[tawm]

As OP hasn't replied yet, I'll take the liberty. The biggest issue is interference (jamming) by malicious actors. This is especially common in the eastern Mediterranean [1]. Earlier this year there have also been reports of interference on Finland's border with Russia [2].

Of course one could imagine other scenarios where GPS might become inaccurate or unavailable on a larger scale, such as an attack on the satellites themselves.

[1] https://safety4sea.com/us-marad-gps-interference-incidents-r...

[2] https://www.traficom.fi/en/news/unusual-amount-reports-about...

(my guess is that _moof is a navigator with experience in the eastern med sea)

[mortenlarsen]

It is not that I do not know that GPS is unreliable. But I wanted to read about what OP had experienced specifically.

[flyinghamster]

> The biggest issue is interference (jamming) by malicious actors.

And not necessarily malicious. Before I ditched Strava (insert separate rant about tech "ecosystems"), one of my bike rides took me near a nuclear power plant. The resulting GPS track had a sudden hundreds-of-feet "climb" near the power plant that didn't exist in the real world, as if I had literally climbed a wall on my bike.

[deepstack]

in android, the GPS config file (some xml) file will do the trick of making the at least the GPS/Location system on the phone unreliable. Apparently each country has their own config file. Found this out when a friend used the Android bought in China in US. So no GPS is NOT reliable for critical situations, it is more a consumer connivence ATM.

[Hitton]

Nope. It's maps in China that are unreliable. On purpose. https://www.serviceobjects.com/blog/why-gps-coordinates-look...