Experts Warn GPS Is More Vulnerable Than We Realize

Bryan Benedict, senior director-innovation and satellite programs at SES Space & Defense, said GPS risks are real. “The U.S. government is looking for multiple sources of alternative PNT, not just one, because they want to make sure that they’re not dependent on just one source,” he said. Europe “is also playing on this” and is looking at various PNT alternatives.

“Adversaries are aware” of U.S. dependence on GPS, Benedict added. As one example, Benedict noted that GPS jamming has been widely deployed in Ukraine. “Overall, we are extremely dependent in this country on military and commercial use of GPS,” he said. “Our timing grids, our economics are all very dependent.”

Jamming is among the major threats to GPS, Benedict said. "The GPS signal is very weak … and easily jammed by transmitters in the same frequency area.” U.S. adversaries intentionally jam signals, he said.

In addition, spoofing disguises itself "as a valid signal, but it leads to providing incorrect information to your GPS receiver,” he said. Anti-satellite weaponry “can actually destroy satellites in orbit,” and others in the same orbit can be affected by the resulting debris field.

“We hugely over-rely on GPS," said Dana Goward, president of the Resilient Navigation and Timing Foundation. "This is a serious national security and economic security problem.” While some GPS disruptions have occurred in the U.S., problems in Europe and the Middle East have been more severe, he said. He also noted that jamming and spoofing of GPS “has been a feature” of the war between Russia and Ukraine.

China isn’t dependent on a single system for PNT, Goward pointed out. Instead, it uses multiple satellite systems for PNT and a terrestrial network called eLoran that covers the entire nation, extending 1,000 miles offshore, as well as a fiber network that provides precision and timing throughout the country and synchronizes other systems, he said. China is “far less vulnerable to having … PNT disrupted than we are.”

The U.S. government has so far done little more than examine PNT alternatives, Goward said. “We’ve had lots of studies but very little action,” he said. “The government has said that PNT vulnerability is a problem and people should protect themselves. But the federal government has done nothing to protect itself.”

Goward welcomed the FCC NOI and said he hopes the rest of the government is paying attention. Congress, acting without federal agency guidance, can't fix the problem, nor can any agency acting alone, he said. “It does, in fact, take a whole-of-government approach.”

The U.S. “is on the right track” on GPS, countered Lisa Dyer, executive director of the GPS Innovation Alliance. She said “excessive harmful interference” will affect the ability of receivers to hear GPS signals, “but our receiver manufacturers are world experts in cybersecurity” and “world experts in how to listen for these signals.”

The FAA has been monitoring GPS signal performance since 1993, and the availability of GPS satellites is more than 99%, Dyer said, adding that there have been no satellite outages due to solar storms and flares. The reported threat to satellites from direct attack has been to those in low earth orbit, below the orbits of GPS satellites, she noted.

Dyer said last week’s FCC NOI was narrowed from the draft version to consider civil uses for GPS and PNT rather than all uses, including by the military. But DOD is “very, very reliant on and gets a lot of service from those civil signals for other operations, whether it’s logistics,” such as transporting heavy equipment on trains, or “emergency and natural disaster responses.” DOD will likely be very interested in the FCC NOI and the comments filed, she added.