Blog Editor’s Note: The three authors of this opinion piece are among the most qualified in the world to opine on this issue. Similar recommendations to these were made by the President’s National PNT Advisory Board in 2017.

FCC must act to avoid a grave threat to GPS


If you like your GPS, you should be worried.

A proposal before the Federal Communications Commission would allow transmissions that will block or degrade GPS service for millions of Americans.

Over the past 20 years, GPS has become a silent utility upon which most of our infrastructure — as well as daily life — now depends. The benefits of GPS run deep throughout our society and economy. Its thousands of uses have greatly improved our lives in areas as varied as:

  • Emergency response, safer air travel and delivery services;
  • Precision surveying, construction and agriculture using less materials, chemicals and energy;
  • Synchronizing wireless networks to enable the continuing cell phone and information technology revolution.

In these and many other ways, GPS has become an economic engine for America. A recent study concluded that a small portion of these applications exceed $65 billion a year in benefits to the U.S. economy. Over half of those benefits come from high-

precision receivers that routinely measure position to accuracies of better than an inch. While many users could be impacted, high-precision receivers are most at risk from the proposal before the FCC.

A U.S. satellite communications company called Ligado Networks is seeking FCC approval to transmit at frequencies near those used by GPS to become a national communications provider like Verizon or AT&T. Ligado would deploy as many as 40,000 towers across the United States and transmit a signal over a billion times more powerful than the GPS signal. If the FCC approves the Ligado application, the value of the company’s spectrum alone could increase by $10B or more.

The cost to America, though, could be staggering.

Multiple recent government studies have shown that such transmissions would severely impact many GPS users up to several miles from each tower. Much like driving past a powerful radio station’s antenna in your car and getting static on the radio, Ligado’s high-power signals would bleed over and disrupt GPS receivers, sometimes within miles of their antennas. Although Ligado has offered modifications to its proposal over the years, in response to potential impact on GPS users, close examination has shown little to no improvement to the disruption its system would cause.

Recent legal action by early investors in Ligado’s predecessor company claims that the impact of these transmissions on GPS should have been disclosed as early as 2001. The suit says tests showed the transmissions “…would effectively cripple receivers used by GPS and would be fatal to the millions of GPS devices already in use, many of which are critical to the national infrastructure and already widely used for aviation, safety, defense, and research purposes across the country.”

Approval of Ligado’s application by the FCC could degrade or prevent current GPS receiver use for aircraft navigation, guidance of drones, precision agriculture, timing in cell phone and information networks, and hosts of other applications — even far away (miles in some cases) from of any of their 40,000 towers. This would also place today’s first-responder helicopter and ground operations at risk, and could effectively cripple development of budding drone aircraft, autonomous vehicle and intelligent transportation systems.

That’s why the administration’s National Advisory Board for GPS, along with many others in the GPS community, strongly argued against the Ligado proposal and similar earlier proposals for the past eight years.

The administration must take a strong stand against the current Ligado proposal. And the FCC must ensure that any proposal it considers in the future minimizes the impact on our ubiquitous and essential GPS services.

America has four major telecommunications providers and dozens of smaller ones.

We have only one GPS. We endanger it at our own peril.

Bradford W. Parkinson was the original chief architect for GPS. He is a co-director at the Stanford Center for Position, Navigation and Time, Stanford University.

James Geringer served as Wyoming’s governor from 1995-2003. He is a senior director with Esri, the leading developer of mapping and spatial analytics software. 

Thad Allen, a retired U.S. Coast Guard admiral, was commandant of the Coast Guard and served as the principal federal official for responses to Hurricane Katrina and the Deepwater Horizon oil spill.

Link to Item in The Hill