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

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

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

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

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 Railroads Communications Recreation You represent the largest community of GPS . The CivilGPS community. Fishing & Boating Off shore Drilling 9

GPS Space Systems 24-satellite (nominal) constellation Block II/IIA Block IIR Your fathers GPS 24-satellite (nominal) constellation Six orbital planes, four satellites per plane Semi-synchronous, circular orbits (~11,000 mi) Block IIF 11 8

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

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

GPS Users “Wants” Civil User Military User 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 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

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

GPS Modernization Block II Space Vehicles Block IIR-M Block IIF 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 L5 New civil signal at 1176MHz

Modernized GPS Signal Evolution 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 L2CS M C/A Civil Safety of Life Applications (Block IIF and beyond) P(Y) P(Y) 1176.45 MHz 1227.60 MHz 1575.42 MHz

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

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

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

Overview Background Advantages of New Signal Design Considerations

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

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

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

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

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

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

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.

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

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

TDM service for both single and dual frequency 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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