You can see only about half the sky that way, which means usually getting almost as good a fix as with a roof mount antenna. For best results, you want the sate

You can see only about half the sky that way, which means usually getting almost as good a fix as with a roof mount antenna. For best results, you want the satellites to be as far apart as possible in the sky (measured by angle from your position, not miles between them). See https://en.wikipedia.org/wiki/Dilution_of_precision_(navigation) https://en.wikipedia.org/wiki/Dilution_of_precision_(navigat... . If you mainly care about time and can tolerate a few microseconds of error, usually being able to see 4 satellites might well be enough. I remember seeing a gps receiver designed just for time that could maintain sync using only one satellite (it assumed that it was bolted to an immovable object, and it might have needed to see 4 satellites at once at some point).