Thirteen agencies responsible for much if not most of the nation’s military, civil, security and economic activity say Ligado Networks’ plan to use satellite frequencies for 5G communications would interfere with GPS users in general and DOD use in particular.
Their conclusions were summarized in a memo that sat stalled in an office of the Department of Commerce (DOC) for nearly two months before rumors that regulators might quietly approve Ligado’s plan created so much pressure that it appears to have shaken the memo loose. The memo could be the last element needed in the decision making process on the controversial request.
At the center of the debate is a proposal to take frequencies allocated primarily for use by satellites and allow them to be used for broadband communications. Extensive testing has shown that the proposal, even in a dialed-back form, would cause interference to GPS receivers. Those receivers are used for navigation and positioning but also for super-accurate timing that enables the synchronization of mobile communications and internet traffic as well a financial transactions and other networked systems like the power grid and the cloud. GPS signals are so important that they are now considered to be an essential element of the nation’s critical infrastructure.
Yes. There’s Interference.
“The Air Force has shown — and Ligado itself has conceded — that the proposed Ligado (previously LightSquared) license modification threatens disruption of GPS,” wrote Thu Luu, the Air Force’s executive agent for GPS. A proposal by the Virginia-based firm to address any problems by replacing government GPS receivers that are affected by its network “is a tacit admission that there would be interference,” she said.
Ligado did not immediately respond to a request for comment.
The February 14 memo focuses on military applications and was co-signed by representatives of the Army, Navy and the U.S. Coast Guard. It also underscores the civil GPS applications the Pentagon relies upon and was co-signed by the Departments of Commerce, Energy, Homeland Security, Interior, Justice and Transportation as well as the Federal Aviation Administration, NASA and National Science Foundation.
The memo was “endorsed by the interagency,” said Deputy Secretary of Defense David Norquist. The interagency reflects the civil and defense agencies that work together to support GPS specifically and position, navigation and timing capabilities in general. In a March 24 letter Norquist urged the National Telecommunications and Information Administration (NTIA) within DOC — which manages federal frequencies, and had failed to forward the memo — to “expeditiously” send the February memo to the Federal Communications Commission, which has been weighing the Ligado’s proposal since 2010, when the firm was called LightSquared.
Rumors had surfaced in Washington just before the Easter weekend suggesting FCC Chairman Ajit Pai was poised to immediately approve Ligado’s request. Though the rumors did not track with FCC procedure and nothing indicating a decision has yet emerged, it is not unusual for government agencies to make contentious moves at a time when fewer people will be watching.
The memo and the March 24 letter — plus a March 12 letter signed by Dana Deasy, DOD’s chief information officer and Under Secretary of Defense for Research and Engineering Michael Griffin asking that the memo be conveyed to the FCC — were finally sent to Pai on Friday April 10 by Douglas Kinkoph, NTIA associate administrator and acting assistant secretary for communications and information; then posted by NITA late that evening.
Kinkoph noted in his letter to Pai that the process for authorizing the request from Ligado would be complete only “‘once the Commission, after consultation with NTIA, concludes that the harmful interference concerns have been resolved.'” That, Kinkoph pointed out, was the criteria set by the FCC itself in the 2011 Report and Order on the matter issued by the FCC’s International Bureau. “We believe the Commission cannot reasonably reach such a conclusion,” wrote Kinkoph.
The 13 agencies signing the February memo comprise the majority of the members of the Interdepartment Radio Advisory Committee (IRAC), which gives technical input to NTIA. The February memo could be seen as the feedback from the IRAC that Pai was reportedly seeking this fall.
On Friday Rep. Peter A. DeFazio (D-Mass.), chairman of the Committee on Transportation and Infrastructure, and Rep. John Garamendi (D-Calif.), set up what appears to have been a backup plan should the NTIA have failed to respond or respond fully to DOD’s send-the-memo requests.
The lawmakers wrote on April 10 to Secretary of Transportation Elaine Chao, asking her to convey to Pai copies of DOT’s correspondence regarding Ligado with the NTIA, FCC, DOD, the National Economic Council. They also ask her to send correspondence with Commerce (of which, as noted, the NTIA is a part) and specifically with DOC’s National Institute of Standards and Technology.
DOD and DOT co-chair the National Executive Committee for Space-Based Positioning, Navigation, and Timing (PNT), which coordinates GPS matters across the full government as part of the interagency process. DOT also conducted key interference testing that looked at the power levels GPS receivers could withstand whatever the source — including from Ligado-like signals. DeFazio and Garamendi zeroed in on testing and data, asking DOT to send any studies and analyses by the IRAC regardless of their state of formal approval as well as correspondence signed by multiple agencies and/or departments, regardless of whether it has been transmitted formally to the FCC.
Broad Impact
Thu underscored that the mitigation proposal by Ligado only covers those receivers owned by the government and would leave out many high-value federal uses of civil GPS receivers not owned by the government. DOD makes use of civil GPS receivers in non-combat environments, such as surveying, flight training, training, exercises, other national security events and scientific applications. Like their civilian counterparts, DOD surveyors and construction units often rely on high-precision GPS receivers that are exceedingly sensitive to interference from signals at nearby frequencies.
The military receivers that could be impacted also go well beyond those used directly by DOD, said Thu. For example, NASA uses high-precision military GPS receivers for its launch anomaly monitoring and destruct systems and Homeland Security and the border patrol use military GPS receivers in unmanned surveillance aircraft. Some law enforcement and intelligence agencies use military GPS in drones and the State Department’s diplomatic security service also uses military GPS receivers.
“It would be untenable for the United States to pursue an initiative that undermines these capabilities,” wrote Thu, “and it would be exceptionally detrimental to national security.”
