The chairman of the House Committee on Transportation and Infrastructure has teamed up with the chairman of the House Armed Services readiness subcommittee to demand answers from the Federal Communications Commission on whether reallocating a band of spectrum will damage the Global Positioning System, or GPS, as the Pentagon claims.

C4ISRNET published a report on the afternoon of April 10 that the FCC intends to approve Ligado Networks, formerly Lightsquard, to operate in L-Band, a region of spectrum near where the Defense Department’s GPS system.

For years, the DoD and other government agencies have warned that Ligado’s plan would cause what one defense official termed “unacceptable operational impacts to the warfighter.” But some experts have argued the Pentagon is being too stringent with the spectrum near GPS and sources said the FCC seemed intent on moving forward despite those concerns. The move is driven in part by pressure from the White House to stimulate the economy and help develop America’s 5G capabilities.

As part of the report, C4ISRNET revealed an Air Force memo and two letters — a March 12 note from Undersecretary of Defense for Research and Engineering Mike Griffin and Chief Information Officer Dana Deasy, as well as a March 24 letter from Deputy Secretary of Defense David Norquist — sent from the Department of Defense arguing against Ligado’s approval.

Despite both letters requesting that their contents be made part of the public record, as of mid-afternoon April 10 they had yet to have been entered into the public docket. Sources said that was due in part to pressure from the White House National Economic Council.

After publication of the story, Rep. Peter DeFazio, D-Oregon, the chairman of the House Transportation and Infrastructure committee, and Rep. John Garamendi, D-Califorinia, who chairs the House Armed Services Committee subcommittee on readiness, sent a letter to Secretary of Transportation Elaine Chao to “express our strong concerns about a decision pending at the Federal Communications Commission (FCC) which could jeopardize not only the development of a back-up signal to GPS, but GPS itself.”

In the letter, the two congressmen said they are “concerned that not all relevant information on this issue within your Department has been made available to Congress, the public or the FCC,” and requested a series of documents, including any correspondence between the transportation department and any other government agency on this matter, as well as “correspondence signed by multiple agencies and/or departments, regardless of whether it has been transmitted formally to the FCC,” a description which would fit the Air Force memo.

Notably, the two congressmen put a deadline of April 15 on their request, a significantly shorter timeline than such letters usually carry and a way for Congress to express its displeasure with government agencies.

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According to a congressional staffer, the committee is waiting for the information to “gain a better understanding of the strong concerns raised by relevant federal agencies involved with the management, operation and utilization of the electromagnetic spectrum and the civilian and military applications of GNSS/GPS.

“Virtually all infrastructure under the committee’s jurisdiction would be directly impacted by future degradation or unreliability of GPS. The committee intends to closely monitor the FCC’s handling of this application,” the staffer added.

Then, late on April 10, the National Telecommunications and Information Administration (NTIA) officially added the memo and two letters sent by the Defense Department on this issue to the FCC’s filing system.

The NTIA associate administrator said in a letter to FCC Commissioner Ajit Pai that the organization cannot “reasonably reach” the conclusion that the Pentagon’s concerns have been resolved.

That comment led to a new filing by Ligado on April 12, in which the company blasted the NTIA statement, and the attached notes from the Pentagon, as “simply astounding" and “replete with fearmongering.”

The company also argued that the DOD’s conclusions that GPS would be impacted are “based on irrelevant and misleading data,” most notably noting that the Air Force test cited in the service’s memo was based on an older plan the company has since abandoned.

Speaking to reporters April 13, Deasy, the Pentagon’s top IT official, made it clear he trusts in the department’s evaluation.

“We have very strong technical evidence that would suggest moving forward with that proposal would cause harm to the adjacent GPS spectrum,” Deasy said. “Therefore, we continue to believe it’s in the best interests — and I believe I can say this on behalf of all the agencies — it’s in the interest of the government not to pursue the Ligado licensing request.”

Deasy added that top defense officials have taken part in “active conversations” about the issue, including Secretary of Defense Mark Esper and Gen. John Hyten, the Vice Chairman of the Joint Chiefs of Staff.

Mike Gruss of C4ISRNET contributed to this story.