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
Overview of GPS Modernization Paul Novak
Advantages of a New L2 CS LCDR Fontana
BREAK
Technical Description of L2CS Tom Stansell
Laboratory and Simulation Dr Dafesh
Results
Almanac Karl Kovach
Question and Answer Session LCDR Fontana
LUNCH

3. GPS L5 Civil Signal Industry Day Agenda
ITEM BRIEFER TIME
Welcome and Introductions Lt Victoria
L5 Design Background Dr Hegarty
L5 Design Background Dr Van Dierendonck
L5 Environmental Studies Dr Hegarty
BREAK
ICD-GPS-705 Organization Dr Slattery
ICD-GPS-705 Review Process Lt Victoria
Question and Answer Lt Victoria

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

6. 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

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

8. GPS Modernization MissionMS 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.

9. 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

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. 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

12. 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)
MHz
MHz
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. 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

15. GPS Deputy Program Manager, DOT
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. 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

27. Back up