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Federal Radionavigation Plan Public Meeting FAA Headquarters, Washington, DC 19 May 2003

Ongoing Loran Evaluations at the Federal Aviation Administration and the US Coast Guard Mitchell J. Narins Systems Engineer Federal Aviation Administration Navigation Integrated Product Team. Federal Radionavigation Plan Public Meeting FAA Headquarters, Washington, DC 19 May 2003.

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Federal Radionavigation Plan Public Meeting FAA Headquarters, Washington, DC 19 May 2003

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  1. Ongoing Loran Evaluations at theFederal Aviation Administration and theUS Coast GuardMitchell J. NarinsSystems EngineerFederal Aviation AdministrationNavigation Integrated Product Team Federal Radionavigation Plan Public Meeting FAA Headquarters, Washington, DC 19 May 2003

  2. Purpose of the Evaluations • To determine whether an enhanced Loran system can provide the: • Accuracy • Availability • Integrity, and • Continuity a) to support Lateral Navigation through all phases of flight – including Non-Precision Approach (NPA) b) to support Harbor Entrance and Approach (HEA) for maritime • To determine what other ancillary benefits can be derived from the continued provision of enhanced Loran services • e.g., to support Stratum 1 timing and frequency users • To determine if provision of enhanced Loran services are cost-beneficial

  3. TTX Stations:11 US, 1 Canadian SSX Stations:13 US, 4 Canadian LSU Control Stations North American Loran System

  4. Program Participants • Government • FAA • Navigation Systems Engineering, AND-702 • Navigation and Landing System Architecture, ASD-140 • CNS Test and Evaluation, ACT-360 • Flight Standards, AFS-400 • Aircraft Certification, AIR-130 • Special Programs, AVN-5 • US Coast Guard • Aids to Navigation • Navigation Center • Loran Support Unit • Volpe National Transportation System Center

  5. Industry Booz|Allen|Hamilton Free Flight Systems Illgen Simulation Technologies, Inc. JJMA Locus, Inc. Megapulse, Inc. Peterson Integrated Geopositioning Reelektronika Rockwell Collins WR Systems Academia Ohio University Stanford University US Coast Guard Academy University of Rhode Island University of Alaska University of Wales Program Participants

  6. Aviation Requirements: RNP* 0.3 (target); RNP* 0.5 (minimum) Performance RequirementValue • Accuracy (target) 307 metersAccuracy (minimum) 802 meters • Alarm Limit (target) 556 metersAlarm Limit (minimum) 926 meters • Integrity 10-7/hour • Time-to-alarm 10 seconds • Availability (minimum) 99.9%Availability (target) 99.99% • Continuity (minimum) 99.9%Continuity (target) 99.99% (Source: FAA Loran Evaluation Report, June 2002) *Required Navigation Performance

  7. Marine HEA Requirements (Primary) Performance RequirementValue • Accuracy (target) 10 meters, 95%Accuracy (threshold) 20 meters, 95% • Alarm Limit (target) 25 metersAlarm Limit (threshold) 50 meters • Integrity (target) 3x10-5 • Time-to-alarm 10 seconds • Availability (threshold) 99.7%Availability (target/VTS) 99.9% • Continuity (threshold) 99.85% over 3 hours Continuity (target) 99.97% over 3 hours (Sources: FRP, DOT Task Force, TASC DGPS Mission Needs Analysis: Harbor Entrance and Approach, IMO Resolutions A.815(19) and draft revisions to A.860(20))

  8. Marine HEA Requirements (Backup) Performance RequirementValue • Accuracy (backup) 20 meters, 95% • Alarm Limit (backup) 50 meters • Integrity (target) 3x10-5 • Time-to-alarm 10 seconds • Availability (minimum) 99.7% • Continuity (minimum) 99.85% (over 3 hours) (Sources: FRP, DOT Task Force, TASC DGPS Mission Needs Analysis: Harbor Entrance and Approach, IMO Resolutions A.815(19) and draft revisions to A.860(20))

  9. Timing and Frequency Specifications Performance SpecificationValue • Frequency Accuracy (threshold) 1 in 1012 (averaged over 24 hrs) • No External Antenna (desired) • Backward Compatibility (desired) • Integrity Data Minimum of USE/NO USE Flag • Higher Accuracy Time of Day Time Tag (Year/DOY/Second) Leap Second information • Timing Accuracy <100nsec • Differential Data Daily Correction (Source: DOT Task Force, T1X1 letter of Oct 2002)

  10. 0.1 ns 1 ns 10 ns 100 ns 1 µs 10 µs 100 µs 1 ms 10 ms 100 ms 1 s PTTI/R&D - NIF Scientific/ Experimental • High Precision Military • GPS Monitor Stations • GPS Weapons • AT3 Airborne Geolocation Demo • Bistatic Radar • Other Applications National Timing Labs Advanced Comms • Power Systems • Fault Location • Phasor Meas • Data Sharing CDMA2000 - Base Stations • Low Precision Military • Ground Terminals • VHF Special Comms • Wide Area Data Logging • Seismic monitoring • Nuclear Blast Detection • Digital Time Servers • NTP, etc Timing user survey not intendend to be a complete representation of all users. Requirements have been generalized and averaged over user groups Astronomy • Authentication • Internet login Financial Transactions Could be served by eLORAN Timing User Spectrum

  11. 10-15 10-14 10-13 10-12 10-11 10-10 10-9 10-8 10-7 10-6 10-5 VLBI National Timing Labs • High Precision Military • GPS Monitor Stations • Various Applications • High Precision Metrology • Equipment Calibration • Stratum 1 Comms • Telcos • Military GT • Digital Wideband CDMA2000 - Base Stations • Low Precision Metrology • Equipment Calibration • Low Precision Military • Combat Control Systems • Oscillator Manufacturers • Cal of low-cost xtal • Misc • Broadcast TV • Digital Modular Radio • IEEE P802.16 Wireless Frequeny user survey not intendend to be a complete representation of all users. Requirements have been generalized and averaged over user groups Could be served by eLORAN Frequency User Range

  12. Loran-C NavigationCurrent Capabilities/Future Needs* Note: Most stringent requirements shown in aviation orange. * Includes Stratum 1 timing and frequency capability.

  13. A Most Substantial Investment

  14. Status of Ongoing Loran Evaluations and System Recapitalization • Accuracy • Availability • Integrity • Continuity Final Report due to the Departments of Transportation and Homeland Security March 2004

  15. Loran Evaluation Activities • To determine Loran Accuracy Potential: • ASF* studies and calibration (for both conductivity and terrain) • Receiver/Integrated receiver studies • Loran Accuracy Performance Panel (LORAPP) • Differential Loran study • To determine Loran Availability Potential: • H-Field Antenna/P-static testing • CONUS All-in-view receiver analysis • Noise analysis • SSX and TFE modification evaluations • To determine Loran Integrity Potential: • Loran Integrity Performance Panel (LORIPP) • Time of Transmission/ASF studies • To determine Loran Continuity Potential: • Receiver/Integrated receiver/antenna studies *additional secondary factors

  16. Loran Issue 1: Accuracy • Current Accuracy: 0.25 nm, 2drms, 95% • Target Accuracy (NPA): 0.16 nm (307 m) - RNP 0.3  0.43 nm (802 m) - RNP 0.5 • Target Accuracy (HEA): 8 – 20 m, 2drms, 95% IssuesPotential Mitigations • Old timing sources New cesium clocks • Old timing equipment New timing suite • Tube technology Solid State Transmitter (SSX) technology • Simple propagation model New ASF* tables/algorithms • No real-time corrections LORAPP (Differential Loran) *additional secondary factors

  17. Flights to support characterization of ASFsConducted in August 2002 and March 2003

  18. Loran 2 Loran 7 Loran 7 Loran 1 ~9.0 m ~3.0 m GPS 1 GPS 7 Loran 3 GPS 8 ~6.0 m GPS 3 Loran 8 GPS 2 GPS 7 ~13.0 m ~6.5 m ~2.0 m Typical Results NPA Requirement: 307 m !

  19. Loran Issue 2: Availability • Current Availability:0.997 • Target Availability (NPA): 0.999 - 0.9999 • Target Availability (HEA): 0.997 – 0.999  IssuesPotential Mitigations • Precipitation Static H-Field Antenna* • Atmospheric Noise H-Field, AIV Receiver • Loss of Station Power UPS • Lightning New Lightning Protection • Chain/Stick Availability All-in-view receivers • Tube overloads Solid State Transmitters *Awaiting safety certification

  20. Loran Issue 3: Integrity • Current Integrity: 10 sec. alert @ + 100ns or other specified error conditions • Target Integrity (NPA): 0.9999999* 556m HPL, 10 sec. alert • Target Integrity (HEA): 0.99997** IssuesPotential Mitigations • Presumed Integrity/ Loran Integrity Panel (LORIPP) Auto Blink System Loran Accuracy Panel (LORAPP) *For Aviation: The probability of providing Hazardous or Misleading Information (HMI) is 1 x 10-7 **For Maritime: The probability of providing Hazardous or Misleading Information (HMI) is 3 x 10-5

  21. Status of Integrity (HMI) Analysis • Results to date: • Developed initial algorithms and fault-trees • Loran integrity • Horizontal protection limit (HPL) • Work continues • Analyzed RNP 0.3 performance • Appears feasible throughout CONUS • May require changes in the system infrastructure, policy, processes, etc. • May require continued operation of Canadian stations • Work continues • Analyzed RNP 0.3 approaches • May be feasible with the improved infrastructure • Work continues

  22. Loran Integrity Fault Tree

  23. Loran Issue 4: Continuity • Current Continuity: 0.997 • Target Continuity (NPA): 0.999 - 0.9999 • Target Continuity (HEA): 0.9985 – 0.9997 IssuesPotential Mitigations Same as Availability plus: • Receiver acquisition time New DSP technology New SSX Switch Units AIV/Integrated Receiver

  24. Loran Continuity Fault Tree

  25. Prototype Brassboard Locus Loran Card Installed in Rockwell Collins Multi-Mode Receiver • Flight Testing to begin this month • Integrated GPS/Loran receiver for general aviation also being developed by Free Flight Systems and Locus

  26. Summary • FY ’02 – Excellent progress, Goals achieved • LORIPP is well on its way to showing that aviation integrity requirements can be met • Flight tests showed that Loran can provide excellent accuracy (approaching GPS accuracies) when used in conjunction with appropriate ASF information • FY ’03 – Work continues: • Development of integrated prototype avionics and H-field antennas to evaluate Loran for all phases of flight in both stand-alone and multi-sensor configurations • Development of better ASF models that include spatial factors based on both conductivity and terrain factors and temporal factors based on multiple seasonal measurements • Publication of final H-Field/P-static test results • Publication of interim LORIPP and LORAPP findings • FY ’04 – Wrapping it up • 31 March 2004 – Final Report due to DOT and DHS

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