Analysis from SkyTruth and Global Fishing Watch shows ship tracks jumping thousands of miles from their true locations.
In December of 2019 SkyTruth reported on a number of locations on the Chinese coast (mostly oil terminals) where ship tracking positions from the automatic identification system (AIS) became scrambled as soon as ships approached within a few miles of a point on shore. Following the findings last year on the Chinese coast, analyst Bjorn Bergman began looking globally for any similar patterns in AIS tracking data around the world. While he hasn’t found the precise pattern observed at the Chinese oil terminals outside of China, he has found a somewhat different false AIS broadcast pattern which appears concentrated above Point Reyes northwest of San Francisco, California. Could this reflect an intentional disruption of the underlying global positioning system that AIS relies on, or is there some other explanation for this pattern?