Document ID: USCG-2018-0133-0001
Agency: uscg
Document Type: Notice
Title: Discontinuance of the Nationwide Differential Global Positioning System (NDGPS)
Posted Date: 2018-03-21T04:00Z

[Federal Register Volume 83, Number 55 (Wednesday, March 21, 2018)]
[Notices]
[Pages 12402-12403]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-05684]

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DEPARTMENT OF HOMELAND SECURITY

Coast Guard

[Docket No. USCG-2018-0133]

Discontinuance of the Nationwide Differential Global Positioning 
System (NDGPS)

AGENCY: Coast Guard, DHS.

ACTION: Notice.

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SUMMARY: The U.S. Coast Guard (USCG) announces the discontinuance of 
its remaining 38 maritime Differential Global Positioning System (DGPS) 
sites. The USCG will implement the closures through a phased reduction 
in service, which will commence in September of 2018, and conclude by 
September of 2020. These closures will culminate in the complete 
cessation of the Nationwide Differential Global Positioning System 
(NDGPS) service. This notice provides the general schedule for the 
discontinuance of the remaining maritime DGPS sites. Specific site 
broadcast termination dates will be published via local notices to 
mariners (LNMs).

FOR FURTHER INFORMATION CONTACT: If you have questions on this notice, 
contact CAPT Mary Ellen Durley, Coast Guard, telephone (202) 372-1605 
or email [email protected].

SUPPLEMENTARY INFORMATION:

Background and Purpose

    The Maritime Differential GPS system was established in the late 
1980s to augment the existing GPS signal with accuracy corrections and 
integrity monitoring. This augmentation signal was broadcast over 
Medium Frequency from terrestrial broadcast sites. At the time, the 
publicly available GPS signal was intentionally degraded through 
Selective Availability (SA), and thus augmentation was necessary to 
meet minimum requirements for maritime positioning and navigation. 
Selective Availability was permanently discontinued in 2000, and as 
system technology has improved, observed positional accuracy for un-
augmented GPS consistently meets requirements for harbor/harbor-
approach navigation on modern GPS receivers.
    On July 5, 2016, the USCG, the U.S. Department of Transportation 
(DOT), and the U.S. Army Corps of Engineers (USACE) published a notice 
in the Federal Register (81 FR 43613), which announced that the 
Nationwide Differential Global Positioning System (NDGPS) would remain 
operational with a total of 46 USCG and USACE sites available to users 
in the maritime and coastal regions. Since 2016, the USACE has 
discontinued 7 sites, and the USCG has discontinued 1 site in Aransas, 
TX due to storm damage from Hurricane Harvey. Currently, there are only 
38 remaining NDGPS sites, all of which are maritime sites.

Discussion

    The USCG has continued assessments and outreach affirming that the 
positional accuracy provided by un-augmented GPS and GPS augmented by 
the U.S. Wide Area Augmentation System (WAAS) is sufficient to meet its 
mission requirements and navigational safety requirements for harbor 
approaches. Because there is no regulatory requirement for the carriage 
of Differential Global Positioning System (DGPS) equipment, and other 
GPS augmentation systems such as WAAS are already in prevalent use by 
marine navigation equipment, the USCG cannot justify further investment 
to upgrade and maintain the NDGPS system. Additionally, the Coast Guard 
no longer has a mission requirement for DGPS to position Maritime Aids 
to Navigation because current Coast Guard policy allows the placement 
of aids to navigation with un-augmented GPS or GPS augmented by WAAS. 
Finally, other government and commercial augmentation systems (e.g. 
WAAS) are readily available to provide GPS accuracy corrections. For 
these reasons,

[[Page 12403]]

the NDGPS system was reduced from the 2015 constellation of 84 sites, 
to the current constellation of 38 maritime sites. Pursuant to this 
announcement, the USCG's remaining 38 maritime sites will be 
discontinued in stages, beginning in September of 2018 and ending in 
September of 2020.

Timeline of Maritime Sites To Be Discontinued

    Termination of the NDGPS broadcast during Fiscal Year 2018 is 
planned to occur at the following sites. Specific broadcast 
discontinuance dates for each site will be announced via Local Notices 
to Mariners (LNMs) 60 days in advance of the termination of the NDGPS 
broadcast.
     Annapolis, MD
     New Bern, NC
     Robinson Point, WA
     Pigeon Point, CA
     Bobo, MS
    Termination of the NDGPS broadcast at the following sites is 
planned to occur in Fiscal Year 2019.
     Whidbey Island, WA
     Appleton, WA
     Fort Stevens, OR
     Cape Mendocino, CA
     Lincoln, CA
     Point Loma, CA
     Kokole Point, HI
     Upolu Point, HI
     Driver, VA
     Kensington, SC
     Cape Canaveral, FL
     Card Sound, FL
     Tampa, FL
     Wisconsin Point, WI
     Mequon, WI
     Upper Keweenaw, MI
     Cheboygan, MI
     Detroit, MI
     Youngstown, NY
    Termination of the NDGPS broadcast at the following sites is 
planned to occur in Fiscal Year 2020.
     Penobscot, ME
     Acushnet, MA
     Hudson Falls, NY
     Moriches, NY
     Sandy Hook, NJ
     English Turn, LA
     Angleton, TX
     Annette Island, AK
     Biorka, AK
     Kenai, AK
     Kodiak, AK
     Gustavus, AK
     Potato Point, AK
     Level Island, AK
    General information regarding the NDGPS Service and graphics 
depicting the proposed changes to NDGPS coverage are available at the 
USCG's NDGPS General Information website at: http://www.navcen.uscg.gov/?pageName=dgpsMain.
    For more information on the NDGPS outages and broadcast termination 
dates, visit the USCG's website at https://www.navcen.uscg.gov/?pageName=dgpsSiteInfo¤tOutages.
    Additional information on GPS, NDGPS, and other GPS augmentation 
systems is also available in the 2017 Federal Radionavigation Plan, 
which is published by the Department of Defense, Department of Homeland 
Security, and U.S. DOT, and is also available at the USCG's website at 
http://www.navcen.uscg.gov/?pageName=pubsMain.

    Authority: This notice is issued under the authority of 5 U.S.C. 
552(a) and 14 U.S.C. 81.

    Issued in Washington, DC, on March 14, 2018.
Michael D. Emerson,
Director of Marine Transportation Systems, U.S. Coast Guard.
[FR Doc. 2018-05684 Filed 3-20-18; 8:45 am]
 BILLING CODE 9110-04-P