1. A tracking system for a fleet of machines, comprising: a locating device located on board each machine of the fleet of machines and being configured to determine a current location of an associated machine; a communicating device located onboard each machine in communication with the locating device; and a central controller located offboard the fleet of machines in communication with each communicating device and configured to: receive an unacknowledged message from each communicating device relaying the current location of the associated machine, wherein the frequency of the unacknowledged message from each communicating device is based on the speed of the associated machine, the location of the associated machine, or the speed and location of the associated machine; update a location listing of the fleet of machines with the current location; and repetitively multicast the location listing to the communicating devices.