It this dispatching method, the central computer issues commands to the vehicles in the system concerning their destinations and the operations they must perform. To accomplish the dispatching function,the central computer must possess current information on the location of each vehicle in the system so that it can make appropriate decisions about which vehicles to dispatch to what location. Hence, the vehicles must continually communicate their whereabouts to the central controller. Radio
frequency (RF) is commonly used to achieve the required communication links.