Alternative Positioning, Navigation & Timing (APNT) Study Update

1. Alternative Positioning, Navigation & Timing (APNT)Study Update Leo Eldredge October 14, 2010

2. Why APNT? The transformation of the National Airspace System (NAS) to the Next Generation Air Transportation System (NextGen) relies on GPS-Based PNT services and suitable alternate PNT services Current ATC system cannot be scaled up to handle 2X traffic 2X traffic is more than a controller can handle using radar vectors RNAV and RNP procedures for trajectory-based operations (TBO) Automation will separate aircraft performing trajectory based operations (TBO) Controllers intercede to provide “control by exception” TBO Operations may require PNT performance that exceeds DME/DME/IRU GPS vulnerability to radio frequency interference (RFI) requires mitigation Waiting for the source of the interference to be located and turned off is not an acceptable alternative

3. Baseline Airspace Condition En Route Sector 01 (BAASS) Ghost Sector (not depicted) Terminal Sector D En Route Sector 02 (GRUPR) Terminal Sector A Enabled by Legacy NAVAIDs • VOR/DME, VORTAC, NDB • Point-to-Point Navigation

4. Dynamic Airspace 1 Arrival Transition Sector 01 (BAASS) Ghost Sector Dynamic Airspace 2 Airport Departure Sector - D D D Departure Transition Sector 02 (GRUPR) Feeder Sector - A Big Airspace Concept Enabled by PBN • GPS, WAAS, LAAS, DD, DDI • Area Navigation (RNAV) • Required Navigation Performance (RNP)

5. TBO 3-Mile Separation with RNP 3 Mile Separation DME / DME / IRU Performance Limit RNP-1.0 1 nm Overlap 2 x RNP 1.0 TBO (APNT) Requirement 2 x RNP 0.3 2 x RNP 0.3 Primary PNT Service: GPS meets all TBO requirements Alternate PNT Service: DME/DME/IRU won’t support 3 NM separation

6. GNSS Enables PBN and ADS-B APNT * Operational requirements are defined for total system accuracy, which is dominated by fight technical error. Position accuracy for these operations is negligible. ** Containment for RNP AR is specified as a total system requirement; value representative of current approvals. Dependent Parallel Approach (DPA) Independent Parallel Approach (IPA) Surveillance Integrity Level (SIL) Navigation Integrity Category (NIC) Navigation Accuracy Category for Position (NACp)

7. PNT Performance Zones Zone- 1 Enroute High CONUS FL-600 FL-180 Zone-3 Terminal OEPs + Next 100 Busiest Airports Zone- 2 Enroute Low CONUS 5000’ AGL 2° Slopefrom500’ AGL 5 SM of Airport 27 SM 89 SM

8. Zone 1, 2, and 3 Geographic Areas

9. GNSS Challenges: GPS Testing by DOD 9 Month Duration • Duration • Geographical Area Impacted Geographical Area Impacted 141 • 141 NOTAMs • NOTAMs • Minimum Minimum • Average Average • Maximum Maximum • 2 Shortest • Shortest 1.0 hour • 1.0 hour • 2 2 • 2 2 2 • Miles Miles Miles • Miles Miles • Miles 455,805 • 455,805 66,018 • 66,018 • 139,795 139,795 Average • Average 6.63 hours • 6.63 hours Longest • Longest 72 hours • 72 hours • 782 Hours 782 Hours • Cumulative Cumulative 90 days • 90 days

10. Commercially Available GPS Jammer(so called “Personal Privacy Device”)

11. LAAS Antenna Location

12. Zeta “SnapShot” System Data Broadband RFI straddling L1 Baseline/Nominal L1 RF

13. … and a few more “Personal Privacy Devices” $110 Ebay $92 Ebay $55 Ebay $335 Ebay $152 Ebay $40 GPS&GSM www.chinavasion.com $83 GPS&GSM www.Tayx.co.uk

14. RFI Challenges without APNT • Transitioning from 3-mile to 5-mile separation en route and on arrivals outside of 40 nm when a GPS RFI event occurs • Shifting some aircraft to radar vectors – significant implications • Rerouting aircraft around interference area to reduce demand • Throttle back demand to compensate for loss of capabilities like parallel runway approaches • Limit RNAV/RNP arrivals and departures and reduce options to handling arrivals

15. APNT Alternative 1Optimized DME Network

16. 1100 DMEs in Current Nework

17. DME-DME Alternative Strengths Leverage existing technology and systems Least Impact on Avionics for Air Carriers Weaknesses General Aviation generally does not equip with DME DME-DME equipped aircraft without Inertial are not currently authorized to fly RNAV/RNP routes DME-DME, even with Inertial, is not authorized for pubic approach operations less than RNAV/RNP-1.0 DME-DME interrogations saturate in very high traffic environments Will require retention and capitalization of nearly half the VORs unless GA equipped with DME/DME inertial

18. APNT Alternative 2Wide Area Multi-Lateration

19. Passive Wide-Area Multi-Lateration (WAM) 1 –Aircraft Transmits ADS-B Signal 6 – Aircraft Uses Own Position for Navigation 5 - TIS-B Sends Position to Aircraft Combined DME/GBT Network 2 - WAM Receives Signal 3 - Aircraft Position Determined 4 - Aircraft Position Sent to GBT’s

20. 656 GBT’s for National Coverage Communication Coverage: Not Navigation

21. Combined Network of DMEs and GBTs

22. Approaches HistogramNavCanada Independent Verification Of Data

23. MLAT Alternative Strengths Accuracy Demonstrated to be within target levels Compatible with existing WAM Systems Weaknesses Throughput on 1090ES may limit availability Minimum of 3 sites required to compute aircraft position Integrity monitoring and Time to Alert may be challenging More sites may be needed due to limited signal range Requires a GPS-Independent common time reference Significant investment in processing facilities and terrestrial communications network may be required Use of MLAT for Navigation will require avionics changes

24. APNT Alternative 3DME Pseudolites (DMPL)

25. Pseudolite Alternative Concept • Aircraft Calculates Position • RAIM Based Integrity Solution • Combined Network of DME/GBTs etc • GPS-Independent Time Reference • 1 Hz Message ID and Time @ Transmit • PNT Data Broadcast Channel

26. Pseudolite Alternative Strengths Unlimited capacity Less complexity for ground-based system Potential for aircraft based integrity solution Potential to leverage use of existing DMEs and GBTs Potential to uplink data other navigation data to aircraft Weaknesses Minimum of 3 sites required to compute aircraft position Significant investment in processing facilities and terrestrial communications network may be required Common GPS-independent timing reference needed Greatest Impact to Aircraft Avionics Least mature concept, no standards exist

27. APNT Timing Service

28. Ground-to-Ground Time Synchronization GEO: WAAS L5 MEO: GNSS LEO: MSS 30 dB of processing gain DMEs + Planned DMEs + GBTs

29. WAAS L5 for Ground-to-Ground Synch. STAP J/S = 45 dB

30. Summary • NextGen Operational Improvements enabled by performance based navigation capabilities increases dependence on GPS and alternate PNT services • GPS vulnerability to radio frequency interference needs to be addressed for trajectory based operations at some locations • Alternatives are being studied for further consideration

31. Questions