Vehicle-mounted GPS jammer is a kind of equipment specially designed to jam and block GPS signals. It is mainly installed on vehicles and covers or interferes with the signals sent by GPS satellites by emitting electromagnetic waves with specific frequencies. Therefore, the vehicle-mounted GPS navigation system, positioning and tracking equipment and other related equipment relying on GPS signals cannot work normally.

This jammer generally consists of the following core components:
1. Transmitter: responsible for generating the same or similar frequency signal as the GPS satellite signal.
2. Power amplifier: Enhance the signal power sent by the transmitter to ensure that the signal can cover a long enough distance.
3. Directional antenna: transmit the enhanced signal directionally to ensure that the signal can effectively cover the target area.
4. Control unit: It is used to control the working state of the whole equipment, including functions such as on-off and signal intensity adjustment.

The working principle of vehicle-mounted GPS jammer is based on electromagnetic interference theory. The GPS satellite sends signals of specific frequency to the earth, and the GPS receiver on the vehicle receives these signals and calculates the position information of the vehicle. Vehicle-mounted GPS jammers emit electromagnetic waves with the same or similar frequency as GPS signals, and these jamming signals compete with GPS satellite signals for receiver resources in the same frequency band, resulting in the receiver being unable to correctly analyze effective GPS signals, and thus unable to determine the position of the vehicle.

On-board GPS jammers may be used in some specific situations, for example, in order to protect personal privacy, car owners may install jammers on their vehicles to prevent them from being tracked and located; Or in military exercises and covert operations, in order to prevent the enemy from using GPS signals for navigation and positioning, such equipment may be used to interfere with the enemy’s GPS system. However, it should be emphasized that it is illegal to abuse the vehicle-mounted GPS jammer, because it will not only affect other users who normally use GPS services, but also seriously affect traffic safety and emergency rescue.

Therefore, the use of vehicle-mounted GPS jammers should be strictly restricted and bound by laws and regulations. Governments of various countries usually strictly supervise the production, sale and use of such equipment to maintain public safety and order. At the same time, with the development of technology, more intelligent and efficient positioning technology and anti-interference measures are developed to deal with the increasingly complex positioning interference problem.