Let’s take the mystery out of Internal Measurement Unit (IMU) and help you understand what it is, why it exists and when to Calibrate your Drone is necessary.
The IMU is a device that measures and reports a drones specific force, angular velocity and attitude by using data from an accelerometer, gyroscope, thermometer and barometer. Big words right there I know and we will describe what these mean also in a sec. In short in IMU helps set a standard for your aircraft attitude and therefore reduces errors caused by inaccurate sensor measurement
If your drone hovers at an angle without any commands then your accelerometer needs IMU Calibration. A gyroscope is a spinning wheel which the axis of rotation is free to assume orientation by itself. By calibrating this you help maintain the Drones attitude, so it can hover as stable as possible.
If your drone takes quite a while to ”warm up” then an IMU calibration is also needed. It is important to undertake an IMU calibration in a cooled environment as the temperature taken on the calibration will be the temperature used for all future “warm-ups”. So f you IMU calibrate in hot conditions, the drone will spend a long time warming up.
The barometer on your drone measures changes in height. If it is dropping altitude during flight it would be also worth doing an IMU calibration to reset and get it working correctly.
So remember a few things during an IMU calibration. Make sure the drone is cooled off, the surface you are conducting your calibration is on is a flat surface, that no ones touches the drone during calibration, and ensure you have a minimum 50% battery before you start. The IMU Calibration can take between 5-10 minutes then should be back to flying again safely again.
Due to improvements in technology these days, with Mavic and new Phantoms, the need for IMU calibrations is becoming less and less frequent compared to the good old days where one was required every other flight. If you are travelling far distances with your drone I would recommend an IMU calibration when landing in a new country as the drone’s sensors can get knocked around a little during flights.
Still confused when to conduct an IMU calibration? Don’t worry as if you are one of the 98% of the population that uses a DJI drone, the DJI app will tell you when to do it. Get out, capture some amazing footage and fly safely.