Two satnav superpowers battled it out aboard a superyacht in the Mediterranean this summer, as a spoofing detector designed to differentiate between real and fake GPS signals came to grips with a spoofing device previously responsible for hijacking a sophisticated drone helicopter, deceiving it into landing when it was trying to hover, and for misdirecting the same luxury yacht in tests last summer.
Mark Psiaki, Cornell University professor of mechanical and aerospace engineering, and graduate student Brady O’Hanlon spent a week aboard the White Rose of Drachs, a luxury superyacht, testing their second-generation spoofing detector as the boat cruised from Monaco around the boot of Italy to Venice at the head of the Adriatic Sea. Also on board was a researcher from assistant professor Todd Humphreys’ Radionavigation Laboratory at the University of Texas at Austin. Humphreys tested his latest spoofer aboard the same yacht last year; this year, Psiaki and O’Hanlon embarked for a follow-up experiment to see if they could outsmart the spoofer.
Both researchers have published earlier versions of their work in GPS World magazine, Psiaki in “GNSS Spoofing Detection,” the Innovation column in the June 2013 issue, and Humphreys in “Drone Hack” in the August 2012 issue.
The former story relates how Humphreys and Psiaki began their investigations as far back as 2008. “There was no intention to help bad actors deceive GNSS user equipment. Rather, our goal was to field a formidable ‘Red Team’ as part of a ‘Red Team/Blue Team’ (foe/friend) strategy for developing advanced ‘Blue Team’ spoofing defenses.”
In international waters this summer, the Cornell and Texas teams could conduct their research unhindered; on land, it’s very difficult to get permission to hack a GPS signal, even for research purposes, Psiaki said.
Aboard the White Rose, Humphreys’ team initiated an attack of the boat’s GPS receiver, overlaying a disguised false signal on top of the real one, and attempting to send the boat off-course without generating any obvious warning signs. Stationed in a different area of the boat, Psiaki and O’Hanlon’s device set itself to detect the false signals through real-time analysis of their properties, and to provide protection against any attack by issuing a definitive warning whenever false signal characteristics were identified.
“We tested numerous spoofing scenarios,” recalled Psiaki. “We proved the efficacy of the new two-antenna version of one of our spoofing detection systems. It is the functional equivalent of our previous moving-antenna spoofing detection system. With two antennas we can simulate the effects of antenna motion without any need for moving parts. The only problems we encountered were with the initial spoofing drag-off, at which point the true and spoofed signals interfere with each other, and signal tracking can be tricky.
“We recorded wide-band data for all these cases. We think that we know how to enhance our defenses to hold on to the signals and recognizing spoofing during the initial drag-off. We also think that we know how to recover the true signals after an attack. The recorded wide-band data should enable us to develop and test these refinements in the lab, i.e., without the need to go back to sea — not that we would mind having to take another cruise on the White Rose of Drachs.”
In one test, the yacht’s GPS receiver was spoofed into believing that it was veering off its course, set northwards to Venice, and heading south to Libya at a very high speed. The Cornell detector was able to warn the White Rose’s bridge crew about the attack before the yacht was 20 meters off course.
“We want to progress to the point where not only can we tell it’s a false signal, but we can also say, ‘Here is the true signal; here is the true position,’” Psiaki added.
The owner of the White Rose of Drachs, an anonymous businessman, allows the boat to be used for scientific purposes during off seasons.
Psiaki will present a paper on the superyacht experiments at the Institute of Navigation’s GNSS+ conference in September in Tampa, Florida, and GPS World will publish an article based on this paper in the November issue.
This story draws on initial reporting by Anne Ju in the July 28 Cornell Chronicle, with additional material and photos supplied by Mark Psiaki.