GPS jamming is the process of using a drone radio frequency jamming transmitting device to block or interfere with radio communications. Types of communications that can be jammed include phone calls, text messages, GPS systems and Wi-Fi networks. The term is also known as GPS spoofing and the devices used can also be referred to as cell phone or signal blockers.

　　GPS jammers were initially developed by the military to misguide the enemy about geographic locations and targets. The devices were then adapted for consumers that wanted to ensure their privacy or prevent tracking. However, without proper technical knowledge or when placed into the wrong hands, GPS jammers can cause potentially damaging disruptions in communications.

　　GPS jamming devices can be used for a variety of applications, such as:

　　Concealing the location of a device or vehicle.

　　Inhibiting mobile devices from being able to make or receive calls, text messages or emails.

　　Hiding, changing or obscuring positioning signals from GPS units.

　　Blocking Wi-Fi enabled devices from successfully connecting to the internet.

　　While GPS jammers can cause minor disturbances, such as signal loss, they can also pose a large risk to public safety. For instance, GPS jammers cannot distinguish between types of communications and may block ingoing or outgoing calls from emergency responders. Additionally, the devices could block more than calls and disrupt all communications within a broad frequency range.

　　As more industries -- like law enforcement and transportation -- rely on GPS-enabled devices, jamming has the potential to interfere with business-critical operations and data. In fleet management tracking, GPS information can be connected to data such as fuel use, driving behavior, engine health, vehicle synchronization and safety metrics. Therefore, jammers can disrupt all of this information and cause major outages.

　　Once the signal jammer is operational, you can practice testing it by monitoring the signal on a common consumer GPS receiver or high quality communications receiver. A GPS receiver close to the jammer will not be able to acquire C/A-code lock and any operating GPS in the jammer's radiation pattern will lose C/A-code lock. Higher quality GPS receivers tend to be less susceptible to low power jamming, so you'll need to be in the antenna's near-field radiation pattern (i.e. close) for it to work.

　　Any obstructions near the jammer's own antenna (trees, houses, hills,walls, etc.) will decrease the jamming range. The best placement is where the jammer's antenna is line-of-sight to the antenna of the GPS receiver you're trying to jam. Real world results will vary drastically, but you should be able to obtain a jam radius of a few hundred feet even in heavily obstructed areas with the higher power (AH102) option and a simple antenna.

　　You can even practice counter-jamming methods to protect yourself against hostile or accidental GPS jamming. Try to shield your GPS receiver from the interference source by placing your body, trees, hills, rocks or other obstructions in-between your position and the interference. More advanced methods involve using directional or steerable phased-array antennas on your GPS receiver (pointed skyward) to nullify any ground based interference.