LORAN _ DGPS by xiuliliaofz



   Briefing to National PNT Advisory Board
            Captain Curtis Dubay, PE
         Department of Homeland Security
                U. S. Coast Guard

             Friday, October 5, 2007
   Loran Decision Background
• Congressionally directed program since 1997
  – $160M of modernization funding provided over past
  – 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
  – Congressional Direction (Appropriations Language)

                         Page 2
   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

                                   Page 3
                                    Enhanced Loran (eLoran)
               Operational Concept
                                                                               Operational Capability to be Provided
                                                                          •   eLoran can be used as backup/complement to GPS.
                                                                          •   Terrestrial, high power, low freq; inverse of GPS;
                                             Accuracy                         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.
                                                        & Integrity       •   Meets Aviation Required Navigation Performance of 0.3
                                   Loran Data
                                                                              nautical miles for Non-Precision Approach & integrity.
                                   Channel (LDC)
                                   Timing/Integrity                       •   Meets precise frequency & timing requirements.
                                                                          •   Coverage in many obstructed areas not served by GPS.

               Technical Approach:                                                       ROM Cost & Schedule:
•   Upgrade existing station transmitting equipment to                    •   Loran-C Modernization ongoing since 1997. $160M
    new solid state transmitters (NSSX) & associated                          invested to date.
    timing equipment. CONUS stations have all been
                                                                          •   Additional ~$400M (high end estimate) to achieve 20
    upgraded. 5 Alaska stations still need upgrades.                          year system service life, inclusive of:
•   Complete transition to Time of Arrival (TOA), known                         –   3 new stations (Gulf Coast, Southern CA, Caribbean)
    as “pseudo-range” navigation (same as GPS).                                 –   Installation of ASF monitors at specified ports
•   Incorporate new messaging channel to increase                               –   Relocation of 2 Alaska Loran Stations
                                                                                –   Tower Replacements
    position & time accuracy (differential Loran, integrity,
                                                                                –   Complete modernization in AK
    & time messages)
                                                                                –   Complete modernization in CONUS (SSX rehab/replacement)
•   Support operation of modern all-in-view equipment                           –   Civil Engineering
    (improves fix geometry for better accuracy & extends
                                                                          •  Operations and maintenance cost (FY’06) $45M
                                                                      Page 4 annually. $22M/year projected upon implementation of
•   Support wide user-base (maritime, aviation, timing,                      full eLoran system architecture / de-staffed operations.
    land-mobile navigation).
            Capabilities Progression
          User Required Capabilities           Loran-C                   eLoran
                                                          Loran - 2007
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

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

                                          Page 5
          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)

                         Page 6
Global Loran Coverage

         Page 7
   St. Paul complete Dec 07

                                  U.S. Loran System
            Clarence               Tok
 St. Paul

Attu                      Shoal
          Kodiak          Cove
                                            George        Havre
                                                                                               Seneca          Caribou

                    Middletown                                    Gillette
                                         Fallon                                                              LSU
                    NAVCEN                                           City                                    Carolina
                    WEST                                                                                     Beach
                                                       Las Cruces
       Tube Type Stations                                                                                      Jupiter

       Control Stations


                                                             Page 8
       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

                      Page 9
 Modernization Funding History
       Total - ~$160M





      1997   1999   2001         2003   2005   2007

                           Page 10
            Notional Funding Profile to
               Complete Upgrades


60                                                       Total Modernization &
                                                         Recap ~$400M (high-
50                                                       end estimate)
40                                                       Core Modernization
                                                         & Recap ~$350M (high-
                                                         Coverage Expansion
10                                                       ~$50M
     2009    2010    2011     2012      2013   2014

                    Core OE   Upgrade
             Notional initial upgrade funding ~$15-25M

                                     Page 11
Current Loran Data Channel Coverage

                            Blue – Single
                            Green – Dual
                            Red - Triple

                Page 12

  Page 13
Backup Slides

     Page 14
           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

                                 Page 15

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