An anonymous reader writes "A simple $30 GPS jamer made in china can ruin your day. Not just affecting your car navigation — ATM machines, cell phone towers, plane, boat, train navigation systems all depend upon GPS signals that are easily blocked. These devices fail badly — with no redundancy. These jamers can be used to defeat vehicle tracking products — but end up causing a moving cloud of chaos. Next wave of anti-GPS devices include GPS spoofers to trick or confuse nearby devices — scary."
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