I. S2 Overview
1.1. Main Items
1.2. Ports and Definitions
Flight Control Status Light Meaning:
Red & blue rapid blinking: IMU initialization in progress
Red & blue & green rapid blinking: ESC calibration mode
Blue & yellow alternately blinking: GPS failure
Red &yellow blinking: EKF failure
Yellow blinking: battery failure/remote control signal loss
Green light is always on: unlock status + 3D positioning
Blue light is always on: unlocked status+no positioning
Green light blinking: unlocked status + 3D positioning
Blue light blinking:unlocked status + un-positioning
1.3. Technical Parameters
| S2 Avionics Systems | ||
| Hardware parameters | Main processor | CKS32F407 |
| Gyroscope | BMI088 | |
| Barometer | LPS22HB | |
| External interfaces | PWM output | 12 |
| SBUS OUT | 1 | |
| GPD serial port | 1 | |
| Compass serial port | 1 | |
| POWER | 1 | |
| Digital transmission interface | 2 | |
| SBUS input | 1 | |
| CAN interface | 2 | |
| Obstacle avoidance interface | 1 | |
| TYPE-C interface | 1 | |
| Supported Models | Unmanned vehicles, unmanned boats, 3~8-axis multi-rotors | |
| Working environment & physical parameters | POWER input voltage | 2S~18S |
| USB voltage | 5V±0.3V | |
| Servo voltage | 5V±0.3V | |
| Operating temperature | -40℃~80℃ | |
| Weight & Size | Size | 68*47*13mm |
| Weight | 56g | |
1.4. Recommendations for use
For first time users of the S2 flight control, it is recommended to complete the introductory use of the flight control in steps:
1.Assemble the aircraft and complete the assembly of the power set;
2.Firstly, install the ground station control software and familiarize with the various menu functions of the ground station interface;
3.Remote control connected to the flight control to complete the compass calibration and motor calibration;
4.Check all kinds of parameter settings;
5.First unlocked take-off;
6.Advanced Applications of Flight Controllers and Auxiliary Channel Configuration.
II. First Contact Preparation
2.1. Installation of Flight Control
S2 should be installed close to the centre of gravity of the vehicle using the provided shock absorbing foam, if it is installed away from the centre of gravity of the carrier, the IMU position offset parameter needs to be set.
The default installation direction is the nose direction, when installing in other directions, you need to use FLY GCS to adjust the parameter setting.
2.2. Installation of GNSS Antenna
①Install the GPS module
Install the GPS bracket to the aircraft, tighten the screws, GPS is not fixed installation direction.
Suggestion: The GPS module has a magnetic compass, install it away from equipment with magnetic interference such as flight control main boards and power distribution boards.
② Installation of directional modules and antennas
RTK Antenna Mounting Bracket Installation Schematic Diagram
The directional module has no installation position requirements. There are four installation methods for the RTK helical antenna in total. The distance between the master and slave antennas should be more than 30 cm. The longer the distance is, the higher the accuracy will be. (For specific details and settings, please refer to 4.4 GPS Settings.)
2.3. Installation of Receiver
Take the Skydroid GR01 receiver as an example, install the receiver and connect to the flight controller.
2.4. Motor Sequence and Rotation Direction
According to the serial number of the motor, plug it into the corresponding PWM port, e.g.: No.1 motor plug PWM1.
Note: Since there is no voltage output from the flight controller, the 3-axis model needs additional BEC module pins to supply power to the servo.
III. Fly GCS APP use
3.1. Main Home of APP
Flight Mode Introduction
Five channels of the remote control can switch flight modes
| Flight Mode | Height setting mode | The vehicle will automatically control the throttle to maintain a constant altitude. In windy conditions, the pilot will need to constantly correct roll and pitch to keep the vehicle in position. |
| GPS mode | The vehicle automatically maintains its current position, pointing, and altitude. GPS position good, compass low EMI, and low vibration are all very important. | |
| Return mode | The vehicle will automatically return to its home position. When the vehicle reaches the point directly above the return point, the pilot can use the remote control to adjust the landing position of the vehicle, and after landing, the vehicle will automatically lock up. |
3.2. Registration& Activation
Network the remote control, open the Fly GCS APP and select New User Registration.
Fill in the mobile phone number, password, get the verification code, the verification code is case-sensitive, after successful registration login.
After logging in, the digital transfer will be connected automatically, at this time, the first time you use it, an activation box will pop up, please click on ‘Go Now’ to activate the activation interface.
IV. Flight Control Tuning(Tuning Code 999)
4.1. Rack type selection
Select the appropriate rack type according to the actual model and click on the pattern to save the rack type.
4.2. Flight control monitoring
Channel View: Check the current rudder value of the remote control channel.
Output View: Check the PWM channel output signal value of the flight control system.
4.3. Head-stock orientation
The mounting direction of the flight control can be modified, after modification, please reboot and
perform six-side calibration.
Note: The arrow direction of the flight control housing is the head-stock orientation.
4.4. GPS setting
Select the type of GPS, the default is GPS/single antenna RTK;
When using the directional module, you need to set it as ‘Dual Antenna RTK’, choose the installation method according to the actual demand, it is recommended that the distance between the two antennas is more than 30cm.
Mode 1: The slave antenna is installed in front of the flight control, the master antenna is installed behind the flight control, the straight line where the two antennas are located must be parallel to the flight control.
Way 2: Slave antenna is installed on the right side of the flight control, master antenna is installed on the left side of the flight control, the straight line where the two antennas are located must be perpendicular to the flight control.
Mode 3: The slave antenna is installed behind the flight control, the master antenna is installed in front of the flight control, the straight line where the two antennas are located must be parallel to the flight control.
Mode 4: The slave antenna is installed on the left side of the flight control, the master antenna is installed on the right side of the flight control, the straight line where the two antennas are located must be perpendicular to the flight control.
4.5. Compass calibration
Perform a compass calibration in an outdoor environment, making sure the GPS signal is good.
Ellipsoid Calibration: Perform a complete 360 degree rotation of the vehicle, make sure that during each rotation, the vehicle can point to the ground in all directions and rotate in a circle.
Horizontal plus Vertical: First rotate the vehicle horizontally until prompted for the next step; then rotate the nose down vertically until prompted for success.
Note: Compass calibration is not required when using the Orienteering Kit.
4.6. ESC calibration
Step 1: Connect the vehicle and remove the propeller from the machine.
Step 2: Click [Calibrate].
Step 3: Disconnect the battery of the vehicle.
Step 4: Re-insert the battery.
Step 5: The programme will automatically calibrate the ESC (about 15 seconds);
Step 6: Unplug and re-insert the batteries again for normal use.
4.7. Motor test
Step 1: Enter the throttle setting value, the recommended range is 5%-10% (for large vehicle, this
value can be increased appropriately due to the lower KV value of the motor);
Step 2: Set the duration in seconds;
Step 3: Refer to the instructions in the picture to test whether the rotation direction of each motor is correct.
4.8. Basic Setting
4.8.1 Attitude Setting
By adjusting the sensitivity and damping, you can optimize the flying attitude of the vehicle. (For detailed information on the parameters, please click on the ‘question mark’ next to it.
4.8.2 Brake Setting
Adjust the braking parameters to optimize the braking attitude of the vehicle. (For specific parameter information, click on the ‘question mark’ next to it.)
Adjustment of flight parameters of the vehicle in route missions (for more information, click on the ‘question mark’ next to it).
4.8.4 Speed setting
Adjust the airspeed of the aircraft(for more information, click on the ‘question mark’ next to it).
4.8.5 Power setting
Low Voltage Return Alert: When this voltage value is reached, APP will send return alarm alert.
Forced Return Voltage: When this voltage value is reached, the aircraft will be forced to return to flight.
Forced Landing Voltage Alert: When this voltage value is reached, APP will issue landing alarm.
Forced Landing Voltage: when this voltage value is reached, the aircraft will be forced to land in place.
Unlocked Compensation Voltage: the vehicle is powered on and kept in unlocked state, the multi-meter will measure the current voltage of the battery, then look at the voltage shown on the digital transmission and fill in the difference.
Full Load Compensation Voltage: the vehicle needs to be fully loaded, hover for 20 seconds and record the current voltage. Then land immediately, wait for 20 seconds, record the landing voltage and fill in the difference.
Note: Click on the ‘question mark’ next to the specific voltage setting for reference.
4.9. Other settings
In the Other Settings screen, motor locking options can be configured, as well as corrections to the flight control and GPS mounting positions (i.e. IMU corrections).
4.10.Auxiliary settings
The mapped channels of the flight control PWM9-12 ports can be set, and the corresponding fail-safe values can be set.
4.11. Geo-fencing
Geo-fence is disabled by default, if you need to turn it on in Flight Control – Geo-fence.
This is a kind of safety protection mechanism to protect the vehicle from flying out of the range you set, turn on this mechanism will detect whether the GPS is positioning, when there is no positioning can not be unlocked.
4.12. Log Download and View
After entering the log download interface, please click the Refresh button on the upper right corner, and then select the corresponding log file to download. After downloading, you can use the Bluetooth function to share.
Note: Log analysis requires the use of professional software tools, and requires the analyst to have the appropriate log analysis skills.
4.13. RTK Positioning Settings (Optional orientation module required)
①Network RTK Setting
Click More -> General Settings -> Other Settings -> Advanced Settings -> RTK -> Select the corresponding network RTK -> RTK parameter settings, and enter the network RTK account.
Note: The remote controller needs to maintain network connection during the entire process.
②Connecting the Skydroid Base Station
Connecting the Skydroid base station needs to cooperate with the 915 receiver, the wiring is as shown in the picture above, turn on the base station can automatically complete the connection and positioning.
V. Loss-of-control protection
The vehicle return modes are RTL return, intelligent low battery return and uncontrolled return. If the GPS is >12 stars at take-off, the vehicle will successfully record the return point. If there is no GPS signal for forced take-off, the position of the latest GPS>12 stars will be recorded as the return point.
| Return process | 1.Record the return point 2.Trigger the return condition 3.Adjust the head direction 4.Return to the altitude set by APP. (1) Regardless of the current altitude of the vehicle, if the vehicle is within 5 meters of the horizontal distance, it will land directly. (2) If the vehicle is beyond 5 meters or within 20 meters, it will return at the current altitude, with a minimum return altitude of 5 meters. (3) Beyond 20 meters, if the vehicle is above the return altitude, it will return directly, and if it is below the return altitude, it will raise to the return altitude and then perform the return. |
| One-click return | APP one-click return/remote control button one-touch return |
| Low voltage return | 1. The vehicle will automatically perform a low voltage return according to the forced return voltage. 2. If there is no GPS signal or the signal is not strong at the time of low voltage return, the drone will land automatically. 3. If the takeoff is forced with bad GPS signal, the UAV will automatically return to the location where it got good GPS signal the first time. 4. If the power is lower than the forced landing voltage, it will enter the landing mode. |
| Lose contact and return to flight | When the vehicle loses connection with the remote control for more than 2 seconds, the vehicle automatically returns to flight. Performance Requirements: (1) The automatic return flight is triggered after the vehicle loses control for 2 seconds; (2) During the lost connection return flight, if the UAV restores the connection, the UAV will continue to execute the return flight procedure; (3) Direct landing when there is no GPS signal or the signal is not strong. |
VI.Flight control
Pre-flight check
1. Whether the equipment such as remote controller and vehicle batteries are fully charged.
2. Whether the propeller is correctly and firmly installed.
3. Whether the vehicle battery is installed and connected securely.
4. Whether the camera and gimbal work properly after the power is turned on.
5. Whether the motor can start normally after the power is switched on.
6. Whether the remote control is working normally and displaying the camera’s picture transmission screen.
7. Make sure the antenna of the vehicle is firmly installed and the antenna of the remote control is unfolded.
8. Check whether the compass heading is accurate, open the mobile phone to point the compass to the head of the vehicle, compare the APP home page attitude ball heading degrees, if the difference is large, please carry out compass calibration, specific calibration steps to see the 8th point of the compass calibration.
9. Be sure to use the original parts, the use of non-original parts may cause danger to the safe use of the vehicle.
Unlock take-off
Fixed Altitude/GPS Mode
Taking the American hand mode as an example, performing the action of pushing the control sticks to the inner bottom corners can unlock the vehicle. After the motors start rotating, please release the joystick immediately and slowly push the throttle to take off.
Landing lock
Fixed Altitude/GPS Mode
After the vehicle lands, push the throttle stick to the lowest position and hold it for 3 seconds, after which the motor stops.
In case of special circumstances such as landing upside down or hitting the ground during landing, and when the throttle stick cannot lock the motors by being pulled down, please use the action of pushing the control sticks to the outer bottom corners to forcibly lock the motors.
Note: If the action of pushing the control sticks to the outer bottom corners (default) lasts for more than
1.5 seconds, the motors will be forcibly locked. Please do not perform this action during normal flight in the air.
VII.Frequently Asked Questions
1.The remote control cannot be connected.
①Check whether the type of APP is selected correctly.
②Check whether the FLY GCS ground station is occupied by other background applications.
2.The vehicle hovers unstably.
①Change the flight site. Do not fly near high-rise buildings or signal towers.
②Calibrate the vehicle’s compass and perform horizontal calibration.
③Determine whether the excessive wind affects the flight.
④Make fine adjustments to the sensitivity.
3.The GPS accuracy of the vehicle is inaccurate or it fails to pass the GPS accuracy test.
① Search for GPS signals in an open outdoor area until 11 or more GPS satellites are detected.
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