Gyro zero turn rate offset correction over temperature in a personal mobile device

A personal mobile device comprising:

• a gyro sensor having a zero turn rate output that is capable of containing an offset;
• an accelerometer that generates data indicative of linear acceleration of the device;
• storage containing a plurality of initial entries that were written to the storage during manufacturing test of the device, wherein each entry includes a different temperature value and a respective gyro zero turn rate offset correction value;
• and
• a programmed processor to access the storage to correct an output of the gyro sensor for zero turn rate offset, wherein the programmed processor is to add a plurality of new entries to the storage during in-the-field use of the device, wherein for each new entry the programmed processor is to (a) automatically determine that the device is in a motionless state by determining when output from the accelerometer remains within a predetermined zero threshold range for a predetermined time interval, and (b) based on gyro sensor output, add a zero turn rate offset correction value to the storage as part of a pair of associated temperature and zero turn rate offset correction values included in the new entry.

A method for operating a personal mobile device having a gyro sensor, comprising:

• correcting an output of a gyro sensor in the device by accessing a plurality of storage entries some of which were stored during manufacturing test of the device, wherein each entry includes a different temperature value and a respective gyro zero turn rate offset correction value;
• and
• adding a plurality of new entries to the storage during in-the-field use of the device, by, for each new entry,
• determining that the device is in a motionless state by determining when output from a motion sensor remains within a predetermined zero threshold range for a predetermined time interval and
• adding a zero turn rate offset correct value, based on gyro sensor output, as part of a pair of associated temperature and zero turn rate offset correction values included in the new entry.