Vast coalition seeks reversal of Ligado Order

April 26, 2023  - By
Credit: YinYang/E+/Getty Images

Credit: YinYang/E+/Getty Images

The same 91 signers also sent an identical letter to President Biden.

 April 24, 2023 

Dear Senators and Members of Congress:

Last year, many of the undersigned wrote in reflection of the unprecedented opposition to the Federal Communications Commission’s (FCC’s) Ligado Order (1) across the vast federal and commercial user base of Global Positioning System (GPS), satellite communications and weather forecasting services. Three years after adoption of the Order, as eight petitions for reconsideration remain pending, (2) we again urge you to work together with the FCC to stay and ultimately set aside the Order. (3) Critically, this is now necessitated by the crucial, previously unavailable information that was produced at the direction of Congress: the independent technical review undertaken by the National Academies of Sciences, Engineering, and Medicine (NAS) (4) analyzing the potential interference issues related to the Ligado Order.

We greatly appreciate your administration’s opposition to the Ligado Order and commitment that the National Telecommunications and Information Administration (NTIA), on behalf of the executive branch, will continue to actively pursue its petition for reconsideration of the Order. (5) As you know, the pending petitions for reconsideration convincingly demonstrate that the Ligado Order is legally and factually deficient. In the pending petitions, parties showed that the Ligado Order is fundamentally flawed, incompatible with the FCC’s rules and inadequate in protecting incumbent services from the harmful interference from Ligado’s proposed operations. This substantial documentation, among many other concerns from federal and commercial users, resulted in Congress enacting bipartisan legislation in consecutive years after the FCC’s adoption of the Ligado Order, mandating NAS’s independent technical review and requiring the Department of Defense (DoD) to brief federal representatives across the government “at the highest level of classification” on the potential for widespread harm from Ligado’s proposed terrestrial operations. (6) On this basis alone, the FCC should stay the Order in an acknowledgement that it clearly did not account for the full, real-world risk of harm associated with a nationwide terrestrial deployment in the L-band.

While the pending petitions have a strong likelihood of success on their own merits, the FCC’s rules and the public interest now require the FCC to reconsider the Order in response to the extensive analysis in the NAS Report. (7) This new, previously unavailable information presented in the Congressionally-mandated independent technical review confirms that Ligado’s proposed terrestrial operations would cause harmful interference (8) at significant ranges to incumbent L-band services across a broad range of deployment scenarios. This is consistent with the well-supported and robustly documented analyses and determinations of the federal government, (9) including fourteen federal agencies and departments, (10) and commercial parties (11) alike. Importantly, as concisely stated by DoD and detailed in the NAS Report, “[t]he terrestrial network authorized by [the Ligado Order] will create unacceptable harmful interference for DoD missions. The mitigation techniques and other regulatory provision [sic] in [the Ligado Order] are insufficient to protect national security missions.”(12)

The unequivocal conclusions of the NAS Report constitute the exact type of previously unavailable information that the FCC’s rules (13) dictate must be addressed on reconsideration. Indeed, NTIA stated on behalf of the executive branch that the NAS Report “offers the [FCC] an important opportunity to reconsider Ligado’s Authorization.”(14) We therefore urge you to work with the FCC to address the harm from Ligado’s proposed terrestrial network to critical GPS, satellite communications, and weather forecasting services by staying the Order, addressing the previously unavailable information contained in the NAS Report, and resolving the pending petitions for reconsideration.


AccuWeather, Inc.

Aerospace Industries Association

Agricultural Retailers Association

Airborne Public Safety Association

Aircraft Electronics Association

Aircraft Owners and Pilots Association

Airlines for America

Alabama Agricultural Aviation Association

ALERT Users Group

Allied Pilots Association

Air Line Pilots Association, International

American Geophysical Union

American Meteorological Society

American Rental Association

American Road & Transportation Builders Association

American Weather and Climate Industry Association

Arizona Agricultural Aviation Association

Arkansas Agricultural Aviation Association

Associated Equipment Distributors

Association for Uncrewed Vehicle Systems International

Association of Aerial Applicators Washington

Association of Equipment Manufacturers

Association of Marina Industries

Association of Montana Aerial Applicators

Aviation Spectrum Resources, Inc.


California Agricultural Aircraft Association

Cargo Airline Association

CNH Industrial

Coalition of Airline Pilots Associations


Colorado Agricultural Aviation Association

EarthScope Consortium

Florida Agricultural Aviation Association

General Aviation Manufacturers Association

GeoOptics, Inc.

George Washington University

Georgia Agricultural Aviation Association

Helicopter Association International

Idaho Agricultural Aviation Association

Illinois Agricultural Aviation Association

Indiana Agricultural Aviation Association

International Air Transport Association

Iowa Agricultural Aviation Association

Iridium Communications Inc.

Kansas Agricultural Aviation Association

Land Improvement Contractors of America

Lockheed Martin Corporation

Louisiana Agricultural Aviation Association

Marine Retailers Association of the Americas

Michigan Agricultural Aviation Association

Microcom Environmental

Minnesota Agricultural Aircraft Association

Mississippi Agricultural Aviation Association

Missouri Agricultural Aviation Association

Narayan Strategy

National Agricultural Aviation Association

National Air Carrier Association

National Business Aviation Association

National Cotton Council

National Society of Professional Surveyors

National Weather Association

Nebraska Aviation Trades Association

NetJets Association of Shared Aircraft Pilots

New Mexico Agricultural Aviation Association

North Carolina Agricultural Aviation Association

North Dakota Agricultural Aviation Association

Northeast Agricultural Aviation Association

Ohio Agricultural Aviation Association

Oklahoma Agricultural Aviation Association

Oregon Agricultural Aviation Association

Pacific Northwest Aerial Applicators Alliance


Recreational Boaters of California

Resilient Navigation and Timing Foundation

Seafarers International Union

South Dakota Aviation Association

Southeast Aero Cultural Fair

Space Science and Engineering Center at the University of Wisconsin-Madison

Subsurface Utility Engineering Association

Tennessee Aerial Applicators Association

Texas Agricultural Aviation Association

The Airo Group, Inc.

The Semaphore Group

Trimble Inc.

U.S. Geospatial Executives Organization

University Corporation for Atmospheric Research

USA Rice

Vertical Flight Society

Westwind Helicopters

Wisconsin Agricultural Aviation Association

(1) Ligado Amendment to License Modification Applications, IBFS File Nos. SES-MOD-20151231-00981, SAT-MOD-20151231-00090, and SAT-MOD-20151231-00091, Order and Authorization, 35 FCC Rcd 3772 (2020) (“Ligado Order” or “Order”).

(2) More than twenty parties in total signed petitions for reconsideration of the Ligado Order and all of these petitions remain pending before the FCC. See Petitions for Reconsideration of the National Telecommunications and Information Administration; the Air Line Pilots Association, International; the American Road & Transportation Builders Association, the American Farm Bureau Federation, and the Association of Equipment Manufacturers; the Joint Aviation Petitioners; Iridium Communications Inc., Flyht Aerospace Solutions Ltd., Aireon LLC, and Skytrac Systems Ltd.; Lockheed Martin Corporation; Trimble Inc.; and the Resilient Navigation and Timing Foundation, IB Docket Nos. 11-109 & 12-340 (all filed on or about May 22, 2020). The ten “Joint Aviation Petitioners” consist of the Aerospace Industries Association, the Aircraft Owners and Pilots Association, Airlines for America, Aviation Spectrum Resources, Inc., the Cargo Airline Association, the General Aviation Manufacturers Association, the Helicopter Association International, the International Air Transport Association, the National Air Transportation Association and the National Business Aviation Association.

(3) The Commission should also not proceed with any companion rulemakings causing harmful interference to weather forecasting and hydrology services that could result in Ligado deployments, particularly in light of the analysis and recommendations presented in the “Spectrum Pipeline Reallocation 1675–1680 MHz Engineering Study (SPRES) Program Report. See Allocation and Service Rules for the 1675-1680 MHz Band, Notice of Proposed Rulemaking, 34 FCC Rcd 3352 (2019); U.S. Department of Commerce. National Oceanic and Atmospheric Administration. National Environmental Satellite Data Information Service. Spectrum Pipeline Reallocation 1675–1680 MHz Engineering Study (SPRES) Program Report. Silver Spring, MD: NESDIS, October 2020 (public release August 2022).

(4) National Academies of Sciences, Engineering, and Medicine, Analysis of Potential Interference Issues Related to FCC Order 20-48 (2022), (“NAS Report”).

(5) Letter from Gina Raimondo, Secretary of Commerce, U.S. Dept. of Commerce, to The Honorable James M. Inhofe, ranking member, U.S. Senate Committee on Armed Services (June 22, 2021) (reiterating the NTIA’s position opposing the Ligado Order).

(6) William M. (Mac) Thornberry National Defense Authorization Act (“NDAA”) for Fiscal Year 2021, Pub. L. 116-283, 134 Stat. 4074 § 1663; NDAA for Fiscal Year 2022, Pub. L. 117-81, 135 Stat. 1541 § 1613.

(7) These statements are based on the publicly available portions of the NAS committee’s work. In addition, NAS prepared a classified annex, which further details the risks of Ligado’s proposed terrestrial network and additionally warrants FCC action.

(8) The term “harmful interference” is herein used to describe the results of the NAS Report. In turn, the undersigned believe the results of the NAS Report dictate that the FCC must reach the legal conclusion that Ligado’s operations would cause harmful interference under the FCC’s rules.

(9) See, e.g., National Telecommunications and Information Administration Reply to Ligado Networks LLC’s Opposition to Petitions for Reconsideration or Clarification, IB Docket Nos. 11-109 & 12-340, at 10 n.26 (filed June 8, 2020); U.S. Department of Transportation, Global Positioning System (GPS) Adjacent Band Compatibility Assessment, Final Report (Apr. 2018) (“DOT ABC Report”),

(10) See Memorandum from Thu Luu, Executive Agent for GPS, Department of the Air Force, to IRAC Chairman (Feb. 14, 2020).

(11) See, e.g., Letter from J. David Grossman, Executive Director, GPSIA, to Marlene H. Dortch, Secretary, FCC, IB Docket Nos. 11-109 et al., at 6 (Sept. 17, 2020); Letter from Bryan N. Tramont, Counsel to Iridium Communications Inc., to Marlene H. Dortch, Secretary, Federal Communications Commission, IB Docket Nos. 11-109 et al. (Jan. 19, 2022); Update to 2016 Technical Assessment of Ligado User Terminal Interference to Iridium attached to Iridium Communications Inc. et al., Petition for Reconsideration, IB Docket Nos. 11-109 et al. ( May 22, 2020).

(12) NAS Report at 6, 73.

(13) 47 C.F.R. § 1.106(c)(2).

(14) Press Release, NTIA, NTIA Statement on National Academies of Sciences Report (Sept. 9, 2022).