GPS jammers are useful, this kind of device can block the GPS signal, suitable for some users who don't want others to know their location. Some cars purchased by installments or mortgaged cars are equipped with a GPS system, and the real-time location of the car can be known through GPS. If the user does not repay on time, the bank can find a tow truck to tow the user's car away. In general long-distance buses, the mortgage car will be equipped with a GPS positioning device. Some people can find the location of the GPS through the detector and remove it, and some people will put a GPS jammer on the car. If it is a car purchased by installments, it is recommended that car owners repay on time and do not use gps jammers. Some people are eager to buy a mortgage car cheaply, and users are advised not to buy a mortgage car. This kind of car cannot be transferred, and there is a greater risk in the later use process. Some coach drivers often use GPS jammers so that companies can't see their location. Drivers are also advised not to use jammers, and to take a 20-minute break for four consecutive hours of long-distance driving. Generally, there are active and passive GPS positioning devices installed on automobiles. The passive GPS positioning device does not need to rely on the electricity in the car battery to work. This kind of GPS has its own battery and can send signals at regular intervals. Active GPS needs to rely on the electricity in the battery to work properly.