1. 1 L2 and L5 Civil Signal Industry Day 2 May 2001 LCDR Richard Fontana GPS Deputy Program Manager, DOT

2. 2 GPS L2 Civil Signal Industry Day Agenda ITEMBRIEFERTIME Welcome and Introductions LCDR Fontana0900-0910 Overview of GPS Modernization Paul Novak0910-0920 Advantages of a New L2 CS LCDR Fontana0920-0945 BREAK0945-1000 Technical Description of L2CSTom Stansell1000-1100 Laboratory and Simulation Dr Dafesh1100-1130 Results AlmanacKarl Kovach1130-1200 Question and Answer Session LCDR Fontana1200-1215 LUNCH1215-1330

3. 3 GPS L5 Civil Signal Industry Day Agenda ITEMBRIEFERTIME Welcome and Introductions Lt Victoria1330-1340 L5 Design Background Dr Hegarty1340-1400 L5 Design Background Dr Van Dierendonck1400-1445 L5 Environmental StudiesDr Hegarty1445-1500 BREAK1500-1515 ICD-GPS-705 OrganizationDr Slattery1515-1540 ICD-GPS-705 Review ProcessLt Victoria1540-1600 Question and AnswerLt Victoria1600-1630

4. 4 L2 and L5 Civil Signal Industry Day 2 May 2001 Paul Novak SMC/CZC (SAIC)

5. Communications Surveying & Mapping Fishing & Boating Off shore Drilling Recreation Trucking & Shipping Personal Navigation Aviation Railroads Power Grid Interfaces Civil Use of GPS “The nation’s reliance on GPS has become an issue of national security -- national security in its broadest sense, that goes beyond merely national defense.” -- Dr. James Schlesinger, March 1997

6. 6 Block IIR Block II/IIA Block IIF 24-satellite (nominal) constellation Six orbital planes, four satellites per plane Semi-synchronous, circular orbits (~11,000 mi) GPS Space Systems

7. 7 Civil GPS, Summary of Key Events 1978 - First Global Positioning System satellite launch 1983 - President Reagan offers GPS to the world “free of charge” 1993 - GPS Standard Positioning Service available 1994 - FAA approves GPS for use in National Airspace System 1996 - Presidential Decision Directive, first National GPS policy 1998 - Two new GPS civil signals (L2 and L5) announced 1999 - Third civil signal (L5) at 1176.45 MHz announced 2000 - Congress funds GPS Modernization in DoD budget 2000 - Selective Availability set to zero 2000 - GPS JPO begins modifications to IIR-M and IIF satellites 2000 - JPO awards Boeing and Lockheed Martin GPS III contracts

8. 8 GPS Modernization Mission Precise & Continuous, 3-D Position, Velocity and Timing Information to an unlimited number of military and civil users Current Mission Anti-Jam/Anti-Spoof Protection, Civilian “Safety of Life” Signals, Upgraded & Redundant Control, and demonstrate Legacy and Upgraded Military Receivers. MS GA MCS L-Band NDS Downlink S-band Alternate MCS UHF Crosslink Additional Modernization Mission

9. 9 GPS Users “Wants” More jam resistance More security Anti-spoof User discrimination Shorter “time to first fix” Backward compatibility Accuracy Availability Coverage Integrity Robustness Redundant signals More power Higher power New military signal Spectral separation from civil signals Faster signal acquisition Improved security codes Selective Availability (SA) to zero Second civil signal Ionospheric correction Redundancy Third civil signal High accuracy real-time applications Spectrum protection for “safety of life” applications Civil User Military code L1 / L2 L2 Civil Signal Military User L5

10. 10 Why Modernize GPS? The Civil GPS Perspective Better support to civil GPS customers worldwide New civil signals for improved accuracy, integrity and continuity of service = robustness Global utility = economic enabler Optimize GPS PVT and augmentation systems in a overall national network architecture Presidential Decision Directive - Mar 96 Vice Presidential Announcements - Mar 98 and Jan 99

11. 11 GPS Modernization Block II Space Vehicles  L1 Enhancements  New developmental Military code (M-code)  L2 Enhancements  New L2 civil signal  New developmental M- code  L1 Enhancements  Similar to IIR-M  Operational M-code  L2 Enhancements  Similar to IIR-M  Operational M-code  L5  New civil signal at 1176MHz Block IIR-MBlock IIF

12. 12 1227.60 MHz1575.42 MHz1176.45 MHz L2L1L5 P(Y) C/A P(Y) C/A P(Y) P(Y) L2CS P(Y) C/A P(Y) L2CS M M Present Signal (Block II/IIA/IIR) Next Generation Of Capability (Block IIR-M) Civil Safety of Life Applications (Block IIF and beyond) Modernized GPS Signal Evolution M M

13. 13 GPS III Architecture Studies Military missions Precision bombing Mine clearing Situational awareness Civilian missions Precision farming Building/ urban canyon personnel tracking Global Air Traffic Management (GATM) Time synchronization for utilities/ telecommunications

14. 14 GPS Modernization Program Summary

15. L2 Civil Signal LCDR Richard Fontana GPS Deputy Program Manager, DOT May 2, 2001

16. 16 Overview  Background  Advantages of New Signal  Design Considerations

17. 17 Background  Option to implement a new signal  Did not want to limit future GPS by what is implemented on IIR/IIF  Overcome some limitations of C/A coded signals  Can make significant improvements with new technology signal  C/A code designed as an acquisition signal  1070s technology

18. 18 Advantages of a New Signal  Improved Cross Correlation Properties  Improves ability to transmit more signals (SBAS,Pseudolytes)  Improves the tolerance to interference  Improves susceptibility to self interference  Improves the dynamic rage of receivers Can receive weaker signals without self interference  Enables operation in more stressful environments (wooded area, buildings, urban canyons)  Enables ability for higher power signals on future satellites

19. 19 Advantages of a New Signal  Improved Tracking capability  Enables operation in more stressful environments (wooded area, buildings, urban canyons)  Improved Data Demodulation  Want equivalent to tracking threshold  Again, enables operation in more stressful environments  Acquisition Capability  Dependent on user equipment  Design trade with code length  Not limited by code. With right UE, can acquire signal in more stressful environments than C/A code

20. 20 Design Considerations  Enhance existing professional/commercial dual frequency applications  Provide more robust iono correction signal  Provide a more effective single frequency navigation signal  Drives need for data  Simple to implement in the SV and UE  Schedule and Cost (both SV and UE)  Replacement for C/A signal

21. 21 Design Considerations (continued)  Compatible with L2 M-code  Spectral Separation  Ensure no detriment to Codeless/Semi Codeless L2 P(Y) receivers  As a result of two earlier objectives  Same power level and spectral shape as C/A code…no additional testing required  Risk Mitigation  Design schedule short, IIR implementation schedule short, coordination process short  C/A code switch

22. 22 Design Considerations (continued)  What is optimum in the future (GPS III) to determine the best step now.  Did not want to artificially constrain thinking due to possible IIR/IIF perceived limitations.  Perceived cost/schedule limitations.  Design for future, provide natural migration path  Then determine what portion could be implemented on IIR and IIF  L2 C/A code compatibility  Assess impact on both military and civilian receivers  Not a design driver but have C/A switch as risk mitigation

23. 23 Signal Characteristics  Two codes one with & one without data  Serves single and dual frequency users  Signal characteristics:  Codes longer than C/A to minimize cross correlation  Separated by time – Time Division Multiplexed (TDM)  Narrow band signal – Spectral separation  Improved data structure – Enhanced Data demodulation  Enhance cross correlation, tacking threshold, data demodulation threshold.

24. 24 Signal Comparison  L2 splits power 50/50 between data and data-less channels  Medium Code with Data, Long code no data  Higher effective L2 channel for tracking  3db higher than C/A on L2  Approximately 3dB better Data demodulation capability  Enhanced data structure

25. 25 Signal Comparison  24dB better cross-correlation protection.  C/A code cross correlation “protection” is ~21 dB. The L2CS signal is ~45dB “protection”  Dynamic range improvement.  Better capability to receive both weak and strong signals  Acquisition threshold  Given assumptions of improved UE, not harmed  Under stressful conditions improved

26. 26 L2CS Summary  TDM service for both single and dual frequency  Significant improvements in  Cross correlation performance  Tracking threshold  Data recovery threshold  Acquisition Capability  Modern signal for future GPS

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