A few years ago I read a report about the russians screwing around with the GPS system... they were testing its vulnerabilities, apparently. I wonder if this event is related.I myself saw this a couple months back while working on my senior design project for graduation for my degree. My group's project sponsor (an engineer at a Navy base) sent a similar report from MIT to us. In that case, it only occurs to GPS systems (not just AIS from ships, but any GPS signal - even bicyclists' signals end up in these circles) that approach certain areas of China.

