You still end up with a bunch of messages that end up saying "at time T I was at position X" where T is off in absolute terms (which you indeed can solve by usi

You still end up with a bunch of messages that end up saying "at time T I was at position X" where T is off in absolute terms (which you indeed can solve by using an additional satellite to synchronize your clock) and is measure with a different rate (which you cannot solve, unless you know a leap smear is occurring, or by using yet another extra satellite and some mathematics that I don't think anyone's ever bothered working out yet).