Status

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Status U.S. Maritime Backup Issues

• Session 2 , 28 October 2002
• Status Plans of LORAN-C Service Providers
• 31st Annual
• Convention Technical
• Symposium
• of the
• International LORAN Association
• Crowne Plaza
• Washington National Airport

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Status U.S. Maritime Backup Issues

• FY2002 U.S. LORAN-C Performance
• LCDR Max Caruso, USCGNAVCEN Western Operations
  Officer
• Synchronization to UTC
• Gene SchlechteNAVCEN Operations Planning
  Division
• Maritime Backup Assessment
• CAPT Curtis Dubay, USCGNAVCEN Commanding Officer

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FY02 LORAN-C Performance

• A year of recapitalization and system
  modernization

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FY02 LORAN-C Performance

• LORAN-C Availability Review for the Period 1
  October 2001 to 1 October 2002
• The LORAN Operations Information System (LOIS 2
  NT) was used to generate this report
• LT Bob Berger and CWO Scott McDonald, NAVCEN
  LORAN Planning Branch provided the data analysis

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LOIS DATA GOA 7960 Oct 1, 01 Oct 1, 02
NC
Tok
SC
PC
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NOCUS (8290) UUT by Cause
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GLKS (8970) UUT by Cause
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SOCUS (9610) UUT by Cause
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USWC (9940) UUT by Cause
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NEUS (9960) UUT by Cause
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NORPAC (9990) UUT by Cause
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FY02 LORAN-C AVAILABILITY
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FY02 AVAILABILITY (less AUTM)
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FY02 AVAILABILITY (less AUTM Solar)
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Status U.S. Maritime Backup Issues

• FY2002 U.S. LORAN-C Performance
• LCDR Max Caruso, USCGNAVCEN Western Operations
  Officer
• Synchronization to UTC
• Gene SchlechteNAVCEN Operations Planning
  Division
• Maritime Backup Assessment
• CAPT Curtis Dubay, USCGNAVCEN Commanding Officer

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LORAN Synchronization to UTC

• Time Of Transmission Measurement (TOTM) Project
  started at LSU in late 1990s
• 1997 - TOTM equipment installed at Williams
  Lake
• Now - TTM installed at every US Master including
  the two in Alaska.

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LORAN Synchronization to UTC

• US Public Law 100-223, Section 310 requires the
  control the transmission of LORAN signals to
  within /- 100 nanoseconds of UTC at times of
  coincidence (TOC).
• The Coast Guard has worked with USNO to steer
  LORAN transmissions to UTC
• USNO monitors measures LORAN time differences
  (TD) in far field to determine difference between
  LORAN Chain UTC

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North American Loran-C System
PORT CLARENCE
ALEXANDROVSK, RUSSIA
GALENA
TOK
FAIRBANKS
ST. PAUL
PETROPAVLOVSK, RUSSIA
NARROW CAPE
SPRUCE CAPE
JUNEAU
ATTU
SHOAL COVE
WILLIAMS LAKE
COLD BAY
FOX HARBOR
ST. ANTHONY
PORT HARDY
COMFORT COVE
SAND SPIT
BAUDETTE
CARIBOU
LUMSDEN
SPOKANE
HAVRE
WHIDBEY ISLAND
MONTAGUE
GEORGE
DUNBAR FOREST
MEDICAL LAKE
BISMARK
CAPE RACE
CONTROL SITE
GREAT FALLS
GILLETE
CAPE ELIZABETH
SENECA
TRANSMITTER STATION
NANTUCKET
MIDDLETOWN
DANA
PT. CABRILLO
PLUMBROOK
FALLON
PCMS SITE
LSU
GRAND JUNCTION
SANDY HOOK
BOISE CITY
USNO Monitor
NAVCENDET
NAVCEN
PETALUMA
ALEXANDRIA
PT. PINOS
SEARCHLIGHT
LITTLE ROCK
CAROLINA BEACH
GRANGEVILLE
MIDLAND
LAS CRUCES
MALONE
DESTIN
MAYPORT
NEW ORLEANS
RAYMONDVILLE
JUPITER INLET
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Time of Transmission System

• Provides a means to monitor Loran transmissions
  directly at the transmitting antenna.
• Eliminates propagation path uncertainties making
  /- 100 nanosecond control possible

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Time of Transmission System
Cesium at Master stations
UTC at USNO
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TTM Installation at Master Station
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SOCUS (9610) TTM Data Plot 15JUL -13OCT 2002
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SOCUS (9610) TTM Log Sheet
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NEUS (9960) TTM Data Plot 15JUL -13OCT 2002
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NEUS (9960) TTM Data Plot 15JUL -13OCT 2002
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TTM Calculation

• TTM Formula for USCG installation
• Sample TTM Calculation for NEUS (9960) on 13
  October 2002

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Summary of UTC Measured Offsets

• The following offsets have been established
  utilizing the installed TTM equipment
• NOCUS (8290-M) 2.3 usec
• NORPAC (9990-M) 2.5 usec
• SOCUS (9610-M) 1.8 usec
• USWC (9940-M) 1.3 usec
• GOA (7960-M) 1.2 usec
• GLKS (8970-M) -0.4 usec
• SEUS (7980- M) 0.1 usec
• NEUS (9960-M) 0.02 usec

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Plan to Remove LORAN UTC Offsets

• NAVCEN is planning to time step one chain per
  week
• starting with the West Coast Chains
• then East coast chains
• last will be the two Alaskan chains
• We will send advance user notice before a Chain
  time step
• We Plan to insert one time step for each chain on
  a Tuesday at 0900 Local time
• The time step amount (in microseconds) will be
  included in the user notice
• This process is considered to be the least
  problematic for the timing/legacy user.

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USCG LORAN TTM Contacts

• Navigation Center (Operations Planning)
• LT Bob Berger, RBerger_at_navcen.uscg.mil
• LORAN Support Unit (Technical)
• Mike Campbell, MCampbell_at_lsu.uscg.mil
• Program Managers Staff (Policy)
• LCDR John Merrill, JMerrill_at_comdt.uscg.mil

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Status U.S. Maritime Backup Issues

• FY2002 U.S. LORAN-C Performance
• LCDR Max Caruso, USCGNAVCEN Western Operations
  Officer
• Synchronization to UTC
• Gene SchlechteNAVCEN Operations Planning
  Division
• Maritime Backup Assessment
• CAPT Curtis Dubay, USCGNAVCEN Commanding Officer

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Maritime Assessment

• Volpe Study shows vulnerability of GPS
• Maritime modes concur
• Current infrastructure satisfactory
• E-navigation poses growing vulnerability

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Maritime Assessment

• Future vision System of systems that
  incorporates adequate backups
• Conventional navigation capability,
• Regulatory procedures,
• Development of alternate e-inputs

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Maritime Assessment

• Two Safety Critical Applications
• Harbor, harbor approach, and constricted
  waterways
• Total reliance on DGPS is a concern
• Automatic Identification System (AIS)
• Positioning and timing are concerns

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Maritime Assessment

• Comments on Study Recommendations
• Continue LORAN-C modernization
• Assess capabilities of enhanced LORAN
• Certification of GPS receivers
• By July 2002, a maritime certification program
  will be in place under SOLAS
• USCG participation in domestic and international
  standards setting bodies

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Maritime Assessment

• Backup System Initiatives
• Leverage FAAs LNAV LORAN study
• Partner with industry to analyze enhanced LORAN
  capabilities
• Develop assess integrated maritime receiver
  technology

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Status U.S. Maritime Backup Issues

• Session 2 , 28 October 2002
• Status Plans of LORAN-C Service Providers
• 31st Annual
• Convention Technical
• Symposium
• of the
• International LORAN Association
• Crowne Plaza
• Washington National Airport