High Accuracy Indoor Location Tracking?

aletterman asks: "I am looking for technology that can allow my company to track the position of a fork lift as it moves around a warehouse. This would allow us to factor out one problem situation - where the lift was when the driver dropped off the product. Based on the width of our warehouse locations, we need a resolution of about +-1ft. Standard GPS can't get that accurate or work well indoors. The fork lifts already have a VT220 terminal running 802.11b, so adding another device would not be difficult. I am currently looking at a product that can triangulate via the RSSI of the 802.11b network, but I am concerned the changes in the product mix and density of the corrugated boxes will change the RSSI and introduce a mis-positioning of the locations. I would prefer that the device transmit a position either serially or via our 802.11b network. Our warehouses are fairly large (300,000+ sqft) and have a large of amount of corrugated boxes. Any suggestions are greatly appreciated!"

Comments

Has been done before

[freshmkr]

Take heart---the problem you're contemplating has been fairly well studied.

I remember a professor here at CMU saying that you could do localization for forklifts by pointing a camera at the floor. Most warehouse floors have enough scratches and marks on them that as you wander around, you can get a pretty good idea of where you are by comparing them to a map (using techniques like Monte Carlo localization---google it!). Combined with encoders on the forklift wheels, you may be able to get the resolution you need.

Here is a paper describing technology like this. In the results they say they get accuracy down to a millimeter.

So, those talking about painting a grid on the floor have the right idea---but perhaps you don't even have to do that!