公开(公告)号：US09915550B2

公开(公告)日：2018-03-13

申请号：US14418761

申请日：2013-08-01

Applicant: Memsic, Inc.

Inventor： Dong An ,  Yang Zhao ,  Haipeng Ding ,  Jong-Ki Lee

IPC: G01C17/38 ,  G01C25/00 ,  G06K9/62 ,  G01P21/00 ,  G01R35/00 ,  G01P15/00

CPC classification number: G01C25/00 ,  G01C17/38 ,  G01P15/00 ,  G01P21/00 ,  G01R35/00 ,  G06K9/6293

Abstract: Method and apparatus of integrating a three-axis magnetometer and a three-axis accelerometer to provide attitude and heading, calibrated magnetometer and accelerometer data, and angular rate, while removing sensor error sources over time and temperature and to compensate for hard and soft iron distortions of the Earth magnetic field. Filtered accelerometer data are corrected to account for various error sources. The magnetic heading is calculated from a horizontal magnetic field vector transformed from three dimensional Earth's magnetic field vector by using quasi-static roll and pitch angles from the filtered accelerometer data. A first Kalman filter estimates the state vector, based on the principle that the magnitude of local Earth's magnetic field vector is constant, to form hard and soft iron correction matrices. A second Kalman filter estimates a correction matrix of coupled remaining soft iron and the misalignment of the magnetometer and the accelerometer, as the dot product of local Earth's magnetic field vector and a corrected gravitational acceleration vector, at a quasi-static position, is constant. The three dimensional Earth's magnetic field vector is received by removing the hard and soft irons through the soft iron and hard iron correction matrixes.

公开(公告)号：US20150177020A1

公开(公告)日：2015-06-25

申请号：US14418761

申请日：2013-08-01

Applicant: Memsic, Inc.

Inventor： Dong An ,  Yang Zhao ,  Haipeng Ding ,  Jong-Ki Lee

IPC: G01C25/00 ,  G01P21/00 ,  G01R35/00

CPC classification number: G01C25/00 ,  G01C17/38 ,  G01P15/00 ,  G01P21/00 ,  G01R35/00 ,  G06K9/6293

Abstract: Method and apparatus of integrating a three-axis magnetometer and a three-axis accelerometer to provide attitude and heading, calibrated magnetometer and accelerometer data, and angular rate, while removing sensor error sources over time and temperature and to compensate for hard and soft iron distortions of the Earth magnetic field. Filtered accelerometer data are corrected to account for various error sources. The magnetic heading is calculated from a horizontal magnetic field vector transformed from three dimensional Earth's magnetic field vector by using quasi-static roll and pitch angles from the filtered accelerometer data. A first Kalman filter estimates the state vector, based on the principle that the magnitude of local Earth's magnetic field vector is constant, to form hard and soft iron correction matrices. A second Kalman filter estimates a correction matrix of coupled remaining soft iron and the misalignment of the magnetometer and the accelerometer, as the dot product of local Earth's magnetic field vector and a corrected gravitational acceleration vector, at a quasi-static position, is constant. The three dimensional Earth's magnetic field vector is received by removing the hard and soft irons through the soft iron and hard iron correction matrixes.

Abstract translation: 集成三轴磁力计和三轴加速度计的方法和装置，以提供姿态和航向，校准磁力计和加速度计数据以及角速率，同时消除传感器误差源随时间和温度，并补偿硬和软铁的失真 的地磁场。 过滤的加速度计数据被更正以解决各种错误源。 通过使用来自滤波的加速度计数据的准静态滚动和俯仰角从由三维地球磁场矢量变换的水平磁场矢量计算磁道。 第一卡尔曼滤波器基于局部地球的磁场矢量的大小恒定的原理来估计状态矢量，以形成硬和软铁校正矩阵。 第二卡尔曼滤波器估计耦合的剩余软铁的校正矩阵和磁力计和加速度计的未对准，因为在准静态位置处的局部地球磁场矢量和校正的重力加速度矢量的积积是恒定的。 通过软铁和硬铁校正矩阵去除硬和软铁来接收三维地球的磁场矢量。