Asset Tracking

GPS Blockers, Scramblers & Signal Jammers: How to Combat these Devices

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In August of 2013, a New Jersey man was fined $32,000 by the Federal Communications Commission for operating a GPS blocker. The FCC revealed that the man, a driver using a work-supplied vehicle, had “claimed that he installed and operated the jamming device in his company-supplied vehicle to block the GPS … system that his employer installed in the vehicle.”

Gizmodo, a tech news source, looked into GPS tracker jammers and found they are “dangerous, cheap, and easy [to obtain and operate].” They are also illegal, but that doesn’t stop people, including drivers, from using them. Beyond harming your business, GPS scramblers can interfere with emergency service frequencies used by 9-1-1, ambulance, fire, and police services. GPS signal jammers have even been responsible for disrupting airplane navigation.

The use of GPS jamming devices may be more widespread than you thought. According to a 2012 study (known as the Sentinel Project), there are between 50 and 450 instances of GPS tracker jamming across the United Kingdom every day. Fleet drivers and truckers were responsible for 90% of those instances. Another study done in 2014 by Rohde & Schwarz found that around every 3rd truck on a major highway in the United States was broadcasting at the same frequency as GPS—and implied that these trucks were likely using GPS signal jammers.

What are GPS Blockers, Scramblers & Signal Jammers?

In order to understand how GPS blockers work, it helps to be familiar with how GPS works. GPS stands for Global Positioning System and functions using the Global Navigation Satellite System (GNSS) network. A GPS tracker works by connecting to the GNSS network. GPS signal jammers send out a radio signal at the exact same frequency as the GPS device which overrides the signals sent out by the satellite. When this occurs, a GPS tracking device is unable to determine its exact location because the scrambler is interfering with its signal.

GPS jammers disrupt all functions of GPS systems including navigation and tracking.

GPS blockers are generally small in size and simple to install. They take less than a minute to power on and can be discreetly installed and removed. Under federal law, they are illegal and using one can cost individuals fines or imprisonment. Despite this, GPS tracker jammers are widely available and often cheap.

Four Types of GPS Blockers

The easiest way to stop a GPS tracker from working is to destroy the device so it can’t function. However, there are many ways to achieve a similar result in a more discreet way by using technology. Here are four types of GPS blockers:

1. A Metal Box

The simplest way to stop a GPS tracking device from functioning is to place it in a metal box. Any electrically conductive metal will reflect and absorb the device’s incoming and outgoing signals and interfere with its operation. Wrapping a GPS tracker in aluminum foil is enough to do the job—although copper and even silver work as well. This is an incredibly cheap and easy method of GPS jamming. However, the perpetrator must have physical access to the GPS device to use this method.

2. GPS Scrambling Gadgets

GPS scrambling gadgets are widely available online for less than a hundred dollars. These devices are simple to operate and can be discreetly installed and removed. They emit a frequency that blocks incoming and outgoing GPS signals and jam GPS devices from functioning properly.

3. Mobile Phone Jammers

It may surprise some to know that cell phones also use GPS signals. Mobile phone jammers prevent the exchange of real-time location information—one of the most important data points for monitoring drivers. Cell phone jammers are also widely available online, however, this technology is much more expensive than other options.

4. GPS Spoofing

GPS spoofing devices send out fake GPS signals which traditional tracking devices pick up and understand to be true. Brent Ledvina, professor of electrical and computer engineering at Virginia Tech, said GPS spoofing is “almost like someone nearby is spoofing your favorite radio station by transmitting at the same frequency but higher power, fooling your receiver into believing it is getting the right station.”

GPS Fleet Tracking that is simple to use, affordable, and powerful enough to run any size fleet

3 Tips to Combat GPS Blockers, Scramblers & Signal Jammers

Tip #1: Authorize Privacy Mode

Some drivers are authorized to use their work vehicle for personal uses in certain situations. For example, many drivers take their work vehicle home with them each night. In other circumstances, drivers may take an hour off for lunch to run errands and eat while using a company vehicle. In both of these situations and others, drivers use their work vehicle for personal use and may not want to be tracked. Many instances of drivers using GPS signal jammers are because they would prefer not to be tracked during these private times.

Many GPS tracking devices offer a “privacy mode” setting. This feature gives drivers (and dispatchers) the ability to hide their driving activity for a period of time. When enabled, a vehicle’s position, speed, and engine data will not be readily available. However, in exceptional circumstances, such as accidents, the data can be manually extracted in order to assist with investigations. Having privacy mode available mitigates the risk of drivers using GPS jamming devices in order to shield their personal data from their employer. 

Tip #2: Enable GPS Signal Jamming Detection

Some state-of-the-art GPS tracking devices have the capability to detect GPS signal jamming. Products like Azuga’s Fleet tracking software include signal jamming detection. This protective measure can detect the use of GPS and GSM (Global System for Mobile Communications) jammers. This feature helps prevent vehicle theft and even be used to retrieve stolen commercial fleet vehicles.

Tip #3: Find Employees Using GPS Scramblers Though Tracking Data

Even without jamming detection, you can still catch employees using GPS blockers. While drivers may think that using GPS scramblers makes them invisible, doing so actually draws more attention to their behavior.

When an employee uses a GPS blocker it shows up on the live tracking map or trip history map as a missing or interrupted trip. In addition, if the renegade employee activates their GPS jamming device during only a part of their trip a line appears from where the scrambler was started to when it was turned off. You can even create an exception rule that seeks out GPS signal errors and triggers an email alert when an interference happens.


GPS blockers can be a hindrance to fleet management. They are dangerous, inexpensive, and easy to acquire. Luckily, there are ways to combat these types of devices. Enabling privacy mode on your GPS tracker discourages employees from using GPS jamming devices to shield their movements while off company time.

High-tech models of GPS tracking devices contain signal jamming detection, a great tool for fleet managers to use against GPS signal jammers. You can also detect employees using GPS tracker jammers by reviewing drivers’ trip history and live map tracking. Hopefully, the tips in this article can help you detect any GPS blockers that may be in operation amongst your fleet.

By implementing smart technology, like Azuga’s fleet asset tracking software, managers will be able to keep tabs on their drivers at all times. This advanced software will easily track your assets of all sizes, boost productivity, and save your company thousands each year. Learn what the Azuga team can do for your company today.