phased PRS
  1575.42 MHz

C/A
CS
OS/GPS III
PRS
PRS
E5b
L5
E5a
M
P(Y)
L1 (1575.42 MHz)
E6 (1278.75 MHz)
L2 (1227.6 MHz)
L5/E5A (1164-1214
E5b MHz)
U.S. Europe have agreed to a common baseline L1
open civil signal that can become a global
standard and is compatible with
national/allied/NATO security
BOC(15,10) modulation option shown for E5a/E5b.
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GPS Signal in Space Modernization
GPS IIR
L1 1575.42 MHz
L2 1227.6 MHz
GPS IIR-M
GPS IIF
L5 1176.45 MHz
GPS III
Galileo
E5a 1176.45 MHz
E5b 1207.14 MHz
E6 1278.75 MHz
L1 1575.42 MHz