Notthing found in europe either. BTW i tought it was a gps + wifi signal, but at that point i cant get the "content" of those 20 and more patent...so maybe is somethink different never used before?
If anyone has any ideas to achieve this working it would be cool.
I was thinking about a gps-like positioning system, two or more antennas and a delay signal interpolation to get the positive ( in front of the device ) position.