System and method for magnetometer calibration and compensation

Abstract

A system comprises an inertial measurement unit comprising one or more gyroscopes configured to measure angular velocity about a respective one of three independent axes and one or more accelerometers configured to measure specific force along a respective one of the three independent axes; a magnetometer configured to measure strength of a local magnetic field along each of the three independent axes; and a processing device coupled to the inertial measurement unit and the magnetometer; the processing device configured to compute kinematic state data for the system based on measurements received from the magnetometer and the inertial measurement unit. The processing device is further configured to calculate magnetometer measurement calibration parameters using a first technique when position data is unavailable and to calculate magnetometer measurement calibration parameters using a second technique when position data is available.

Description

technical field

[0001] The present invention relates to systems and methods for magnetometer calibration and compensation. Background technique

[0002] A magnetic compass can be used to determine the vehicle's heading angle or as part of a vector matching algorithm to determine the vehicle's attitude (roll and pitch) and heading angles. A three-axis magnetometer, which measures all three components of the Earth's magnetic field, can still be used to determine the vehicle's heading angle even if the vehicle is tilted by some value of pitch and roll angles. However, the measurements of a magnetometer can be distorted by various types of magnetic disturbances in the vicinity of the magnetometer. Some types of magnetic perturbations, such as ferromagnetic materials, are known as "hard iron" biases and can add to the magnetic field measured by a magnetometer. Other types of magnetic perturbations, known as "soft iron" biases, can change the magnitude and direction of the magne...

Images