The idea of using low-earth-orbit satellites to provide greater GPS/GNSS accuracy isn’t limited to commandeering the Starlink constellation. The European Space Agency is exploring the idea of using low-flying satellites to increase Galileo’s accuracy and robustness: make it possible to use indoors, make it more resistant to jamming and interference, and enable positioning at the centimetre level. They’re planning an in-orbit demonstration of around six satellites to test the proposition. The satellites would supplement the existing Galileo constellation rather than replace it: for one thing, they would rely on the Galileo satellites’ atomic clocks, which would allow the low-flying satellites to be an order of magnitude smaller in size. [Universe Today]