GNSS
Jamming
How Does GNSS Jamming Work?
GNSS jamming is carried out by producing Radio Frequency signals that are strong enough to overpower transmissions from GNSS satellites. Since GNSS signals are sent from orbit, typically from more than 20,000 feet above the surface of the Earth, they must travel long distances before reaching ground stations or receivers. This ultimately creates a low power signal and makes them vulnerable to radio interference or carry-off attack (a common GNSS spoofing attack).
While real satellite signals can be jammed unintentionally, it is often a deliberate action, and more people and entities are beginning to adopt GNSS jamming strategies to support their goals - most often to prevent a device, vehicle, ship, or aircraft from being tracked.
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Typically, GNSS satellites operate in three Radio Frequency bands: L1, L2, and L5. While most existing GNSS satellites operate in the L1 or L2 bands, newer satellites are being developed that operate in the L5 band.
Since GNSS and GPS devices use relatively weak RF signals, all sorts of RF interference can severely disrupt or alter velocity, timing, and position data - ultimately leading to inadequate global positioning and navigation.
Depending on the application of interference, the possibility of causing harm or economic loss is high, as much of our world's critical infrastructure is intertwined with GNSS systems.
Who Typically Jams GNSS Signals?
There are numerous different reasons someone might want to jam a GNSS signal, the most common being those operating vehicles, ships, or aircraft that do not want to be tracked. ​
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Some truck drivers use GPS jammers when they want to avoid monitoring by their company, while others with more vague concerns choose to use jammers to avoid government tracking.
So, while there is no defined and limited base of who benefits from and carries out GNSS jamming, it is important to consider the wide range of applications that may benefit from such actions.
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While illegal in the United States, instances of minor GNSS and GPS interference are becoming relatively common - mostly due to how easy GPS jammers are to find and buy from online outlets.
Types of GNSS Jamming
GNSS signals can be jammed or interrupted intentionally or unintentionally.
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Unintentional jamming or unintentional interference is typically credited to the rapid growth of wireless technology and is often caused by nearby electronic devices broadcasting at a frequency that is strong enough to disrupt the L-band of the transmitted signal.
Intentional GNSS interference, on the other hand, are primarily carried out in one of two ways: Jamming or Spoofing.
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GNSS jamming knocks out the ability of a GNSS receiver to receive a signal, while GNSS spoofing broadcasts false signals that trick the target receiver with fake location and/or time stamps.
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Dangers of GNSS Jamming
GNSS and GPS jammers pose numerous risks to users and the public.
For example, when a GPS jammer is being used, it can prevent people from dialing 911 in emergencies.
Jammed signals could prevent a drone from flying on target, potentially resulting in a crash in a crowded area, and they could even disrupt communications between law enforcement and other authorities, which poses a significant risk to public health and safety.
Simply put, there are countless ways in which jammed GPS signals could pose a health or safety risk.
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Apart from public safety, GNSS jamming poses a significant economic risk - as GNSS technology is part of nearly everything we do in the modern world.
If a jammed GNSS signal disrupted a single ship or even a shipping fleet, for example, the economic losses probably wouldn't be catastrophic outside of the organization. However, if a far-reaching maritime navigation disruption were to create widespread complications, the losses could within the maritime sector be crippling.
Construction is another sector that could see huge economic losses if a widespread GPS disruption occurred. According to research conducted by the Rand Corporation, the construction sector in Houston alone could see losses as high as $85 million per day during such scenarios.
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While illegal, GNSS and GPS jammers can be found relatively easily online, creating a significant cause for concern and making it imperative for authorities to have the technologies and resources available to monitor, identify, and track potential threats.
