Faraday Cage: What Is It and How Does It Affect GPS Trackers?

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You may have vaguely heard of this phenomenon: the Faraday cage. But what is it really? For those who are not familiar, the Faraday cage is a fascinating invention based on the ability of certain materials to block electromagnetic fields.

Its principle relies on the ability of conductive materials, particularly metals, to redistribute electric charges on their surface, thus preventing electromagnetic fields from penetrating inside. In simple terms, a Faraday cage works like a shield that blocks waves, whether they are radio, Wi-Fi, or GPS.

In everyday life, the Faraday cage is used in many contexts: it protects sensitive equipment in laboratories, minimizes interference in sensitive infrastructures, and can even be exploited for security purposes.

But what happens when this technology encounters another device based on signal reception, like a GPS tracker? The answer comes from Martin, Embedded Software Engineer at Invoxia!

How Does the Faraday Cage Affect GPS Trackers?
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GPS trackers are devices designed to track and locate objects or vehicles. At Invoxia, they operate thanks to various surrounding WiFi networks, but also via signals sent by a network of satellites orbiting the Earth. By capturing these signals, GPS trackers can determine the exact position of the object they are tracking.

However, the very principle of the Faraday cage poses a problem for GPS trackers. Indeed, by blocking electromagnetic waves, a Faraday cage prevents GPS and WiFi signals from reaching the tracker. This means that when placed inside a metallic structure or any other conductive object acting as a Faraday cage, it becomes unusable for localization.

In What Contexts Can the Faraday Cage Apply to GPS Trackers?
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The principle of the Faraday cage can be accidentally or intentionally applied to GPS trackers in many situations. Here are some concrete examples:

Cars with tinted windows: Some cars are equipped with windows treated with metallic particles to reduce glare or improve thermal insulation. While this may enhance passenger comfort, these windows can also block GPS signals, especially if the tracker is poorly positioned inside the vehicle.
Anti-tracker pouches: These devices, increasingly used for malicious purposes, function as portable Faraday cages. They are designed to block GPS signals and prevent the tracking of stolen objects or vehicles. Such accessories become common tools to thwart GPS tracking systems if spotted by the thief.
Security cases: Some cases designed to protect sensitive documents or objects may be made from conductive materials to shield the contents from electromagnetic interference. However, this can also block GPS signals if a tracker is placed inside.

These situations, all quite different from one another, show how a Faraday cage can compromise the effectiveness of GPS trackers. The challenge is to understand how to prevent this type of protection from disabling your tracking device.

Fun fact: At Invoxia, we intentionally use Faraday cages to enhance the service we provide to you! Indeed, our features are developed under good conditions, in urban areas, which sometimes does not allow us to detect issues occurring during the life of the GPS tracker. One use case can be to simulate white zones, or areas with low coverage, to replicate the usage conditions of people in rural or mountainous areas.

Martin, Embedded Software Engineer

Faraday Cage: its principle and effects on GPS trackers explained — Our engineer Martin uses a Faraday Cage to demonstrate its effects on GPS trackers

Faraday Cage: How to Avoid the Bad Surprise on My GPS Tracker?
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When you place your GPS tracker in your car or motorcycle, for example, it often happens that the location is not ideal. Indeed, these vehicles are largely made of metal, and the Faraday cage can quickly become a concern. But how can you avoid this when hiding your GPS tracker inside?

Positioning GPS Trackers
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The positioning of the tracker plays a crucial role in its ability to capture GPS signals. If a tracker is poorly positioned, particularly inside or near metallic objects, the GPS signal can be weakened or even completely blocked.

To ensure optimal localization, it is recommended to place the tracker in areas where it will not be subjected to interference. In a vehicle, for example, compartments close to the windows, the windshield, or even the dashboard (when it is not metal) can be safer locations.

Here are some ideas for hiding your GPS tracker in a car:

In a kangaroo pocket at the back of a seat
At the back of a headrest
Under the passenger seat
In a tissue box placed on the dashboard
In the central armrest

And to improve the performance of your GPS tracker, preferably place it with the logo facing outward!

Faraday Cage: choose a location with little metal around — The format of Invoxia’s GPS tracker allows it to discreetly fit into the central armrest.

Avoid Anti-GPS Pouches
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One of the main ways to prevent a GPS tracker from functioning is to use anti-GPS pouches, which exploit the principle of the Faraday cage to block incoming and outgoing signals. Although these devices are often used for malicious purposes, it is important to raise awareness among tracker users about this threat.

Indeed, you may be tempted to opt for a protective pouch for your GPS tracker. But be cautious about the materials used for it. If you have chosen an GPS Tracker Classic or Pro from Invoxia, it is possible to equip them with their own protective pouch. And the bonus with this one? It is completely waterproof!

Learn More

And that’s it for this detailed explanation from our engineer Martin! Now that the principle of the Faraday cage and its effects on GPS trackers are no longer a secret to you, all you have to do is follow our recommendations for optimal use of your devices.