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Purpose of the EvaluationsTo determine whether Loran-C can provide the:

AccuracyAvailabilityIntegrityContinuity, andCoverage

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 modesA Stratum I timing source (i.e., accuracy of 110-11 or better) to serve as an alternate/robust/backup in case GPS/WAAS timing becomes unavailable

Overview of US Loran-C EvaluationsFederal Aviation Administration Mitchell J. NarinsSystems EngineerNavigation Integrated Product TeamAND-702

International Loran Association Washington, DC

28 October 2002

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Loran-C Navigation

Accuracy Availability Integrity Continuity

Current Definition of Capability * (FRP)

0.25 nm

(463 m)

0.997 10 second alarm/

25m error

0.997

FAA NPA (RNP.3) Requirements

0.16 nm

(307 m)

0.999 – 0.9999 0.9999999 0.999 - 0.9999

USCG Harbor Requirements

(to date)

0.004 - 0.01 nm

(8 – 20 m)

0.997 - 0.999 10 second alarm/

25m error

0.9985 – 0.9997 over 3 hours

Current Capabilities/Future Needs*

* Loran also provides Stratum 1 level of timing capability.

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GovernmentFAA

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

FAA Program Participants

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FAA Program ParticipantsIndustry

Locus, Inc.Rockwell CollinsPeterson Integrated GeopositioningIllgen Simulation Technologies, Inc.JJMAWR SystemsBooz Allen and Hamilton

AcademiaOhio UniversityStanford UniversityUS Coast Guard AcademyUniversity of Rhode IslandUniversity of Alaska

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Program Logo Collection

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Loran-C Evaluation Program FY 1994

Federal Radionavigation Plan (FRP) announced that Loran-C service would terminate 31 December 2000Congressional 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.”

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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.”

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A Most Substantial InvestmentUS Loran Evaluation Program

Cumulative Expenditures

0

10

20

30

40

50

60

70

80

90

100

97 98 99 00 01 02 03

Fiscal Year

Do

lla

rs (

mil

lio

ns

)

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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

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…a very full program29 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

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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

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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.”

…but Loran still has issues

This Year’s Challenges

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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

Issues Potential MitigationsOld 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

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FAA Loran Issue 2: Availability

Current Availability: 0.997

Target Availability (NPA): 0.999 - 0.9999

Issues Potential MitigationsPrecipitation Static H-Field Antenna

Loss of Station Power UPS

Lightning New Lightning Protection

Chain Availability All-in-view receivers

Tube overloads Solid State Transmitters

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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

Issues Potential MitigationsPresumed Integrity Loran Integrity Panel (LORIPP)

*the probability of providing Hazardous or Misleading Information (HMI) is 1 x 10-7

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FAA Loran Issue 4: Continuity

Current Continuity: 0.997

Target Continuity (NPA): 0.999 - 0.9999

Issues Potential MitigationsSame as Availability plus:

Receiver acquisition time New DSP technology

New SSX Switch Units

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FAA Loran Issue 5: Coverage

Current Coverage: See FRP Chart

Target Coverage (NPA): NAS

Issues Potential Mitigations

Lack of navigation coverage Additional Loran stations on Alaskan North slope and Policy/Process Changes

Southern Florida

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FY ‘03 FAA Loran-C Plans To determine Loran Accuracy:

ASF studies and calibrationReceiver studies

To determine Loran Availability:H-Field Antenna/P-static testingCONUS All-in-view receiver analysisNoise analysisSSX and TFE modifications and evaluations

To determine Loran IntegrityLoran Integrity Performance Panel (LORIPP) Time of Transmission studies

To determine Loran ContinuityReceiver studies (in concert with availability efforts)Combined GPS/Loran receiver/antenna research

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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

Status of H-Field Test Activities

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E-Field - H-Field Comparison

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E-Field - H-Field Comparison

0 20 40 60 80 100 120

- 9

- 5

- 1

5

Time in minutes

SN

R (

dB

)

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)

Severe P-Static (Snow)

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

E-Field

H-FieldE-Field

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Status of Integrity (HMI) AnalysisObjectives

Develop error models and mitigation techniques to ensure LNAV integrityDevelop software to predict coverage and to determine sensitivity of coverage to various parametersDetermine where effort needs to be placed to achieve desired levels of availability and continuity

ApproachAd hoc integrity performance panel akin to WAAS Integrity Performance Panel (WIPP) or RTCA Working Group

Key ParticipantsDr. Per Enge, Dr. Todd Walter, Dr. Sherman Lo, and Mr. Lee Boyce, Stanford UniversityDr. Ben Peterson, Peterson Integrated GeopositioningMr. Robert Wenzel, Booz Allen Hamilton

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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

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FY 03 Highlights and GoalsBuilding 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.

Oh yes…

…by the way

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

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…we managed to build a few things…

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…and we also got some rather nice results!

Loran 7

Loran 1 GPS 1

Loran 8GPS 7

GPS 8

~13.0 m~3.0 m

~2.0 m

Loran 2

Loran 7

GPS 2Loran 3GPS 7

GPS 3

~9.0 m~6.0 m

~6.5 m

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SummaryWe 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 metFlight 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 configurationsDevelopment of better ASF modelsPublication of our H-Field/P-static test resultsPublication of interim LORIPP findingsContinuation of the Loran community’s support while we continue our evaluation

Questions