US Patent 9120568 Autonomous resupply system and method

Some embodiments relate to a system and method of automatically transporting cargo from a loading station to an unloading station using a vehicle. Loading and unloading of cargo may be accomplished automatically without the need for human operators of either the loading station, the unloading station, or the vehicle. The unloading and loading station each comprise guide rails and a plurality of directional signal sources used by the vehicle to control its current position so that it may retrieve and deliver a target load. The vehicle comprises at least one sensor for detecting modulated directional signals and a controller to control the current position of the vehicle based on the received signals.