SYSTEM AND METHOD OF DIRECTIONAL SENSOR CALIBRATION

摘要

An improved total field calibration system and method is disclosed for reducing the rotational misalignment between magnetic and gravity sensors in a directional sensing system. A method of calibrating a tri-axial directional sensor comprising orthonormal accelerometers and orthonormal magnetometers, comprises measuring Earth's magnetic and gravity fields with said directional sensor in at least 4 sensor orientations; obtaining at least one reference field value of dip drift of Earth's magnetic field from at least one source independent of said directional sensor corresponding to said orientations; and, determining and applying rotational misalignments between said magnetometers and said accelerometers so that measured magnetic dip drifts are substantially equal to said reference values. The calibration process can be performed without monitoring the declination change during the calibration process. Directional sensing systems can be calibrated accurately during a period when the Earth's magnetic field changes rapidly.

主权项

1. A system for calibrating a directional sensor having a plurality of magnetometers and a plurality of accelerometers, the system comprising:
a reference magnetometer system obtaining magnetic dip reference values of Earth's magnetic field; and; a computer system communicating with the directional sensor system and the magnetometer system, the computer system executing calibration software for the directional sensor and reading: at least one data table storing measured magnetic field values of the magnetometers of the directional sensor system in at least three sensor orientations; at least one data table storing measured gravitational field values of the accelerometers of the directional sensor system in at least three sensor orientations; and; at least one data table storing the magnetic dip reference values obtained by the magnetometer system; and, wherein the calibration software executed by the computer system determines rotational misalignments between the magnetometers of the directional sensor system and accelerometers of the directional sensor system using magnetic dip reference values of Earth's magnetic field.