icao car/sam atn/gnss seminar
DESCRIPTION
Presentation GNSS 4.2 by H. Cabler. ICAO CAR/SAM ATN/GNSS SEMINAR. Modernization History. Need for GPS Modernization recognized by US as GPS entered Full Operational Capability (1995) Recognized growing importance of GPS to both sectors - PowerPoint PPT PresentationTRANSCRIPT
ICAO CAR/SAM ATN/GNSS SEMINAR
Presentation GNSS 4.2
by H. Cabler
Presentation GNSS 4.2
by H. Cabler
2
Need for GPS Modernization recognized by US as GPS entered Full Operational Capability (1995) Recognized growing importance of GPS to both sectors National Policy imperative to enhance GPS as single world
standard Better, more reliable civilian service Need to rethink GPS architecture for the future
Multiple studies indicated diverse set of needs New signals, Higher Power, Greater Accuracy Greater focus on dual-use nature System Integrity, Survivability, and Prevention of hostile use Better Spectrum Management
Modernization History
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Background
1996 Presidential Decision Directive (PDD) and 1998/99 Vice Presidential announcements committed US to modernization and improvement path Selective Availability (SA) turned to zero NLT 2006 Two new civil signals and new military signals Free world-wide use
Move from studies to action initiated in FY 2000 SA Set to zero in May 00 directed changes to existing and future satellites IIF program terminated at 12 satellites and GPS III development
began
Modernization Now in Full SwingModernization Now in Full Swing
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GPS IIA/IIR
GPS III
GPS IIR-M, IIF
IIR-M: Improved on all IIA capabilities and added
• 2nd Civil Signal on L2• New L1 & L2 M-CodeIIF: IIR-M capability and:• Add 3rd Civil Signal on L5
• Standard Service (~100 m)• Precise Service (~16 m)• Two Nav frequencies L1: Civil (C/A) & Precise code, Navigation L-2: P-code Nav
GPS-III:• Increased power (+20dB)• Increased Accuracy• Greater Availability• Controlled Integrity• Greater Survivability
Basic GPS
L2C on L2
Full Civil RqmtsAdd’l Capabilities
New Civil Signal – L5
GPS Modernization at a Glance
Increasing System Capabilities
Increasing Civil/Defense Benefit
SA Setto 0
5
New Civil Signals
Many consider setting SA = 0 as the 1st step in modernization
New Signals can be considered the 2nd/3rd Steps Civil Users Currently Limited to One GPS Signal
C/A-code at L1 frequency (1575.42 MHz)
Adding a Second Civil Signal C/A-type code at L2 frequency (1227.60 MHz)
Adding a Third Civil Signal P-type codes at L5 frequency (1176.45 MHz)
Higher power signal, intended for precision navigation
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SA Set to Zero on 2 May 2000
Selective Availability (SA) = Intentional Degradation President decided to discontinue SA to aid peaceful civil users Civil user accuracy dramatically increased on 2 May 2000
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Block IIR Modernization
Pre-Modernization/IIR
Heritage SignalsL1 C/AL1, L2 P(Y)
On Orbit Life~10.6 Years MMD*
Post Modernization/IIR-M
Modernized Signals Flexible, Higher Power L1 C/A, L2C** (or C/A) L1, L2 P(Y) L1, L2 M-Code)
On-Orbit Life ~8.6 Years MMD
* Design Life/MMD analysis completed Nov 01.** L2 Second Civil signal design supports varying code length and data structure
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Block IIF Modernization
Pre-Modernization
Heritage SignalsL1, L2 C/AL1, L2 P(Y)
Design Life15 Years
* L2 Second Civil signal design supports varying code length and data structure** L5 Third Civil signal at -154dBw
Post Modernization
Modernized Signals Flexible, Higher Power L1 C/A, L2C* L1, L2 P(Y) L1, L2 M-Code L5 Third Civil**
Design Life 12 Years 10 Year MMD
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Second Civil Signal (L2C) - Block IIR-M Satellites First launch in 2003, then every satellite thereafter Provides a redundant signal for civil users
Improved continuity in case L1 signal reception is lost Improved accuracy via dual-frequency ionosphere correction Wide-lane for extremely-precise local area differential GPS
Third Civil Signal (L5) - Block IIF Satellites First launch in 2005, then subsequent satellites thereafter Provides redundant dual-frequency capability for civil users
Improved continuity in case L1 or L2 signal reception is lost Improved accuracy via triple-frequency ionosphere correction Tri-lane for ultra-precise local area differential GPS
New Civil Signal Roll-Out
10SAASM M-Code
SystemMilestones
Space Segment
1801 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 19FY
Modernized (IIR-M/IIF) Launches
Heritage Launches
GPS-IIIFOC
GPS-IIIIOC
GPS III Launches1st IIR-M 1st IIF
GPS III Launches
L5IOC
L5FOC
EMD
1st GPS-III SV1st
L5 SV1st
L2C SV
1st GPS III
New Capability Schedule
L2CIOC
L2CFOC
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Second Civil Signal
Third Civil Signal
1 ON 3menu
2
Rockwell
4 5 6
7 WPT
8 POS
9 NAV
CLRMARK
0 OFF
NUM LOCK
FIX FOM 1N 42* 01” 46.12”W 091* 38’ 54.36”EL + 00862 ft
ZEROIZE
The GPS IIISystem
• Relook at Entire GPS Architecture to:– Achieve long term GPS performance goals– Reduce long term total ownership costs
• Ensure GPS III is Synergized with:– Military and Civil Needs/Systems– Possible augmentation opportunities
• Build Best GPS for the Next 30 Years
• Relook at Entire GPS Architecture to:– Achieve long term GPS performance goals– Reduce long term total ownership costs
• Ensure GPS III is Synergized with:– Military and Civil Needs/Systems– Possible augmentation opportunities
• Build Best GPS for the Next 30 Years
GPS III System Vision
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GPS III Addresses MultipleGPS Needs
Significantly Increased Integrity Crucial for anticipated civil aviation uses Also important for military use
High level of Signal Availability Equally important to both military and civilian
Significantly Increased Accuracy Driven by evolving nature of warfare and civil uses
Additional GPS needs: Future flexibility, nav related messaging, reprogramability
These Needs not able to be addressed without significant architectural change
These Needs not able to be addressed without significant architectural change
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GPS III Integrated Approach
GPS Originally Designed without benefit of an Established User Base
Civil Users Previously Solicited for Suggested Changes to Existing System to Meet their Needs
GPS III has Novel Approach for Integrating Needs of the DoD, DOT, FAA… Just completed System Architecture and Requirements Definition
phase gathered and identified future requirements Interagency Forum for Operation Requirements created to identify and
assemble new requirements for GPS Civil and military requirements to be approved in totality by joint
committee Coast Guard Navigation Center soliciting requirements via website
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Other Civil Missions (over 140 total)
Other Civil Missions
Stressing Civil Missions
• Category IIIB/C instrument landing at approved airport• Precision automatic highway vehicle guidance (including collision avoidance),
including in urban canyon conditions• Mobile personal systems wireless communications synchronization for advanced
performance signaling protocols• Computing/communications network synchronization• Electric power grid synchronization• Precision construction equipment guidance• Construction surveying• Crustal motion monitoring• Weather monitoring (tropospheric water content)• Scientific instrument synchronization• Open loop antenna pointing for mobile satcomm users, other instrument pointing• Hiker navigation• Civilian spacecraft position and attitude determination for sensor pointing
Stressing Civil Missions
. ..
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GPS III Increased Capability
Assured Delivery of GPS Signals
Higher Power Military & Civil Signals
Higher Accuracy Service for All Users
Increased Integrity Inherent in GPS
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GPS III Assured Delivery
Dual-Use GPS is more than just Adding Civil Signals Assuring availability and continuity of signals
Realization that GPS is considered a Critical Part of Worldwide Infrastructure
Availability/Continuity Key Factors in GPS III Design Crosslink architecture Number of orbital planes Number of satellites Sparing strategy Replacement strategy Control segment
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GPS III Increased Accuracy
Augmented and standalone missions identified that require more accuracy than modernized GPS
Signal-in-space improvements must keep pace with those in users equipment Advanced technology clocks Inter-satellite ranging Improved ephemeris and orbital models Age of Data reduction and more timely updates via
crosslinks
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GPS Accuracy
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
SIS
Ps
ue
do
Ra
ng
e E
rro
r (m
ete
rs 1
-σ)
1996TodayWith AII (2005)IIF (2010)GPS III (2015)
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GPS III Increased Integrity
Aviation applications one of key drivers GPS III architectural changes
Improved monitoring and reporting Planned interfaces between GPS and augmentations
Potential for meeting broad array of civil and military needs via GPS alone
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Sufficient Means of Navigation?
Sufficient to be used anywhere, anytime Without precluding use of other systems or
augmentations Without requiring use of other systems or
augmentations Except for most demanding applications (LAAS)
With assured delivery Availability and continuity (and higher power)
With high accuracy With high integrity
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Ground Augmentation
By itself, GPS III will have very good Accuracy and Integrity Good enough for most navigation applications
Ground Augmentation Gives Major Improvements For Ultra High Accuracy
~1 m with Local Area Differential GPS (LADGPS) ~1 cm with Real-Time Kinematic (RTK)
For Ultra High Integrity 1-1x10-9/operation or even better is achievable
Precision Landing Needs High Accuracy/Integrity Prime example of GPS ground augmentation system usage
Civil: Local Area Augmentation System (LAAS)
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Challenges
Maintaining a healthy constellation while adding system capabilities Constellation sustainment strategies Operational Control Segment (OCS) upgrades Testing / validating new signals - design and
operations Transition to modernized OCS
Spectrum Protection International Cooperation
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International Cooperation
Need a strategic view for US interaction with Galileo Work the policy and technical issues on how these
two system can coexist and leverage one another Opportunity is now for us to begin working to ensure
a single, integrated Navigation service Improves civil aviation, interoperability, and spectrum
protection Will save money if done properly
GPS III Acquisition effort is the right place to push for this to happen
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Summary
GPS Modernization activities well underway GPS Modernization offers superb opportunity to
satisfy both military requirements and civil needs GPS III exploring complementary DoD/civil augmentation
opportunities
Working through challenges GPS III Architecture – Working hard toward a
robust, supportable, flexible, international capability for the next 30 years