The Global Positioning System International Cooperation

1
The Global Positioning System International
Cooperation
Presented by Julie Karner U.S. Department of
State February 2003
2
U.S. GPS Policy

• Dual-use (civil-military) system
• Civil signals free of direct user charges (policy
  since 1983)
• Open specifications (No licensing fee or
  royalties)
• Consistent U.S. National Policy statements from
  both Executive and Legislative Branches
• Congressional guidance 1983
• Presidential Decision Directive, March 1996
• U.S. Public Law, December 1998
• Interagency GPS Executive Board to manage GPS as
  a national asset
• Selective Availability turned to zero in May 2000
• Six years ahead of schedule
• Encourage private sector use of GPS technologies
  and services
• Open specifications for civil signals
• Available on an equal basis to users and industry
  worldwide

3
International Outreach

• Encourage use of GPS show how it is being used
• GPS Exhibit
• Promote global interoperability
• Open communication lines with users
• CGSIC IIS
• Report problems/interference to NAVCEN
• www.navcen.uscg.gov
• Provide accurate information on U.S. policy and
  plans for GPS
• www.igeb.gov

4
Who uses GPS - Everybody

• GPS supports a wide variety of applications
• GPS 2-10 meters
• GPS with augmentations 50 centimeter 3 meters
• GPS with advanced techniques (ex. RTK)
• Moving centimeter level
• Static millimeter - centimeter
• Combined with other technologies and information
  resources
• Remote sensing
• Geographic Information Systems (GIS)

5
Today,Tomorrow, and Future Concepts

• Today
• GPS
• DGPS and GBAS
• SBAS (pre IOC)
• Combined GPS/GLONASS receivers
• Pseudolites
• Combined with other technologies (ex. - GSM)
• Tomorrow
• Operational SBAS
• GBAS LAAS, GRAS
• Galileo
• Japanese Quasi Zenith Satellite System
• Future Concepts
• WAAS broadcast by LORAN C
• RTK on DGPS

6
Civil Benefits of GPS Modernization

• More robust GPS service
• Reduces vulnerability to unintentional
  interference
• Unlikely to simultaneously affect L1, L2 and L5
• Worldwide dual frequency for en-route navigation
  and precision approach
• Dual Frequency (L1, L5) allows ionospheric
  corrections in avionics onboard the aircraft
• Fewer reference stations may be needed for
  space-based augmentation systems (e.g. WAAS)
• Centimeter-level accuracy for scientific survey
  applications
• Tri-laning L1 - L5, L1 - L2, and L2 - L5

7
Compatibility and Interoperability

• GPS is an existing system with millions of users
  around the world
• Standard for satellite-based navigation
• To bring greatest benefit to users, new systems
  or augmentations should
• Be compatible with GPS not cause degradation
  for users
• Be interoperable with GPS to the greatest extent
  possible
• More satellites visible ideally used to derive
  a single solution
• Good opportunities with L2C and L5 some
  limitations with L1
• Cheaper receivers so greatest number of users can
  benefit
• Goal Seamless worldwide service

8
What is Compatibility and Interoperability?

• Radio Frequency Compatibility -- GPS and
  Galileo/QZSS civil signals are compatible from a
  radio frequency perspective, if it is assured
  that one system will not cause interference that
  unacceptably degrades the stand alone service
  that the other system provides
• Backward compatibility is often applied to this
  concept for users with existing receivers
• Forward compatibility is often applied when new
  receiver designs are being considered
• National Security Compatibility -- GPS and
  Galileo/QZSS civil signals are are compatible
  from a national security perspective if the
  ability to protect military service while
  simultaneously preventing hostile use and
  preserving civil service outside the area of
  hostilities is preserved through the spectral
  separation of civil and military signals

9
What is Compatibility and Interoperability?

• Interoperability -- GPS and Galileo/QZSS are
  interoperable if a combined system receiver with
  a mix of multiple GPS or Galileo/QZSS satellites
  in view can achieve position, navigation and
  timing solutions at the user level that are equal
  to or better than the position, navigation or
  timing solutions that could be achieved by either
  system alone.

10
Relative Importance of Compatibility and
Interoperability

• Interoperability (as defined on the previous
  chart) is a very important goal
• However
• The US Government considers the assurance of
  Compatibility as the primary requirement for the
  GPS user community
• Existing and future GPS receivers must be
  protected

Existing and future GPS users must be protected
from harmful service degradation
11
Interoperability GPS and Galileo

• Two independent systems
• Goal is to provide the greatest possible benefit
  to the largest number of users
• Simple, inexpensive receivers
• Range of end results
• Compatibility Seamless identical
  systems
• Depends on standards selected
• Different ways to consider interoperability
• User perspective
• Equipment
• Policy

12
User perspective

• Compatibility (ex. - GPS-GLONASS)
• Systems operate independently
• Do not interfere with each other
• Need independent solution
• Some improved performance
• Modernization
• Each can modernize without impacting the other
• Consistent performance
• Can use both and get at least as good as with
  only one
• Improved performance
• Can use both and get improved performance
• Ideal use satellites interchangeably to derive
  a single solution
• Get greatest benefit from larger number of
  visible satellites
• RAIM

13
Implications of System Standards for Receivers

• Receiver complexity and cost depend on standards
  chosen
• Geodesy (different standards selected)
• Timing (different standards selected)
• Signal structures
• L1 - C/A code limits number of satellites, power,
  signal structure
• L2C No backward compatibility issues
• L5 Greatest potential for interoperability

14
Policy Interoperability

• Similar policies enhance interoperability for
  users
• Free, open signals and open specifications
• Users choose which system or combination of
  systems meet their needs
• and
• Manufacturers choose which system or
  combination provides optimum business case
• GPS
• GLONASS
• Galileo
• QZSS
• Combination
• Combined with other technologies GSM, UMTS,
  Pseudolites
• Open market-driven competition
• Innovation
• Better/cheaper equipment and services
• Protect radionavigation spectrum from
  interference
• Preserve Allied military use of GPS in hostile
  environment

15
International Consultations - Europe

• Last plenary talks - June 2002
• Technical talks - Oct. 21-23 and Jan 30-31
• Goals
• Alternative signal structure for Galileo PRS
• No M-code overlay
• Compatibility Future Galileo service will not
  degrade service for GPS users
• Interoperability Users can use both systems
  together to get improved capability
• Ideal case use satellite signal interchangeably
  so users can take greatest advantage of larger
  number of visible satellites
• Greatest issue with Galileo is M-code overlay
• Impacts U.S., NATO, and Allied military forces

16
National Security Compatibility

• U.S. Policy and Public Law require
• Protection of Allied military use of GPS
• Prevention of hostile use
• Preservation of civil use outside an area of
  conflict
• NAVWAR concept enables localized denial of
  service rather than global degradation
• New military (M-code) signals developed to be
  spectrally separated from civil signals
• Without spectral separation, security is weakened

Overlay of M-code signals is not dual-service
compatible and is unacceptable to the U.S.
17
International Consultations - Japan

• Japan
• Plenary - October 2002
• Technical discussions - December 2002
• Key interest area is close cooperation with
  Japans QZSS
• Goal maximize interoperability with GPS
• Increase satellites in view for users
• Increase commercial opportunities for GPS/QZSS
  applications

18
Summary

• GPS is a key component of the global information
  infrastructure
• U.S. intends to continue to provide GPS service
  free of direct user fees to users worldwide
• Consistent U.S. principles has led to GPS
  standardization and market growth
• GPS modernization is under way
• Continuing international outreach to further
  understanding of GPS, its augmentations, and its
  applications
• Compatibility/Interoperability for the benefit of
  users worldwide

19
Back Up
20
M-code and PRS are different

• No common user base
• M-code is strictly for military users
• Designed to meet specific U.S. and allied
  military requirements
• Combat environment
• PRS is advertised as a civil service
• M-code and PRS are not competing for market share
• M-code will never be used for a PRS-like or
  commercial service
• No intention or need to have M-code - PRS
  interoperability

21
U.S. Proposed PRS Signal Alternatives

• Meet PRS requirements as stated by EC
• L1 band BOC (5,2)
• GLONASS band (18 MHz available) BPSK-R(5),
  BPSK-R(8), BOC (6,3), BOC (6,4), BOC (5,2.5),
  BOC (5,5), BOC (4,4)
• All options are feasible - provide robust signal
  designs
• Resistant to interference and jamming
• Spectral separation from Galileo Open services
• High accuracy solutions
• Signals can be efficiently generated and
  transmitted by the same satellites producing
  other Galileo signals
• No legal or technical impediment to using GLONASS
  band frequencies

22
GPS-Galileo Cooperation Status

• U.S. believes Galileo will benefit civil users
  worldwide
• Not opposed to PRS
• Single major issue, M-code overlay, is impeding
  real progress on cooperation agreement
• PRS and GPS Military Service (M-code) are not
  equivalent services and are not competing
  services
• No common user base or markets
• M-code strictly for military users not
  commercialized
• U.S. wants issue resolved as soon as possible so
  real cooperation progress can begin
• Places Trans Atlantic relationship at risk

23
M-Code Overlay is Unacceptable

• Not a matter of trust
• M-code overlay places NATO and allied operations
  and troops lives at risk
• All NATO nations agree
• No matter how secure
• No matter how well the service is encrypted
• No matter how rigorous equipment access is
  controlled
• Risk of compromise cannot be ruled out
• U.S. proposed PRS alternatives and civil
  compatibility interoperability discussions at
  technical working group in Paris, January 30-31
• U.S. is willing to discuss the issue through NATO
  channels or with countries who have security
  arrangements with U.S. , but will not negotiate
  M-code overlay

24
GPS-Galileo Technical Working Group Meeting

• Goddard Space Flight Center, October 21-23, 2002
  and ESA Headquarters, January 30-31, 2003
• Technical compatibility/interoperability of civil
  GPS and Galileo services discussed
• U.S. and E.C./ESA interference analyses and
  criteria for determining signal non-interference
• Galileo L1 L5/E5 signal structures and code
  selection
• Timing and geodesy interoperability issues
• Paris Technical Working Group to address U.S.
  proposed alternatives for PRS signals
• Follow-up sub-teams were identified for specific
  issue areas such as timing and signal
  interference analyses

25
Why Flexible Signal Plan Wont Work

• Security of a planned NATO operation may not
  permit coordination with outside (Non NATO)
  organization
• EU Rapid Response Center would still have to
  inform the commercial operator, compromising
  Operational Security
• Approval cannot be guaranteed
• EC statement to NATO
• Timeline not consistent with military operations
• Military field commander cannot be restrained by
  waiting for outside agency to approve and
  implement switch
• Change in Galileo frequencies provides indication
  and warning to hostile forces

26
BOC 10,5 Signal Alternatives Will Not Make
Galileo a Second Status Service

• GPS-Galileo System Comparison (Circa 2008)

27
GPS-Galileo Comparison (Circa 2008)
GPS
Galileo
Services
Signals
Users
Signals
Users
MHz
MHz
8 (5,2) 5-16 G1 band
L1 L2
U.S. proposed alternatives to M-code overlay