Automatic calibration method for use in electronic compass

Abstract

An automatic calibration method used in an electronic compass. Using this automatic calibration method, the electronic compass automatically calculates and corrects the offset and scale values ​​of the geomagnetic signal by detecting one rotation of the geomagnetic axis during a predetermined period. The electronic compass calculates the azimuth when it receives the geomagnetic data from the geomagnetic sensor and uses the received geomagnetic data to find the maximum and minimum values ​​of the sensor signals of the individual axes of the geomagnetic sensor so that it can correct or calibrate the deviation of the azimuth . When the time taken for calibration is equal to or shorter than the maximum calibration valid time, the electronic compass determines whether the current state of the detected input signal indicates a predetermined steady state flow. If the current state represents a steady state flow, while a signal representing one revolution of the geomagnetic sensor is received, and the calibration takes longer than the predetermined minimum calibration valid time, the electronic compass uses the maximum and minimum values ​​to calculate the offset and scale values ​​and store the calculated offset and scale values.

Description

technical field [0001] The present invention relates to an automatic calibration method for use in an electronic compass, and more particularly to an automatic calculation and correction of an offset of a geomagnetic signal for use in an electronic compass by detecting one rotation of the geomagnetic axis during a predetermined period using a timer and scale values, performing automatic calibration capable of calculating the offset and scale values ​​of the geomagnetic signal without receiving additional input data from the user, and an automatic calibration method that quickly responds to environmental changes. Background technique [0002] Recently, small and low-priced geomagnetic sensor modules and electronic compasses have been developed. With the increasing development of MEMS (Micro Electro Mechanical System) technology, chip-sized geomagnetic sensor modules have been newly developed and used for various applications. There is a need for a geomagnetic sensor that con...

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Problems solved by technology

[0019] However, a drawback of the conventional calibration method determined above is that it requires a data input process by the user to perform a calibration process capable of calculating the offset and scale values ​​for the individual axes of the geomagnetic sensor

In addition, assuming that the surrounding environmental conditions change unexpectedly during the operation time of the electronic compass, the conventional calibration method described above cannot update the calibration data according to the changed surrounding environmental conditions.

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