Re: a few more points
Um couple of bits, with respect
the traditional GPS system used by the US is almost 1.5 tons in high orbit - designed for long life and really expensive per shot.
The oneweb orbits at LEO, and has a much shorter life - true, but, there are potentially a lot more of them. There are 23 GPS sattelites operational or in reserve - Oneweb has 68 operational today - with proposals for a further 80 of them to be GPS enabled. That is a lot of redundancy.
even in LEO, you would get at least 20+ satellites in coverage at any time - it would work better (most like), round towerblocks/skyscrapers etc.
onewebs plans were for 1000 satellites - but had licenses for 48,000