Apparatus and methodology for calibration of a gyroscope and a compass included in a handheld device

摘要

Techniques for estimating compass and gyroscope biases for handheld devices are disclosed. The compass bias can be determined by causing a small movement of the handheld device and comparing the data obtained from the compass with the data obtained from the gyroscope. The gyroscope bias can be determined by obtaining a quaternion based angular velocity term of the handheld device when the accelerometer and compass data are reliable, and then comparing the angular velocity term with the gyro data to estimate the gyro bias. When the compass and/or the accelerometer data are unreliable, a previously determined quaternion angular velocity term is used. The gyroscope bias can also be determined by measuring gyroscope biases at various temperatures in a non-factory setting, storing the data in a memory, and using the data to estimate gyro biases when the accelerometer and/or the compass data are unreliable.