The UK enthusiastically backed the idea of a closed shop, where non EU entities would not be allowed to work on this project.

The idea was to limit competition against the UK's space sector, which is quite large.

This ofcourse means that now they have left the union, they are not allowed to participate.

This is entirely EU internal politics, from what I can tell - the UK has nothing to do with it. One of the author's earlier posts has some discussion about it: https://berthub.eu/articles/posts/state-of-galileo-and-accid... To cut a long story short, the satellites themselves and probably also the physical ground station infrastructure are provided by the ESA, which is not actually an EU institution and has non-EU members. Ther ground operations, however, are contracted out by the EU to various companies spread across the core EU states. The EU wants to take over European space activities for the same reasons they want everything else in Europe to fall under their control, so they're probably not on the best of terms with the ESA right now. I think there was also more political wrangling and changes of control that weren't covered in that post.

Possibly, what you're thinking of is the EU deciding that the UK won't have access to Galileo military positioning after leaving and pointing to the fact that the UK didn't want other non-EU states to have access to it as justification. Which of course they can do - it's just possibly a little counterproductive, given that the UK is still the big military power in the region due to the lack of willingness for anyone else to take that on.

It puts into context why the UK have been funding Atomic Interferometry research recently. If AI works, the likes of GPS, GNSS, Galileo etc. become obsolete because then we have GPS level accurate accelerometers which don't rely on satellite infrastructure at all

You're assuming the UK has a coherent policy that stems from brexit. I would dearly love that this is part of a grand unified 25 year plan (or in fact any plan that isn't "get boris to PM and keep him there")

The UK isn't a singular mind of Dominic Cummings. Plenty of institutional individuals and experts across multiple domains and departments have their own insights and directions to pursue.

But plans of mice and men rarely survive the heat of battle and political incompetence. But they try none the less.

> It puts into context why the UK have been funding Atomic Interferometry research recently. If AI works, the likes of GPS, GNSS, Galileo etc. become obsolete because then we have GPS level accurate accelerometers which don't rely on satellite infrastructure at all

I don't know about Atomic Interferometry specifically, but to me accelerometers -> inertial navigation -> intermittent need for an accurate external location fix -> GNSS not obsolete.