International Loran Association Conference Boulder, Colorado 4 November 2003

Ongoing Loran Evaluations at theFederal Aviation Administration and theUS Coast Guard Mitchell J. NarinsSystems EngineerFederal Aviation AdministrationNavigation Integrated Product Team

International Loran Association Conference

Boulder, Colorado4 November 2003

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Purpose of the Evaluations

To determine whether an enhanced Loran system can provide the:

AccuracyAvailabilityIntegrityContinuity

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)

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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

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GovernmentFAA

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

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Program ParticipantsIndustry

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

AcademiaOhio University

Stanford University

US Coast Guard Academy

University of Rhode Island

University of Alaska

University of Wales*

*New FY 2003 Team Member

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Loran Program Logo Collection

Booz|Allen|Hamilton

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Team Contributions to ILA 2003

4 November:Loran Integrity Certification

Dr. Per Enge, Stanford University

Loran of the 21st 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 NovemberLoran-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:

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Loran-C Evaluation Program

FY 1994Federal 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.”


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


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

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A Most Substantial Investment

U.S. Loran Evaluation Program Cumulative Expenditures

FY 97 - FY 04

0

20

40

60

80

100

120

140

97 98 99 00 01 02 03 04

Fiscal Year

Do

lla

rs (

mil

lio

ns

) *

*Assumes $25 M in FY 04

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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.”

2001 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 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.”

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Loran’s Potential as a GPS Backup Parameter Loran GPS

Frequency 100 kHz 1.2-1.5 GHz

Propagation Groundwave Line of Sight

Chief Propagation Errors Conductivity, troposphere Iono delay variations*

variations

Penetration Walls, ground, 6' seawater Very little penetration

Modulation TD + CD Spread spectrum CD

Coverage To ground level To ground level

Signal Strength Relatively high Very low by design

Timing Basis Triple Cesium Rubidium at present

Tx Location Ground - stationary Space - moving

Utility: Aviation example En route, terminal airspace En route, terminal airspace Lateral-guided approach Lateral-vertical approach**

User communities Multiple (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.

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Loran-C Navigation Current Capabilities/Future Needs*

Accuracy Availability Integrity Continuity

Current Definition of Capability * (FRP)

0.25 nm

(463 m)0.997

10 second alarm/

25m error0.997

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

Note: Most stringent requirements shown in aviation orange.

* Includes Stratum 1 timing and frequency capability.

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Timing User Spectrum

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

Advanced Comms

Power Systems- Fault Location- Phasor Meas- Data Sharing

CDMA2000- 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

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Frequency User Range

10-15

VLBI

High Precision Military- GPS Monitor Stations- Various Applications

Stratum 1 Comms- Telcos- Military GT- Digital Wideband

Low Precision Metrology

- Equipment Calibration

CDMA2000- Base Stations

Low Precision Military- Combat Control Systems

Misc- Broadcast TV- Digital Modular

Radio- IEEE P802.16

Wireless

10-14 10-13 10-12 10-11 10-10 10-9 10-8 10-7 10-6 10-5

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

Status of the

Ongoing Loran Evaluation and

Associated System Recapitalization

Final Report due to the Departments of Transportation and Homeland SecurityMarch 2004

AccuracyAvailability

IntegrityContinuity

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Loran Evaluation Activities

To determine Loran Accuracy Potential:ASF* studies and calibration (for both conductivity and terrain)Receiver/Integrated receiver studiesLoran Accuracy Performance Panel (LORAPP)Differential Loran study

To determine Loran Availability Potential:H-Field Antenna/P-static testingCONUS All-in-view receiver analysisNoise analysisSSX 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

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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%

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

No real-time corrections LORAPP (Differential Loran)

*additional secondary factors

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Flights to Support Characterization of ASFsAugust 2002 and March 2003

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Typical 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

NPA Requirement: 307 m!

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Flights to Support Characterization of ASFs July – September 2003

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Loran ASF Measurement CampaignLots of Miles – Lots of Data

Monterey, California Pensacola/Destin, Florida

Grand Junction, Colorado Little Rock, Arkansas

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Loran Issue 2: Availability

Current Availability: 0.997

Target Availability (NPA): 0.999 - 0.9999

Target Availability (HEA): 0.997 – 0.999

Issues Potential MitigationsPrecipitation 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

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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**

Issues Potential MitigationsPresumed 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

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Loran Issue 4: Continuity

Current Continuity: 0.997

Target Continuity (NPA): 0.999 - 0.9999

Target Continuity (HEA): 0.9985 – 0.9997

Issues Potential MitigationsSame as Availability plus:

Receiver acquisition time New DSP technology

New SSX Switch Units

AIV/Integrated Receiver

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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

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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

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FreeFlight/Locus GA Multi-Mode Receiver

Phase II Prototype to be available for testing Spring 2004

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Megapulse/Reelektronika/Si-TekMulti-Mode Marine Receiver

Front End & ADC77 x 47 mm

Signal Processor

77 x 51 mm

The Loran Decision Process

Final Report due to the Departments of Transportation and Homeland SecurityMarch 2004

What are we doing?When are we doing it?

When will we be finished?When will there be a decision?

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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 2004.



4. Positioning and Navigation (PosNav) Committee of the Department of Transportation

5. Secretary of Transportation

Action Responsibility

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Loran Evaluation Team compiles technical

findings and BCA Data into Draft Report

December 2003

LORIPP LORAPP

Volpe FAATC

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

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Department of Transportation Pos/Nav Committee

Hon. Jeffrey Shane, Undersecretary of Transportation for Policy, ChairmanMembers

Federal Aviation AdministrationFederal Highway AdministrationFederal Motor Carrier Safety AdministrationFederal Railroad AdministrationFederal Transit AdministrationMaritime AdministrationNational Highway Traffic Safety AdministrationSaint Lawrence Seaway Development CorporationSurface Transportation BoardResearch and Special Programs AdministrationUS Coast GuardUS Department of Commerce (Geodetic Survey/Weather/Time)US Department of DefenseUS Department of Homeland Security (?)

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SummaryFY ’03 – Team continued its excellent progressFY ’04 – Work continues:

Development of multi-mode receivers for aviation and maritime usersDevelopment of ASF models that include spatial factors based on both conductivity and terrain factors and temporal factors based on multiple seasonal measurements to support NPADesign and development of differential Loran system and means to transmit ASF “corrections” to users to support HEATest of Differential LoranCompletion of timing and frequency testing to determine potential level of support to user communitiesCompletion of Benefit/Cost AnalysisCompletion of p-static testingCompletion of LORIPP and LORAPP activitiesPublication of evaluation reportUS Government Loran Decision

Questions

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Aviation Requirements: RNP* 0.3 (target); RNP* 0.5 (minimum)

Performance Requirement Value

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

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Marine HEA Requirements (Primary)


Accuracy (target) 10 meters, 95%Accuracy (threshold) 20 meters, 95%

Alarm Limit (target) 25 metersAlarm Limit (threshold) 50 meters

Integrity (target) 3x10-5


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))

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Marine HEA Requirements (Backup)


Accuracy (backup) 20 meters, 95%

Alarm Limit (backup) 50 meters

Integrity (target) 3x10-5


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))

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Performance Specification Value

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)

Timing and Frequency Specifications

Documents

International Loran Association Conference Boulder, Colorado 4 November 2003