A GPS or Global Positioning System that would work underwater would be an interesting piece of equipment. I could be incorrect, but being a line of sight type system I do not think it is possible to use the GPS signal through water. In the past, underwater marking or locating devices have used a type of sonar or ultra-sonic type medium. They are also line of sight, so rocks, wrecks or any solid mass between the transceivers would hinder effectiveness. For recreational diving the cost would have to be relatively low. Until the technology is available and provides enough improvement to features and benefits, say over the compass and depth gauge, the market would be small. Much like the dive computer has almost replaced dive tables. Once the cost and reliability became reasonable, divers switched to the dive computer.
Edited by BillL (06/29/09 10:10 AM)