We don’t realize how heavily dependent we are on GPS in our car navigation systems, our location-based smartphone apps, the timing of our access to cell towers – until the technology experiences interference and failures.

Global navigation satellite system (GNSS) signal interference, which can be accidental or intentional, has the potential to cause widespread delays in taut supply chains and cascading failures across GPS-timing-based networks. Jamming occurs when GPS signals are overpowered locally by other radio frequency signals so that the receiver can no longer operate. Spoofing can be even more dangerous, as the receiver is tricked into calculating a false position. 

While this may be a mild annoyance for some, jamming or spoofing signals can wreak havoc across multiple modes of transportation infrastructures, including commercial ships, trains, and shipping trucks. In 2021 alone, a major aircraft manufacturer reported more than 10,000 GNSS interference events.

To enhance the resilience of transportation infrastructure against such cyber-physical threats and develop advanced countermeasures for GPS jamming and spoofing, the Department of Transportation has awarded a multi-university partnership $10 million in federal funding and $5 million in cost-share to create a new Tier 1 University Transportation Center. 

The new Center for Assured and Resilient Navigation in Advanced Transportation Systems (CARNATIONS) will be led by Illinois Institute of Technology and includes university partners:

  • Virginia Tech
  • Stanford University 
  •  Chicago State University
  • University of California Riverside

The goal

The consortium of university partners aims to enhance the resilience of transportation infrastructure against cyber-physical threats and develop advanced countermeasures for GPS jamming and spoofing. 

“GPS is the most precise clock we have, accurate down to the nanosecond,” said Mathieu Joerger, assistant professor in the Kevin T. Crofton Department of Aerospace and Ocean Engineering. “If the accuracy of the timing is jeopardized, it can alter the performance of cell phone towers and electrical grid monitoring systems. On more than one occasion, navigation accuracy degradation has had costly cascading effects including runway shutdowns, stressed air traffic management systems, and customer travel delays. It is critical that we preserve GNSS accuracy and protect it from spoofing and jamming incidents.” 

Virginia Tech’s voice

This research brings together a group of GNSS, communication, cyber-resilience, and transportation experts from across the College of Engineering and the university, whose expertise lies in high integrity resilience in positioning, navigation and timing. 

While GNSS research at Virginia Tech has been typically geared toward the aviation and military sector, the team aims to utilize methods to protect, toughen, and augment position, navigation, and timing technology for applications in surface vehicles. The team of faculty experts includes

  • Joerger, an expert focused on investigating multisensory localization safety for autonomous transportation systems, including high-integrity GNSS based vertical guidance for aircraft
  • Mark Psiaki, whose expertise spans GPS/GNSS signal processing, security, estimation and Kalman filtering, and inertial navigation
  • Laura Freeman, whose research brings together cyber-physical systems, data science, artificial intelligence, and machine learning to address critical challenges in national security
  • Hesham Rakha, an expert in transportation infrastructure and systems engineering, specifically large scale transportation optimization, modeling and assessment
  • Walid Saad, whose research interests include wireless networks, machine learning, security and resilience, unmanned autonomous vehicles, semantic communications, and cyber-physical systems

According to Joerger, the collective group plans to tackle the GNSS interference issue from several angles, including developing sophisticated algorithms that can tell the difference between authentic or spoofed GPS signals and improving GPS receivers by combining them with other types of sensors that are immune to jamming and spoofing.

“Our group is looking to toughen, augment and protect GPS systems,” said Joerger. “We will toughen position, navigation, and timing with new GNSS antennas and receiver signal processing, augment through multisensor systems and space-based radio-frequency beacons, and protect via machine learning and vehicle collaboration.”

Casey Smith and Sandeep Jada work on a multi-sensor system, to be affixed on a roof rack of a vehicle for field testing.
Casey Smith (at left) and Sandeep Jada work on a multisensor system to be affixed on a roof rack of a vehicle for field testing. Virginia Tech’s team previously partnered with the Town of Blacksburg to deploy GNSS interference monitors in the Blacksburg area. The multi-sensor system includes lidar, radar, GPS and inertial navigation to capture data, with the goal of making GPS systems more robust. Photo by Jama Green for Virginia Tech.

The CARNATIONS partners will be completing comprehensive testing and evaluation of resilient systems across a number of university research facilities. At Virginia Tech, the group will use the Virginia Smart Roads, a state-of-the-art, closed test bed research facility at the Virginia Tech Transportation Institute, to complete field testing with one or two vehicles and a radio frequency testbed. 

Results from the field testing will then be implemented into Virginia Tech’s multimodal agent-based simulation software, INTEGRATION for “war-gaming” exercises. Within a virtual environment, faculty and students will model jamming and spoofing attacks to assess the impact on the transportation system performance as well as execute defenses to resolve the issues created by these cyber attacks. The team will develop mitigation strategies to detect weaknesses and strengthen transportation and communication networks from instances of signal interference. It aims to prevent network-wide disruptions and also to look into ways to make the transportation system more resilient to such attacks.

The team also will prepare current and future transportation professionals to tackle such interference challenges. Building upon existing cybersecurity programs at the National Security Institute at Virginia Tech, training for undergraduates, graduate students, and professionals will be held to address current cyber-physical threats and anticipate future attacks on position, navigation, and timing in transportation systems.

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