As requested in section 1662 of the FY2021 National Defense Authorization Act, an ad hoc committee of the National Academies of Sciences, Engineering, and Medicine will provide “an independent technical review of the order and authorization adopted by the Federal Communications Commission on April 19, 2020 (FCC 20-48),” which authorized Ligado Networks LLC to operate a low-power terrestrial radio network adjacent to the Global Positioning System (GPS) frequency band.

The study will consider:

(1) Which of the two prevailing proposed approaches to evaluating harmful interference concerns -- one based on a signal-to-noise interference protection criterion and the other based on a device-by-device measurement of the GPS position error -- most effectively mitigates risks of harmful interference with GPS services and DOD operations and activities.

(2) The potential for harmful interference from the proposed Ligado network to mobile satellite services including GPS and other commercial or DOD services including the potential to affect Department of Defense (DOD) operations, and activities.

(3) The feasibility, practicality, and effectiveness of the mitigation measures proposed in the FCC order with respect to DOD devices, operations, and activities.

The committee’s final report(s) will include the Academies findings and recommendations with respect to these issues as well as other related issues the study committee determines relevant.

The bulk of the technical analysis is expected to be performed based on public reports and open science and engineering literature and practice and result in an entirely unclassified report. This unclassified report is also expected to provide most, or all of the analytical framework needed for assessing the impact on classified systems and capabilities.

Appropriately cleared members of the study committee will receive classified briefings and, if they determine it necessary, will prepare a classified annex.