As is the case with electricity and communications, society has been deeply involved and ‘decisively engaged’ with technology-based Position, Navigation, and Timing (PNT) services. PNT services are critical to nearly all sectors that comprise the nation’s critical infrastructure.  Disruption of or interference with these systems adversely affects individuals, businesses, and the nation’s economic and national security.

However, the ubiquitous use of the Global Positioning System (GPS) as the primary source of PNT information makes these sectors vulnerable to adversaries seeking to cause harm by disrupting or manipulating the GPS signal and to the effects of coronal mass ejections or, more commonly, solar flares. Risk assessments conducted by government, commercial, and utility emergency planners should address the following hazards, fragility, and consequences.

Hazards.

GPS signals can be intentionally disrupted by an adversary through jamming or spoofing. Jamming blocks the signals and spoofing sends false signals to mislead receivers. Both methods can be used to disrupt location, navigation, and timing services.

Space weather can also disrupt GPS services, which can damage electronics, disrupt satellite-to-ground communications, or move satellites out of position. An adversary can target GPS signals to aggravate conjunctive disruptions to emergency services following a large terrestrial storm or grid restoration efforts following a large outage. Planners should expect GPS disruption during a cyberattack as both attacks share many attributes in common.

Fragility.

GPS signals are relatively weak when they reach the Earth’s surface, making them susceptible to interference from natural and man-made sources. Furthermore, reliance on a single system, like GPS, creates a single point of failure for the PNT services.

Consequences.

Loss of PNT services from disruption to GPS can lead to significant economic losses, cause cascading effects crossing critical infrastructures, and severely hinder response and recovery efforts following a natural or intentionally caused disaster-level event. 

Explore the cost of unpreparedness: economic impacts of infrastructure failures here. 

Mitigation Strategies

The major vectors for mitigating the consequences of PNT disruptions include creating awareness, developing resilience, investing in redundancy and diversification of PNT service sources, and implementing policies to ensure protection.  Mitigations regarding the loss of PNT services should be incorporated into emergency response and continuity of operations plans, as well as exercises. Emergency planners should recognize the close dependencies existing among electricity, communications, and PNT services and how the loss of any can adversely affect others.

The Cybersecurity and Infrastructure Security Agency (CISA), in conjunction with the Department of Defense (DoD), the National Institute of Standards and Technology (NIST), and the Department of Homeland Security Science and Technology Directorate have developed a large body of knowledge on mitigating PNT risks and on building resilience.

Emergency planners and interested readers should become familiar with the published PNT resilience resources. 

By: John Organek