GPS, global positioning system built into vehicle tracking devices enables the tracking of a vehicle's location. Receivers detect and collect signal information transmitted to earth by GPS satellites. They are best used in areas with clear view of the sky. So, they may be less effective near skyscrapers and in dense forests where it is difficult to receive signals. GPS systems use an accurate time reference, which is provided by an atomic clock on board the satellite.

There are many benefits to using vehicle tracking devices. Companies use them to track business mileage and job productivity. A vehicle tracker enables the police to recover a stolen vehicle more quickly and easily. Many auto insurance companies offer reduced insurance premium to those who install a vehicle tracking device in their vehicle. As a navigation tool, it can hooked on-board the vehicle to provide the driver with location and direction of travel. Besides keeping track of a vehicle, the tracking device allows you to monitor the whereabouts of family members, especially teenagers who are only allowed minimal vehicle access. In an emergency situation, certain GPS systems allow you to call 911 and report your location for emergency responders to find you.

The 2 types of vehicle tracking device are real-time and passive. The real time tracking system enables you to track a vehicle instantaneously on the internet. A special software is loaded onto the computer to access real time information on the location, speed and direction of travel of a vehicle. Do make sure your computer systems meet the requirements of the tracking software before you buy a real time vehicle tracking device.

There is usually a monthly subscription to a GPS service for real time vehicle tracking devices. Although the price differs from company to company, it is normally under $20 per month. The subscription is typically purchased along with the tracking device.

Passive GPS tracking system isn't as sophisticated as real-time system, but is cheaper. Information stored in the tracking device can be retrieved at a later time and viewed on a computer. This allows you to know where the vehicle has been, often recorded at 15-minute intervals.

There are numerous companies selling GPS systems but you are strongly advised to buy your vehicle tracking device from a reputable company. You can easily locate a good dealer on the internet. There are some well-known companies that are adept at providing high-quality tracking service. If you are not computer savvy most companies offer to help you get started and can assist on an ongoing basis if problems occur.