The complaints started a few weeks ago, when the Apple iPhone 5S first hit shelves: The motion sensors appeared to be malfunctioning. Not cataclysmically, but enough that many users reported compass and level readings that were off.
Independent tests conducted Mario Aguilar at Gizmodo confirmed that the gyroscope, compass, level, and accelerometer readings on iPhone 5S did not match readings from traditional devices. "This compass shortfall won't have you confusing east from west when you get out of the subway," Mr. Aguilar wrote. "But for more detailed mapping and way-finding apps, a 10 degrees disparity could impact what an app thinks you're doing and which way you're going."
So what's the source of the discrepancies? Well, it could have something to do with hardware. Alex Colon of GigaOM points to a new RealityCap report that traces the problem to a Bosch Sensortech accelerometer, a change from the STMicroelectronics accelerometer included in previous iPhones. The whole thing gets extremely technical, but here's the CliffsNotes: That Sensortech accelerometer may be calibrated incorrectly.
Either way, Apple hasn't confirmed the existence of sensor-related issues, so it's unclear if any long-term fix is forthcoming. But if you're looking for something a little shorter-term, you could take the advice of Serenity Caldwell of MacWorld, and attempt to recalibrate the sensors within the compass app.
In related news, many users have complained that the iPhone 5S is afflicted by a "blue screen of death" error that seems to occur when users attempt to access iWork apps. There's some hope, however, that the new iOS 7.0.3 update, which is expected to be launched at some point this month, could include a fix for the BSOD. Hey, maybe a sensor fix is forthcoming, too.