What methods did early Automated Guided Vehicle (AGV) guidance systems use to stay on course?

Following a wire embedded in the floor or using magnetic tape

The early Automated Guided Vehicles (AGVs) emerged using relatively simple and fixed methods of navigation, predating modern sensor fusion technology. These systems were essentially programmed to follow a predefined path etched into the physical environment. The primary guidance mechanisms included physical contact methods, such as following a conductive wire embedded directly beneath the floor surface, or using non-contact methods like following magnetic tape or specialized paint strips laid out on the floor to keep the vehicle on its designated, high-volume route.