Global Positioning System

1
Global Positioning System Constellation
Update Modernization and Policy
3rd GNSS Vulnerability Solutions
Conference Baska, Krk Island, Croatia 6 September
2010
Hank Skalski DOT Liaison to Air Force Space
Command U.S. Department of Transportation
2
GPS enables a diverse array of applications
Satellite Operations
Power Grids
Surveying Mapping
Transit Operations
NextGen
Precision Agriculture
Disease Control
TeleComm
IntelliDrive
Trucking Shipping
Personal Navigation
Oil Exploration
Fishing Boating
3
GPS Constellation Status
Baseline Constellation 24 Expandable

• Very robust constellation exceeds user
  requirements
• 31 satellites currently in operation
• 11 GPS IIA
• 12 GPS IIR
• 7 GPS IIR-M
• 1 GPS IIF (set healthy 26 Aug 2010)
• 4 additional satellites in residual status
• 1 additional IIR-M waiting to be set healthy
• Global GPS civil service performance commitment
  met continuously since December 1993

4
GPS Operational Control Segment (OCS)
Alaska
England
Schriever AFB Colorado
S Korea
Vandenberg AFB California
USNO
Cape Canaveral
Hawaii
Bahrain
Kwajalein
Ecuador
Tahiti
Diego Garcia
Ascension
S Africa
Argentina
Australia
New Zealand
Ground Antenna
OCS Monitor Station
Master Control Station
Monitor Station
NGA Monitor Station
Alternate Master Control Station
Ground Antenna
Future Monitor Station
Master Control Station (Schriever AFB)
5
Current GPS Accuracy
N/A
N/A
N/A
N/A
N/A
7
Signal-in-Space User Range Error is the
difference between a GPS satellites navigation
data (position and clock) and the truth,
projected on the line-of-sight to the user
2001 SPS Performance Standard (RMS over all SPS
SIS URE)
6
5
2008 SPS Performance Standard (Worst of any SPS
SIS URE)
4
RMS SIS URE (m)
RMS Signal-in-Space User Range Error (URE), meters
3
2
Decreasing range error
1.6
1.2
1.1
1.0
0.9
1
0
1990
1992
1994
1996
1997
2001
2004
2006
2009
2008
Selective Availability (SA)
System accuracy exceeds published standard
6
GPS Modernization
Architecture Evolution Plan (AEP)
Next Generation Control Segment (OCX)
Legacy Control System
7
Latest U.S. Policy

• Provide continuous worldwide access for peaceful
  uses, free of direct user charges
• Encourage compatibility and interoperability with
  foreign GNSS services
• Operate and maintain constellation to satisfy
  civil and national security needs
• Foreign PNT may be used to strengthen resiliency
• Invest in domestic capabilities and support
  international activities to detect, mitigate and
  increase resiliency to harmful interference

8
Summary

• GPS performance is better than ever and will
  continue to improve
• Augmentations enable even higher performance
• New civil GPS signal available now
• Many additional upgrades scheduled
• U.S. policy encourages worldwide use of civil GPS
  and augmentations
• Permits U.S use of foreign PNT to increase
  resiliency
• International cooperation is a priority
• Compatibility and interoperability are critical

9
For Additional Information
PNT.gov
GPS.gov
10
Contact Information
Hank Skalski DOT Liaison to Air Force Space
Command Air Force Space Command
Headquarters AFSPC/OST 150 Vandenberg St., Suite
1105 Peterson AFB, CO 80914 Phone
01.719.554.2570 Fax [phone]
Email Hank.Skalski_at_peterson.af.mil