imu_tools.h

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#ifndef IMU_FILTER_IMU_TOOLS_H_
#define IMU_FILTER_IMU_TOOLS_H_

#include <Eigen/Geometry>

namespace imu_filter
{
        namespace tools
        {

                static inline void remove_gravity( const Eigen::Quaterniond & orientation,
                                                                                   const Eigen::Vector3d & measured_acc,
                                                                                   const Eigen::Vector3d & acc_bias,
                                                                                   const Eigen::Vector3d & gravity,
                                                                                   Eigen::Vector3d & acc )
                {
                        acc = orientation * ( measured_acc - acc_bias ) + gravity;
                }

                static inline void perturb_orientation( const Eigen::Vector3d & angular_rate, Eigen::Quaterniond & rotation )
                {
                        Eigen::Quaterniond perturb_quat;
                        perturb_quat.coeffs().head<3>() = 0.5 * angular_rate;
                        perturb_quat.w() = 1;

                        rotation *= perturb_quat;
                        rotation.normalize();
                }
        }
}

#endif