• Can the magnetometer data be neglected from the VN-200 INS solution?

    Yes, the VN-200 only uses the magnetometer data at startup to generate an initial heading and is tuned out of the navigation solution once sufficient dynamic motion is achieved.

    The user can configure the VN-200 to tune the magnetic measurements in or out of the solution as desired.

  • How the magnetometer measurements are used in the attitude estimation?

    The VN-100/VN-200 EKF relies on comparing measurements from the onboard inertial sensors to two reference vectors in calculating the attitude estimates: gravity down and magnetic North. Measurements from the three-axis accelerometer are compared to the expected magnitude and direction of gravity in determining the pitch and roll angles while measurements from the three-axis magnetometer are compared to the expected magnitude and direction of Earth’s background magnetic field in determining the heading angle (i.e. yaw angle with respect to Magnetic North).

  • What is the Hard/Soft Iron Estimator?

    Hard and soft iron distortions are local magnetic field distortions created by nearby ferrous material that move with the sensor (attached to the same vehicle or rigid-body as the sensor). These ferrous materials distort the direction and magnitude of the local measured magnetic field, thus negatively impacting the ability of an AHRS to reliably and accurately estimate heading based on the magnetometer measurements.

    To remove the unwanted effect of these materials, a hard & soft iron calibration needs to be performed, which requires rotating the sensor around in multiple circles while collecting magnetic data for off-line calculation of the magnetic hard & soft iron calibration coefficients. This calibration can be very time consuming, and might not be possible for some applications.

  • How to estimate the Hard/Soft Iron compensation?

    Hard/Soft Iron Compensation:

    • Sensor Explorer Provides 3D & 2D HSI Tools
    • On-board HSI Calibration
      • Auto-background Mode w/Configurable Convergence Rate
      • Manual Calibration
    hard soft iron calibration

    Hard Soft Iron Calibration Wizard
  • What are the Limitations if the individual Magnetometer Sensors?

    The Magnetometer error sources include Hard/soft iron effects, Nearby batteries, motors, ferrous materials, etc.