As required by Congress in section 1663 of the 2021 National Defense Authorization Act, the National Academies of Science, Engineering and Medicine (NASEM) committee recently released its study on Ligado’s planned deployment of terrestrial services and its potential to interfere with GPS capabilities essential for DoD’s mission execution. National security missions that our service men and women execute every day are of the utmost importance and require a solution that ensures continued operations of critical systems.
The NASEM study confirms that Ligado's system will interfere with DoD GPS receivers, which include high-precision GPS receivers. The study also confirms that Iridium satellite communications will experience harmful interference caused by Ligado user terminals. Further, the study notes that when DoD’s testing approach, which is based on signal-to-noise ratio, is correctly applied, it is the more comprehensive and informative approach to assessing interference. The study also concludes that the Federal Communication Commission’s (FCC) proposed mitigation and replacement measures are impractical, cost prohibitive, and possibly ineffective.
These conclusions are consistent with DoD’s longstanding view that Ligado’s system will interfere with critical GPS receivers and that it is impractical to mitigate the impact of that interference.
DoD looks forward to continuing to work with the National Telecommunications and Information Administration, FCC and Ligado on this complex and important issue.