Phil Stanton wrote:
Come off it , amateurs. I hold the record. Frequently get ships about 3200
miles away. Odd though - distance from here to the line where the Equator
crosses the Grenwich Meridian is about 3200 miles.

Joking apart, here in the UK, I have freqently found ships displaying duff
information, and I suspect that if their GPS is not working, they display
their position as zero degrees east and zero degrees north. In fact on
Saturday I saw a freighter goind up the Thames, but announcing she was in
the way to Liverpool. The previous week we were watching a Roll on Roll Off
ferry, 400/500 foot long with no AIS signal being broadcast. It is a
brilliant system, but always to be used with a pinch of salt.


They seem to congregate off the coast of Africa, don't they?

The position indicating no input is 91/181 and some software doesn't
check properly so it sets the position to 0/0

I once spotted a cruise ship going through Admiralty Inlet that jumped
sideways every couple of miles. While talking to a USCG guy I found
that they were experimenting with a new GPS system that wasn't working
all that well.

..cp