The Global Positioning System (GPS) maintained by the US government is one of several Global Navigational Satellite Systems (GNSS). GNSS technology, including GPS, provides positional, navigational, and timing (PNT) data and supports a wide array of critical systems in transport, communications, finance, natural resources, safety and emergency services, location-based services, and the military.
In addition to the US GPS system, other GNSS systems that are planned, under development, or in place include GLONASS (Russia, in place), Galileo (EU, in planning), Compass (China, under development), IRNSS (Indian regional system, first satellite launched in summer 2013), and Japan’s Quasi-Zenith Satellite System (QZSS, regional, expansion under way).2 For simplicity, this brief uses the familiar GPS acronym to refer to any and all GNSS.
GPS failure—whether in whole or in part, whether briefly or for an extended period—is a possibility and would impact a wide variety of industries, government activities, and services that consumers have come to take for granted. Consequences could include everything from inconvenience to financial loss to public safety risk to inability to execute critical military missions. This brief explores the factors that could drive or impede a failure of the GPS system and possible outcomes and implications of such a failure.
3 KEY FINDINGS
- A wide array of critical systems in transport, communications, finance, natural resources, safety and emergency services, location-based services, and the military rely on GPS.
- GPS is vulnerable to brief or prolonged, local or widespread failure due to system issues, atmospheric interference, malicious attack, or failure to maintain the system.
- Consequences of GPS failure could be widespread and include everything from inconvenience to business disruption and financial loss to public safety risk.
A number of factors could contribute to the failure of the GPS system. Note that the GPS system includes three primary components—the ground, space, and user segments, all of which are vulnerable to various sorts of failures.
Failures may be related to the system (involving signals and receivers), to problems with signal propagation, and to accidental or intentional interference.
With regard to the latter, one consultant has suggested that the GPS security situation today is equivalent to the ICT security situation in the 1980s—in other words, it is at a relatively early stage of development. Another has noted that as sensitive, high- value GPS applications grow (e.g., asset monitoring), the motivation for intentional attacks will increase.
- System issues. Broadcast of incorrect information (e.g., due to inadvertent errors in data uploaded to satellites), incorrect processing of valid signals by faulty receivers, and failure of the receiver to locate enough visible satellites can all lead to location errors. Going forward, GPS systems will also depend on a variety of “overlay systems” added to enhance performance; these will also be subject to failure.
- Atmospheric interference. Ordinary variations in space weather can generally be corrected for by GPS systems (or at least identified to avoid the dissemination of unreliable information), but a major solar flare event could have widespread, long-lasting impact on many parts of the electric and electronic infrastructure, including GPS. Catastrophic solar flare events are estimated to occur every 200 years or so; the last one took place in 1859.
- Satellite attack. GPS receivers need contact with at least four satellites; reducing the number of satellites below a critical level significantly degrades system performance. Thus the GPS system is potentially vulnerable to attack by anti-satellite missiles taking out multiple GPS satellites. A number of nations have demonstrated or publicly announced plans to develop anti- satellite missiles.12 It should also be noted that an attack on the ground portion of the GPS system is also possible, though the facilities are built to withstand military attack.
3 POTENTIAL OBSTACLES
There are factors that may prevent GPS failures or provide alternate sources of PNT information.
- Defense imperative. The development of the GPS system was motivated by the need of the US military to precisely position missile launchers, whether submarine or ground- based.18 The need for GPS to support military technology makes the maintenance of the system a high priority.
- Redundant systems. Multi-signal receivers that tap into all four planned GNSS systems—GPS, GLONASS (Russia), Galileo (EU), and Compass (China)—to improve availability, accuracy, and system integrity will become the norm, making disruption of one system or an attack on a single satellite less of an issue.
- System improvements. Improved engineering of receivers, incorporation of additional correction techniques in position and time calculations, algorithms to detect jamming, and the use of additional satellites when available will help to detect and reduce errors.
3 BUSINESS IMPLICATIONS
- Businesses should consider creating contingency plans for an extended failure of the GPS system. They should seek to understand primary, secondary, and tertiary impacts of such an event, as well as how operations for their customers and key partners would be impacted. Consumer-facing companies need to understand how daily life—and purchasing—would be altered by this kind of wildcard event.
- Businesses should identify and map the nature and extent of their reliance on GPS. Because GPS has become deeply ingrained in infrastructure, many businesses may be unaware of the extent to which different functions in the organization depend on the technology—from procurement and supply chain professionals, to marketing groups that use mobile ads to offer consumers location-based deals.
- Businesses that depend directly or indirectly on GPS services should document the risks associated with outages of various extent and duration and, where appropriate, take action to mitigate the risks.