Let us take the mystery out of the Inertial Measurement Unit (IMU) and help you understand what it is, why it exists, and when calibrating your drone is necessary.
What the IMU actually does
The IMU measures and reports your drone’s specific force, angular velocity and attitude using data from an accelerometer, gyroscope, thermometer and barometer. In short, the IMU sets a baseline for your aircraft’s attitude and reduces errors caused by inaccurate sensor readings.
Signs your drone needs an IMU calibration
- The drone hovers at an angle without any stick input: the accelerometer needs calibrating
- The drone drifts or struggles to hold a stable hover: the gyroscope, which maintains attitude, needs a reset
- The drone takes a long time to warm up before flight
- The drone loses altitude during flight: the barometer, which measures height changes, may need recalibrating
How to calibrate correctly
- Let the drone cool down first. The temperature recorded during calibration becomes the reference for all future warm-ups, so calibrating hot means slow warm-ups later
- Place the drone on a genuinely flat, level surface
- Do not touch the drone during calibration
- Start with at least 50% battery
- Allow 5 to 10 minutes for the process to complete
How often is calibration needed?
Thanks to improvements in technology, modern drones need IMU calibration far less often than the early days, when one was required every other flight. One good habit remains: if you travel long distances with your drone, run an IMU calibration when you arrive, as the sensors can get knocked around in transit.
Still not sure when to calibrate? If you fly a DJI drone, like most pilots, the DJI app will tell you when it is needed. Get out there, capture some amazing footage and fly safely.