1. ICAO CAR/SAM ATN/GNSS SEMINAR Presentation GNSS 4.2 by H. Cabler Presentation GNSS 4.2 by H. Cabler

2. 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

3. 3 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 Swing

4. 4 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-Code IIF: 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 Rqmts Add’l Capabilities New Civil Signal – L5 GPS Modernization at a Glance Increasing System Capabilities Increasing Civil/Defense Benefit SA Set to 0

5. 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

6. 6 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

7. 7 Block IIR Modernization Pre-Modernization/IIR Heritage Signals L1 C/A L1, 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

8. 8 Block IIF Modernization Pre-Modernization Heritage Signals L1, L2 C/A L1, L2 P(Y) Design Life 15 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

9. 9 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

10. 10 SAASMM-Code System Milestones Space Segment 18010203040506070809101112131415161719FY Modernized (IIR-M/IIF) Launches Heritage Launches GPS-III FOC GPS-III IOC GPS III Launches 1st IIR-M1st IIF GPS III Launches L5 IOC L5 FOC EMD 1 st GPS-III SV 1 st L5 SV 1 st L2C SV 1st GPS III New Capability Schedule L2C IOC L2C FOC

11. 11 Second Civil Signal Third Civil Signal 1 ON 3 menu 2 Rockwell 4 5 6 7 WPT 8 POS 9 NAV CLR MARK 0 OFF NUM LOCK FIX FOM 1 N 42* 01” 46.12” W 091* 38’ 54.36” EL + 00862 ft ZEROIZE The GPS III System 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

12. 12 GPS III Addresses Multiple GPS 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

13. 13 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

14. 14 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...

15. 15 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

16. 16 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

17. 17 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

18. 18 GPS Accuracy

19. 19 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

20. 20 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

21. 21 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)

22. 22 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

23. 23 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

24. 24 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