iPhone compass: magnetometer or gyro?
I have been reading contradictory info on whether the compass is based on gyro or magnetometer. Does anyone has official info? Thanks.
5 replies
Gyros don't measure heading.
Chris Habig wrote:
Gyros don't measure heading.
Actually they do if you point them at a reference. Most light airplanes have a gyro compass that works fine and stays accurate within a few degrees on flights of several hours.
That said, there ain't any way Apple could fit a gyro in a iphone and IF they could, the phone would require much more battery power to keep it running.
I haven't seen my new IP yet as its scheduled to arrive sometime today. So, IF the compass works immediately when the phone is turned on AND spins while you turn in a circle, then its probably magnetic. IF it doesn't do the above, then it has to be using the GPS and when you start moving, the GPS could compute a compass reading.
This post by an old AF Navigator.
"Actually they do if you point them at a reference."
Perhaps I stated it too simply. Gyros don't measure heading, they measure rotation or orientation and must be given a reference heading as you said. Gyros by themselves don't measure heading.
Perhaps I stated it too simply. Gyros don't measure heading, they measure rotation or orientation and must be given a reference heading as you said. Gyros by themselves don't measure heading.
Its pretty well know that it is a magnetometer. I'm pretty sure this was discussed at WWDC. I imagine some people may get the idea its gyroscopic because of the way you calibrate it. If you put a magnet near the phone, its hard to mistake it for being gyroscopic.
iPhone compass: magnetometer or gyro?