March 2021: GPS interference has been a worsening problem for the past decade, particularly for aviation. This article from IEEE spectrum covers current research efforts to detect and monitor GPS interference. Data from ADS-B and terrestrial GPS receivers offer a good start, but Dr. Humphreys explains that these sources are limited by sensor sparsity: 

"There are fewer than 3000 GPS reference stations with publicly-accessible data across the globe; these can be separated by hundreds of miles. Likewise, global coverage by ships and planes is still sparse enough to make detection challenging, and localization nearly impossible, except around ports and airports."

The Radionavigation Lab's recent paper, GNSS Interference Monitoring from Low-Earth Orbit, shows how satellites in low-earth orbit (LEO) can be used to monitor terrestrial GPS interference. A network of GPS-monitoring satellites in LEO may be the solution to global detection and monitoring of GPS interference. 

January 2021: This recent article from The New York Times summarizes America's extreme dependence on GPS and the resulting vulnerabilities. They credit Dr. Humphreys's 2008 paper on GPS spoofing with bringing the weakness to light. When asked about the urgency of finding alternatives to GPS, Dr. Humphreys said

"If we don’t get good backups on line, then GPS is just a soft rib of ours, and we could be punched here very quickly."

The article underscores several of the Radionavigation Lab's research areas, including Russian GPS interference and maritime GPS spoofing.  

January 2021: FAA pilot reports have revealed that military tests are interfering with airline flights. The military is presumably generating GPS interference to test their latest positioning technology, but the interference is reaching beyond the test sites and jamming passenger aircraft that routinely rely on GPS for navigation and landing. Although pilots are trained for such scenarios, the loss of GPS is so rare that it can still cause disorientation and confusion in the cockpit. In this article from IEEE Spectrum, Dr. Humphreys explains: 

"I don’t blame pilots for getting a little addicted to GPS. When something works well 99.99 percent of the time, humans don’t do well in being vigilant for that 0.01 percent of the time that it doesn’t."