GLOBAL POSITIONING SYSTEM

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GLOBAL POSITIONING SYSTEM

• Space Enterprise Council Capitol Hill Day
• 14 March 2008

Major Charlie Daniels, U.S. Air Force National
Coordination Office
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What You Know

• Like the Internet, GPS is a critical component of
  the global information infrastructure
• Scalable applications enabling broad new
  capabilities
• Facilitating innovations in efficiency, safety,
  environmental, public security and science
• Over the past decade, GPS has grown into a global
  utility providing space-based positioning,
  navigation and timing (PNT)
• Consistent, predictable, dependable performance
• Augmentations improve performance

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Briefing Overview

• GPS System
• GPS Applications
• GPS Modernization

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GPS Introduction

• Owned and operated by the U.S. Government
• Paid for by U.S. taxpayers
• Managed at a national level as multi-use asset
• Acquired and operated by the U.S. Air Force on
  behalf of the U.S. Government per Title 10,
  Section 2281.
• GPS service is a one-way broadcast, like FM radio
• Unlimited number of users
• Access to civilian GPS signals is free of direct
  user fees
• Public domain documentation
• Available on an equal basis to users and industry
  
• Anyone in the world can develop GPS user equipment

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GPS Segments
Space Segment
Satellite Constellation
User Segment
Ground Antennas
AFSCN
MonitorStations
Master Control Station
Control Segment
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GPS Ground Control Segment

• Navigation message generation
• Satellite position data
• Monitor L-Band signals
• Adjust GPS signal as needed

• Command Control satellites
• Perform maneuvers
• Monitor satellite health

The control segment keeps the GPS
constellation operating and performing within
specification
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GPS User Segment

• Unlimited
• Broadcast system
• More users can join system
• U.S. International
• Multi purpose
• Civil
• Military
• Commercial

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8
GPS Space Segment
31 GPS Satellites Set Healthy (as of 10 Mar
08) (Baseline Constellation 24)

• 14 Block IIA satellites
• 12 Block IIR satellites
• 5 Block IIR-M satellites
• Transmitting new second civil signal (L2C)
• Transmitting new military signal (M code)
• Next launch March 15, 2008

30 Years of Success First Operational Launch 22
Feb 1978
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Continuous Performance Improvement
Accuracy
Global GPS civil service performance
commitment continuously met since 1993
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GPS Constellation StatusSatellite Age as of
March 2008
16
14
12
10
Years
8
6
BLOCK IIA
BLOCK IIR
BLOCK IIR-M
4
2
Satellite
53
25
26
27
52
58
24
23
39
35
34
36
33
40
30
38
43
46
47
59
60
61
32
37
55
57
51
44
41
54
56
45
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GPS Applications

• Civil/Commercial briefed earlier
• Military Applications
• Force location
• Navigation
• Force employment
• Weapon guidance
• All weather ops
• Satellite positioning
• Comm network timing

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GPS Force Multiplier

• WWII Schweinfurt-Regensburg Raids
• Dropped 24 million pounds of bombs to strike 5
  ball bearing plants
• 376 B-17s

5 Targets Hit
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All Segment GPS Modernization
Satellites

• GPS III (Block III)
• Increased accuracy
• Increased signal strength
• Signal integrity
• Search and Rescue
• Common Galileosignal (L1C)

• Modernized (Block IIR-M)
• 2nd civil signal (L2C)
• M-Code signals

• Modernized (Block IIF)
• 3rd civil signal (L5)

• Legacy (Block IIA/IIR)
• Basic GPS
• C/A civil signal (L1C/A)
• Std Pos. Service
• Precise Pos. Service
• L1 L2 P(Y) nav

Control Systems

• OCX (Modernized)
• New Architecture
• L1C, L2C, L5, M-Code
• Flex Power

• Legacy
• TTC
• L1 L2 monitoring

• Upgraded (AEP)
• IIR-M IIF TTC
• WAGE, AII, LADO
• New MCS/AMCS

User Equipment

• Upgrading
• Military User Equipment

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Modernized GPS New Signals

• Second civil signal (L2C)
• Designed to meet commercial needs
• Higher accuracy through ionospheric correction
• Began with GPS Block IIR-M in Sep 2005 24
  satellites 2014
• Third civil signal (L5)
• Designed to meet demanding requirements for
  transportation safety (safety-of-life)
• Begins with GPS Block IIF
• First launch 2008 (GPS IIR-M Demo) 2009 (GPS
  IIF) 24 satellites 2016
• Fourth civil signal (L1C)
• Designed with international partners to enable
  GNSS interoperability
• Begins with GPS Block III First launch 2014
  24 satellites 2021

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Benefits of GPS Modernization

• System-wide improvements in accuracy,
  availability, integrity, and reliability to
• Meet increasing civil, commercial and military
  demands
• Remain the pre-eminent space-based military PNT
  system
• Higher standalone accuracy
• More robust against interference
• Provides separate more secure Military signal
• Capability for second (L2C) and third (L5) civil
  signals
• Delivers L1C for interoperability with other GNSS
• Improved indoor, mobile, and urban use

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Summary

• GPS System
• 3 Segments Ground Control, Space and User
• Sustaining aging constellation while providing
  best accuracy
• GPS Applications
• Unlimited civil/commercial global user capacity
• Military users
• GPS Modernization
• Key to meeting emerging civil/commercial demands
• Key to remaining the preeminent military
  space-based PNT service

GPS The Worlds Gold Standard in Space-Based
PNT Services
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Contact Info

• Major Charles Daniels, U.S. Air Force
• National Coordination Office for Space-Based PNT
• 1401 Constitution Ave, NW, Room 6822
• Washington, DC 20230
• Tele 202-482-6726
• Email charles.daniels_at_pnt.g
  ov
• Web sites http//pnt.gov
• http//gps.gov