$a$	Linear Acceleration
$\delta$	Dip Angle
$\eta$	Rotation Vector
$\varphi$	Roll Angle
$g$	Earth’s Gravity
$\mathsf{\Gamma }$	Weakening Effects
$K$	Kalman Gain
$\lambda$	Correlation Time Factor
$m$	Earth’s Magnetic Field
$\omega$	Angular Velocity
$P$	State Covariance
$Q$	Process Noise Covariance
$q_t^{nb}$	Unit Quaternion
$R$	Measurement Noise Covariance
$R_t^{nb}$	Rotation Matrix
$S$	Innovation Matrix
$\theta$	Pitch Angle
$v$	Measurement White Noise
$w_t$	Process Noise
$x$	Bias
$x_t$	System States
$y_t$	Measurement
$\psi$	Yaw Angle