As the battlespace moves into a more digital and information-packed state, all warfighting organizations need to seek ways to stay ahead of their competitors. Offensive and defensive information warfare technologies must be prioritized. In particular, the U.S. Navy should pursue a novel antijamming method using synergistic sensor nodes on uncrewed surface vessels (USVs).
New sensor technology is often required to combat ever-evolving cyber threats. USVs depend on global navigation satellite systems (GNSS), known for their safety and security vulnerabilities.1 Malicious attacks that interrupt the operations of cyber-enabled USVs could lead to major environmental and financial damage—even risks to human safety.2 Antijamming synergistic sensor nodes with artificial noise could protect against third-party actors jamming signals needed for effective communication with the GNSS. This could help reduce or eliminate the cost incurred when cyberattacks impede the operations of important USV systems.
GNSS play a pivotal role in providing positional information to USVs for safe navigation and to keep them on predetermined routes.3 The GNSS is vulnerable to a multitude of intrusions such as denial-of-service (DOS) attacks that disrupt a network’s service, package changes that compromise a router and direct it to discard packet information rather than relaying it, and man-in-the-middle attacks in which attackers position themselves between a system and a user to intercept information passing between them. Jamming is a special type of DOS attack that prevents legitimate nodes from transmitting or receiving important data.4 A GNSS failure can lead to a breakdown of many other systems on board a USV, such as the automatic identification system.
Antijamming Nodes
The antijamming synergistic sensor nodes are capable of data retrieval, transmission, and processing, which enables the novel antijamming technique. This technique involves deploying artificial noise through the nodes to an adversary’s jammer, degrading its ability to decode sensitive information from the data packets. As the signal is passed between legitimate users, the jammer is unable to properly process the signal. Because of the amount of artificial noise the sensors produce, the jammer is unable to properly decode the transmission because of the low signal-to-noise ratio, but the technique does not degrade the packet-send and -delivery ratios at the legitimate transmitter and receiver.5 The degradation of the jammer’s decoding ability prevents an adversary from launching another timely attack that would disrupt the transmission of a signal to GNSS and shut down the system.
Current antijamming methods include a frequency-hopping spread spectrum that transmits radio signals by changing frequencies and antenna polarization with directional transmission methods that specify the direction of signal polarization to inhibit the jamming. Both methods rely on additional hardware that can be corrupted by an invasion inside the transmitted signal, such as from a GNSS. However, the proposed sensor method can block an attack even if it comes from the inside because the nodes are equipped with omnidirectional antennas that can send out the artificial noise in any direction with no specified target. Attaching these nodes to USVs could strengthen security for the weak and vulnerable unencrypted signal on which the GNSS relies.
Furthermore, the technology could also be applied to important sensors on board the USVs themselves. The method and technology could possibly be applied to many different sectors of the autonomous vehicle industry in the ever-growing cyber threat environment.
One challenge the technology faces is the cost of power consumption. As the nodes are continuously sending out artificial noise, they use more power than for what they were originally adapted. Also, the amount of artificial noise the nodes produce could change depending on the proposed application in different markets.
The Navy should explore synergistic sensor nodes to protect a USV’s data transmission to and from GNSS as it builds a larger uncrewed fleet. This and other potential methods are urgently needed to thwart or limit cyber attacks on USV navigation and operations in a rapidly evolving unmanned systems era.
1. Tope Omitola et al., “Securing Navigation of Unmanned Maritime Systems,” paper presented to the Proceedings of the 11th International Robotic Sailing Conference, Southampton, UK, 2018, 53–62.
2. Frank Akpan et al., “Cybersecurity Challenges in the Maritime Sector,” Network 2, no. 1 (March 2022): 123–38.
3. Septentrio, “Top 3 Positioning Challenges in Autonomous Marine Navigation,” Septentrio.com, 2022.
4. Liang Pang and Zhi Xue, “A Novel Anti-Jamming Method in Wireless Sensor Networks: Using Artificial Noise to Actively Interfere the Intelligent Jammer,” paper presented to the 4th International Conference on Systems and Informatics, Hangzhou, China, 11–13 November 2017, 954–59.
5. Pang and Xue, “A Novel Anti-Jamming Method.”
