An electronic device may be provided with an electronic compass. The electronic compass may include magnetic sensors. The magnetic sensors may include thin-film magnetic sensor elements such as giant magnetoresistance sensor elements. Magnetic flux concentrators may be used to guide magnetic fields through the sensor elements. The magnetic flux concentrators may be configured to reduce the angular sensitivity of the magnetic sensors. A magnetic flux concentrator may be formed from multiple stacked layers of soft magnetic material separated by non-magnetic material. The non-magnetic material may have a thickness allows the magnetic layers to magnetically couple through the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction.

An electronic device may have electrical components mounted in alignment with an electronic device housing. A compass in the electronic device housing may potentially be misaligned with respect to the electrical components and the electronic device housing. Reference devices having compasses may be used to gather compass data while one or more electrical components in the reference devices are controlled to generate magnetic fields that are detected by the compasses. An electronic device may be calibrated in a factory or in the field using calibration data produced by comparing compass readings gathered from the compass in the device while controlling electrical components in the device to compass data from the reference devices. Calibration data may be applied to compass readings in real time to correct for misalignment between the compass and the electronic device housing.

An electronic device may have electrical components mounted in alignment with an electronic device housing. A compass in the electronic device housing may potentially be misaligned with respect to the electrical components and the electronic device housing. Reference devices having compasses may be used to gather compass data while one or more electrical components in the reference devices are controlled to generate magnetic fields that are detected by the compasses. An electronic device may be calibrated in a factory or in the field using calibration data produced by comparing compass readings gathered from the compass in the device while controlling electrical components in the device to compass data from the reference devices. Calibration data may be applied to compass readings in real time to correct for misalignment between the compass and the electronic device housing.

A heading calibration method, adapted for a compass sensor is provided. The heading calibration method includes the following steps. R data segments are sequentially generated by rotating the compass sensor by a predetermined angle, wherein the data segments includes a plurality of magnetic data respectively. A partial calibration process is executed to calibrate a reference point coordinate according to the magnetic data in r.sup.th data segment and a initial value of the reference point coordinate, wherein r is between 1 and the R. Parts of the magnetic data in the r.sup.th data segment is extracted as whole data, and a whole calibration process is executed according to the whole data to update an initial value of the reference point coordinate. The partial calibration process is executed according to the updated initial value of the reference point coordinate and the magnetic data in a (r+1).sup.th data segment.

An electronic timepiece includes a magnetic sensor that serves as a magnetic detection unit, a GPS reception unit that serves as a reception unit receiving positional information of a current position, a time zone setting unit that sets a time zone, a specifying unit that specifies a declination angle based on the positional information of the current position, a decision unit that decides a direction of a due north based on an output of the magnetic sensor and a declination angle, and an azimuth display unit that displays the direction of the due north decided by the decision unit.

A method and system are provided for determining a heading angle of a user of a portable electronic device in an indoor environment. In an embodiment, the device collects rotational movement information indicative of rotational movement of the device and determines a first heading angle of the device. The first heading angle is determined by using the downward direction of the device to determine the vertical angular rate in the horizontal plane, and integrating the vertical angular rate to form the first heading angle. The device collects first direction information from a first direction sensor and second direction information from a second direction sensor and uses it determine which of the first and second direction information is an outlier, e.g., inaccurate due to an occurrence of a disturbance. The device then corrects the heading angle by comparing the heading angle to the first and second direction information.

A method and system are provided for determining a heading angle of a user of a portable electronic device in an indoor environment. In an embodiment, the device collects rotational movement information indicative of rotational movement of the device and determines a first heading angle of the device. The first heading angle is determined by using the downward direction of the device to determine the vertical angular rate in the horizontal plane, and integrating the vertical angular rate to form the first heading angle. The device collects first direction information from a first direction sensor and second direction information from a second direction sensor and uses it determine which of the first and second direction information is an outlier, e.g., inaccurate due to an occurrence of a disturbance. The device then corrects the heading angle by comparing the heading angle to the first and second direction information.

A navigation instrument including an orientation angle calculation unit, in particular the first and second orientation angles, wherein the orientation angle calculation unit is configured to be able to determine the first and second orientation angles in a given order and also in reverse order; and wherein the calculation unit is arranged to be able to choose between said given order and said reverse order, to calculate the first and second orientation angles, based on a comparison between an indicator of a risk of error, quantifying a risk of instability of said unit during the determination of the first and second orientation angles, and a predetermined threshold.

An electronic device, the electronic device includes: a printed circuit board PCB substrate (201, 31); a magnetometer (202, 32), where the magnetometer (202, 32) is mounted on the PCB substrate (201, 31); and a protection apparatus (203, 33), where the protection apparatus (203, 33) is mounted on the PCB substrate (201, 31) and is disposed at a periphery of the magnetometer (202, 32), and is configured to protect the magnetometer (202, 32). According to the electronic device, sensitivity of the magnetometer (202, 32) can be improved, and the magnetometer (202, 32) can be protected from being damaged.

An electronic device, the electronic device includes: a printed circuit board PCB substrate (201, 31); a magnetometer (202, 32), where the magnetometer (202, 32) is mounted on the PCB substrate (201, 31); and a protection apparatus (203, 33), where the protection apparatus (203, 33) is mounted on the PCB substrate (201, 31) and is disposed at a periphery of the magnetometer (202, 32), and is configured to protect the magnetometer (202, 32). According to the electronic device, sensitivity of the magnetometer (202, 32) can be improved, and the magnetometer (202, 32) can be protected from being damaged.