A study by the National Academies of Sciences determined that most civilian GPS services won’t experience significant interference from Ligado’s new 5G cellular and data service, but the military could have issues. The study, which was commissioned by Congress and funded by the Pentagon, determined that the Ligado network, which will carry 5G signals in frequency bands close to those used by GPS, “will not cause general navigation the no longer commercially produced, timekeeping, cellular or certified”. aviation GPS receivers from harmful interference.
The study indicated that some high-accuracy commercial GPS receivers used in agriculture, surveying, and geodesy (the science that accurately measures and understands the geometric shape, size, and orientation of the Earth in the space, as well as gravity) sold before 2012 “may be vulnerable to significant interference damage.” But it looks like the main effect will be on the Iridium satellites, which are under contract with the Department of Defense. It says Iridium terminals will “experience harmful interference” within 2,401 feet of Ligado terminals. He also noted that satellite services provided to the military by Iridium competitor Globalstar are unlikely to be affected.
Iridium spokesman Jordan Hassin told Defense News that the study confirms what Iridium opponents have always said. “The conclusions of the [National Academies of Sciences] are consistent with opposition from 14 federal agencies, more than 80 stakeholders, and Iridium’s concerns that Ligado’s proposed operations will cause harmful interference,” he said.
Ligado spokeswoman Ashley Durmer said the study also confirms what her company and supporters have argued. “A small percentage of very old and poorly designed GPS devices may need upgrading,” Durmer said. « Ligado, in tandem with the FCC [Federal Communications Commission], established a program two years ago to upgrade or replace Federal equipment, and we remain ready to assist any agency that offers obsolete devices. So far, none have.
Ligado will soon begin operational testing of its 5G system. The FCC granted it a license to use part of the L-band radio spectrum two years ago. This prompted the formation of the Keep GPS Working Coalition which lobbied Congress and organized the opposition to force the FCC to rescind its spectrum allocation to Ligado.