Why Use Signal Jammers?
There are many forces out there that may potentially want to track you with GPS units. Criminal suspects in a number of states may have their cars tracked, while convicted criminals may be required to wear GPS tracking units at all times. On a different note, you may want to keep yourself from being tracked by a crazed ex or a stalker if you enter into a potentially dangerous situation with them. Or maybe you want to take that company car (or rented car) where you aren’t precisely supposed to, perhaps for an unauthorized lunch break. Or maybe you just don’t want to be tracked on principle and have a well developed sense of privacy. There are plenty of potential reasons to use them, and plenty of potential legal arguments for and against any of them.
Despite some seemingly obvious legal issues, there have been no official rulings with regard to their legality in the US. While their existence has been noted by the FCC, they have only taken action against one individual who has sold GPS jamming devices. The legal basis for the ruling on the case was that the marketing of these devices was in breach of the Communications Act of 1934, which prohibits blocking or interfering with radio communications, under which GPS units clearly fall. However, since then, no official rulings or statements have emerged from the FCC or the US government in general specifically with regards to GPS jamming devices.
In other countries… well, it’s a different picture. Due to their enormous potential for misuse, especially by terrorists who would wish to confuse military aircraft, missiles, and other devices that utilize GPS, many countries have made them strictly illegal. For information on individual countries other than the US, please research independently.
Something that many people bring up is potential jamming of military GPS signals by civilian jammers, which would be a big no-no with regards to national security and possibly considered a terrorist threat – not the best legal mess to get yourself into. However, civilian GPS units use a very different radio frequency than military units, and so, commercial GPS jammers are designed to block civilian units only. That being said, many military GPS units do use the civilian GPS frequency to log onto the GPS network. This could spell out potential conflict between military use and civilian jammer use.
This is all assuming you’re attempting to block civilian units only, of course. Intentionally jamming military units…. is a whole other can of worms. For some perspectives on GPS jamming warfare, check out this article from GPS world.
A Future for GPS Signal Jamming?
While the capability to jam GPS signals hasn’t entirely hit mainstream consciousness quite yet, there are already overtures towards the ability to detect any GPS signal jamming, and even methods of triangulating such interference. Plans could potentially include a built-in ability by all GPS devices to transmit data regarding their surrounding radio environment, rendering every GPS device a tool for enforcement of anti-jamming restrictions. Or, alternatively, it could just turn into an arms race between jamming techniques and the software to get around them. It’s a deeply invasive, deeply powerful idea, and how the ethical and legal issues surrounding it work out is anyone’s guess. A good, albeit somewhat technical introduction into potential anti-jamming technology is in this GPS world article.