No works immediately, but I never use it. For some reason it actually knows when I turn my iPhone where North is. Uses the same info as the GPS I guess
Guess it then takes info secretly, you can't pinpoint north at the spot without either previous GPS data (unless you got military grade GPS, still iffy then) or magnetism (doubt they got that installed

).
Turn the whole thing off, move a bunch and put it in a different but for you known direction and turn it back on without moving an inch, does it do it correctly then?