Definition- A GPS tracking unit is a device that uses the Global Positioning System to determine the exact location of an asset, whether that be a vehicle, person or something else. The device must be attached to the asset in order to record the position at regular intervals. The recorded data can be either stored inside the tracking unit, or it can be sent to a database, or other internet-connected computer, using a modem embedded in the unit. GPS Tracking devices can specify your position wherever you are, on land, air or sea. Depending on the needs of the person using the system, these devices can be one of three different kinds.