Leading a pack of industry and government organizations in opposition, U.S. federal agencies formally petitioned an independent sister agency to reconsider its order allowing Ligado Networks access to radio frequency spectrum near frequencies allocated for GPS.

Representing the Defense Department, the Transportation Department and other executive branch agencies, the National Telecommunications and Information Administration (NTIA) petitioned the independent Federal Communications Commission (FCC) on May 22 to reconsider and stay, or postpone, its order granting Ligado use of L-band mobile satellite services spectrum to build a ground-based 5G cellular network. 

• Industry groups join in petitioning FCC
• Airline pilots raise concern over satcom
• Pentagon officials surprised by decision

The petition states that Ligado should not be permitted to deploy its network until federal agencies’ concerns over its potential harmful effects on GPS devices are resolved. 

A branch of the Commerce Department, the NTIA coordinates federal agencies’ use of spectrum. Several aviation and other industry groups and manufacturers, including GPS Block III satellite manufacturer Lockheed Martin and L-band satellite communications (satcom) provider Iridium Communications have also petitioned the FCC to reconsider its decision.

“The impact of the FCC’s decision is tantamount to permitting a deafening nuisance into a quiet residential neighborhood over the objections of affected neighbors,” Lockheed Martin states its petition. 

“Despite the strong concerns of and opposition from a wide array of private sector and government experts and stakeholders in this community, and a record replete with evidence that granting Ligado’s proposal would cause harmful interference, the commission ignored material questions of fact, did not properly weigh the costs and benefits of Ligado’s proposal, and offered a series of ‘remedies’ that are patently inadequate,” the manufacturer adds. 

The Air Line Pilots Association (ALPA) filed a petition for reconsideration of the Ligado decision on May 20, and a bipartisan group of 32 U.S. senators sent a letter to the FCC on May 15 asking it to reverse course. The bipartisan leadership and 20 members of the House Armed Services Committee (HASC) decried the “unacceptable risk” posed to GPS by Ligado’s network in a May 7 letter to the commission. 

The ALPA petition asks the FCC to disallow Ligado from operating transmitters at frequencies adjacent to the GPS band and in spectrum allocated for mobile satellite services at 1.6 GHz.

FAA-certified avionics are hardened against potential interference by a Ligado transmitter operating at a distance. The pilot union’s concern is that general aviation pilots using tablet devices with uncertified GPS receivers to help them navigate, as well as small drones using uncertified receivers, are much more susceptible to interference, potentially causing them to blunder into the path of airliners. 

The ALPA petition also raises the potential of Ligado-enabled smartphones carried by airline passengers interfering with L-band satcom used for controller-pilot data link communications and automatic dependent surveillance-contract position reports—applications used by air navigation service providers to track and separate aircraft over remote and oceanic areas outside of radar coverage. 

“If Ligado-compatible handsets were carried onboard aircraft by passengers and were to become active when satcom is being used for communications and surveillance, these safety services could potentially be disrupted,” the ALPA petition argues. 

Satcom providers Inmarsat and Iridium provide L-band satellite connectivity for critical aviation applications. In its 74-page order, the FCC states that Ligado has entered into an arrangement with Inmarsat to address potential interference concerns but not with Iridium. 

“Absent an understanding between the parties, we reduce Ligado’s emissions within the frequency band used by Iridium and encourage the parties to engage in further discussions to reach mutually satisfactory arrangements where possible,” the commission’s order states. 

Senators wrote to the FCC following a May 6 hearing held by the Senate Armed Services Committee (SASC), which sought an explanation of the board’s controversial 5-0 decision. Defense Department witnesses testifying at the hearing said they were blindsided by the FCC action. 

The FCC announced on April 20—a Monday—that it had approved the license modifications Ligado sought to build a low-power terrestrial network for 5G and internet of things services with conditions designed to prevent interference with GPS. The approval authorizes the company to use three spectrum bands: one that is adjacent to the 1559-1610 MHz band allocated for radionavigation satellite services, including the GPS L1 signal. 

“A few powerful people made a hasty decision over the weekend in the middle of the [coronavirus] crisis against the judgment of every other agency involved and without clueing the president in on any of this,” said Sen. James Inhofe (R-Okla.), the SASC chairman, in his opening remarks. 

“They waited until the whole world was distracted by the virus, and when everyone was looking the other way—unannounced to the public, in total secrecy on a weekend—passed the most controversial licensing bill, I think, in the history of the FCC,” Inhofe added. 

Witnesses testifying at the hearing had no explanation when pressed by senators on why the FCC approved the Ligado license modifications, which evolved from a network proposal advanced in 2011 by LightSquared, a predecessor company. LightSquared was reorganized in bankruptcy and renamed Ligado Networks in 2016. 

“It’s quizzical,” said U.S. Coast Guard Adm. (ret.) Thad Allen. The lengthy FCC order “had to be in the works for quite a while, and it happened suddenly,” he added. “In my view, that was a breakdown of communications and in building a consensus around proper rulemaking at a regulatory agency.” 

The Defense Department estimates that Ligado transmitters potentially could interfere with any of a million legacy GPS receivers embedded in vehicles and weapon systems, costing the Pentagon billions of dollars to replace and delaying training and readiness of its forces. 

“Ligado maintains that [the Defense Department] can simply replace affected GPS cards,” said Sen. Jack Reed (D-R.I.), ranking member of the SASC. “But there are hundreds of thousands of GPS chips embedded in [Defense Department] weapon systems, and each chip is not only tuned to GPS but embedded with interconnected electronics each tuned to each other.” 

A new generation of Military GPS User Equipment (MGUE) consisting of modernized, jam-resistant receiver cards will not be installed across weapons systems until the 2030s, Reed said. “The best course of action for national security,” he advised, would be for the FCC to stay the license approval until MGUE chipsets are fitted into critical systems. 

Notably unrepresented at the hearing were Reston, Virginia-based Ligado Networks and the FCC. The latter has issued a list of 29 prominent individuals and organizations that support its decision, including U.S. Attorney General William Barr, Secretary of State Mike Pompeo and Sen. Mark Warner (D-Va.). 

Barr and others have argued that freeing spectrum to deploy high-speed 5G wireless technology is key to maintaining a competitive edge against China. Conversely, the Pentagon contends that China’s BeiDou and Russia’s Glonass satellite-positioning systems would benefit from any degradation of GPS.

The office of Rep. Mike Turner (R-Ohio) said May 27 that FCC officials had acknowledged during a conference call with the HASC that they had not sought classified briefings from any of the 13 federal agencies affected by the Ligado order. 

“The FCC is the only federal government entity that thinks this is a good idea,” stated Turner. “I was concerned when I asked the FCC officials on the call if they had convinced any other agency this was good policy or if they had made an attempt to receive a classified briefing on the effects of their decision, and their answer was ‘no’.”