Yes, that section is poorly written. More generally, the assumptions about what things were uncertain and what could be taken as exact were poorly motivated. T

Yes, that section is poorly written. More generally, the assumptions about what things were uncertain and what could be taken as exact were poorly motivated. The author should wither justify them with real-world constraints ("satellites can host atomic clocks but destroyers can't" -- not obvious!) or explicitly announce the assumptions as unjustified, but he shouldn't make it seem like the assumptions could have been reasoned to by the reader. I also was disappointed the author used circles/spheres and guesses for the timing offset rather than the much more edifying choice of hyperbolas. Just as you can think of a sphere as points reachable by the end of a rope of fixed length tied to a post, you can think about a hyperbola as the points reachable by tying separate ropes to two posts and spooling out equal amounts of rope.