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Battle of the bandwidth

FCC vote revives old threat to GPS

Editor's note: This story was updated April 21 to report that the Department of Homeland Security had issued a statement objecting to the Ligado Networks proposal.

Don’t mess with GPS: That’s the message AOPA members want the Federal Communications Commission and Congress to hear loud and clear in proceedings that could revive a wireless network proposal long criticized by aviation groups as a hazard to aerial navigation.

Countless other GPS users who depend on digital technology in their daily lives or to make a living, along with institutions including the Department of Transportation and the Department of Defense, are on the same wavelength as a battle over bandwidth that drove a network company into bankruptcy in 2012 reignites in Washington, D.C.

On April 20, the FCC voted to approve a proposal by Ligado Networks that revives the plan by network venture LightSquared to establish a land-based 5G network on L-band frequencies close enough to those used by GPS to create potential interference with navigation.

The agency issued a news release announcing the unanimous vote of its five members to approve the network that will “primarily support 5G and Internet of Things services.” The action came despite myriad objections AOPA and other organizations have consistently catalogued, ranging from the risk Ligado’s towers would pose to low-altitude aircraft to the federal agencies’ concerns that the Ligado/LightSquared effort could jeopardize emergency 911 service, the financial system, and more.

The announcement noted that regulators “included stringent conditions” to prevent harmful interference.

“The order also requires Ligado to protect adjacent band incumbents by reporting its base station locations and technical operating parameters to potentially affected government and industry stakeholders prior to commencing operations, continuously monitoring the transmit power of its base station sites, and complying with procedures and actions for responding to credible reports of interference, including rapid shutdown of operations where warranted,” it said.

Protecting the GPS bandwidth from interference is a top advocacy concern for AOPA—a priority whose importance was confirmed when hundreds of thousands of readers reacted to our reports in January of temporary GPS jamming by the military during exercises off the east coast, said Rune Duke, AOPA senior director of airspace, air traffic, and aviation security.

“Just about everyone in transportation and national security is against it,” he said. “I think that’s a key point as we consider where we go next.”

On April 21, the Department of Homeland Security issued a statement noting that it had recommended that the FCC deny the Ligado application and reiterating its concerns about the proposal's possible impact on GPS.

Duke added that opponents were disappointed that the FCC has not responded publicly to the studies and tests that vindicated opponents’ concerns about GPS’s vulnerabilities.

In 2015, Ligado (the name signifies “connected,” the company says) emerged after the LightSquared bankruptcy, vowing to continue its plan to provide “seamless satellite and terrestrial connectivity.”

AOPA and other aviation groups said they remained concerned that “interference issues that have the potential to negatively impact the operational aviation environment remain unresolved and require definitive testing and evaluation before any system deployment.”

Also, the opponents noted, the risk to aerial navigation has become exacerbated with the increasing numbers of unmanned aircraft—which fly at low altitude and are reliant on GPS—in the airspace.

AOPA and the other industry groups opposing Ligado reiterated those concerns in an April 15 letter to the FCC.

Duke noted that in addition to AOPA’s advocacy with regulatory agencies and in Congress to protect GPS, we have participated in the RTCA Tactical Operations Committee’s review of Ligado’s plan.

The study resulted in a report noting that concerns about aviation operations and safety remained valid because GPS, by its nature, is very sensitive to “noise” on adjacent frequencies that would make users vulnerable to “a breadth of impacts” difficult to quantity and remedy in advance, Duke said. 

Following the FCC’s ruling for Ligado, Duke said, the effort to block the network’s implementation would shift focus as the proposal moved to its next phase.

Dan Namowitz

Dan Namowitz

Dan Namowitz has been writing for AOPA in a variety of capacities since 1991. He has been a flight instructor since 1990 and is a 35-year AOPA member.
Topics: Advocacy, NextGen, Technology

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