5 THINGS TO LOOK FOR WHEN EVALUATING AN INERTIAL MEASUREMENT UNIT (IMU)

There are many different types of IMU, the three most common types of IMU for mobile mapping applications are:

  • Fibre Optic Gyro (FOG)
  • Ring Laser Gyro (RLG)
  • Micro Electro Mechanical Systems (MEMS)

Generally, FOG and RLG IMUs provide higher performance than a MEMS IMU, but this is not always the case. We highly recommend studying the specifications of each IMU carefully before deciding to ensure you get the right IMU for you.

What to look out for:

  • Roll, Pitch and Heading accuracy
    • Determines how accurate the measured values are compared to their true values
    • Impacts the positional accuracy of the pointcloud, positional error increases with range
  • Gyro-Bias
    • The lower the Gyro-bias the less effort is required for initialising the system
  • Gyro-RW
    • The noise of the sensor, which causes INS error to grow over time during GNSS outages
    • The lower the Gyro-RW the better the system will perform without GNSS
  • Measurement rate
    • The higher the measurement rate the less interpolation is required during laser scanner geo-encoding resulting in improved accuracies
  • Export Control
    • Can you easily move the IMU around the world or will you need an export license to do so?
top tips when evaluating an imu

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