WASHINGTON — A committee charged with giving the U.S. government advice on space-based navigation services concluded that the Federal Communication Commission’s approval of Ligado’s 5G network is a “high-risk” decision that jeopardizes Global Positioning System services.

During a July 1 meeting of the National Space-Based Positioning, Navigation, and Timing Advisory Board, held online, members discussed a report prepared for the committee about the April FCC decision to allow Ligado to operate a 5G terrestrial network on a spectrum band neighboring that used by GPS.

“It abruptly changed the whole character of the radio spectrum near the GPS primary frequency,” said Brad Parkinson, a vice-chair of the committee and chief architect of the GPS system during its development in the 1970s, of the FCC’s approval of Ligado. “The FCC has made a grave error in authorizing the high-power terrestrial comm network in this spectrum right next to GPS.”

That spectrum, he noted, was originally intended for use by mobile satellite systems, with much weaker signals that those Ligado now plans to use in the band. “The repurposing of this spectrum is very high risk, and brings virtually no near-term benefits to the United States,” he said.

The lack of benefits, Parkinson said, is because of a lack of 5G hardware or standards designed to work at the L-band frequencies Ligado plans to use. Any benefits, he argued, would be outweighed by likely interference to GPS signals from Ligado’s higher-power signals, an analysis of which he discussed in detail in his presentation.

“The FCC order doesn’t have a great positive impact on the U.S.’ competitive posture, and it may actually damage the GPS reputation because of the harm it does,” he concluded.

The committee is not alone in its opposition to the FCC decision on Ligado. The FCC has faced fierce criticism from the Defense Department and other government agencies, as well as some members of Congress, because of interference concerns. The FCC, though, whose commissioners unanimously adopted the Ligado order, has continued to argue that the reduced power levels the company agreed to should prevent interference.

Committee members supported Parkinson’s report. Some noted that the Ligado system could result in similar interference for other space-based navigation systems, and that the FCC’s approval of Ligado could set a precedent for establishing similar systems in other countries.

The committee’s chairman, retired U.S. Coast Guard Adm. Thad Allen, read into the record at the meeting a letter from Chesley “Sully” Sullenberger, the retired pilot best known for piloting the crippled airliner in the “Miracle on the Hudson” accident in 2009. Sullenberger also criticized the FCC’s decision because of what he saw as safety impacts on aviation and other industries, as well as national security.

“The FCC’s decision to approve Ligado Networks’ use of a portion of the L-band spectrum is ill-advised, and constitutes a dereliction of duty on the FCC’s part,” Sullenberger wrote, calling the order “a dangerous decision that must be reversed.”

The committee, while unanimously adopting Parkinson’s report, did not provide a recommendation on how to reverse it. “We have no official standing on how the process moves forward,” Allen said. He outlined several options, from an FCC decision to reconsider the order to legal action to congressional legislation.

“Our purpose is to make a public statement on how we feel about this,” Parkinson said.

One committee member pointed out that the opposition to the order might make it impossible for Ligado to raise the money needed to build out its network. “As a matter of observation, I can’t imagine any investor wanting to invest in this proposed 5G network when they realize there is extraordinary liability to them,” said James Geringer, a former governor of Wyoming.

Another pending issue discussed at the committee is an update to national space-based position, navigation and timing policy published in 2004. In a separate presentation, Curtis Hernandez, director of national security space policy at the National Space Council, said a revised version of that policy is nearing completion.

“The goal of the policy is to maintain the United States’ leadership in the service, provision and responsible use of global navigation satellite systems, including GPS and foreign systems,” he said. He declined to go into details about the updated version since it has not yet been approved for release.

A draft of the revised policy was delivered for internal White House review earlier this year, Hernandez said, but consideration of it has been delayed because of the response to the coronavirus pandemic. The policy, he stated, “does complement and is consistent with” an executive order published in February on strengthening national resilience through responsible use of position, navigation and timing services.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...