Letter to NTIA on Ligado Networks

Below is the text of a letter sent to the National Telecommunications and Information Administration (NTIA) on behalf of the National Executive Committee for Space-Based Positioning, Navigation, and Timing (PNT EXCOM).

NTIA released this letter on December 6, 2019, as part of their letter to the Federal Communications Commission (FCC) transmitting the executive branch's position on a spectrum plan proposed by Ligado Networks. View NTIA letter

December 3, 2018

The Honorable David J. Redl
Assistant Secretary for Communications and Information and
  Administrator, National Telecommunications and Information Administration
U.S. Department of Commerce
1401 Constitution Avenue. NW
Washington. DC 20230

Dear Assistant Secretary Redl:

The National Executive Committee for Space-Based Positioning. Navigation, and Timing (PNT EXCOM) requests that the National Telecommunciations [sic] and Information Administration (NTIA) communicate to the Federal Communications Commission (FCC) that it should ensure that any applications for spectrum utilization are evaluated with careful consideration of potential harms to critical uses of Global Positioning System (GPS) services. This Committee supports a thoughtful, science-based review of all available information related to potential interference or other service degredation [sic] prior to approval of any application for services operating on or adjacent to the GPS spectrum bands.

The PNT EXCOM is charged with the responsibility to advise and make recommendations to its member Departments and Agencies that ensure services provided by U.S. space-based PNT infrastructure, including the GPS constellation and GPS augmentations, are made available consistent with the U.S. Space-Based PNT Policy in support of U.S. national security, homeland security, foreign policy, economic, public safety, and scientific interests.

Tests and analyses performed as part of a public process in recent years have provided assessments of the tolerable transmission levels for potential interference to GPS. The results fulfill the PNT EXCOM's commitment in 2012 to develop technical information to inform any current and future proposals for commercial uses in the Mobile Satellite Service bands adjacent to GPS. That research has been completed and no additional testing is warranted.

The tests indicate that proposals to operate services in bands adjacent to GPS should not be approved unless, at a minimum, they do not exceed the tolerable power transmission limits described in the U.S. Department of Transportation's GPS Adjacent Band Compatibility Assessment Final Report (April 2018). The report can be accessed at: https://www.transportation.gov/pnt/global-positioning-systemgps-adjacent-band-compatibility-assessment.

With regard to the license modification application of Ligado Networks to the Federal Communications Commission, it is clear that the proposed service would exceed the tolerable power limits necessary to prevent disruption of GPS receivers. Based on the results of the extensive studies the NTIA should recommend to the FCC against approval of the license modification.


Dana Deasy
EXCOM Acting Co-Chair
Chief Information Officer
Department of Defense

Heidi R. King
EXCOM Acting Co-Chair
Deputy Administrator
National Highway Traffic Safety

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