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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, USCG NAVCEN Western Operations Officer Synchronization to UTC –Gene Schlechte NAVCEN Operations Planning Division Maritime Backup Assessment –CAPT Curtis Dubay, USCG NAVCEN 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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Tok NC SCPC LOIS DATA GOA 7960 Oct 1, 01 – Oct 1, 02
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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, USCG NAVCEN Western Operations Officer Synchronization to UTC –Gene Schlechte NAVCEN Operations Planning Division Maritime Backup Assessment –CAPT Curtis Dubay, USCG NAVCEN 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 DESTIN MIDLAND WHIDBEY ISLAND FAIRBANKS COLD BAY GEORGE NARROW CAPE SHOAL COVE GILLETE NANTUCKET CARIBOU LSU GREAT FALLS GRAND JUNCTION GRANGEVILLE MALONE CAROLINA BEACH MONTAGUE LUMSDEN COMFORT COVE ST. ANTHONY DUNBAR FOREST BAUDETTE HAVRE SPOKANE PORT HARDY SAND SPIT JUNEAU TOK GALENA PORT CLARENCE SPRUCE CAPE ST. PAUL PETROPAVLOVSK, RUSSIA ALEXANDROVSK, RUSSIA WILLIAMS LAKE MEDICAL LAKE PT. PINOS NAVCENDET PETALUMA PT. CABRILLO MIDDLETOWN FALLON SEARCHLIGHT LAS CRUCES BISMARK BOISE CITY LITTLE ROCK DANA NEW ORLEANS JUPITER INLET MAYPORT NAVCEN ALEXANDRIA PLUMBROOK SANDY HOOK CAPE ELIZABETH SENECA CAPE RACE FOX HARBOR RAYMONDVILLE ATTU CONTROL SITE TRANSMITTER STATION PCMS SITE USNO Monitor
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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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Cesium at Master stations UTC at USNO Time of Transmission System GPS Time
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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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= T2 Raw Data Avg + T1 Cal - Pulse Tracking Point - Cable Delays (all in nanoseconds) = ( 5108.6631+ 27088.251 - 30000 - 112 ) = 2085 nanoseconds 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@navcen.uscg.mil LORAN Support Unit (Technical) –Mike Campbell, MCampbell@lsu.uscg.mil Program Manager’s Staff (Policy) –LCDR John Merrill, JMerrill@comdt.uscg.mil
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Status – U.S. Maritime Backup Issues FY2002 U.S. LORAN-C Performance –LCDR Max Caruso, USCG NAVCEN Western Operations Officer Synchronization to UTC –Gene Schlechte NAVCEN Operations Planning Division Maritime Backup Assessment –CAPT Curtis Dubay, USCG NAVCEN 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 FAA’s 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
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