Table 1.
Explanation of symbols used in Equations (1) and (2).
ax | Acceleration in the X direction relative to the IMU sensor coordinate frame (m/s2) |
ay | Acceleration in the Y direction relative to the IMU sensor coordinate frame (m/s2) |
az | Acceleration in the Z direction relative to the IMU sensor coordinate frame (m/s2) |
dt | Measurement time interval (s) |
θ | Current needle angle relative to ground surface (deg) |
θ0 | Previous needle angle relative to ground surface (deg) |
θx | Needle angle derived from gravitational acceleration (deg) |
ν | Angular velocity measured by gyroscope (deg) |