I would like your opinions on an idea that I have, please tell me whether its something that is feasible or not. I thought about using an inductive proximity sensor to keep my robot from straying outside of a target area, but I didn't like the fact that it requires cables which have to be hooked up to a power source, to be used as targets. My idea is instead of using cables, I would use magnets. I would embed small pieces of magnet into the ground at regular intervals which will serve as navigation markers. Then use magnetic field sensors to pickup the magnetic fields of each piece of magnet. I would program the robot to count each magnet piece as it is encountered. The robot will start off from a reference point where everything else is based off of. Each time a piece of magnet is encountered I will tell the robot to do something based on whether it is the first, second, third, etc. magnet to be detected. For example if I put the first piece of magnet on the foot of a round object, when the robot detects this magnet it will be told to circle around this object then keep on going until it picks up a new magnetic field. Then a new set of instructions will be given. If I couple this type of sensor with range finders, I think navigation should be pretty straight forward. Please leave your comments or concerns on this approach to navigation, thanks in advance for your time.