Chapter 1. Product Overview
1.1 Product Features
1. Open-Source Ecosystem Support
The UniFC 6 PICO autopilot supports a wide range of feature‑rich SIYI products and open‑source ecosystem products, easily meeting diverse application needs. By combining high‑performance firmware and software including PX4, ArduPilot, UniGCS, QGroundControl, and Mission Planner, it supports a broad spectrum of use cases and delivers a powerful system‑level solution for users.
At the same time, it lowers the entry barrier for developers, providing a comprehensive development platform that facilitates application development.
2. Dual IMU & dual barometer redundancy, with IMU heating.
The UniFC 6 PICO features built‑in dual IMU redundancy, dual barometer redundancy, and dual magnetometer redundancy (combining the GPS module’s magnetometer with the onboard magnetometer). An integrated heating resistor ensures stable IMU operation even in low‑temperature environments. This comprehensive system design greatly enhances flight stability and reliability.
3. H7 processor with dual‑precision floating‑point unit.
The UniFC 6 PICO flight controller is powered by the STM32H743IIK6 processor, featuring a dual‑precision floating‑point unit (DSP & FPU), a 480 MHz core frequency, 2 MB of flash memory, and 1 MB of RAM. This delivers powerful computing capabilities and high‑speed data processing, significantly enhancing flight stability and opening up broader possibilities for functional development.
1.2 Interface and Pin Definitions
Note
The TELEM1 interface provides 5V output with a continuous current capacity of 1.5A. For all other interfaces, the total continuous current draw from the 5V outputs must not exceed 1.5A. The 5V output on RC_IN is rated for 0.6A continuous current.
1.3 Serial, PWM, and GPIO Configuration Options
Below is the ArduPilot UART mapping for the UniFC 6 PICO autopilot:
| SERIAL 0 | USB |
| SERIAL 1 | TELEM1 (USART2) |
| SERIAL 2 | TELEM2 (USART6) |
| SERIAL 3 | GPS1 (UART1) |
| SERIAL 4 | GPS2 (UART4) |
| SERIAL 5 | SERIAL5(UART3) |
| SERIAL 6 | USB2 |
The TELEM1 and TELEM2 ports are equipped with RTS/CTS pins; other UARTs do not have RTS/CTS.
Note
For more information on serial port configuration, please visit:
https://ardupilot.org/copter/docs/common-serial-options.html
Below is the ArduPilot PWM output mapping for the UniFC 6 PICO autopilot:
| Group | FC PWM Physical Channels | Timer |
| 1 | 1-4 | TIM1 |
| 2 | 5-8 | TIM4 |
| 3 | 9-12 | TIM5 |
| 4 | 13–14 (No Dshot output) | TIM12 |
Note
PWM outputs within the same group must use the same output rate and protocol. If any channel in a group uses DShot, then all channels in that group must use DShot.
BDshot (bidirectional DShot) is supported on channels 1–8 in ArduCopter, ArduPlane, ArduRover, and ArduCopter‑Heli firmware.
Channels 1–14 support switching between 3.3V and 5V PWM output voltage.
In ArduPilot, this can be configured via the BRD_PWM_VOLT_SEL parameter. The default output is 3.3V.
In PX4, switching is done via the PWM_LEVEL_CONT parameter. The default output is 3.3V.
Below is the ArduPilot GPIO mapping for the UniFC 6 PICO autopilot:
| FC physical PWM ports | GPIO |
| 1 | GPIO（50） |
| 2 | GPIO（51） |
| 3 | GPIO（52） |
| 4 | GPIO（53） |
| 5 | GPIO（54） |
| 6 | GPIO（55） |
| 7 | GPIO（56） |
| 8 | GPIO（57） |
| 9 | GPIO（58） |
| 10 | GPIO（59） |
| 11 | GPIO（60） |
| 12 | GPIO（61） |
| 13 | GPIO（62） NODMA |
| 14 | GPIO（63） NODMA |
To use a pin as GPIO, set SERVOx_FUNCTION to -1. If set to 0, the pin functions as a PWM output.
For example:
SERVO1_FUNCTION controls FC PWM output port 1.
SERVO14_FUNCTION controls FC PWM output port 14.
Note
For more information on GPIO configuration, please visit:
Caution
The current drawn from GPIO pins, whether configured as input or output, should be limited to 8mA (absolute maximum: 20mA). These are logic‑level I/Os and must not be used to directly drive relay coils, motors, LED strings, or similar loads. Connecting electromechanical or high‑current devices directly to GPIO pins may cause permanent damage to the UniFC 6 PICO.
Below is the PX4 UART mapping for the UniFC 6 PICO autopilot:
| UART | Device | Port |
| UART1 | /dev/ttyS0 | GPS1 |
| UART2 | /dev/ttyS1 | TELEM1 |
| UART3 | /dev/ttyS2 | SERIAL5=TELEM3 |
| UART4 | /dev/ttyS3 | GPS2 |
| UART6 | /dev/ttyS4 | TELEM2 |
| UART8 | /dev/ttyRC | RC_IN |
1.4 Typical Connection Diagram
1.5 Technical Specifications
Hardware
| Main Processor | STM32H743IIK6 (32 Bit Arm ® Cortex®-M7, 480MHz, 2MB memory, 1MB RAM) |
Sensor
| Accelerometer / Gyroscope | ICM45686/BMI088 |
| Compass | IST8310 |
| Barometer | ICP20100 x2 |
Interface
| UART Serial Port | 5 |
| I2C | 3 |
| CAN Port | 2 |
| PWM Output | 14 |
| RC IN (SBUS、PPM) | 1 |
| PM Power Module Input | 1 |
| USB Port (Type-C) | 1 |
| TF Card Slot | 1 |
Overall
| Models | PX4 / ArduPilot Firmware (Fixed-wing, 3–8 axis multi-rotor, helicopter, VTOL, ugvs, usvs, etc.) |
| Power Port Operating Voltage | 4.5 ~ 5.5 V |
| USB Input Voltage | 5 V (±0.25 V) |
| Servo Input Monitoring Voltage | 0 ~ 9.5V |
| Operating Temperature | -30 ~ 60 ℃ |
| Dimensions | 49×42.6×16.2 mm |
| Weight | About 40g |
Note
To ensure smooth and stable flight log recording, please format the SD card as FAT32 with an allocation unit size of 64 KB before use.
1.6 Package List
| Base Kit | GPS Kit |
| 1 x UniFC 6 PICO Autopilot 1 x Flight Controller Power Module | |
| 1 x UniGNSS M10 Module | |
| 2 x I2C / CAN Adapter Cable | |
| 1 x TELEM1 Adapter Cable | |
| 1 x S.Bus Adapter Cable | |
| 1 x Ethernet Cable | |
| 1 x USB to Type-C Cable | |
| 3 x 3M Double‑sided tape (4×2 cm) | |
1.7 Package List
Rapid alternating red and blue flashes: Initializing (calibrating gyroscope, etc.)
Alternating red‑green‑blue flashes: Saving trim settings, or compass/ESC calibration in progress.
Alternating red and yellow flashes: Kalman filter failsafe.
Alternating blue and yellow flashes: GPS fault.
Rapid yellow flashing: Radio, GCS, or Battery failsafe triggered.
Solid green: Armed – GPS 3D Fix.
Solid blue: Armed – No GPS lock.
Double yellow flash: Disarmed – Pre‑arm check failed.
Rapid green flashing: Disarmed – DGPS Fix.
Slow green flashing: Disarmed – GPS Fix.
Slow blue flashing: Disarmed – No GPS lock.
Chapter 2. First-Time Setup
If you are new to open‑source flight controllers, we recommend visiting the official documentation for your specific firmware to find detailed user guides and tutorials.
ArduPilot Official Documentation:
PX4 Official Documentation:
2.1 Installing the Ground Control Station Software
The ground station software allows you to configure the flight controller, monitor flight status, and control all vehicle attitudes during operation.
Note
It is recommended to use Mission Planner, SIYI UniGCS for Android, or SIYI UniGCS for Windows for parameter tuning.
The following documentation is based on ArduCopter v4.7.0dev.
UniGCS-3.0.1-v527b7522-setup.exe
Download the UniGCS:
Download the Mission Planner：
https://firmware.ardupilot.org/Tools/MissionPlanner/MissionPlannerlatest.msi
2.2 Firmware Update
The UniFC 6 PICO autopilot supports firmware updates via the UniGCS ground station software.
Before performing a firmware update, please prepare the following tools, firmware, and software:
- UniFC 6 PICO Autopilot
- Ardupilot Firmware
- UniGCS for Windows
- Flight controller update cable (Type‑C to USB‑A)
Note
The above tools and firmware are available on the relevant product pages of the SIYI official website (https://siyi.biz).
The ArduPilot firmware for the UniFC 6 PICO provided on the SIYI website is the initial release version at the time of publication. For the latest ArduPilot features, we recommend syncing to the most recent official ArduPilot firmware.
Firmware Upgrade Steps
1. Install the UniGCS ground station software on your Windows device.
2. After installation, connect the flight controller to your Windows device using the provided data cable – plug the USB end into your computer and the Type‑C end into the FC’s update port. Once connected, Windows will automatically detect and install the correct drivers.
3. Launch UniGCS and refer to the picture below. Open the COM port dropdown list in the upper‑right corner of the ground station. Select Serial as the port type, set the baud rate to 57600, and click Connect.
4. In the UniGCS ground station, click here to access more parameter settings.
5. Click the aircraft icon to enter the flight controller parameter settings interface, then locate Firmware Update. Click to enter update mode – the FC will switch to update mode – then select the firmware you wish to flash and proceed with the update.
6. If everything goes smoothly, you will see status updates in the lower‑left corner, including “Erasing…”, “Writing…”, “Verifying…”, and “Upload complete”. At this point, the firmware has been successfully uploaded to the flight controller board.
Note
Updating the flight controller firmware to a different version for the same airframe will not change existing parameters.
If you update the firmware for a different airframe type, the parameters will be reset to the default values for that airframe.
To avoid unintended parameter resets, we recommend exporting your parameters using the “Export Parameters” button in the “Vehicle → Parameter List” tab of UniGCS before updating. After the update, you can re‑import them.
2.3 Installing the Autopilot
The autopilot should be mounted close to the vehicle’s center of gravity, both horizontally and vertically. Generally, this means placing the autopilot as close as possible to the center of the vehicle’s horizontal plane and at the same level as the motors.
If the autopilot is mounted away from the vehicle’s center of gravity, the IMU position offset parameters must be configured accordingly.
2.3.1 Installation Orientation
The arrow on the autopilot casing should point toward the front of the vehicle.
2.3.2 Installing the GPS Module
It is recommended to mount the GPS module away from the autopilot board to minimize magnetic interference, and to keep it facing the sky with the best possible clear view for optimal satellite reception.
Note
The arrow on the GPS module casing should point in the same direction as the vehicle’s nose.
When installing the GPS module:
- It should be mounted externally on the vehicle (As high as possible), facing the sky with a clear, unobstructed view, and positioned as far as possible from motors, ESCs, and wireless devices.
- Keep at least 10 cm of separation from DC power cables and batteries.
- Keep it away from metal objects (non‑magnetic mounts such as plastic or aluminum are recommended).
- If possible, twist the power and ground wires together.
2.3.3 Motor ID and Rotation Direction
The following diagrams show the motor numbering sequence for common frame types. The numbers correspond to the flight controller’s output pins. Propeller rotation directions are indicated in green for clockwise (CW) and blue for counter‑clockwise (CCW).
Common Airframe Types and Motor ID
4-axis Multi-Rotor UAV
6-axis Multi-Rotor UAV
8-axis Multi-Rotor UAV
4‑axis 8‑rotor UAV
Note
The UniFC 6 PICO autopilot with ArduPilot firmware supports a wide range of airframe types. For more information, please visit:
https://ardupilot.org/copter/docs/connect-escs-and-motors.html
2.3.4 Vibration Damping
The high‑precision accelerometer on the autopilot is highly sensitive to vibration. Accelerometer readings, along with barometer and GPS data, are used to calculate the aircraft’s position. If severely affected by vibration, position and altitude calculations will experience significant errors, which can seriously degrade performance in modes that rely on precise positioning, such as AltHold, Loiter, RTL, Guided, Position, and Auto Flight modes.
Note
For guidance on measuring flight controller vibration, we recommend visiting the official ArduPilot link below:
https://ardupilot.org/copter/docs/common-measuring-vibration.html#common-measuring-vibration
The principle of vibration damping is to reduce high‑frequency and mid‑frequency vibrations, while allowing the low‑frequency vibrations caused by the flight controller board’s movement to remain synchronized with the overall motion of the aircraft.
Note
The UniFC 6 PICO autopilot has no built‑in vibration damping. For airframes with high vibration levels, the use of an external damping plate is recommended.
Recommendations for Vibration Damping
The primary source of vibration on a multi‑rotor drone during flight is the passage of the spinning propellers over the arms. Other vibration sources also exist, but most can be reduced by taking the following measures:
- The airframe – especially frame flex – is a major cause of asynchronous vibration. Please choose an airframe and arms with sufficient rigidity whenever possible.
- Ensure that the motors, motor mounts, arms, and frame are securely installed and free from deformation.
- Motors run smoothly (bearings show no signs of wear or noise).
- The propeller mounts and motors must be concentric and perfectly aligned. Propellers should be well‑balanced when installed.
- Propellers are dynamically balanced, with no visible warping or damage.
- All connecting cables between components are securely fastened and do not bounce.
- All wiring connected to the flight controller should use flexible connections.
2.3.5 Magnetic Interference
Magnetic interference on the flight controller’s compass can seriously affect navigation. This chapter covers hardware measures you can take to reduce compass magnetic interference.
Caution
Multi-rotor drones rely heavily on compass guidance for navigation. Alternatively, users may install an RTK module as a replacement for the compass.
Optimizing Autopilot Mounting to Reduce Compass Magnetic Interference
- Prioritize using an external compass, and mount the compass module on a mast to keep it away from magnetic interference sources, including the power distribution board.
- Keep the cables between the power distribution board, ESCs, and battery as short as possible. The three‑phase wires from the ESCs to the motors are less critical, as they carry AC and generate less interference.
- Twist the wires between the power distribution board, ESCs, and battery, and use shielded cables where possible.
- Consider using a 4‑in‑1 ESC instead of separate PDB and ESCs, as they tend to generate less interference – likely due to shorter cables, closer component placement, and the integrated aluminum plate on top that also helps reduce interference.
- Adding aluminum foil shielding around the ESC‑to‑motor cables may help reduce AC interference. However, aluminum foil is not effective for reducing DC interference.
Note
For more detailed information on magnetic interference, please visit:
https://ardupilot.org/copter/docs/common-magnetic-interference.html#common-magnetic-interference
2.4 Mandatory Autopilot Parameter Configuration
This section covers the hardware that requires mandatory parameter configuration before the first flight.
Note
This chapter is compiled based on the SIYI ecosystem products centered around the UniFC 6 PICO autopilot. For more information on hardware commonly used within the ArduPilot ecosystem, please visit:
2.4.1 Basic System Overview
SIYI Technology will be showcasing a selection of typical productivity ecosystem combinations built around the UniFC 6 PICO autopilot, along with their usage guidelines – stay tuned!
2.4.2 Airframe Type
You can modify the airframe type in the UniGCS interface.
Alternatively, you can modify the FRAME_CLASS and FRAME_TYPE parameters in the full parameter list to match the airframe you are using. For more details, please refer to Section 2.3.3 of this manual.
2.4.3 Motor ID and Direction
Please refer to Section 2.3.3 of this manual for basic information on motor ID and direction.
Connecting ESCs and Motors
This section describes how to connect ESCs, motors, and propellers to the UniFC 6 PICO autopilot.
1. In motor numbering order, connect the ground pin (–) and signal pin (S) of each ESC to the corresponding main output pins on the flight controller.
2. Refer to your airframe type to assign the correct motor output order.
2.4.4 Remote Controller Calibration
This section explains how to perform remote controller calibration using UniGCS.
Remote controller calibration captures the maximum, minimum, and trim values of each RC channel, allowing ArduPilot to correctly interpret the channel outputs.
Remote Controller Calibration Procedure
1. Make sure your remote controller and receiver are bound and communicating properly with the autopilot.
2. Connect the autopilot to your PC and launch UniGCS.
3. Click Vehicle → Remote Controller → Calibrate.
4. Move the sticks, switches, and knobs to verify the channel mapping of the remote controller.
5. Click the Calibrate button, then Confirm – and verify that the remote controller is on, the aircraft is powered, and the propellers are not installed.
6. Move the sticks, knobs, and switches on your remote controller to their full travel limits. The red lines on the channel progress bars indicate the maximum and minimum values captured during calibration.
7. UniGCS will display the calibration results. Typically, the maximum output value should be around 1900 and the minimum around 1100.
About Remote Controller Mode 1 and Mode 2
There are two main throttle stick types for remote controllers:
- Mode 1: Throttle on the right stick.
- Mode 2: Throttle on the left stick.
Channel Mapping
For a multi‑rotor drone, the default channel mapping on the flight controller is as follows:
- Channel 1: ROLL
- Channel 2: PITCH
- Channel 3: THROTTLE
- Channel 4: YAW
- Channel 5: Flight mode
Note
The “RC IN” port on the UniFC 6 PICO autopilot supports both S.Bus and PPM signal inputs.
2.4.5 Accelerometer Calibration
This section describes how to perform a six‑position accelerometer calibration for the UniFC 6 PICO autopilot using UniGCS. The calibration corrects accelerometer sensitivity, zero‑offset, and inter‑axis errors. During the procedure, the flight controller is placed in six different orientations to record output values for each position, allowing the accelerometer error model to be determined. Six‑position calibration significantly improves accelerometer accuracy and reliability.
Warning
Accelerometer calibration is a mandatory procedure for the flight controller.
Caution
Do not perform accelerometer calibration while the aircraft is armed. If the flight controller is mounted in a non‑standard orientation (i.e., the arrow does not point toward the vehicle’s heading), make sure the AHRS_ORIENTATION parameter is set correctly before performing accelerometer calibration.
Calibration Steps:
1. Click the “Vehicle → Accelerometer” and perform the accelerometer calibration.
2. Click Calibrate to begin the full three‑axis calibration.
3. UniGCS will prompt you to place the aircraft in six different orientations during calibration. At each orientation, click Next to let the ground station know the FC is in position, then continue to the next orientation.
The six calibration orientations are:
- Level
- Left side
- Right side
- Nose down
- Nose up
- Upside down (back)
4. At each calibration orientation, the flight controller must remain perfectly still immediately after you start the step – this is even more important than achieving the exact angle. Except for the first “Level” orientation, the other orientations may tolerate an angular error of up to 20 degrees.
Level Calibration
The level position is the most critical calibration orientation, as this is the attitude that the flight controller will consider as “level” during flight.
You can also re‑calibrate the level position using UniGCS before installing the flight controller and preparing for flight. Simply place the vehicle in its level flight attitude and click Level Calibrate in the ground station.
Note
Level calibration can only correct angular errors of up to 10 degrees between the initial and final attitudes, and it only adjusts errors on the pitch and roll axes – not on the yaw axis.
2.4.6 Compass Calibration
Before performing compass calibration, make sure your flight controller system has at least one compass – either internal or external – and that it is enabled.
Caution
Do not calibrate the compass near metal parts or magnetic objects (such as computers, phones, metal tables, power supplies, etc.) to avoid calibration failure.
Please prioritize setting the external compass as the primary compass.
Calibration Steps:
1. Launch UniGCS, navigate to Vehicle → Compass, and select Compass Calibration.
2. Click the Start button. If your flight controller has a buzzer connected, you should hear a repeating alert tone once per second along with brief beeps.
3. Hold the aircraft off the ground and point each side (front, back, left, right, top, and bottom) toward the ground in turn, holding each position for a few seconds. Alternatively, perform full 360° rotations – each time pointing a different side of the aircraft toward the ground – and repeat for all six orientations.
4. As you rotate the aircraft, the progress bar will gradually advance until the calibration is complete.
5. When calibration succeeds, the buzzer will sound and a prompt window will appear saying “Please reboot the flight controller”. At this point, you need to restart the flight controller.
Calibration Failure Scenarios
1. The buzzer will sound a failure alert, the progress bar may reset to the left, and the calibration process may restart. UniGCS will automatically retry the calibration, so please continue following the steps outlined above.
2. If calibration continues to fail, try moving to an area free from magnetic interference and away from electronic devices that may cause disturbances.
3. Finally, you may disable the compass that keeps failing calibration and set a reliable one as the primary compass.
Note
Some 900 MHz telemetry radios may interfere with the compass and affect calibration.
2.4.7 Remote Controller Flight Mode Configuration
This chapter explains how to set up to six flight modes on the flight controller using your remote controller.
The mapping between switch positions and flight modes can be configured in the UniGCS Flight Mode menu.
Steps
1. Launch UniGCS and navigate to Vehicle → Flight Modes.
2. Configure the flight modes using the dropdown options.
3. (Multi‑rotor) Ensure at least one switch position is assigned to STABILISE mode.
4. Remember to save the configuration when finished.
Note
ArduPilot supports a wide range of flight modes. For detailed information, please visit the following link:
https://ardupilot.org/copter/docs/flight-modes.html
2.4.8 ESC Calibration
The ESC is responsible for spinning the motor at the speed commanded by the flight controller. Most ESCs require calibration to ensure the motor correctly interprets the minimum and maximum PWM values sent by the FC.
Caution
Before performing ESC calibration, make sure your drone does not have propellers installed, the flight controller is not connected to the PC via USB, and the battery is disconnected.
Note
For more information on ESC calibration, please visit the following link:
https://ardupilot.org/copter/docs/esc-calibration.html
Chapter 3. First Flight and Tuning
This section covers what you need to know before your first flight, along with some basic configurations to help your multi‑rotor drone fly smoothly.
3.1 Pre‑Arm Safety Checks
ArduPilot includes a set of pre‑arm safety checks that prevent the vehicle from arming if any issues are detected – such as incomplete calibration, configuration errors, or abnormal sensor data. These checks help prevent crashes or loss of control, though some of them can be disabled in certain cases.
Caution
Never disable the pre‑arm checks (i.e., do not set ARMING_CHECK to a value other than 1) unless you are performing bench tests. Before any actual flight, you should resolve any pre‑arm or arming failure issues. Failure to do so may result in losing the aircraft.
Common Arming Failure Reasons
- check firmware or FRAME_CLASS: Please select the airframe type.
- 3D Accel calibration needed: Accelerometer calibration is required.
- safe switch: Safety switch not triggered – press and hold until the LED stays solid.
- RC not calibrated: Remote controller not calibrated.
- Baro not healthy: Barometer not healthy.
- Alt disparity: Barometer and inertial navigation system altitude disagreement exceeds 2 meters. This message is usually temporary.
- Compass not healthy: Compass not healthy.
- Compass not calibrated: Compass not healthy.
- Compass offsets too high: Compass offset too large – possibly due to nearby metal or other interference.
- Check mag field: The sensed magnetic field in this area is 35% higher or lower than expected – recalibration of the compass is required.
- Compasses inconsistent: The internal and external compasses point in different directions (more than 45° apart). This is usually caused by inconsistent placement of the external GPS/compass module.
- GPS Glitch: GPS failure. This prompt appears when the selected flight mode requires GPS positioning or when geofencing is enabled, and GPS has not acquired a fix.
- Need 3D Fix: The GPS does not have a 3D fix. This prompt appears when the selected flight mode requires GPS positioning or when geofencing is enabled, and GPS has not acquired a fix.
- High GPS HDOP: GPS accuracy is lower than 2.0 (i.e., HDOP > 2.0). You can check real‑time GPS accuracy data on the main page.
- INS not calibrated: The accelerometer has not been calibrated.
- Accels not healthy: The accelerometer is not healthy – this could indicate a hardware issue, or it may occur after firmware update without a reboot.
- Accels inconsistent: Accelerometer readings differ by more than 1 m/s².
- Gyros not healthy: The gyroscope is not healthy – this could indicate a hardware issue, or it may occur after a firmware update without a reboot.
- Gyro cal failed: The gyroscope calibration failed to capture the offset. This is usually caused by moving the flight controller during startup calibration – the moment when the LED flashes red and blue.
- Gyros inconsistent: Gyroscope readings differ by more than 20°/s.
- Check Board Voltage: The board voltage should be between 4.3V and 5.8V. If powered via USB, try using a different port or cable.
- Ch7 & Ch8 Opt cannot be same: Channels 7 and 8 cannot be set to the same option.
- Check FS_THR_VALUE: Channel 3 minimum value is too close to the failsafe threshold.
- Check ANGLE_MAX: Verify the ANGLE_MAX parameter.
3.2 Arming and Disarming
3.2.1 Arming the Motors
Arming the vehicle means the motors will start spinning. Before arming, make sure all personnel, objects, and any body parts (such as hands) are clear of the propellers. Then follow these steps:
- Turn on the remote controller.
- Power on the flight controller. The red and blue LEDs should flash for a few seconds while the gyroscope is calibrating – do not move the vehicle during this time.
- The pre‑arm checks will run automatically. If any issues are detected, the GPS LED will flash yellow and the ground station will display the corresponding failure message.
- Make sure your flight mode switch is set to Stabilize, AltHold, Loiter, or PosHold.
- Press the flight controller safety switch until the LED turns solid.
- If you plan to use an autonomous mode (such as Loiter, RTL, or Auto), switch the vehicle to Loiter or PosHold and wait for the LED to flash green, indicating a good GPS signal.
- Arm the motors by moving the throttle stick to the lowest position and holding the rudder stick to the right for 5 seconds. Do not hold the rudder to the right for too long (more than 15 seconds), as this will trigger the auto‑calibration function.
- Once armed, the LED will remain solid and the propellers will start spinning.
- Push the throttle to take off.
Note
In any of the above flight modes, the motors will automatically disarm if the throttle is kept at the lowest position for 15 seconds.
3.2.2 Disarming the Motors
Disarming the motors will cause them to stop spinning. To disarm the motors, follow these steps:
- Make sure your flight mode switch is set to Stabilize, ACRO, AltHold, Loiter, or PosHold.
- Keep the throttle at the lowest position and move the rudder stick to the left for 2 seconds.
- The LED will begin to flash, indicating that the vehicle has disarmed.
- Press the flight controller safety switch until the LED starts flashing.
- Disconnect the battery.
- Turn off the remote controller.
Note
For detailed information on arming and disarming, please visit the following link:
https://ardupilot.org/copter/docs/arming_the_motors.html
3.3 Takeoff – Tips for Beginners
This page provides initial flight strategy recommendations for those with little or no experience flying RC aircraft or multi‑rotors.
3.3.1 First Flight
Place the multi‑rotor on flat ground and connect the battery. Do not move it until gyro calibration is complete (LEDs flashing red and blue alternately). Make sure your remote control mode switch is set to Stabilize mode. Slowly increase the throttle until the multi‑rotor lifts off gently. (In Stabilize mode, the throttle stick directly controls the motor output, with no altitude‑hold assistance.)
- If it appears to flip over or does not rise straight up during takeoff, this may be due to an incorrect frame type selection, miswired motors, or incorrect propeller rotation direction.
- If any controls are reversed (i.e., pitch or roll is inverted, causing the multi‑rotor to move in the opposite direction of your stick input), you will need to reverse the affected channel on your remote controller. If you are unfamiliar with this procedure, please refer to your remote controller’s user manual. After reversing the channel, it is recommended that you re‑calibrate the remote controller in the ground station software.
- If it lifts off smoothly, you may notice a slight yaw drift. The yaw angle should not exceed 30 degrees, and it will typically correct itself over more flight time. There should be no significant oscillation – if there is, it may indicate unbalanced propellers or motors.
- The multi‑rotor should also tend to stay in place and not constantly drift left, right, forward, or backward. If you do observe this behavior, do not use your remote controller’s trim function. Instead, it may indicate that the multi‑rotor was not perfectly level during calibration, or that the frame is uneven (e.g., one motor tilted). Land and correct the issue.
- Assuming everything has been fine so far, you can try more advanced modes such as Altitude Hold and Loiter.
3.3.2 First Flight Tips
- Make sure you are flying in a calm, wind‑free environment.
- Make sure your remote controller has no trim adjustments applied (trims should never be used on the remote controller).
- After connecting the battery, keep the multi‑rotor still and level to allow the gyroscope to initialize.
- At an altitude above ground effect – approximately 2–3 meters high.
- We recommend not starting with Simple mode. Begin with the basic Stabilize mode instead.
- The multi‑rotor records the home position when it arms. Therefore, arm your multi‑rotor at the location you want to set as the home point.
- Always keep clear of people and buildings.
3.4 Measuring Vibration
The flight controller’s accelerometer is highly sensitive to vibration. Accelerometer data is combined with barometer and GPS data to estimate the vehicle’s position. If subjected to excessive vibration, the estimation may become inaccurate, leading to degraded performance in flight modes that rely on precise positioning – such as AltHold, Loiter, RTL, Guided, Position, and Auto modes on multi‑rotors.
This section describes how to measure vibration levels.
3.4.1 Ground Station Real‑Time View
The ground station can display a real‑time view of vibration and clipping. Click on Vibe in the UniGCS HUD to show the current vibration level.
Vibration levels below 30 m/s² are generally acceptable. Levels above 30 m/s² may cause issues, and levels above 60 m/s² will almost certainly lead to problems with position or altitude hold.
Note
For more information on measuring vibration, please visit the following link:
https://ardupilot.org/copter/docs/common-measuring-vibration.html
3.5 Thrust Loss and Yaw Imbalance Alerts
If you observe thrust loss or yaw imbalance alerts, the troubleshooting methods outlined on this page can help resolve the issue. In most cases, these alerts are caused by incorrect hardware selection or configuration.
These alerts are designed to detect hardware faults in the propulsion system. If they begin to appear on an aircraft that previously had no such warnings, the propulsion system should be inspected. These warnings are more likely to occur under heavier loads and in strong or gusty wind conditions.
3.5.1Potential Thrust Loss
If you see a potential thrust loss message in the ground station or dataflash logs, you should investigate to determine the cause and solution. The alert will indicate a motor number, for example:
“Potential Thrust Loss (3)”
These warnings are caused by one or more motors reaching 100% throttle saturation. Because of this saturation, ArduCopter can no longer achieve the requested roll, pitch, yaw, and throttle outputs. If this persists for an extended period, the drone will lose altitude and attitude control, and may crash.
If these messages appear during hover or relatively gentle flight, the issue must be resolved through hardware changes. Increasing the aircraft’s thrust‑to‑weight ratio can be achieved by upgrading the propulsion system or reducing the mass.
If the messages appear only during climbs or aggressive maneuvering, reducing the required acceleration and speed may be sufficient. Similarly, increasing the aircraft’s thrust‑to‑weight ratio can allow for higher acceleration and speed.
3.5.2 Yaw Imbalance
The yaw imbalance alert is a measure of how difficult it is for the drone to perform yaw maneuvers. This alert triggers before the yaw output saturates. If the yaw output reaches saturation, the drone’s ability to maintain heading will be impaired. In the worst case, the drone may spin rapidly. The alert message displays the percentage of maximum yaw output – 100% indicates saturation. For example:
“Yaw Imbalance 87%”
If this alert is observed during hover, the issue should be addressed through hardware changes. If the value continues to increase without pilot yaw input, the aircraft should be landed immediately. Yaw imbalance can be identified in the dataflash logs by comparing PWM outputs between opposite motors. It will appear as a difference in throttle levels between clockwise and counter‑clockwise motors, as shown below:
This issue should be addressed through hardware changes. The most common cause is that the motors are not mounted vertically on the motor mounts. If the imbalance persists, you can slightly tilt the motors so that the thrust angle helps the yaw rotation direction. Some aircraft are very sensitive to motor thrust vector angles.
If the warning only appears during large yaw maneuvers, you can increase the warning threshold by raising the ATC_RAT_YAW_IMAX value. However, it may also be worth re‑tuning the yaw parameters.
Note
The thrust loss and yaw imbalance alerts can be disabled using the FLIGHT_OPTIONS parameter. This should only be done after extensive log review and testing to confirm that the alerts are not caused by an actual issue.
Chapter 4. Advanced Configuration
This section will introduce you to more advanced flight controller configuration and tuning.
4.1 Power Module
Common Parameters for Power Configuration
BATT_ARM_VOLT – Minimum voltage allowed for arming
BATT_ARM_MAH – Minimum remaining capacity allowed for arming
BATT_LOW_VOLT – Low battery voltage threshold
BATT_LOW_MAH – Low battery capacity threshold
BATT_LOW_TIMER – Low battery timeout
BATT_FS_LOW_ACT – Low battery failsafe action
Default power module voltage divider ratio: 18.18; current divider ratio: 36.36.
Note
For the complete ArduPilot parameter list, please visit:
https://ardupilot.org/copter/docs/parameters.html#
For more information on low‑battery failsafe settings, please visit:
https://ardupilot.org/copter/docs/failsafe-battery.html#failsafe-battery
4.2 Safety Switch
The safety switch can be used to enable or disable outputs to motors and servos. It controls the “safe” state of the vehicle. In this state, motors are prevented from running (except in fixed‑wing Manual mode, where they are forced on unless the BRD_SAFETY_MASK parameter is set to allow motor control), and servo PWM outputs are disabled. A pre‑arm error is also generated to prevent accidental arming.
Note
For more information on safety switch configuration, please visit:
https://ardupilot.org/copter/docs/common-safety-switch-pixhawk.html
4.3 CAN Bus Configuration
Controller Area Network (CAN bus) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other in applications without a host computer. It is a message‑based protocol originally designed for multiplex wiring in automobiles to save copper, but it is also used in many other environments.
Note
For more information on CAN bus configuration, please visit:
https://ardupilot.org/copter/docs/common-canbus-setup-advanced.html
4.4 LAN Port Settings
ArduPilot 4.5 (and later) provides a networking framework that supports LAN and WAN connections. Some newer autopilots, such as the Pixhawk‑6X and CubePilot CubeRed, include an Ethernet MAC interface that allows ArduPilot to connect to vehicle peripherals, data servers, and even WAN networks via IP using UDP or TCP transport‑layer protocols.
Note
For more information on LAN / Ethernet settings, please visit:
https://ardupilot.org/copter/docs/common-network.html
4.4.1 Ethernet Configuration
ArduPilot firmware version 4.5.0 and later supports Ethernet connectivity.
4.4.1.1 Connecting the Ground Station via Ethernet
Open the Mission Planner ground station software, and in the full parameter list under the Config interface, set NET_ENABLE = 1, restart the flight controller, and then modify the following parameters:
1. Set the controller IP address to 192.168.144.26 and the gateway IP to 192.168.144.1.
2. Disable DHCP by setting NET_DHCP = 0, and set the subnet mask with NET_NETMASK = 24.
ArduPilot Port Configuration
Set NET_P1_TYPE = 1 (UDP client port type), restart the flight controller, and then modify the following parameters:
1. Set the computer IP to 192.168.144.27, set the network port NET_P1_PORT to 15000, and select MAVLink2 as the port protocol.
System Hardware Connection
Connect the flight controller’s LAN port to your computer using an Ethernet cable, and power on the controller.
On your computer, navigate to Change Adapter Settings → Ethernet Properties → Internet Protocol Version 4 (TCP/IPv4), and manually configure the network settings (set IP to 192.168.144.27 and subnet mask to 255.255.255.0). Click OK to apply the configuration.
Connect to the Ground Station
Open the Mission Planner ground station software, select UDP as the connection type, enter port number 15000, and connect to the ground station.
4.4.1.2 Controlling the Gimbal Camera via Ethernet (Using the SIYI A8_mini as an Example)
Open the Mission Planner ground station software, go to the Config tab, open the Full Parameter List, set NET_ENABLE = 1, and restart the flight controller.
Gimbal Camera Settings
1. Set the camera type: CAM1_TYPE = 4 (Mount (Siyi)).
2. Set the gimbal mount type: MNT1_TYPE = 8 (Siyi), then restart the flight controller.
The default IP address for the SIYI gimbal camera is 192.168.144.25. To change it, download SIYI Assistant, and use it to configure both the gimbal camera’s IP address and gateway, ensuring they are on the same subnet as the ground station.
ArduPilot Port Configuration
Set NET_P1_TYPE = 1 (UDP client port type), disable DHCP by setting NET_DHCP = 0, restart the flight controller, and then modify the following parameters:
1. Enter the gimbal IP address:
NET_P1_IP0 = 192
NET_P1_IP1 = 168
NET_P1_IP2 = 144
NET_P1_IP3 = 25
2. Set the network port NET_P1_PORT = 37260.
3. Set the gimbal serial protocol: NET_P1_PROTOCOL = 8 (Gimbal).
Connect to the Ground Station
Connect the Ethernet interface of the SIYI A8_mini gimbal camera to the flight controller’s LAN port, and power on the gimbal camera.
Upon connecting to the Mission Planner ground station software, the Messages tab will display that the Siyi gimbal camera has been recognized.
In the Flight Data interface, select the Payload Control tab, and use the sliders to adjust the gimbal’s Tilt, Roll, and Pan angles.
4.5 Resetting Parameters
UniGCS has a dedicated reset button to restore the flight controller’s default parameters.
Note
For more information on resetting parameters, please visit:
https://ardupilot.org/copter/docs/common-parameter-reset.html
4.6 Common Parameters for UniFC 6 PICO Autopilot
BRD_SAFETY_DEFLT – Disable safety switch
ARMING_RUDDER – Allow rudder disarm
LOG_BACKEND_TYPE – Disable data logging
ARSPD_AUTOCAL – Airspeed auto-calibration
GPS_TYPE – Set primary GPS type
FS_THR_ENABLE – Failsafe behavior on RC loss
BATT_LOW_VOLT – Low-voltage failsafe trigger
BATT_FS_LOW_ACT – Failsafe action on low battery
AHRS_ORIENTATION – FC mount orientation
Note
For the complete ArduPilot parameter list, please visit:
https://ardupilot.org/copter/docs/parameters.html#
4.7 Flight Logging
There are two ways to log your flight data. With some exceptions, both methods record similar data but in different ways:
1. Dataflash logs: Stored on the SD card in the flight controller and can be downloaded after the flight.
2. Telemetry logs: Stored in the ground station software and locally on the computer, requiring a telemetry link between the ground station and the flight controller.
Common Flight Logging Parameters
LOG_BACKEND_TYPE – Bitmask for selecting log backends.
LOG_BITMASK – Bitmask for selecting which data to log.
LOG_DISARMED – Start logging while the vehicle is disarmed (powered on).
LOG_FILE_DSRMROT – Stop writing to the current log file while disarmed.
LOG_FILE_MB_FREE – Clear old logs from the SD card to maintain sufficient free space.
LOG_FILE_RATEMAX – Limit the rate at which streaming log messages are written to the file backend, to control file size.
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