Magnetometer calibration method based on known attitude angle

A calibration method and magnetometer technology, which are applied in the directions of instruments, surveying and navigation, measuring devices, etc., to achieve good calibration accuracy and good universality.

Active Publication Date: 2021-03-09
WUHAN UNIV
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  • Abstract
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Problems solved by technology

For cross-calibration between sensors, it is mainly done by relying on local gravity information, but this calibration method relies on accelerometer measurements

Method used

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  • Magnetometer calibration method based on known attitude angle
  • Magnetometer calibration method based on known attitude angle
  • Magnetometer calibration method based on known attitude angle

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Embodiment Construction

[0054] The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0055] Step 1. Select an open outdoor location as the calibration location, obtain the latitude and longitude coordinates and height of the location, and obtain the magnetic field strength M of the location by querying the IGRF (International Geomagnetic Reference Field) model n_IGRF ;

[0056] Step 2, such as figure 1 As shown, take the center of the smart phone (i.e., the carrier) as the center of rotation, and make it rotate 720° around the X, Y, and Z axes of the carrier coordinate system;

[0057] Step 3, through the patented "MEMS gyroscope automatic calibration method", obtain the high-precision attitude rotation matrix from the carrier coordinate system to the local coordinate system of each epoch in the calibration process through pseudo-position constraints and reverse smoothing (The role of the attitude rotation ...

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Abstract

The invention provides a magnetometer calibration method based on a known attitude angle. Based on the assumption that the total intensity of the magnetic field at a certain fixed position is unchanged and the projection component of the magnetic field intensity in the same coordinate system is unchanged, the observed value of a magnetometer is projected to a local coordinate system by using a known attitude angle according to a magnetometer measurement model, and the calibration parameters of the magnetometer are obtained through least square iteration. Compared with an existing calibration technology, the method is simple in algorithm and high in efficiency. Meanwhile, soft and hard magnetic effect calibration of the magnetometer is realized, and a coordinate system of the magnetometer is aligned with a coordinate system of an inertial sensor, so that information of the magnetometer and the inertial sensor is placed in a common frame, and the method can play an important role in multi-source sensor fusion positioning and sensor arrays.

Description

technical field [0001] The invention belongs to the field of magnetometer calibration, in particular to a magnetometer calibration method when the attitude angle is known. Background technique [0002] A magnetometer is a sensor used to measure magnetic induction, which provides a reference to magnetic north and is a key source of information for attitude estimation in low-cost, high-performance navigation systems. Due to the limitation of processing technology, the magnetometer will have problems such as zero offset error, quadrature axis coupling error, and scale factor error, which will affect the measurement accuracy of the magnetometer; moreover, the magnetometer is susceptible to magnetic interference from the surrounding environment, and these interferences are divided into soft magnetic interference and hard magnetic interference. Therefore, in order to measure more accurate magnetic field information, it is necessary to calibrate the magnetometer. In addition, in ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01C17/38G01C25/00G01R35/00
CPCG01C17/38G01C25/005G01R35/00
Inventor 旷俭李泰宇牛小骥刘韬
Owner WUHAN UNIV
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