A pedestrian navigation system can not be developed simply by combining GPS and an Electronic Compass.
There are several issues which needs to be considered when implementing an Electronic Compass and to measure the geomagnetic field.
For example, in portable devices, the extraneous magnetic fields are strong and subject to
frequent change and distortion.
Furthermore, the levels of component magnetization may change in the strong magnetic fields often encountered around trains, stereo speakers, and other electrical equipment.
To address this issue, AKM offers the DOE (Dynamic Offset Estimation) algorithm which enables automatic adjustment of
the compass for extraneous magnetic field changes, and thus eliminates the need for repeated manual adjustment.
The adjustment is automatic, efficient, and highly effective for the maintenance of accurate and reliable direction finding, whether walking along the street, getting off a bus, leaving a subway station, or passing through other environments.