https://rntfnd.org/2020/04/27/norway-powerless-against-gps-interference-nrk/

This issue is not confined to northern Norway. There is a stretch of
the East River in New York Harbor near UN Headquarters where there
have been many well documented instances of GPS jamming. We've
experienced it ourselves.

Apparently jammers are easy to buy:

https://gizmodo.com/jamming-gps-signals-is-illegal-dangerous-cheap-and-e-1796778955

It looks like we're going to need some new form of electronic
navigation some time in the future, something more difficult to jam.

--
This email has been checked for viruses by AVG.
https://www.avg.com