Back in 2008 I was working with a company in the UK that had an API to do this with O2. It only provided a rough area of where the user was, as it was based on which (single) cell tower the user was connected to.
I'd imagine today MIMO data is good enough to triangulate a very accurate (metres) position.
I'd imagine today MIMO data is good enough to triangulate a very accurate (metres) position.