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Purpose of the Evaluations

Purpose of the Evaluations. To determine whether Loran-C can provide the: Accuracy Availability Integrity Continuity, and Coverage to support Lateral Navigation through all phases of flight – including Non-Precision Approach (NPA)

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Purpose of the Evaluations

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  1. Purpose of the Evaluations • To determine whether Loran-C can provide the: • Accuracy • Availability • Integrity • Continuity, and • Coverage to support Lateral Navigation through all phases of flight – including Non-Precision Approach (NPA) • To determine what other ancillary benefits can be derived from the continued provision of Loran-C services, e.g., • An alternate/robust/backup means of transmitting WAAS corrections to aircraft and other transportation modes • A Stratum I timing source (i.e., accuracy of 110-11 or better) to serve as an alternate/robust/backup in case GPS/WAAS timing becomes unavailable

  2. Overview of US Loran-C EvaluationsFederal Aviation AdministrationMitchell J. NarinsSystems EngineerNavigation Integrated Product TeamAND-702 International Loran Association Washington, DC 28 October 2002

  3. Loran-C Navigation Current Capabilities/Future Needs* * Loran also provides Stratum 1 level of timing capability.

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

  5. FAA Program Participants • Industry • Locus, Inc. • Rockwell Collins • Peterson Integrated Geopositioning • Illgen Simulation Technologies, Inc. • JJMA • WR Systems • Booz Allen and Hamilton • Academia • Ohio University • Stanford University • US Coast Guard Academy • University of Rhode Island • University of Alaska

  6. Program Logo Collection

  7. 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.”

  8. 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, $21-25 M expected) • Senate (Appropriations Report) raised the level of funding to $21 Million. • House (Appropriations Report) raised the level of funding to $25 Million and expressed disappointment with the FAA for trying to use Loran funding for “lower priority activities.”

  9. A Most Substantial Investment

  10. Contributions to the ILA • The U.S. Loran-C Evaluation Program has much to be proud of…and equally much to report out at this ILA Meeting. • What you will see and hear over the next few days includes: • 28 October: • The New Loran-C Time Scale and Possibilities for the Future • Timing Solutions Corporation • The New Heartbeat of Loran • U.S. Coast Guard Loran Support Unit • Loran-C Maintenance Support • U.S. Coast Guard Maintenance and Logistics Command

  11. …a very full program • 29 October: • The Loran Integrity Panel • Stanford University, Peterson Integrated Geopositioning, USCG LSU, BAH, FAA • Improving the Availability, Accuracy, Continuity, and Integrity over the Loran-C Coverage Area • U.S. Coast Guard Loran Support Unit • Command and Control of the Loran Signal • U.S. Coast Guard Loran Support Unit • 30 October • Status of GPS/Loran Prototype for FAA Trials • Locus, Inc., Rockwell Collins, FAA • Flight Trials of All-in-View Loran Receiver and H-field Antenna • Ohio University, Locus, Inc, FAA • Loran-C User Position Software Navigation Performance with the August 2001 Cross-country Flight test Data • Illgen Simulation Systems, Inc. • Preliminary Results of Differential Loran Studies with All-in-View Receiver • Locus, Inc. • A Preliminary Study of Loran-C Additional Secondary Factor (ASF) Variations • U.S. Coast Guard Academy, University of Rhode Island, JJMA, FAA

  12. 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.” • Para 3.2.5 B 1999 US Federal Radionavigation Plan

  13. 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 backups 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.”

  14. …but Loran still has issues This Year’s Challenges

  15. FAA 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 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 *additional secondary factors

  16. FAA Loran Issue 2: Availability • Current Availability:0.997 • Target Availability (NPA): 0.999 - 0.9999 IssuesPotential Mitigations • Precipitation Static H-Field Antenna • Loss of Station Power UPS • Lightning New Lightning Protection • Chain Availability All-in-view receivers • Tube overloads Solid State Transmitters

  17. FAA 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 IssuesPotential Mitigations • Presumed Integrity Loran Integrity Panel (LORIPP) *the probability of providing Hazardous or Misleading Information (HMI) is 1 x 10-7

  18. FAA Loran Issue 4: Continuity • Current Continuity: 0.997 • Target Continuity (NPA): 0.999 - 0.9999 IssuesPotential Mitigations Same as Availability plus: • Receiver acquisition time New DSP technology New SSX Switch Units

  19. FAA Loran Issue 5: Coverage • Current Coverage: See FRP Chart • Target Coverage (NPA): NAS IssuesPotential Mitigations • Lack of navigation coverage Additional Loran stations on Alaskan North slope and Policy/Process Changes Southern Florida

  20. FY ‘03 FAA Loran-C Plans • To determine Loran Accuracy: • ASF studies and calibration • Receiver studies • To determine Loran Availability: • H-Field Antenna/P-static testing • CONUS All-in-view receiver analysis • Noise analysis • SSX and TFE modifications and evaluations • To determine Loran Integrity • Loran Integrity Performance Panel (LORIPP) • Time of Transmission studies • To determine Loran Continuity • Receiver studies (in concert with availability efforts) • Combined GPS/Loran receiver/antenna research

  21. Status of H-Field Test Activities • FAATC flight testing of H-Field antennas and all-in-view receivers • Delayed to ensure safety of aircraft static charging system, installation of field mill and measurement equipment, and aircraft structural considerations • Still working issues – hoping for Nov/Dec 2002 test

  22. E-Field - H-Field Comparison

  23. E-Field 5 - 1 H-Field E-Field SNR (dB) - 5 Severe P-Static (Snow) - 9 Secondary Y NorthEast U.S. (9960) Time 0 = 0734 EST on 20 March 2000 Flight from N39 W82 to N36 W83 Avionics Engineering CenterOhio University, Athens, OH 45701 Aircraft: Beechcraft V35A Loran Receivers: II Morrow Apollo 612A (TSO’d) E-field: II Morrow A-16 Whip (TSO’d) H-field: King Radio ADF (TSO’d) 0 20 40 60 80 100 120 Time in minutes E-Field - H-Field Comparison

  24. Status of Integrity (HMI) Analysis • Objectives • Develop error models and mitigation techniques to ensure LNAV integrity • Develop software to predict coverage and to determine sensitivity of coverage to various parameters • Determine where effort needs to be placed to achieve desired levels of availability and continuity • Approach • Ad hoc integrity performance panel akin to WAAS Integrity Performance Panel (WIPP) or RTCA Working Group • Key Participants • Dr. Per Enge, Dr. Todd Walter, Dr. Sherman Lo, and Mr. Lee Boyce, Stanford University • Dr. Ben Peterson, Peterson Integrated Geopositioning • Mr. Robert Wenzel, Booz Allen Hamilton

  25. Status of Integrity (HMI) Analysis • Results to date: • Developed initial algorithms and initial fault-tree for determining Loran integrity and horizontal protection limit-- work continues; • Analyzed RNP 0.3 performance-- feasible throughout CONUS, but may require changes in the system infrastructure, policy, processes etc. and continued operation of Canadian stations -- work continues; • Analyzed RNP 0.3 approaches-- may be feasible with the improved infrastructure -- work continues; and • Developed Web site for project tracking, documentation, and information-- work continues. • Final report expected in 12-18 months • NLT March 2004

  26. FY 03 Highlights and Goals • Building on the excellent progress in FY02 the expected FY03 accomplishments include: • Integrated prototype avionics and antennas that will allow evaluation of Loran for all phases of flight and in both stand-alone and multi-sensor configurations; • Completion of H-Field/P-static testing; • LORIPP results and analysis… ASF, noise, fault trees etc.; • Flight test data showing whether Loran can provide the required accuracy (possibly approaching GPS lateral accuracy) when used in conjunction with appropriate ASF information; • Modernization of the Loran infrastructure to support potential aviation use; • Revised US Signal Specification/Loran Policy; • Determination of need for a Loran data channel; • Activation of evaluation team web-site for internal project tracking and external documentation and information interchange; and • Delivery of 2nd Loran Evaluation Status Report to DOT.

  27. Oh yes… …by the way

  28. …we managed to do a bit of flying this year to help characterize ASFs…

  29. …we managed to build a few things…

  30. 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 …and we also got some rather nice results!

  31. Summary • We made excellent progress – our FY’02 goals have been achieved – and more! • LORIPP is well on its way to showing that aviation integrity requirements can be met • Flight tests are showing that Loran can provide excellent accuracy (approaching GPS accuracies) when used in conjunction with appropriate ASF information • We look forward in FY’03 to: • Development of integrated prototype avionics and antennas to evaluate Loran for all phases of flight in both stand-alone and multi-sensor configurations • Development of better ASF models • Publication of our H-Field/P-static test results • Publication of interim LORIPP findings • Continuation of the Loran community’s support while we continue our evaluation

  32. Questions

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