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Ongoing Loran Evaluations at the Federal Aviation Administration and the US Coast Guard Mitchell J. Narins Systems Engineer Federal Aviation Administration.

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Presentation on theme: "Ongoing Loran Evaluations at the Federal Aviation Administration and the US Coast Guard Mitchell J. Narins Systems Engineer Federal Aviation Administration."— Presentation transcript:

1 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 International Loran Association Conference Boulder, Colorado 4 November 2003

2 2 Purpose of the Evaluations To determine whether an enhanced Loran system can provide the: Accuracy Availability Integrity 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 users 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 providing these services via Loran is cost- beneficial (i.e., Benefits/Costs >1)

3 3 North American Loran System TTX Stations: 11 US, 1 Canadian SSX Stations: 13 US, 4 Canadian LSU Control Stations New SSX Stations: 1 US First New SSX Station Installation George, Washington

4 4 Government FAA Navigation and Landing Systems Engr, AND-740 Navigation and Landing System Architecture, ASD-140 CNS Test and Evaluation, ACB-440 Flight Standards, AFS-400 Aircraft Certification, AIR-130 Special Programs, AVN-5 US Coast Guard HQ Aids to Navigation Navigation Center Loran Support Unit Command and Control Center Volpe National Transportation System Center Program Participants

5 5 Industry Booz|Allen|Hamilton Free Flight Systems* Illgen Simulation Technologies, Inc. JJMA Locus, Inc. Megapulse, Inc. Peterson Integrated Geopositioning Reelektronika* Rockwell Collins Timing Solutions Si-Tex Marine* WR Systems Academia Ohio University Stanford University US Coast Guard Academy University of Rhode Island University of Alaska University of Wales* *New FY 2003 Team Member

6 6 Loran Program Logo Collection Booz|Allen|Hamilton

7 7 Team Contributions to ILA November: Loran Integrity Certification Dr. Per Enge, Stanford University Loran of the 21 st Century CAPT Tom Gunther (USCG Ret.), Booz|Allen|Hamilton Loran-C Maintenance Support CDR John Macaluso, Loran Support Unit The Challenge of Finding Your Way in a World Hostile to Radio Navigation Dr. Durk Van Willigan On-air with the New Solid State Transmitter CDR Chuck Teaney (USCG Ret.) WR Systems The Case for Transitioning to Time of Emission Control in the US CAPT Curt Dubay, USCG Navigation Center Loran Operation Performance Report LCDR Max Caruso, USCG NavCen Detachment Supporting the Enhanced Loran-C System LT (jg) Zach Conover, Loran Support Unit Applications of Differential Loran CDR Doug Taggert (USCG Ret.), Overlook Systems Differential Loran CAPT Ben Peterson (USCG Ret.), Peterson Integrated Geopositioning Common-View LORAN-C for Precision Time and Frequency Recovery Dr. Tom Celano, Timing Solutions Corporation Predicted Differential Loran Performance in Boston Harbor Mr. Andre Grebnev, Megapulse, Inc. 5 November: Early Skywave Propagation Dr. Peter Morris, Northrup Grumman Early Skywave Examples from PCMS Data CAPT Bob Wenzel (USCG Ret.), Booz|Allen|Hamilton Mitigation of the Effects of Early Skywave CAPT Ben Peterson (USCG Ret.), PIG Getting a Bearing of ASF Directional Corrections CAPT Dick Hartnett, USCG Academy Modelling Loran-C Envelope-to-Cycle Differences in Mountainous Terrain Dr. David Last, University of Wales – Bangor Summer Vacation 2003 – ASF Spatial Mapping in CO/AR/FL/CA Mr. Greg Johnson, JJMA Analysis of Groundwave Propagation Effects for Loran RNP 0.3 Dr. Sherman Lo, Stanford University 6 November Loran-C Band Data Collection Efforts at Ohio University Mr. Curt Cutright, Ohio University Atmospheric Noise Analysis Mr. Lee Boyce, Stanford University FAA Tests and H-Field Antenna to Increase Loran-C Availability During P-Static Mr. Robert Erikson, FAA Technical Center Integrated GPS/Loran Navigation Sensor for Aviation Applications Mr. James Doty, Rockwell Collins Development of an Integrated GPS/LORAN Prototype Navigation System for Business and General Aviation Applications Dr. James Davis, Free Flight Systems Integrated GPS/ Loran Sensor for Maritime Operations Mr. Wouter Pelgrum, Reelektronika On Non-iterative Loran-C Time Difference to Latitude/Longitude Converters Dr. Paul Williams, University of Wales - Bangor The U.S. Loran-C Evaluation Program has much to be proud of…and equally much to report out at this ILA Conference:

8 8 Loran-C Evaluation Program FY 1994 Federal Radionavigation Plan (FRP) announced that Loran-C service would terminate 31 December 2000 Congressional lobbying (primarily by aviation groups) resulted in budgetary language to continue system development FY 1997 ($4.6 M) Congressional Mandate The FY 1997 Congressional budget provided funds to the FAA for “upgrades to the Loran-C navigation system and... to implement an automatic blink system (ABS).” FY 1998 ($3 M) Congressional Mandate The FY 1998 Congressional budget directed the FAA “to continue Loran-C upgrades initiated in fiscal 97.” FY 1999 ($7 M) Congressional Mandate The Congressional budget provided funds to the FAA for “further development of the Loran-C navigation system.”

9 9 Loran-C Evaluation Program FY 2000 ($10 M) Congressional Mandate The Congressional budget provided funds to the FAA for “further development of the Loran-C navigation system.” FY 2001 ($20 M requested, $25 M provided) First year included in President’s budget FY 2002 ($13 M requested, $19 M provided) FY 2003 ($13 M requested, $25 M provided) FY 2004 ($0 requested, $20M - $25M expected) Senate (Appropriations Report) raised the level of funding to $20 Million House (Appropriations Report) raised the level of funding to $25 Million Awaiting Conference Decision

10 10 A Most Substantial Investment * *Assumes $25 M in FY 04

11 11 Current US Loran-C Policy “While the Administration continues to evaluate the long-term need for continuation of the Loran-C radionavigation system, the Government will operate the Loran-C system in the short term. The U.S. Government will give users reasonable notice if it concludes that Loran-C is not needed or is not cost effective, so that users will have the opportunity to transition to alternative navigation aids. With this continued sustainment of the Loran-C service, users will be able to realize additional benefits. Improvement of GPS time synchronization of the Loran-C chains and the use of digital receivers may support improved accuracy and coverage of the service. Loran-C will continue to provide a supplemental means of navigation. Current Loran-C receivers do not support nonprecision instrument approach operations.” 2001 US Federal Radionavigation Plan

12 12 Volpe GPS Vulnerability Study The vulnerability study released on 10 September 2001 recognized the potential for Loran-C to be a robust backup system for GPS navigation and augmentation and timing. “In an effort to provide the greatest benefit to the users, encourage the development of affordable vehicle-based backup such as GPS/inertial receivers, and, in the event Loran-C becomes a viable terrestrial backups to GPS, aviation certifiable Loran-C receivers, and GPS/Loran-C receivers.” “Conduct a comprehensive analysis of GPS backup navigation and precise timing options including VOR/DME, ILS, Loran-C, inertial navigation systems, and operating systems. “Continue the Loran-C modernization program of the FAA and USCG, until it is determined whether Loran-C has a role as a GPS backup system. If it is determined that Loran-C has a role in the future navigation mix, DOT should promptly announce this to encourage the electronics manufacturing community to develop new Loran-C technologies.”

13 13 Loran’s Potential as a GPS Backup ParameterLoranGPS Frequency100 kHz GHz PropagationGroundwaveLine of Sight Chief Propagation ErrorsConductivity, troposphere Iono delay variations* variations PenetrationWalls, ground, 6' seawaterVery little penetration ModulationTD + CDSpread spectrum CD CoverageTo ground levelTo ground level Signal StrengthRelatively highVery low by design Timing BasisTriple CesiumRubidium at present Tx LocationGround - stationarySpace - moving Utility: Aviation exampleEn route, terminal airspaceEn route, terminal airspace Lateral-guided approachLateral-vertical approach** User communitiesMultiple (air, land, marine)Multiple ( air, land, marine) * Propagation errors are affected at different times and places by components of solar storms * GPS propagation variations are not correlated with Loran-C propagation errors. ** Vertical-guided "precision" approaches require WAAS or LAAS augmentations.

14 14 Loran-C Navigation Current Capabilities/Future Needs* AccuracyAvailabilityIntegrityContinuity Current Definition of Capability * (FRP) 0.25 nm (463 m) second alarm/ 25m error FAA NPA (RNP.3) Requirements 0.16 nm (307 m) – USCG Harbor Requirements (to date) nm (8 – 20 m) second alarm/ 25m error – over 3 hours Note: Most stringent requirements shown in aviation orange. * Includes Stratum 1 timing and frequency capability.

15 15 Timing User Spectrum 0.1 ns1 ns10 ns100 ns1 µs10 µs100 µs1 ms10 ms100 ms1 s PTTI/R&D - NIF Scientific/ Experimental High Precision Military -GPS Monitor Stations -GPS Weapons -AT3 Airborne Geolocation Demo -Bistatic Radar -Other Applications Advanced Comms Power Systems -Fault Location -Phasor Meas -Data Sharing CDMA Base Stations Low Precision Military -Ground Terminals -VHF Special Comms Astronomy Financial Transactions National Timing Labs Wide Area Data Logging -Seismic monitoring -Nuclear Blast Detection Digital Time Servers -NTP, etc Authentication -Internet login Could be served by Enhanced LORAN (eLoran) Timing user survey not intended to be a complete representation of all users. Requirements have been generalized and averaged over user groups

16 16 Frequency User Range VLBI High Precision Military -GPS Monitor Stations -Various Applications Stratum 1 Comms -Telcos -Military GT -Digital Wideband Low Precision Metrology -Equipment Calibration CDMA Base Stations Low Precision Military -Combat Control Systems Misc -Broadcast TV -Digital Modular Radio -IEEE P Wireless Oscillator Manufacturers -Cal of low-cost xtal Could be served by eLORAN High Precision Metrology -Equipment Calibration National Timing Labs Frequency user survey not intended to be a complete representation of all users. Requirements have been generalized and averaged over user groups

17 Status of the Ongoing Loran Evaluation and Associated System Recapitalization Final Report due to the Departments of Transportation and Homeland Security March 2004 Accuracy Availability Integrity Continuity

18 18 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

19 19 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

20 20 Flights to Support Characterization of ASFs August 2002 and March 2003

21 21 Typical Results Loran 7 Loran 1 GPS 1 Loran 8 GPS 7 GPS 8 ~13.0 m ~3.0 m ~2.0 m Loran 2 Loran 7 GPS 2 Loran 3 GPS 7 GPS 3 ~9.0 m ~6.0 m ~6.5 m NPA Requirement: 307 m!

22 22 Flights to Support Characterization of ASFs July – September 2003

23 23 Loran ASF Measurement Campaign Lots of Miles – Lots of Data Monterey, CaliforniaPensacola/Destin, Florida Grand Junction, Colorado Little Rock, Arkansas

24 24 Loran Issue 2: Availability Current Availability: Target Availability (NPA): Target Availability (HEA): –  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

25 25 Loran Issue 3: Integrity Current Integrity: 10 sec ns or other specified error conditions Target Integrity (NPA): * 556m HPL, 10 sec. alert Target Integrity (HEA): ** 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 **For Maritime: The probability of providing Hazardous or Misleading Information (HMI) is 3 x 10 -5

26 26 Loran Issue 4: Continuity Current Continuity: Target Continuity (NPA): Target Continuity (HEA): – IssuesPotential Mitigations Same as Availability plus: Receiver acquisition time  New DSP technology  New SSX Switch Units  AIV/Integrated Receiver

27 27 Prototype Brassboard Locus Loran Card Installed in Rockwell Collins Multi-Mode Receiver Flight Testing Results will be reported out on Thursday Integrated GPS/Loran receiver for general aviation also being developed by Free Flight Systems and Locus

28 28 FreeFlight/Locus GA Multi-Mode Receiver Similar to GPS/WAAS/Loran MMR development Phase I Prototype testing of Integrated GPS/WAAS/Loran receiver testing to commence this fall

29 29 FreeFlight/Locus GA Multi-Mode Receiver Phase II Prototype to be available for testing Spring 2004

30 30 Megapulse/Reelektronika/Si-Tek Multi-Mode Marine Receiver Front End & ADC 77 x 47 mm Signal Processor 77 x 51 mm

31 The Loran Decision Process Final Report due to the Departments of Transportation and Homeland Security March 2004 What are we doing? When are we doing it? When will we be finished? When will there be a decision?

32 32 The Loran Decision Process 1. Determine if Loran can provide the accuracy, availability, integrity, and continuity to support non-precision approach for aviation and harbor entrance and approach for maritime. 2. Determine if Loran can provide benefits to timing and frequency users. 3. Determine if Loran can provide navigation, timing, and frequency benefits in a cost effective manner (i.e., B/C >1.0). 4. Review results of evaluation and make recommendation to Secretary of Transportation. 5. Announce US Gov’t Decision regarding future of Loran. 1. Loran Evaluation Team will provide report to the Department of Transportation NLT 31 March Loran Evaluation Team will provide report to the Department of Transportation NLT 31 March Loran Evaluation Team will provide report to the Department of Transportation NLT 31 March Positioning and Navigation (PosNav) Committee of the Department of Transportation 5. Secretary of Transportation Action Responsibility

33 33 The Loran Decision Process Loran Evaluation Team compiles technical findings and BCA Data into Draft Report December 2003 LORIPPLORAPP VolpeFAATC Internal FAA Review Internal USCG Review Loran Evaluation Team compiles comments into Final Report March 2004 PosNav Committee members review the report PosNav Committee meets to discuss report findings and determine what recommendation should be forwarded to The Secretary of Transportation Department of Homeland Security PosNav Committee recommends decision to SecDOT Secretary of Transportation Announces Decision

34 34 Department of Transportation Pos/Nav Committee Hon. Jeffrey Shane, Undersecretary of Transportation for Policy, Chairman Members Federal Aviation Administration Federal Highway Administration Federal Motor Carrier Safety Administration Federal Railroad Administration Federal Transit Administration Maritime Administration National Highway Traffic Safety Administration Saint Lawrence Seaway Development Corporation Surface Transportation Board Research and Special Programs Administration US Coast Guard US Department of Commerce (Geodetic Survey/Weather/Time) US Department of Defense US Department of Homeland Security (?)

35 35 Summary FY ’03 – Team continued its excellent progress FY ’04 – Work continues: Development of multi-mode receivers for aviation and maritime users Development of ASF models that include spatial factors based on both conductivity and terrain factors and temporal factors based on multiple seasonal measurements to support NPA Design and development of differential Loran system and means to transmit ASF “corrections” to users to support HEA Test of Differential Loran Completion of timing and frequency testing to determine potential level of support to user communities Completion of Benefit/Cost Analysis Completion of p-static testing Completion of LORIPP and LORAPP activities Publication of evaluation report US Government Loran Decision

36 Questions

37 37 Aviation Requirements: RNP* 0.3 (target); RNP* 0.5 (minimum) Performance Requirement Value Accuracy (target)307 meters Accuracy (minimum)802 meters Alarm Limit (target)556 meters Alarm Limit (minimum)926 meters Integrity10 -7 /hour Time-to-alarm10 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

38 38 Marine HEA Requirements (Primary) Performance Requirement Value Accuracy (target)10 meters, 95% Accuracy (threshold)20 meters, 95% Alarm Limit (target) 25 meters Alarm 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))

39 39 Marine HEA Requirements (Backup) Performance Requirement Value Accuracy (backup)20 meters, 95% Alarm Limit (backup)50 meters Integrity (target) 3x10 -5 Time-to-alarm10 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))

40 40 Performance Specification Value Frequency Accuracy (threshold) 1 in (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) Timing and Frequency Specifications


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