Flying a drone is all fun and games until you get a compass or calibration error.
Sometimes it may not show as an error, but you may observe your drone swaying, drifting, struggling to maintain its height, or even refusing to take off.
If you have never seen this before, don’t panic. Calibration is not that complex.
So, how do you calibrate a drone?
Each drone comes with specific calibration instructions, but the process often involves placing it on a level surface, rotating it at different axes, or connecting it to a PC.
Keep reading to learn more about calibrating your drone, its significance, and when to do it.
Drone calibration involves aligning and fine-tuning the drone’s internal and external sensors to establish an accurate reference point that will allow these sensors to stabilize the drone and do what you tell it.
Drone flight isn’t as easy as just powering up the motors and taking off. Many components are in play, and some of these are the sensors.
The sensors include the compass, IMU, accelerometer, gyroscopes, and gimbal. They allow the drone to take off and hover in the air and accurately take instructions from the controller.
If the sensors are not aligned or communicating correctly, it could lead to drifting, flyaways, or even fatal crashes.
Each drone has specific guidelines on calibration, but most of the concepts work similarly. Therefore, check your drone manufacturer’s instructions before attempting calibration.
Here’s what you need to calibrate your drone
A level surface: You must place your drone on a level surface to calibrate it correctly, whether the ground, a table, a piece of wood, or whatever it is.
USB cable: Some calibration processes may need you to connect your drone to a PC. That’s why you will need a USB cable.
Most drones come with a USB cable, but you can purchase a high-quality cable if yours doesn’t, or you lost it.
A string or a plumbline: You may need a string or plumbline to establish an accurately level surface.
When leveling, place the drone on a flat surface and use a string or a plumbline for horizontal and vertical alignment.
The string must have some weight, so consider adding a stone.
Before we go into how to calibrate your drone, let’s review the parts that need fine-tuning.
This will help you better understand the essence of calibrating them.
The compass is one of the most critical parts of a drone. It measures the earth’s magnetic field and orients the drone to true north, magnetic north, and other cardinal points.
That helps in navigating the drone. Here’s how.
Direction and reference: The compass establishes an accurate reference regarding compass directions.
Once it orients the drone about the Earth’s magnetic field, it can determine which way is north, south, east, or west.
This comes in handy, especially when controlling a drone beyond visual line of sight because all you have is a map and the drone’s position on the map.
Stability: Once the drone knows its orientation relative to the earth’s magnetic field, it will not drift or veer off the course you have set it in.
The compass constantly sends data to the flight controller, allowing it to adjust the motor power inputs to stabilize the drone’s flight at all times.
Return To Home functionality: Most drones now have an RTH capability that allows them to automatically fly back to the takeoff point in case of a lost connection or any other emergencies.
While GPS plays a significant role in the RTH function, it only shows the drone’s location.
On the other hand, the compass helps the drone know which way to face to fly back home.
If the compass is not working correctly, the drone may fly to a different location, flying away and crashing.
Waypoint navigation: Drones have waypoint capability.
I have used this feature to map and automate flights, especially when doing surveillance or inspections.
This feature is also useful when automating activities like crop spraying or mapping.
Like with RTH, the waypoint feature will not work if the drone can’t orient itself.
While the compass is vital to drone flight, it’s also susceptible to electromagnetic interference.
Metallic objects, power lines, electronics, or environmental factors like strong magnetic fields or high altitudes may disrupt the compass, necessitating calibration.
Due to such issues, the compass needs regular calibration to maintain accuracy and reliable flight and prevent issues like incorrect navigation or erratic flight behavior.
The IMU (Inertia Measurement Unit) is another vital drone component that maintains a drone’s stability, control, and orientation.
It comprises the accelerometer, gyroscopes, magnetometers, barometers, and other sensors, which collect data and send it to the IM, allowing it to make calculations and send information on the adjustments the flight controller should make to keep the drone stable.
The primary sensors in an IMU are the accelerometer and the gyroscope.
The accelerometer measures the drone’s linear motion in X, Y, and Z axes, allowing it to detect its velocity.
On the other hand, the gyroscopes measure the drone’s angular velocity and rotational motion in the same three axes.
By sending the information from these sensors, the flight controller can compensate for external forces like wind by adjusting the motor inputs, keeping the drone stable even in turbulence.
Drones that feature a barometer can maintain altitude since the barometer can measure changes in air pressure, and the flight controller adjusts the altitude accordingly.
Why you should calibrate the IMU regularly
Like with the compass, failing to calibrate the IMU could lead to unpredictable flights and even crashing.
As I have mentioned, the IMU plays a significant role in the drone’s stability and flight, and a small error could disrupt the overall drone’s performance.
If you observe a drone’s flight keenly, you will notice it vibrates a lot.
The shaking and drifting get even worse if there is wind or turbulence. However, if your drone has a camera, you will not see the vibration in the footage.
Why? Because camera drones have a gimbal.
Gimbals come in different sizes and types, but they all have one vital function: canceling out the drone’s vibration and shakiness to keep the footage stable.
When you want to do a POI (point of interest), hyperlapse, or create a cinematic video, the gimbal will help keep the camera level.
Why you should calibrate the gimbal regularly
The gimbal is one of the most sensitive parts of a drone and the most expensive.
Like with the IMU or compass, the gimbal is susceptible to calibration errors.
A poorly calibrated gimbal can lead to shaky and unusable footage or gimbal overload errors which, if not fixed, could cause damage to the gimbal.
As mentioned earlier, drone calibration for each drone might vary, with some only needing an app to calibrate.
Here is how to calibrate a drone correctly based on the most popular brand, DJI.
- Ensure your drone and the controller are fully charged.
- Power on the drone and the transmitter or remote control.
- Choose an open area without electronic interference for calibration.
- Follow the instructions the drone’s application or controller provides for compass calibration.
- Typically, this involves holding the drone parallel to the ground, rotating it horizontally and vertically until indicated by lights or prompts.
- Ensure no metal or magnetic objects are nearby during calibration, as they can interfere with the compass readings.
- Repeat the calibration process if any errors or issues occur.
- Place the drone on a level surface.
- Allow the drone to reach room temperature.
- Check the battery level, ensuring it is at least 50 percent or more for calibration.
- Open the drone application on your device and turn on the drone.
- Access the main controller settings, select the advanced settings or sensors, and choose to calibrate the IMU.
- Follow the drone application’s instructions, which may involve moving the drone in different directions as indicated on the screen.
- Restart the drone after the calibration to ensure proper initialization.
- Make sure the gimbal is connected to the drone correctly.
- Ensure nothing obstructs the gimbal, such as dust, rocks, or any other debris.
- Power on the controller, go to the camera settings, and scroll until you find gimbal settings.
- Click on gimbal calibration and follow the prompts provided by the app.
- The app will notify you once the calibration is complete.
This involves calibrating the magnetometer, which, as mentioned earlier, establishes accurate compass readings and is responsible for detecting the drone’s orientation relative to the earth’s magnetic field.
Calibrating the magnetometer involves placing it in an area free of electromagnetic interference.
It may also entail rotating the drone in various directions to collect data which will be used to set a baseline of reference for the drone.
To calibrate the gryoscope, you may have to place the drone on a level surface, and the drone will collect data which it will use to form a reference point.
As mentioned earlier, the accelerometer measures the drone’s linear velocity and the forces acting on it. You may have to place the drone stationary on a level surface to calibrate it.
You should get a notification when it’s done.
This calibration applies to drones with vision sensors, such as those with obstacle avoidance.
As the name suggests, these vision sensors “see” or detect obstacles, especially in areas without GPS.
The calibration of vision sensors may involve the drone taking images of the surroundings and creating a map for reference.
Note: Calibration of the gyroscope, accelerometer, and magnetometer is often done within the IMU calibration, and the whole process is usually automated. For most drones, you will not be asked to calibrate the vision sensors; the drone often does this automatically.
Below are some reasons you need to calibrate or recalibrate your drone.
- It’s a new drone.
- You’re updating the drone to the latest firmware version. Sometimes firmware updates mess up the previous drone settings.
- You have moved to a new geographic area.
- You’ve noticed a decrease in the drone’s performance.
- When the drone lands at high speed or on an irregular surface.
- When the drone takes long to respond to the commands you enter.
- When you notice the drone is unstable while flying or starts to drift in a certain direction.
- If the drone starts to lose altitude when flying.
- The drone begins to hover incorrectly at one altitude, yet the weather is calm, or there is not much wind to make it hover.
- The compass fails to work because a drone was placed or stored near magnets found in speakers or other devices.
Vibrations during transportation and drastic temperature changes can affect the drone’s sensors.
Regular calibration will help restore the sensors to optimal functioning.
How often you should calibrate your drone depends on factors like how often you use your drone, how often the manufacturer releases firmware updates, and any issues the drone may have faced as you use it.
Below are some guidelines on when to calibrate.
- New drone – Make sure you calibrate all sensors when you first get the drone.
- Relocation – If you move to a different location, recalibrate so the drone gathers info specific to that region.
- After Irregular flight, landing, or crashes.
- After a few months – Calibrate the sensors every four to six months to maintain optimum performance, even if your drone has been operating normally.
- After firmware updates in case the update disrupted the calibration.
If your drone still drifts or exhibits erratic flight behavior after calibration, the following steps can help you fix it.
- Confirm that you did the calibration correctly. The guidelines given above are general guidelines. Make sure you follow the instructions provided by the manufacturer.
- Check if there’s a new firmware update and update your drone. If you just updated your firmware and started experiencing erratic flight behavior, you can try downgrading to the previous versions.
- Check for physical damage, loose parts or connections, or worn-out parts such as propellers, hulls, or motors.
- Reach out to your drone manufacturer’s technical support team. Some drones may be shipped with defects, and fixing them may not be possible; the only option would be to get a replacement from the manufacturer.