L2 and L5 Civil Signal Industry Day 2 May 2001 LCDR Richard Fontana

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

2. GPS L2 Civil Signal Industry Day Agenda ITEM BRIEFER TIME Welcome and Introductions LCDR Fontana 0900-0910 Overview of GPS Modernization Paul Novak 0910-0920 Advantages of a New L2 CS LCDR Fontana 0920-0945 BREAK 0945-1000 Technical Description of L2CS Tom Stansell 1000-1100 Laboratory and Simulation Dr Dafesh 1100-1130 Results Almanac Karl Kovach 1130-1200 Question and Answer Session LCDR Fontana 1200-1215 LUNCH 1215-1330

3. GPS L5 Civil Signal Industry Day Agenda ITEM BRIEFER TIME Welcome and Introductions Lt Victoria 1330-1340 L5 Design Background Dr Hegarty 1340-1400 L5 Design Background Dr Van Dierendonck 1400-1445 L5 Environmental Studies Dr Hegarty 1445-1500 BREAK 1500-1515 ICD-GPS-705 Organization Dr Slattery 1515-1540 ICD-GPS-705 Review Process Lt Victoria 1540-1600 Question and Answer Lt Victoria 1600-1630

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

5. 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 Power Grid Interfaces Personal Navigation Surveying & Mapping Trucking & Shipping Aviation Communications Railroads Recreation Fishing & Boating Off shore Drilling

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

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

9. GPS Users “Wants” Civil User • Accuracy • Availability • Coverage • Integrity • Robustness • Redundant signals • More power • More jam resistance • More security • Anti-spoof • User discrimination • Shorter “time to first fix” • Backward compatibility Military User • 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 L2 Civil Signal Military code L1 / L2 • Higher power • New military signal • Spectral separation • from civil signals • Faster signal acquisition • Improved security codes L5

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. 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 GPS ModernizationBlock II Space Vehicles Block IIR-M Block IIF

12. Modernized GPS Signal Evolution L5 L2 L1 C/A P(Y) P(Y) Present Signal (Block II/IIA/IIR) M M L2CS C/A Next Generation Of Capability (Block IIR-M) P(Y) P(Y) M M L2CS C/A Civil Safety of Life Applications (Block IIF and beyond) P(Y) P(Y) 1176.45 MHz 1227.60 MHz 1575.42 MHz

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. CY 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 SAASM OA L2CS& M-Code IOC L2CS& M-code FOC L5 IOC L5 FOC M+Power IOC M+Power FOC M-Code IOC M-Code IOC System Milestones Space Segment Heritage Launches M-Code (IIRM/IIF) Launches 1st IIR Mod 1st IIF GPS III Launches GPS III Launches EMD Control Segment Functionality SAASM Capable Dev Test M-Code Capable Dev Test Dev Test M-Code + Power Capable 1st LRIP RCVRs User Equipment SAASM UE Producton / Platform Installs 1st LRIP RCVRs M-Code UE Development Production / Platform Installs Increasing Percent Fielding 1st LRIP AE High Power AE Development Production / Platform Installs UE Fielding GPS Modernization Program Summary

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

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

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. 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. 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. 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. 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. 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. 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. 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. 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. 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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