NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Paul Saffo
Date: 2020 Dec 12, 14:48 -0800
I wonder why all the signals are pointing to Pt. Reyes. Might it have something to do with that Utah monolith? ;-)
GPS mystery is making ships appear to teleport and move in circles
TECHNOLOGY 4 June 2020
By David Hambling
Ships around the world are reporting false locations, seeming to circle Point Reyes near San Francisco when they are actually thousands of kilometres away.
The locations are broadcast by each ship’s Automatic Identification System (AIS). These are required under international law to signal a vessel’s identity and GPS location. Bjorn Bergman of the environmental watchdogs SkyTruth and Global Fishing Watch discovered the anomalies from a historical database of AIS information.
Bergman was tipped off when he noticed records from 2018 and 2019 of satellites receiving AIS locations outside areas they cover, for example, a satellite over West Africa picking up a ship supposedly off California. Vessels affected included a livestock carrier near Libya, a cargo ship in the Suez Canal, a small boat off Chile and a Norwegian tug.
(snip)
