Orientation data generation method, orientation sensor unit and portable electronic equipment

An orientation sensor unit comprising:

• a geomagnetic sensor that detects magnetic fields in three axial directions;
• a magnetic field data measurement section that inputs data outputted from said geomagnetic sensor and measures magnetic field data on the basis of the inputted data;
• a storage section that sequentially stores the magnetic field data measured by said magnetic field data measurement section;
• a determination section that determines whether or not a plurality of the magnetic field data stored in said storage section lie within a same plane in a three-dimensional orientation space;
• a provisional offset calculation section that, when said determination section has determined that the plurality of the magnetic field data, stored in said storage section, lie within the same plane in the three-dimensional orientation space, calculates, as provisional offset values, center coordinates of a circular arc where the plurality of the stored magnetic field data lie, on the basis of the magnetic field data and in accordance with a predetermined algorithm;
• and
• an arithmetic operation section that corrects, with the provisional offset values, magnetic field data measured after calculation, by said provisional offset calculation section, of the provisional offset values and performs an arithmetic operation for determining orientation data on the basis of the corrected magnetic field data.

A storage medium readable by a computer and containing a group of instructions for causing the computer to perform orientation data calculation processing on the basis of data outputted from a geomagnetic sensor that detects magnetic fields in three axial directions, said orientation data calculation processing comprising:

• a measurement step of inputting data outputted from said geomagnetic sensor and then measuring magnetic field data on the basis of the inputted data;
• a storage step of sequentially storing the magnetic field data measured by said measurement step;
• a determination step of determining whether or not a plurality of the magnetic field data stored by said storage step lie within a same plane in a three-dimensional orientation space;
• a provisional offset calculation step of, when said determination step has determined that the plurality of the magnetic field data, stored by said storage step, lie within the same plane in the three-dimensional orientation space, calculating, as provisional offset values, center coordinates of a circular arc where the stored magnetic field data lie, on the basis of the magnetic field data and in accordance with a predetermined algorithm;
• and
• an arithmetic operation step of correcting, with the provisional offset values, magnetic field data measured after calculation, by said provisional offset calculation step, of the provisional offset values and performing an arithmetic operation for determining orientation data on the basis of the corrected magnetic field data.