May 2021: Reports of maritime GNSS spoofing have become all but routine in recent years. Ships navigating the Strait of Hormuz have been reporting suspicious navigation problems which may be the result of Iranian spoofing. Many theorize that Iran uses spoofing to lead unsuspecting vessels into Iranian waters where they may be captured. This article from The Economist mentions Dr. Humphreys’s experiments in GPS spoofing as the first public demonstrations of such technology.
May 2021: Ligado, an American communications company, received approval from the FCC in 2020 to build a terrestrial 5G network which will operate in the spectrum adjacent to GPS. Many worry that Ligado’s network will inadvertently jam GPS receivers because the frequencies are near one another and Ligado’s signals will be much stronger. Interestingly, the FCC only requires Ligado to pay for accidental damages to federal GPS users. This has sparked a wave of controversy, considering that private companies would also suffer substantial losses if their GPS-dependent systems are disrupted. Read the article from RealClearMarkets here.
May 2021: German broadcasting station Südwestrundfunk (SWR) featured Dr. Humphreys in their news report on GNSS spoofing. In his interview, Dr. Humphreys explains the leading theory on GNSS spoofing in Syria: that the Russian military has been deploying a “bubble of GPS spoofing” to help protect Vladimir Putin on his visits there. Watch the news broadcast on YouTube here.
This report, entitled “Above Us Only Stars,” is an in-depth review of the Russian spoofing activity. The RNL was a major contributor to this report.
RNL member Matthew Murrian’s paper “GNSS Interference Monitoring from Low Earth Orbit” describes how the RNL detected spoofing activity in Syria via a receiver on the International Space Station.
April 2021: The prevalence of unmanned aerial vehicles has caused a plethora of safety and regulatory problems in recent years, which is why several companies are developing counter-UAV technologies. Some of these use kinetic methods to disable offending drones, but others use microwave radiation to either jam or disable the drones’ onboard electronics.
“A ray gun that can fry a drone’s electronics at hundreds of meters sounds like something Tony Stark would invent” says Dr. Humphreys.
Amazing as it sounds, such devices are being developed today. But companies seeking to test their devices are being denied by the FCC and referred to the National Telecommunications and Information Administration (NTIA), which has jurisdiction over military spectrum experiments. Read the IEEE Spectrum article here.
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.”
October 2020: Check out our videos page for an update on the Radionavigation Lab’s research! We’ve been working hard to produce short video summaries of our recent papers. Enjoy!
October 2020: This recent article from BBC explores the modern world’s dependence on GPS and some possible position, navigation, and timing alternatives. We depend on GPS for everything from turn-by-turn navigation to banking transactions, but the system has some critical vulnerabilities to jamming and spoofing.
“There is a growing recognition of the need to protect, toughen, and augment GPS,” Humphreys said, “There is also the remote threat that the whole GPS constellation could be rendered inoperable in the initial salvo of a war targeting the US economy by attacking critical infrastructure.”
Many research groups are developing possible alternatives like terrestrial, inertial, and even celestial navigation, but none of these have been able to fully replace GPS.
October 2020: Dr. Peter Iannucci’s recently-submitted paper, Fused Low-Earth-Orbit GNSS, was highlighted in the MIT technology review for its expected impact on the US Army’s navigation technologies. The paper proposes to leverage low-earth-orbit internet constellations, like SpaceX’s Starlink, to provide strong, jam-resistant positioning signals that augment the existing GPS. The need for this augmentation is emphasized by the recent emergence of low-cost GNSS jammers and spoofers, which have been appearing across the globe. Dr. Iannucci and his coauthor Dr. Humphreys are optimistic that this technology will prove indispensable for high-integrity navigation.
