LORAN TRANSITION

Briefing to National PNT Advisory Board

Captain Curtis Dubay, PEDepartment of Homeland Security

U. S. Coast Guard

Friday, October 5, 2007

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Loran Decision Background• Congressionally directed program since 1997

– $160M of modernization funding provided over past decade

– Decision required to either terminate or sustain/enhance system (non-decision = terminate)

• DOT and DHS tasked with responsibility to make decision on Loran– 2005 Federal Radionavigation Plan– NSPD (National Space-Based PNT Policy of Dec

2004)– Congressional Direction (Appropriations Language)

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DOT/DHS Loran Decision Process • Loran Independent Assessment Team commissioned

– Commissioned August 2006– Tasked to assess the U.S. national need for continuing Loran

• Federal Register Notice released for public comment– Nearly 1000 Comments received– 92% of comments support Loran-C and/or eLoran– 8% support termination of Loran-C– 80% support a national backup for GPS

• DHS & DOT utilizing established PNT Exec. Committees– DOT Extended POS/NAV Executive Committee– DHS Geospatial/PNT Executive Committee – National PNT Executive Committee

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Technical Approach:• Upgrade existing station transmitting equipment to

new solid state transmitters (NSSX) & associated timing equipment. CONUS stations have all been upgraded. 5 Alaska stations still need upgrades.

• Complete transition to Time of Arrival (TOA), known as “pseudo-range” navigation (same as GPS).

• Incorporate new messaging channel to increase position & time accuracy (differential Loran, integrity, & time messages)

• Support operation of modern all-in-view equipment (improves fix geometry for better accuracy & extends coverage).

• Support wide user-base (maritime, aviation, timing, land-mobile navigation).

Operational Capability to be Provided• eLoran can be used as backup/complement to GPS.

• Terrestrial, high power, low freq; inverse of GPS;

Inherently less susceptible to deliberate interference.

• GPS-like, digital user equipment . Position data

presented in LAT/LON coordinates.

• Meets Maritime Harbor Entrance & Approach accuracy

requirement of 10-20M.

• Meets Aviation Required Navigation Performance of 0.3

nautical miles for Non-Precision Approach & integrity.

• Meets precise frequency & timing requirements.

• Coverage in many obstructed areas not served by GPS.

ROM Cost & Schedule:• Loran-C Modernization ongoing since 1997. $160M

invested to date.

• Additional ~$400M (high end estimate) to achieve 20 year system service life, inclusive of:

– 3 new stations (Gulf Coast, Southern CA, Caribbean)– Installation of ASF monitors at specified ports– Relocation of 2 Alaska Loran Stations– Tower Replacements– Complete modernization in AK– Complete modernization in CONUS (SSX rehab/replacement)– Civil Engineering

• Operations and maintenance cost (FY’06) $45M annually. $22M/year projected upon implementation of full eLoran system architecture / de-staffed operations.

Enhanced Loran (eLoran)Operational Concept

TransmittingStations

DifferentialLoran

Ref. Station

MonitoringSites

Control Center

Maritime Service Provision

Core eLoran Service Provision

Diff. Loran Corrections

Diff. Loran Corrections

Diff. Loran Corrections

eLoranSignal

eLoranSignal

eLoran Integrity

eLoran Integrity

eLoran Integrity

eLoranSignal

The Maritime Service Provider is responsible for generating the Diff Loran

Corrections and providing Signal Propagation Maps

Loran Data Channel (LDC)Timing/Integrity

Accuracy

& Integrity

Timing

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Capabilities ProgressionUser Required Capabilities Loran-C

ModernizedLoran - 2007

eLoran

Aviation

En Route (RNP 2.0 ->1.0) Yes Yes Yes

Terminal (RNP 0.3) No No Yes

Non-Precision Approach (NPA) - RNP 0.3 No No Yes

Maritime

Oceanic Yes Yes Yes

Coastal Confluence Zone (CCZ) Yes Yes Yes

Harbor Entrance and Approach (HEA) No No Yes

Telecom & Other (Time/Frequency)

Stratum 1 Frequency Yes Yes Yes

Time of Day/Leap Second/UTC Reference No Yes Yes

Precise Time [<50 ns UTC(USNO)] No No Yes

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eLoran Way Ahead

• Primary focus to upgrade transmitting sites– 19 of 24 stations modernized and Loran Data

Channel Capable – key element of eLoran

• Getting to eLoran– Upgrade remaining 5 stations (reduces to 4 - Dec 07)– Install monitor network (integrity/accuracy/time)– Expand coverage (three new stations)

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Global Loran Coverage

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U.S. Loran System

Kodiak

Port Clarence Tok

St. Paul

Shoal Cove

NAVCEN WEST

George HavreBaudette

Fallon

Searchlight

Middletown

Las Cruces

Raymondville

Gillette

Boise City

Dana

Jupiter

CaribouSeneca

Malone

Carolina Beach

Grangeville

LSUNAVCEN

Tube Type Stations

Control Stations

Modernized

St. Paul complete Dec 07

Attu

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Modernization Status

• 19 of 24 (Conus + Kodiak) transmitting stations are modernized:– Tube-type transmitter replaced with New Solid

State transmitter (NSSX) capable of transmitting loran data channel

– New signal/system control equipment

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Modernization Funding HistoryTotal - ~$160M

$0

$5

$10

$15

$20

$25

1997 1999 2001 2003 2005 2007

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Notional Funding Profile to Complete Upgrades

0

10

20

30

40

50

60

70

80

2009 2010 2011 2012 2013 2014

Core OE Upgrade

Notional initial upgrade funding ~$15-25M

Total Modernization & Recap ~$400M (high-end estimate)

Core Modernization& Recap ~$350M (high-end-estimate)

Coverage Expansion~$50M

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Current Loran Data Channel Coverage

Legend

Blue – Single

Green – Dual

Red - Triple

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QUESTIONS?

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Backup Slides

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Independent Assessment Team (IAT) Charter

• Conduct independent assessment of Loran– Assemble team of experts to review and assess continuing

need for the current US Loran infrastructure – Report findings & recommendations directly to Under

Secretary of Transportation for Policy

• Assess information from recent studies, working group reports, and interviews with SMEs

– Use reports/studies by Volpe Center, FAA, USCG, DHS, HSI, NSSO/RITA, JPDO, and others as appropriate

– Supplement with information from key stakeholders and industry representatives