Headlines: GPS OCX Program Under Termination Review; 37 Nationwide Differential GPS Sites Shut Down, Leaving 46 Operational
GPS Bulletin

Information for Policymakers from the National Coordination Office for Space-Based Positioning, Navigation, and Timing (PNT)

September 19, 2016 

GPS OCX Program Under Termination Review

On June 30, the Air Force announced a critical Nunn-McCurdy breach (cost overrun) in the Next Generation Operational Control System (OCX) budget, triggering a mandatory process to either cancel or restructure the program (10 U.S.C. § 2433a). OCX is the future version of the GPS control segment. The Nunn-McCurdy process is expected to conclude in mid-October of this year.

Prior to June 30, both the House and Senate passed specific legislative provisions addressing their respective concerns with the OCX program. In addition, the Senate Appropriations Committee recommended terminating most of OCX.

37 Nationwide Differential GPS Sites Shut Down,
Leaving 46 Operational

On August 4, the U.S. Department of Transportation (DOT) and the U.S. Coast Guard (USCG) ceased broadcasting from 37 sites of the Nationwide Differential Global Positioning System (NDGPS). Fielded in the 1990s, NDGPS service augments GPS by providing increased accuracy and integrity using land-based reference stations to transmit correction messages over radiobeacon frequencies.

Due to the improved accuracy of standalone GPS, and with the availability of other GPS augmentation solutions, the government decided to downsize NDGPS, eliminating the inland component and providing single coverage of coasts and waterways. The decision was reached after reviewing public comments on several Federal Register notices issued by DOT and USCG.

Map of current NDGPS coverage

Deactivated Sites - Inland

Albuquerque, NM; Austin, NV; Bakersfield, CA; Billings, MT; Chico, CA; Clark, SD; Dandridge, TN; Essex, CA; Flagstaff, AZ; Greensboro, NC; Hackleburg, AL; Hagerstown, MD; Hartsville, TN; Hawk Run, PA; Klamath Falls, OR; Macon, GA; Medora, ND; Myton, UT; Pine River, MN; Polson, MT; Pueblo, CO; Savannah, GA; Seneca, OR; Spokane, WA; St. Marys, WV; Summerfield, TX; Topeka, KS; Whitney, NE.

Deactivated Sites - Maritime

Brunswick, ME; Cold Bay, AK; Eglin, FL; Isabela, PR; Lompoc, CA; Pickford, MI; Saginaw Bay, MI; Sturgeon Bay, WI; Key West, FL.

Learn more at the Coast Guard Navigation Center.

National Coordination Office logo
This newsletter is produced and distributed by the National Coordination Office for Space-Based PNT, a central resource within the government for GPS policy information. The National Coordination Office highlights legislation for information only and does not endorse any pending legislation except where explicitly noted. For more information, visit
You are receiving this newsletter because of your interest / involvement in legislative affairs that are pertinent to the Global Positioning System (GPS), which affects national defense, transportation, science & technology, energy & environment, commerce, communications, privacy, and many other aspects of society.

Forward to a colleague >>

This email was sent to <<Email Address>>
why did I get this?    unsubscribe from this list    update subscription preferences
National Coordination Office for Space-Based Positioning, Navigation & Timing · Herbert C. Hoover Bldg., Room 2518 · 1401 Constitution Ave., NW · Washington, DC 20230 · USA