"Instead, calibration will be done on the fly without input from the player as the match loads"

I think that solves the question. They will have long load times which lets it calibrate.

Calibration doesn't take a long time. It probably means that it will calibrate WM+ at the moment you click the "start match" button. It will make you use IR to click the button, rather than selecting it with the D-pad like you can in Wii Sports or Wii Fit.

Yea, that probably makes more sense. Looking at what you said that after 1 minute it is 6 degrees off then at the latter part of a match it may not be as accurate.

^Thanks, I looked through the documentation at Invensense but I couldn't find the accuracy numbers.

Please also note that the gyro won't drift that much, even in the worst case, unless it always drifts in the same direction all the time. These kinds of behaviour are described  by the "drunkman's walk model" :)

@sethnintendo

Yep, but the question was not about the time it takes to make the calibration (it will be istantaneous) but the absence of any player input. As in: what happens if the player doesn't point the wiimote at the screen during all the loading time? You can't correct the horizontal drift.

My suspicion is that a "minor" input will be required at least once per loading, in the form of one on-screen button click or something like that.

edit: I see our monkey friend said the same yet. Oh, well, repetita iuvant :)

I noticed you said that Grand SLam Tennis requires buttons but that's actually not true and was a mis-quote. It requires buttons only if you are not using MotionPlus for lobs and slices otherwise it does not require any use of buttons during gameplay.