The incredible disappearing car: combating GPS jammers
What is a GPS Jamming Device? Learn how Geotab detects and eliminates threats from GPS jammers. See what GPS jammers looks like in MyGeotab.
GPS tracking technologies are on the rise as new innovations continue to be developed. With the prevalence of smartphones and IoT devices, every location, online search, visited website and purchase made is being tracked. While many people are willing to share their location for good purposes, there is another set of people who want to hide their location.
What is a GPS Jammer?
A GPS jammer is a device used to conceal one’s whereabouts by sending radio signals with the same frequency as the GPS device. Once this occurs, the GPS device is unable to determine its position due to interference.
The GPS jamming unit itself is typically a small, self-contained, transmitter that generates a 1575.42 Mhz interference signal over a 5 to 10 meter radius.
Typically, the user plugs the jammer into a cigarette lighter and places the unit close enough to a GPS tracker to disrupt the GPS satellite signal. Once powered up, they become fully operational in less than 20 seconds. The relatively low power and quick start up time allow the jammers to be used only when required. Criminals will switch them off as soon as possible to avoid detection. These jammers can be purchased cheaply on the Internet for less than $100.
Although the purchase of GPS jammers is strongly discouraged, various types of jammers are available for purchase online, such as physical shields, Wi-Fi/Bluetooth jammers, remote control jammers, spy camera jammers and drone jammers, just to name a few.
To law enforcement and the transportation industry, GPS jammers are both a nuisance and cause for concern. Jamming interferes with GPS vehicle tracking, also known as fleet tracking or telematics, which is critical source of business data to many companies.
Open platform telematics is more than simply vehicle tracking — it’s the collection of data on fuel use, idling, driving behavior, engine health and other aspects of the vehicle and operations. This vehicle data is essential for helping companies manage a fleet of vehicles and achieve goals such as improve driver safety, productivity, efficiency, or compliance. Read more about the benefits of telematics here.
Who Uses GPS Jammers?
Originally created by the government, GPS jammers were designed for military endeavours in which concealing vehicle location was crucial to the success of a mission. The jammers act as a “cloak” giving the military privacy, increased safety and an overall advantage in high-risk situations.
The reasons for jamming are varied. Some speeders may use jamming to try to prevent detection by police and avoid fines. Criminals use GPS jammers as cover for vehicle theft or illegal activity. In the fleet world, GPS jamming could be used by a driver to prevent the employer from knowing where there are going with the company vehicle.
Are GPS Jammers Legal?
U.S. and Canadian law both prohibit jamming devices. In the U.S., the federal Communications Act of 1934 outlaws the marketing, sale, or use of a jammer. The Canadian Radiocommunication Act (Sections 4, 9 and 10) prohibits the importing, manufacturing, distribution, selling, possession and use of radiocommunication jamming devices in Canada.
Harsh penalties exist for using a jammer. In the United States, penalties for jamming range from fines up up to $112,500 and even jail time, depending on the gravity of the offense. Canadian legislation allows for a fine up to $5,000 and/or imprisonment for an individual, and up to $25,000 for corporations based on conviction.
Not only is the use of jammers unethical and illegal, but it can also be potentially dangerous. In one case, a New Jersey truck driver was fined almost $32,000 by the Federal Communications Commission (FCC) when the GPS jamming device he was using in his work truck at the Newark Liberty International Airport interrupted air traffic control information. The driver was using the jammer to hide his location from his employer, who had installed a GPS vehicle tracking system in the truck. An FCC investigator was able to locate the jammer using radio monitoring equipment and prove that it was causing interference.
See Also: Is Your GPS Tracker Device Safe?
Where in the World Am I? How a GPS System Works
To understand how a jammer functions, we must first understand how the global positioning system (GPS) works. A GPS tracker receives microwave signals from an array of satellite transmitters orbiting the Earth at an altitude of approximately 20,200 km. Once the tracker receives signals from four or more satellites, it determines its position through a series of time calculations and trilateration.
Figure 1: GPS satellite broadcasting signals.
The receiver relies on these precise and specific satellite signals to determine where it is in the world. The GPS tracking device then transmits this position and velocity information to a monitoring location. Usually, this data is communicated over the cellular network.
In some cases, satellite malfunction or solar flares can temporarily disrupt the transmission of GPS signals. A GPS jammer sends out a radio signals or signal noise with the same frequency as the GPS device, to override or distort the GPS satellite signals. The GPS device can then no longer calculate its position because the satellite signal is masked by the interference.
If you’d like to read more about GPS, see our Introduction to GPS technology.
How Geotab Detects and Eliminates GPS Jamming Threats
There will always be a segment of the population that wants to “fly under the radar” and attempt to defeat GPS tracking devices with GPS jammers. Fortunately, the negative effects and usefulness of jammers are minimized with Geotab devices.
Geotab’s GO device tracks vehicle location, amongst other important data related to the vehicle in question. The data collected through the GO device gets displayed in the MyGeotab software and it is here that users can see if GPS signal disruption.
When a GPS signal is not received, the Trips History map will show a missing or interrupted trip — clearly calling attention to an issue.
If GPS jamming occurs mid-trip, a straight line will be displayed from when jamming starts to the point where the jamming device is turned off. Anyone monitoring the vehicle will quickly see this and can investigate the cause of the missing trip information.
Figure 2: A straight line in MyGeotab indicates GPS disruption.
More immediate jammer detection is also available. The GPS module in later Geotab GO units has a jamming detection function that will trigger our device to report a debug log. This can be found in the log details of MyGeotab, appearing as: GpsJammingDetected.
For simplified monitoring of GPS related issues, an exception rule can be created in MyGeotab. For example, you can add a new rule that looks for these two faults:
- Telematics device fault: GPS quality poor (bad device install or vehicle undercover), and
- Telematics device fault: Remove device and report to Reseller - GPS module not responding. This rule can be setup to trigger an alert or email for the event and be included in a scheduled report displaying these faults and exceptions.
It is important to note that a GPS jammer disrupts GPS receiver functionality but all other functions are unaffected. Despite the lost GPS connection, the Geotab GO device will continue to gather and send critical vehicle-related data such as engine data, error codes, and auxiliaries, etc.
Geotab is dedicated to maintaining a robust and stable system and will continue to make its Geotab GO devices as tamper-proof as possible. To learn more about Geotab’s security policies, please visit the Geotab Security Center page.
- FCC, (n.d.). GPS, Wi-Fi, and Cell Phone Jammers: Frequently Asked Questions (FAQs). Retrieved from: https://transition.fcc.gov/eb/jammerenforcement/jamfaq.pdf
- How do GPS Jammers Operate. (n.d.). Retrieved from: https://www.thesignaljammer.com/pages/How-GPS-Jammers-Work.html
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Geotab's blog posts are intended to provide information and encourage discussion on topics of interest to the telematics community at large. Geotab is not providing technical, professional or legal advice through these blog posts. While every effort has been made to ensure the information in this blog post is timely and accurate, errors and omissions may occur, and the information presented here may become out-of-date with the passage of time.
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