Global Positioning System Policy and Program Update
-
Upload
veda-everett -
Category
Documents
-
view
24 -
download
0
description
Transcript of Global Positioning System Policy and Program Update
Global Positioning System Policy and Program Update
Inaugural Forum
Satellite Positioning Research and Application Center
Tokyo, Japan
23 April 2007
James J. Miller, Senior GPS Technologist
Space Communications and Navigation
Space Operations Mission Directorate
2
• GPS Policy
– Objectives and Management
• System Improvements & Modernization
• Interoperability & International Collaboration
• NASA GPS Space Activities
• Summary
Overview
3
• U.S. Space-Based Positioning, Navigation, and Timing (PNT) Policy– Signed on 8 Dec 04; publicly released on 15 Dec 04– Updated U.S. policy while retaining prior GPS principles
• Established a stronger National Space-Based PNT Executive Committee; IGEB disestablished – Chaired by Deputy Secretaries of Defense and
Transportation• Created a new National Coordination Office• Created a new Advisory Board from private sector• Enabled new ways to fund future GPS modernization for civil
applications
2004 U.S. PNT Policy Overview (GPS!)
4
U.S. Policy Principles
• No direct user fees for civil GPS services• Open public signal structure for all civil services
– Promotes equal access for user equipment manufacture, applications development and value-added services
– Facilitates open market driven competition• Use of GPS time, geodesy, and signal standards• Global compatibility and interoperability of future systems
with GPS • Protect the current radionavigation spectrum from disruption
and interference• Recognition of national and international security issues and
protecting against misuse
5
New Policy: Goals
• Provide uninterrupted availability of PNT services• Meet growing demands in national, homeland, economic
security, scientific, and commercial uses• Continue to provide civil PNT services
– Ensure they exceed, or are at least equivalent to, those of foreign civil space-based PNT services
• U.S. space-based PNT services remain essential components of internationally accepted services
6
National Management of GPS
WHITE HOUSEWHITE HOUSE
NATIONALSPACE-BASED PNT
EXECUTIVE COMMITTEE
Co-Chairs: Defense, Transportation
NATIONALSPACE-BASED PNT
EXECUTIVE COMMITTEE
Co-Chairs: Defense, Transportation
ADVISORYBOARD
Sponsor: NASA
ADVISORYBOARD
Sponsor: NASA
DefenseDefense
TransportationTransportation
StateState
CommerceCommerce
Homeland SecurityHomeland Security
NASANASA
Joint Chiefs of StaffJoint Chiefs of StaffCOORDINATION
OFFICE
Host: Commerce
COORDINATIONOFFICE
Host: Commerce
7
• GPS Policy
• System Improvements & Modernization
– GPS Constellation Status
– Next Steps for Space and Control Segments
• Interoperability & International Collaboration
• NASA R&D Activities
• Summary
Overview
8
The 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• Two types of services:
– Standard (free of direct user fees)– Precise (U.S. and Allied military)
• Three segments: – Space– Ground control– User equipment
9
GPS is a Global “Public Good”
• GPS services are like a “super lighthouse” – USG Owned & Operated
– Paid for by U.S. taxpayers and provided free to the world– Users are not hailed at port for fee or tax collection– Managed at a national level as a multi-use asset– Acquired and operated by Air Force on behalf of USG
• GPS receivers are like AM/FM radios– Whenever, wherever -- without advertising!! – Adding users costs nothing– Tracking its usage is impossible through GPS itself
• GPS is not a fee-for-service utility like cable TV– Usage is not metered -- direct cost to user is “zero” – Civil access is open and unconstrained by “locks” or
encryption – Public domain documentation
» Available on an equal basis to users and industry worldwide
» Anyone can develop user equipment
“Lighthouses in the sky, serving all mankind”
Dr. Ivan A. Getting (1912–2003)
10
GPS Constellation Statusas of 12 Feb 07
• 15 Block IIA satellites operational
• 12 Block IIR satellites operational
• 3 Block IIR-M satellites operational
– 5 additional IIR-M satellites to launch
– Since Dec 93, U.S. Government met/exceeded
civil GPS service performance commitments
– SPS Performance Standard (PS)
– U.S. DoD committed to superior GPS service
30 Healthy SatellitesBaseline Constellation: 24
11
GPS Monitoring Stations
Cape Canaveral
Original USAF Sites - 6NGA sites transmitting to OCS since Aug 2005 - 6NGA sites transmitting to OCS since Dec 2006 - 5
12
GPS Single Frequency Performance
System accuracy far exceeds current standardSystem accuracy far exceeds current standard
Steady decrease in error due to improvements such as the addition of new monitoring stations, tighter control of clocks, etc.
13
• GPS Policy
• System Improvements & Modernization
– GPS Constellation Status
– Next Steps for Space and Control Segments
• Interoperability & International Collaboration
• NASA R&D Activities
• Summary
Overview
14
GPS Modernization Goals
• System-wide improvements in: – Accuracy– Availability– Integrity– Reliability
• Robustness against interference• Improved indoor, mobile, and urban use• Interoperability with other GNSS constellations• Backward compatibility
15
Block IIA/IIR Block IIIBlock IIR-M, IIF•Backward compatibility•4th civil signal (L1C)•Increased accuracy•Increased anti-jam power•Assured availability•Increased security•System survivability•Search and Rescue
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– Single frequency
(L1)– Coarse acquisition
(C/A) code navigation
•Precise Service– Y-Code (L1Y & L2Y)– Y-Code navigation
Increasing System Capabilities Increasing Defense / Civil Benefit
GPS Modernization Program
16
Modernized GPS – Civil Signals
• Second civil signal (“L2C”)– Designed to meet commercial needs
» Higher accuracy through ionospheric correction» Higher effective power and improved data structure reduce interference, speed
up signal acquisition, enable miniaturization of receivers, may enable indoor use
– 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)» Uses highly protected Aeronautical Radio Navigation Service (ARNS) band
– Begins with GPS Block IIF– First launch: ~2008; 24 satellites: ~2016
• Fourth civil signal (“L1C”)– Designed with international partners to enable GNSS interoperability– Begins with GPS Block III– First launch: ~2013; 24 satellites: ~2021
17
GPS Modernization – Spectrum
ARNS Band RNSS Band ARNS Band
1575.421227.6Frequency (MHz)
1176.45
-250
-240
-230
-220
Pow
er S
pect
rum
(dB
W/H
z)
1575.421227.6
-250
-240
-230
-220
Pow
er S
pect
rum
(dB
W/H
z)Frequency (MHz)
1575.421227.6Frequency (MHz)
1176.45
-250
-240
-230
-220
Pow
er S
pect
rum
(dB
W/H
z)
1575.421227.6
-250
-240
-230
-220
Pow
er S
pect
rum
(dB
W/H
z)
Frequency (MHz)
P(Y) C/A
L5
ML2C
L1C
L1L2
L5
Block IIA, 1990
Block III, 2013
Block IIR-M, 2005
Block IIF, 2008
as of Dec 2005
(artist’s concept)
planned
previous
18
IIR-15(M) Launch & View From Space 25 September 2006
19
GPS III Acquisition Approach
Block A Configuration• New L1C Signal• New GPS III SV Platform
Block A Configuration
Block A Configuration
Technology Development / Capability Insertion Program Plan
Plus demo high-speed communication (uplink, downlink & crosslink)
Plus new capabilities demo
Plus new capabilities demo
Block A Configuration
Increment IIIA
Increment IIIB
Increment IIIC
20
The next generation GPS control segment (OCX) includes a new infrastructure with functionality that completes modernization capabilities.
MonitorStationsMonitorStations
AdvancedGroundAntennas
AdvancedGroundAntennas
IIFIIF IIIIII
C2 Uplin
k
and Downlin
k
C2 Uplin
k
and Downlin
k
Position, Velocity,
Time Data
Position, Velocity,
Time Data
Master Control StationMaster Control Station
FAIRBANKS
USNO WASH D.C.
NEW ZEALAND
ECUADOR
ARGENTINA
ENGLAND
BAHRAIN
SOUTH AFRICA
SOUTH KOREA
COLORADO SPRINGS
VANDENBERG, AFB
HAWAII
CAPE CANAVERAL
ASCENSION DIEGO
GARCIA
KWAJALEIN
TAHITI
Master Control Station (MCS) Advanced Ground Antenna
Ground Antenna (GA) USAF Monitor Station (MS)
National Geospatial-Intelligence Agency (NGA) Tracking Station
Alternate Master Control Station (AMCS) AUSTRALIA
IIR/MIIR/M
Battlespace AwarenessBattlespace Awareness
OCX Program Description
21
• GPS Policy
• System Improvements & Modernization
– GPS Constellation Status
– Next Steps for Space and Control Segments
• Interoperability & International Collaboration
– GPS-QZSS Progress
• NASA R&D Activities
• Summary
Overview
22
GPS/QZSS Agreement – 27 January 2006Unprecedented Compatibility & Interoperability
• QZSS designed to work with & enhance civil services of GPS– Availability enhancement– Performance enhancement
• GPS & QZSS have established that their signals are RF compatible
23
GPS-QZSS Technical Working Group (TWG)
• Civil system for Asia-Pacific region• Enhances civil GPS services• First QZSS launch expected in 2009• GPS-QZSS technical meetings
– Nov 04 in Washington, DC, US– July 05 in Hawaii, US– January 06 in Tokyo, Japan– Aug 06 in Hawaii– Next mtg. in Washington, DC, in May
• GPS & QZSS success in designing “common” signals– Five of six QZSS signals use same
signal structures, frequencies, spreading code families, data message formats as GPS or SBAS signals
• Draft interface specification (IS) for QZSS released in January 2007– IS-GPS-200, IS-GPS-705, & IS-GPS-800 are baseline documents
% Time that at Least 1 of 3 QZSS Satellites Is Visible
24
• GPS Policy
• System Improvements & Modernization
– GPS Constellation Status
– Next Steps for Space and Control Segments
• Interoperability & International Collaboration
– GPS-QZSS Progress
• NASA R&D Activities
– GPS to Earth Orbit, and Beyond
• Summary
Overview
25
GPS and Human Space Flight
Miniaturized Airborne GPS Receiver (MAGR-S) • Modified DoD receiver to replace TACAN
on-board the Space Shuttle• Designed to accept inertial aiding and
capable of using PPS • Single-string system (retaining three-string
TACAN) installed on OV-103 Discovery and OV-104 Atlantis, three-string system installed on OV-105 Endeavour (TACAN removed)
• GPS taken to navigation for the first time on STS-115 / OV-104 Atlantis STS-115 Landing
Space Integrated INS/GPS (SIGI)• Receiver tested on shuttle flights prior to
deployment on International Space Station (ISS)
• The ISS has an array of 4 antennas on the T1 truss assembly for orbit and attitude determination
26
Navigation with GPS: Space-Based Range
• Space-based navigation, GPS, and Space Based Range Safety technologies are key components of the next generation launch and test range architecture
• Provides a more cost-effective launch and range safety infrastructure while augmenting range flexibility, safety, and operability
• Memorandum signed in November 2006 for GPS Metric Tracking (GPS MT) by January 1, 2011 for all DoD, NASA, and commercial vehicles launched at the Eastern and Western ranges
GPS-TDRSS Space-Based Range
27
Augmentation of GPS in Space: GDGPS & TASS
• TDRS Augmentation Service for Satellites (TASS) provides Global Differential GPS (GDGPS) corrections via TDRSS satellites
• Integrates NASA’s Ground and Space Infrastructures
• Provides user navigational data needed to locate the orbit and position of NASA user satellites
47o W171o W
85o E
~18-20o
28
Navigation with GPS beyond LEO
• GPS Terrestrial Service Volume– Up to 3000 km altitude– Many current applications
• GPS Space Service Volume (SSV)– 3000 km altitude to GEO– Many emerging space users– Geostationary Satellites– High Earth Orbits (Apogee above GEO altitude)
• SSV users share unique GPS signal challenges– Signal availability becomes more limited
– GPS first side lobe signals are important
– Robust GPS signals in the Space Service Volume needed
– NASA GPS Navigator Receiver in development
29
Navigation with GPS beyond Earth Orbit… and on to the Moon
• GPS signals effective up to the Earth-Moon 1st Lagrange Point (L1)• 322,000 km from Earth• Approximately 4/5 the distance to the Moon
• GPS signals can be tracked to the surface of the Moon, but not usable with current GPS receiver technology
30
Earth-Moon Communications and Navigation Architecture
• Options for Communications and/or Navigation:– Earth-based tracking, GPS, Lunar-orbiting communication and navigation satellites
with GPS-like signals, Lunar surface beacons and/or Pseudolites• The objective is integrated interplanetary communications, time dissemination, and
navigation
31
Summary
• Continuing success in GPS sustainment & modernization– New capabilities delivering enhanced performance– Developments on track to enhance space and control segments
• Civilian use of GPS, and GPS-derived systems, is already extending well beyond Earth
• International participation will make new worldwide GPS applications grow more robust and valuable for generations to come