Gemini Flight Controller Manual

V1.1

Zero UAV (Beijing) Intelligence Technology Co., Ltd.
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | 1

Table of Contents

1 Warning and Disclaimer ..................................................................................................................1

2 Terms and Abbreviations ................................................................................................................3

3 Functions ........................................................................................................................................4

4 In the Box........................................................................................................................................5

5 Installation......................................................................................................................................6

5.1 Airframe Types..............................................................................................................................6

5.2 Installation of Flight Controller.....................................................................................................7

5.3 Installation of the GPS ..................................................................................................................7

6 Wiring .............................................................................................................................................8

6.1 Port Definitions.............................................................................................................................8

6.2 Wiring Diagram.............................................................................................................................9

7 System Preparation and Debugging ..............................................................................................11

7.1 GCS Installation...........................................................................................................................11

7.1.1 Installation of Mobile GCS ...............................................................................................11

7.1.2 Installation of PC GCS ......................................................................................................11

7.2 Wi-Fi Configuration.....................................................................................................................11

7.2.1 Wi-Fi Communication Mode............................................................................................11

7.2.2 Wi-Fi Configuration..........................................................................................................11

7.3 Setting up the Transmitter(s)......................................................................................................14

7.3.1 Setting up Dual Transmitter Mode ..................................................................................15

7.3.2 Setting up Single Transmitter Mode................................................................................16

8 Ground Control Software setup and Debugging ............................................................................17

8.1 Mobile Ground Station Debugging .............................................................................................17

8.1.1 Ground Station Software Auxiliary Setting (Installation Guideline) ................................17

8.1.2 Manual Settings...............................................................................................................19

8.2 PC Ground Station Setup and Debugging ...................................................................................24

8.2.1 Ground Station Software Auxiliary Setting (Installation Guideline) ................................24

8.2.2 Manual Settings...............................................................................................................26

9 Pre Flight Inspection......................................................................................................................31

9.1 Test Parachute Opening/Closing ................................................................................................31

9.2 Calibrating the Magnetic Compass.............................................................................................32

9.2.1 Using the Android GCS.....................................................................................................32

9.2.2 Compass Calibration Using a PC Ground Station.............................................................33

9.3 Unlocking and Arming the Motors .............................................................................................35
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9.4 Inspecting Motor Rotational Direction.......................................................................................36

10 Flying at the Field ........................................................................................................................39

10.1 Flight Status..............................................................................................................................39

10.1.1 LED Status Indications....................................................................................................39

10.1.2 Motor Balance and Real Throttle Position.....................................................................40

10.1.3 Adjusting Aircraft Vibration Parameters .......................................................................41

10.2 Flight Functions.........................................................................................................................43

10.2.1 Basic Flight Operation....................................................................................................43

10.2.2 Professional Flight Operation ........................................................................................54

11 Tasks...........................................................................................................................................63

11.1 Gimbal ......................................................................................................................................63

11.1.1 Servo Driven Gimbal ......................................................................................................63

11.1.2 Brushless Gimbal ...........................................................................................................64

11.2 Photography .............................................................................................................................64

11.3 POS Info Data Download ..........................................................................................................67

11.3.1 Mobile Ground Station Data Download ........................................................................67

11.3.2 PC Ground Station Data Download................................................................................67

12 Safety Features ...........................................................................................................................68

12.1 Starting and Stopping the Motors............................................................................................68

12.1.1 To Start Motors..............................................................................................................68

12.1.2 To Stop Motors..............................................................................................................68

12.2 F/S Protection...........................................................................................................................68

12.3 Parachute Protection................................................................................................................68

12.4 Data Record ..............................................................................................................................69

12.4.1 Flight Data Record - “Black Box Function”.....................................................................69

12.4.2 GCS Data Record............................................................................................................70

13 Extending the Range of Capabilities ............................................................................................71

13.1 Radio Connection .....................................................................................................................71

13.1.1 Airborne Radio Connection ...........................................................................................71

13.1.2 Ground Radio Connection .............................................................................................71

13.2 Connecting the Power Management Module ..........................................................................71

13.3 OSD Connection........................................................................................................................72

14 Upgrading the Firmware .............................................................................................................73

Appendix .........................................................................................................................................75

Appendix 1 Introduction to Mobile Ground Station (Android) ........................................................75

Appendix 2 Introduction to PC Ground Station................................................................................79
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | 3

Appendix 3 Installation and Configuration Videos...........................................................................81

Appendix 4 Technical Support..........................................................................................................82

Appendix 5 Reference Manual Update History ................................................................................82
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Warning and Disclaimer 1

1 Warning and Disclaimer

Danger

Thank you for purchasing this ZERO UAV product. The product is an advanced and specifically 

dedicated control item. Any misuse may result in damage to property, injury or even death. The user 

must conform to the law and use the equipment responsibly. This product is not suitable for people under 

the age of 18. Please read this disclaimer carefully before using the product, or visit the GEMINI web 

page at http://www.zerouav.com to refer to relevant updates or information.

Caution

1. Please keep the product out of reach of children.

2. Make sure the aircraft is kept away from people and dangers such as buildings roads and property. 

We suggest you fly your aircraft at specially designated areas.

3. Please do NOT fly this product when affected by drunkenness, tiredness, drugs, dizziness fatigue, 

nausea or any other condition that might impair your ability to control the aircraft. 

4. Please strictly follow the user manual when operating the device. 

5. Please make sure all components of the device are connected and work well, otherwise your unit 

may be damaged, destroyed or even buried!

6. Please power off and remove propellers before making any adjustments to the unit such as 

calibrating, upgrading firmware or changing parameters. There is an ever present danger of the 

propellers starting unexpectedly and causing injury. 

7. Please do NOT fly in unfavorable conditions.

8. Please do NOT open or modify the autopilot, there are no user serviceable parts inside.

Disclaimer

1. Zero UAV (Beijing) Intelligence Technology Co. Ltd. products are specially controlled devices. 

The user shall be responsible for any and all activities connected with the use of all their 

products. The manufacturer shall not be reliable for any consequences directly or 

indirectly caused by all their products. 

2. The user is responsible for abiding with the law and not behaving contrary to public order 

or public safety by using this product. 

3. We shall not provide technical support or security warranty for any of the following 

conditions: 
2 Warning and Disclaimer | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

1) Units or individuals obtaining the product from agents or channels not authorized by 

Zero UAV (Beijing) Intelligence Technology Co. Ltd. 

2) Products after modification, debugging or replacing parts without authorization; 

3) Products losing warranty card, serial number or flight data; 

4) Injuries and property losses due to mis-operation or force majeure of natural 

disasters. 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Terms and Abbreviations 3

2 Terms and Abbreviations

Name Description

Gemini Gemini, dual redundancy(M+S) 

Gemini M Host controller

Gemini S Slave controller

GCS Ground control station 

SSID Service Set Identifier, name of wireless network

Dual controller operation Aircraft radio control transmitter +Gimbal radio control

transmitter

Single controller operation To control the aircraft and gimbal with a single radio control 

(RC) transmitter 

CH

Channel, for example CH5 means channel 5

Channel switches assigned to different functions 

F/S Fail/Safe control 
4 Functions | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

3 Functions

The types and related functions of the aircraft are as follows: 

 Airframe type: 4-axis X-type, 4-axis cross type, 6-axis X-type, 6-axis cross type, 8-axis 

X-type, 8-axis cross type, 6-axis reverse Y-type, 6-axis Y-type, 4-axis X-type with 8 motors 

and customized types (irregular or quasi-irregular); 

 Firmware upgrading: PC upgrading (standard USB serial port cable); 

 Control mode: transmitter radio control/mobile control; 

 Parameter adjustment mode: PC/tablet PC/mobile ground station ; 

 Operation mode: manual stabilization, automatic hover, automatic navigation and return 

and land; 

 Status indication: LED 

 Security measures: auto return on loss of control, black box flight recorder and protection 

by deployment of parachute.

 Photography: manual and automatic (user customized) acquisition of stills and video; 

 PTZ: brushless Gimbal (ZERO Z series), servo PTZ; 

 Receiver: Standard receiver, S-BUS receiver
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | In the Box 5

4 In the Box

 Key: ■Hardware □Software (download)

■Controller X2 ■GPS+COMPASS (hereinafter referred 

to as GPS)X2

The MC (Master Controller) combines and 

communicates with the other modules and external 

electronic devices to carry out its function as a 

complete autopilot system. Firmware is updated in 

this unit via its RS232 COM port. The YS-GCS 

(Ground control Station) records real time flight state 

via WI-FI.

The GPS/Compass modules are for sensing 

the orientation of the aircraft by reading its 

position and direction.

■External LED indicator X1 ■Power module X1

The LED indicates current flight status of the craft. 

The light shows information such as flight mode, 

number of satellites in view and battery used.

Supplies regulated power for the autopilot and 

the Wi-Fi module.

■WIFI module X1 ■R232 serial port to USB converter cable 

(FTDI) X1

Connects the Auto Pilot to the Ground Station via 

WI-FI (Wireless Network) Supports 2 work modes: 

Peer to Peer and Router

Connects PC and autopilot via USB to 

update firmware.

■GPS bracket X2 ■Warranty card X1

The GPS + COMPASS is sensitive to magnetic 

interference. This bracket is used to mount the GPS 

module where necessary and to keep it far away 

from EMI sources.

This provides Product Serial No., Purchase 

Date. Please fill out the relevant information 

and return to Zero UAV Intelligence 

Technology Co. to register your product 

warranty.

□Ground station software □Upgrade software
6 Installation | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

5 Installation

5.1 Airframe Types

The Gemini flight controller provides support for aircraft in a cross (+), X and Y configurations 

of rotor arms and propellers.

In the figures below, the yellow arrow at the position of the central plate indicates the direction 

of the aircraft nose; the blue curved arrow indicates the direction of rotation of the upper 

propeller and the purple curved arrow the direction of rotation of the lower propeller. 

NB 

Install the motor and propellers according to the following modes.

 

Quad-Rotor +4 Quad-Rotor x4 Hexa-Rotor +6 

 

Hexa-Rotor x6 Octo-Rotor +8 Octo-Rotor x8

 

Hex-Rotor reverse Y6 Hex-Rotor Y6 Quad-Rotor X8
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Installation 7

5.2 Installation of Flight Controller 

Install the Gemini flight controller on the central deck of the aircraft horizontally, with the 

arrow labelled “Front” pointing to the aircraft nose, as indicated in the following diagrams: 

Direction of aircraft nose

5.3 Installation of the GPS 

Install the GPS on the bracket with the GPS

label facing upwards and the small arrow

pointing to the aircraft nose.

The appearance of the bracket is as shown in 

Figure 1.

Figure 1

NB 

 Make sure the small arrow points to the aircraft nose. If not the aircraft will circle (toilet 

bowl) when in auto-hover; 

 Place the GPS module in an elevated and horizontal position, away from equipment 

which can produce magnetic fields such as cables, transmitters and cameras without 

screening.
8 Wiring | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

6 Wiring 

6.1 Port Definitions

 Port Definitions: Gemini M flight controller

Port Port function Port Port function

M1 ESC for Motor #1 PTZ1 Gimbal PTZ1 (Servo)

M2 ESC for Motor #2 PTZ2 Gimbal PTZ2 (Servo) 

M3 ESC for Motor #3 PTZ3 Gimbal PTZ3 (Servo) 

M4 ESC for Motor #4 PAR/PITCH Parachute or Gimbal Tilt control 

M5 ESC for Motor #5 PHO/ROLL Camera shutter release or 

gimbal roll control

M6 ESC for Motor #6 EXT1 EXT1 to EXT1 on Gemini S 

M7 ESC for Motor #7 S-BUS

Connect S-BUS receiver (NOT

support S-BUS2 port of 7008SB)

M8 ESC for Motor #8 EXT2 EXT2 to EXT2 on Gemini S

COM

Wi-Fi data unit or to PC via USB 

for updating firmware etc. AI1

Power management module 

(option)

LED LED indicator POW

5.7V output from power 

module 

GPS-R

GPS-B

GPS-R: Red terminal from GPS 

module 

GPS-B: Black terminal from GPS 

module 

 Port Definitions: Gemini S flight controller

Port Port function Port Port function

M1 No connection PTZ1 No connection

M2 No connection PTZ2 No connection

M3 No connection PTZ3 No connection

M4 No connection PAR/PITCH No connection

M5 No connection PHO/ROLL No connection

M6 No connection EXT1 EXT1 to EXT1 on Gemini M

M7 No connection S-BUS No connection
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Wiring 9

Port Port function Port Port function

M8 No connection EXT2 EXT1 to EXT1 on Gemini M

COM No connection AI1 No connection

LED No connection POW

5.7V output from power 

module

GPS-R

GPS-B

GPS-R: Red terminal from GPS 

module 

GPS-B: Black terminal from GPS 

module

6.2 Wiring Diagram

Notes:

a. The power supply range for the power module and Wi-Fi module should be a Lipo battery 

of between 3S and 6S, namely 10.8v-25.5v; 

b. The RC receiver should be powered directly from the flight controller. If an external power 

supply is used at the same time the equipment may be destroyed.

c. The ESCs and motors can cause serious magnetic interference. The GPS and magnetic 

sensor modules must be installed as far away as possible from motors and ESCs 

(particularly where there are multiple ESCs). The arrow on the GPS must be pointed at 

the aircraft nose. The power lead from the battery will create a large magnetic field 

particularly when large currents are drawn. Keep this as far away as possible from the 

GPS module to avoid flight artefacts such as “toilet bowling”.

d. A servo driven gimbal should not be powered from the receiver but should be powered 

separately.

e. The video transmitter (VTX) must be kept as far away from the aircraft electronics as 

possible to avoid serious interference.

f. Make sure the full system power is not connected directly to the flight controller. This will 

destroy the flight controller which should be powered by a 5.7 V output only. The LED 

indicator will flash three times after the initialization of the flight controller, indicating that

correct correction has been made and the system started normally.
10 Wiring | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

Wiring diagram

Electronic Speed Controllers (M1-M8)

Main Controllers(GEMINI M and S) · The main controllers are horizontally mounted in the centre of the aircraft with the arrows marked “front” pointing forward. The controllers may be mounted direct without damping. · Ensure that all terminals of the flight controllers are uncovered; this facilitates the wiring and makes it easier to connect to a PC for firmware upgrade. · Finalize the position of all flight control components and complete the wiring before finally fixing them in position.

RC Receiver · First set up the aileron, elevator, throttle and rudder on the remote controller(RC transmitter). · The S-BUS receiver is powered by the controller ; an external power supply is not needed. · If your receiver is not compatible with S-BUS, you must use the S-BUS converter.

LED Indicator · Install the LED in a convenient position, away from the GPS GPS Module · The GPS and magnetic compass module is magnetically sensitive equipment, which should be kept away from other electronic equipment. · Use the original GPS housing to install the GPS module. · The GPS is also sensitive to shaking. Please secure the frame of the GPS firmly and install with the logo facing upwards and the arrow facing farwards. 3S-6S Lipo WiFi com3

+ Power -

LED

Gimbal Connector

Parachute Control Unit

Camera Shutter

S-BUS receiver

Power Unit Option

Power Supply Unit 3S-6S Lipo

Gimbal Pitch

Gimbal Roll

EXT2 EXT1

5.7V

5.7V

PC or OSD expansion interface

Power Supply Unit
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | System Preparation and Debugging 11

7 System Preparation and Debugging 

The Gemini Aircraft system links to PC or Android ground station software. As the Android is 

more convenient for debugging and flight monitoring at the field, this is the recommended 

system. 

7.1 GCS Installation

7.1.1 Installation of Mobile GCS 

Android mobile GCS should be installed as follows: 

1. Download YS-GCS Android mobile software from the download section in the support 

zone of the official website (www.zerouav.com).

2. Automatically install the software by clicking on the APK file in the 

file manager. The ground station App will appear on the mobile 

device desktop after installation as shown in Figure 2. The GCS 

must be installed in the memory of the mobile. Figure 2

7.1.2 Installation of PC GCS 

Download the YS-GCS PC software from the download section in the support zone of the 

official website (www.zerouav.com). After decompressing, double-click the ZERO-GCS Rotor 

Ground Station.exe file to install the program. 

7.2 Wi-Fi Configuration 

7.2.1 Wi-Fi Communication Mode 

The Gemini Wi-Fi system can support two communication modes: point-to-point (P2P) and 

router. The delivery default setting is point-to-point mode with an SSID of ZERO-TECH and no 

password. 

After the link is completed all flight data will be recorded to the ground station. The file with the 

extension of “.hjext2” can be found in the directory “YShj” in the root directory of a mobile 

device or in the file folder “Hj” in the PC ground station software package. This file can be 

replayed and analyzed in the PC GCS application. 

A Wi-Fi configuration tutorial can be found at: 

http://v.youku.com/v_show/id_XNTE2OTY4MjQ4.html

7.2.2 Wi-Fi Configuration 

7.2.2.1 Firmware Connection

The firmware can be updated using the following procedure: 
12 System Preparation and Debugging | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

1. Download the USB driver from the ZERO 

official website and install it; 

2. Connect the Wi-Fi module to a PC with the 

supplied USB serial port cable shown below. 

Connect the USB terminal to any USB port 

on the PC and the serial terminal to the com

port of the Wi-Fi module; 

3. Plug the lead reserved for the Wi-Fi module 

from the power supply into the Power port of 

(3S-6S input) of the Wi-Fi module. 

WiFi com3

+ Power - Note:

 When connecting the Wi-Fi module to the Computer, the WHITE wire of the 

communication cable is located at the upper right hand corner of the Wi-Fi module.

 When connecting the Wi-Fi module to the Gemini M, the BLACK wire of the 

communication cable is located at the upper right hand corner of the Wi-Fi module. 

WiFi

com3

+ Power - WiFi

com3

+ Power - Connect with PC Connect with

the flight

controller

7.2.2.2 Software Set-up

7.2.2.2.1 Point-to-point Mode

It is possible to use the wireless router in the point-to-point mode and the password can be set 

up in this mode to make sure no other user can connect to the Wi-Fi. Setup procedure is as 

follows:

1. Download Wi-Fi configuration software from 

the Zero UAV site.

2. Double-click “SeanyConfig.exe” after 

decompression and a “SeanyConfig” 

window will pop up, as shown in Figure 3.

3. Click “Setting” for the main interface, as 

shown in Figure 4.

Figure 3
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | System Preparation and Debugging 13

Figure 4

4. Select the correct COM port. If you are unsure which port this is you can search for the 

“Prolific USB-to-Serial Comm Port” in your Windows Device Manager. This will give you 

the port number. Check "AP" (Access Point) which is "PTP mode".

To check your port: right-click “My computer”→“Properties”→“Device manager”→“Port 

(Com and LPT), as indicated in Figure 5.

Figure 5

5. Set up the SSID of Wi-Fi module,

default is “ZERO-TECH”.

6. Uncheck “No Passphrase”; the Wi-Fi

password must be five digits; as 

shown in Figure 6.

7. Click “Apply” and wait for completion 

of the software configuration; click

“Yes” to exit after the window “Ap 

mode OK” pops up, as shown in Figure 

7.

8. Connect your mobile device or PC 

GCS to the SSID via wireless after set 

up.

9. The Wi-Fi blue indicator changes from 

solid to flashing to indicate the GCS is 

connected and receiving data.

Figure 6

Figure 7

7.2.2.2.2 Router Mode 

Set up Wi-Fi router mode if your mobile device or PC is incompatible with P2P. 
14 System Preparation and Debugging | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

Configuration of router mode is similar to that of point-to-point mode and you should proceed 

as follows: 

1. Download Wi-Fi configuration software 

from the ZERO official website to your

PC; 

2. Double-click “SeanyConfig.exe” after 

decompression and a “SeanyConfig” 

window will pop up, as shown in Figure 8.

3. Click “Setting” and the main interface will 

pop up, as shown in Figure 9.

4. Select the correct port and check “Infra 

station”, as shown in Figure 10.

5. Set up the SSID of Wi-Fi module, default 

is “ZERO-TECH” it is case-sensitive and 

the default password is 82890430.

6. Complete the configuration modification 

by clicking “Apply”.

7. A video showing how to configure the 

route can be seen at:

http://v.youku.com/v_show/id_XNTE3Nz

E1NDcy.html/; 

8. Connect your mobile device or PC GCS

to the SSID via wireless after set up.

9. The Wi-Fi blue indicator changes from 

flashing to solid to indicate the GCS is 

connected and receiving data.

Figure 8

Figure 9

Figure 10

Note: 

 The SSID and password of the router must be consistent with those of the Wi-Fi module; 

 TP-LINK is taken as an example for the router configuration in the video; 

 WPA2-PSK AES encryption method is used with an IP of 192.168.1.1.

7.3 Setting up the Transmitter(s)

Fixed wing mode must be used in the RC transmitter without any mixes configured. If you are 

using FUTABA none of the channels should be reversed. All channels should be reversed for a 

JR or WFLY transmitter.

Note: 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | System Preparation and Debugging 15

 A ZERO Z serial brushless gimbal can support two control modes: Dual transmitter

operation or single transmitter operation; Dual transmitter mode means the aircraft and 

the gimbal are controlled by two different transmitters separately. Single transmitter mode 

means that the aircraft and gimbal are simultaneously controlled with a single transmitter.

 The Z2000 and Z1400 gimbals can both be controlled from a ground station.

7.3.1 Setting up Dual Transmitter Mode 

7.3.1.1 Setting up the Flight Transmitter

The transmitter of the aircraft can be set up as follows:

1. Set three-position switches to CH5 and CH6 on the transmitter as indicated in the 

following diagram:

2. To set up F/S (Fail safe) protection set both CH5 and CH6 of the transmitter to Position 3 

and the accelerator near central position (50%).

The relationship of four operation modes is indicated in the following table: 

CH5 status CH6 status Operation mode

Position 1 X, (Any Position)

Manual stabilisation

If Channel 5 is switched to position1 then the aircraft 

will be in manual stability mode whatever the position 

of Channel 6

Position 3 Position 1 Automatic hovering 

Position 3 Position 2 Automatic navigation 

Position 3 Position 3 Returning and landing 

Note: Position 2 of CH5 is a functional Position in which the Carefree mode or FPV mode can be 

selected. Refer to “10.2.2 Professional Flight Operation” for more information.

Refer to your transmitter manual for specific instructions to set up failsafe and take a look at 

this video: http://www.tudou.com/programs/view/e1ai526Mbt4/. 

7.3.1.2 Setting up the Gimbal Transmitter

The gimbal transmitter can be set up as follows: 
16 System Preparation and Debugging | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

1. Set up a three position switch to CH5 to control the operation mode of the gimbal and a

three position switch to CH6 of the transmitter to control the rotation speed of gimbal, as 

indicated in the following diagram.

2. Set a knob switch to CH7 of the transmitter to control the deployment of retractable 

undercarriage as indicated below.

3. Set a two position switch to CH8 on the transmitter radio, one for On and the other for Off 

to control the camera, as indicated below: 

7.3.2 Setting up Single Transmitter Mode 

A single transmitter can be set as follows: 

1. Set up a three position switch to CH5 and CH6 of the transmitter, as indicated below.

2. Set a 2 position switch to CH8 of the transmitter to control the camera.

3. Set up a lever switch (RS or LS on FUTABA) to

CH7 of the transmitter to control gimbal tilt, as 

shown in Figure 11.

4. To set up F/S (Fail safe) protection set both CH5 

and CH6 of the transmitter to Position 3 and the 

accelerator near central position (50%); 

Refer to your transmitter manual for specific 

instructions to set up failsafe and take a look at this

video:

http://www.tudou.com/programs/view/e1ai526Mbt4/. Figure 11
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Ground Control Software setup and 

Debugging 17

8 Ground Control Software setup and Debugging 

The aircraft will be set up by following the GCS installation guide. We can follow your own 

customized setup in the GCS app. It is recommended that you follow the GCS installation 

guide because it is easy to miss out essential steps if you do it yourself and you may damage 

the equipment as a result. 

You should pay attention to the following points during the installation: 

 Before turning on the transmitter or powering the flight controller when you are installing 

or debugging, make sure the propellers are removed, and it is recommended that you are 

able to power the motors separately from the controller. 

 Switch your transmitter to manual mode and advance the throttle before entering settings, 

otherwise it will not be possible to make changes. 

Note: 

 Carry out the following inspections if there is no data transmission during installation or 

debugging: 

1. Examine whether the wires are connected correctly; 

 2. Examine whether there is any problem with the flight controller; connect the flight 

controller to the PC and see whether there is any data transmission from the flight 

controller; the flight controller can be considered faulty if there is no data transmission 

but the USB serial port lead is working okay. 

3. Check Wi-Fi configuration; 

 An automatic alarm will be made by the mobile ground station if the difference between 

the magnetic headings of the host and slave controllers differ by more than 15° or if the 

voltage is too low. 

8.1 Mobile Ground Station Debugging 

8.1.1 Ground Station Software Auxiliary Setting (Installation Guideline)

The ground station software auxiliary settings are as follows: 

1. Connect the ZERO-GCS app on your android mobile device or tablet to the autopilot by 

Wi-Fi to enter the initial interface screen, as shown in Figure 12.

2. Click “Settings ” for the settings interface, as shown in Figure 13.

3. Click “Installation Guide” to start the installation, as shown in Figure 14.
18 Ground Control Software setup and Debugging | Zero UAV (Beijing) Intelligence Technology 

Co., Ltd.

Figure 12 Figure 13 Figure 14

4. Click “Next” to start setting up or debugging by following the on-screen instructions: 

 

Step 1 Step 2 Step 3

 

Step 4 Step 5 Step 6 

5. Click “Next” to exit the installation guidelines. An instructional video can be found here:

http://www.tudou.com/programs/view/h6Umvfs1my8/. 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Ground Control Software setup and 

Debugging 19

8.1.2 Manual Settings

8.1.2.1 Transmitter Mode Set Up

Powers to the motors should be off or propellers removed to guarantee safety.

1. Select correct operational mode; 

a) Click menu on your android to open the dialogue, as shown in Figure 15.

b) Click “Set” to open the setting window, as shown in Figure 16.

c) Open the drop-down menu next to “Stick mode”, as shown in Figure 17.

Figure 15 Figure 16 Figure 17

d) Check next to your stick mode; for example “US” would be mode two (left-hand 

throttle).

2. Verify correct stick movement.

a) Press “Adjust Transmitter” in the settings interface, 

and then press “OK” to confirm.

b) Within 5 seconds rotate the left and right transmitter 

sticks to their extremes in all directions, as shown 

in Figure 18. The flight controller will

automatically collect maximum, minimum and 

neutral values for each channel.

Figure 18

3. Now make sure that the direction of movement of the sticks is reflected accurately in the 

diagram below. You can only proceed to the next step after confirming this.

c) How to check stick position: 

– In the diagram below showing “Manual Servo Data” in the data interface, the left 

stick is rotor and elevator and the right is aileron and throttle, as shown in Figure 

19.
20 Ground Control Software setup and Debugging | Zero UAV (Beijing) Intelligence Technology 

Co., Ltd.

– When the sticks are in neutral position they will 

be shown as green. The vertical will be shown 

the yellow when fully extended and the sticks 

will be shown as red in any other position than 

neutral.

d) It is necessary to select “capture transmitter central 

point” in the settings interface to make the flight 

controller record the correct neutral position of the 

sticks if, for example, if either stick is not in the 

central position after fine tuning. 

Figure 19

8.1.2.2 Check CH5 and CH6 for F/S (fail/safe protection) 

 Check operation mode switching is correct:

You need to check with mode switching is normal each 

time you connect the GCS.

For example, looking at the data interface on the GCS, 

flight mode should display “Manual” when CH5 is at 

position 1 and CH6 is at any position, as shown in Figure 

20. This is not the case you should look at the data link 

or the settings in your transmitter.

 Check F/S protection 

Turn off your transmitter, the flight mode should display 

“Returning to land” and the throttle should show is 

neutral (green). This is not the case you should reset 

F/S protection. 

Figure 20

8.1.2.3 Setting up Aircraft Parameters

The autopilot is set to 4-axis X-type 

mode as default before delivery and 

the parameters should be set up 

according to the following procedure:

1. Click the “Parameter” tab for the 

parameter interface, as shown in 

Figure 21.

2. Click “Get” to load the existing 

parameters of the aircraft; 

Figure 21
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Ground Control Software setup and 

Debugging 21

3. Click “Send” after any alterations to send the modified parameters to the aircraft; 

Please refer to the following table specific parameter descriptions: 

Note: 

 Click Get or Send multiple times to avoid failure in obtaining or sending parameters; 

 Click “Default” to recover factory setting values. 

Parameter name Setting description

Roll Sensitivity

Pitch Sensitivity

This is the sensitivity of roll and pitch of the aircraft. The value will

have a direct effect on the sensitivity of the controls, too small or

too large settings will make the aircraft unstable. 

Settings represent the angle speed error and are in the range of 

0 to 255. The larger the value of the sensitivity, the more rapid 

the response of the aircraft, but too much sensitivity will result in 

high frequency vibration. Sensitivity needs to be reduced for 

aircraft with high-speed, smaller propellers.

Sway Compensation This sets up vibration dampening for aircraft with a lower 

propeller rotation speed; this will improve the stability but reduce 

sensitivity. The range is from 0 to 255. A value too high or too low 

will cause instability.

If there is no sway compensation, the aircraft will rock backwards 

and forwards rather than snapping directly into its neutral 

position.

– If your aircraft repeatedly rocks, then the value needs to be 

increased to stop the aircraft rocking.

– This value should be reduced when the high-speed vibration

appeared.

Photo spacing Sets up the distance interval (in meters) between two photograph 

captures within the range of 5m- 255m. 

This parameter is only available in automatic photography mode.

PTZ Roll Sensitivity

PTZ Pitch Sensitivity

The PTZ (Gimbal) roll output and PTZ pitch output sensitivity is 

used to adjust the compensation angle of the PTZ data for your 

Gimbal. 

You can compensate high or low for aircraft movement within a 

range from -127 to 127.

Note: You can enter a negative value to reverse the direction of 

compensation.

Cell Num Enter the cell number of your flight battery (4S shown)

The autopilot can calculate the low voltage alert according to the 

Cell Number filled in by the user. If your cellphone vibrates once 

every 2 seconds it is a reminder that the power is getting low. 

When it vibrates continuously it means the power is getting very 

low and you should land at once.

Altitude Limit

Distance Limit

This shows the highest and furthest distance which the aircraft can fly. 

You can enter the value 0 for unlimited distance. You can also fill in your 

own distance limit value. 

Note: The aircraft will automatically return to the starting position 
22 Ground Control Software setup and Debugging | Zero UAV (Beijing) Intelligence Technology 

Co., Ltd.

Parameter name Setting description

if the height or distance limit is exceeded after taking off in 

manual or GPS mode. It is not possible to regain control of the 

aircraft until it is back within the permitted range.

Volt Alert Threshold Enter the voltage per cell required to activate a low voltage alert, 

for a Lipo battery this would be normally 3.65v.

PAR+PHO Multiplex 1. If using a brushless gimbal: select parachute-opening + 

photograph

2. Servo Gimbal: select 2-axis PTZ 

Aircraft Type Set according to the type of aircraft in use.

Handle Mode To select speed mode or status mode The speed mode is the 

speed in GPS mode while the status mode is the speed in 

manual mode. It‟s necessary to fill in maximum flight speed when

selecting status mode. 

Max Fly Speed Flight speed is governed to the value selected.

4. Customized parameter setup (Users of common standard aircraft patterns may skip 

this bit) If you are using a non-standard multirotor with an irregular flight configuration 

you may set up the parameters according to your own requirements, customizing the 

speed increase and decrease ratios of the roll, pitch and yaw channels of each axis.

The specific definitions are as follows:

Channel Aircraft activity Required parameter values

Throttle Climb or descent 100 for all 

Yaw Rotate to the right Decrease to -100 or increase to 100 

Pitching Pitch down Decrease to -100 or increase to 100

Rolling Roll to the right Decrease to -100 or increase to 100

Flight parameters can be set up using 4-axis X-type

quadcopter as an example, as shown in Figure 22.

Set up as follows: 

a) Click “Settings” in the GCS; 

b) Click “Mixing Define” for the parameter setting 

interface; 

c) Fill in the necessary parameters and click “Send” to 

send your modified values to the flight controller; 

click “Get” to download the parameters again from 

the GCS to check whether parameters are 

uploaded successfully. Figure 22
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Ground Control Software setup and 

Debugging 23

d) Click on the “parameter” interface and select “aircraft type” and select “user-define”; 

e) After successful modification of parameters, power up the aircraft, throttle up gently 

and carefully note that the aircraft response is consistent with your settings; now you 

can confirm this with a trial flight.

NB 

Because the motors might immediately rotate at high speed after the aircraft type has been 

modified, it is strongly recommended to remove propellers to make sure of safety.

8.1.2.4 ESC Stroke Calibration

Please remove propellers before ESC stroke calibration. 

Some ESCs which have been designed specifically for multi-rotors do not need to be 

calibrated. Here we take the Hobbywing I did as yours ESC as example: hi DDM goodtime.

1. Connect the autopilot power 

only, pull the throttle to the 

bottom and put CH5 to 

position 1.

2. Click "Init Setup" in "Setting" 

page, as shown in Figure 23.

Click "Confirm" button in the 

dialog box. Now the "Flight 

Mode" should be displaying 

as "Settings" in the Data 

screen of the GCS, as shown 

in Figure 24. Figure 23 Figure 24

3. After arming the motors with CSC (Section 9.3 Unlocking and Arming the Motors), push the throttle 

all the way to the top and then connect power on (No propellers!)

4. Pull the throttle to its lowest position after two confirmatory sound signals from the ESCs 

and the gimbal controller will also sound a number of beeps to indicate the number of 

cells in the battery. This will complete ESC calibration.

5. Click “Quit Setup” and confirm in the dialog box that pops up.

6. To check whether verification is successful, push the throttle after unlocking and all my 

motors should work simultaneously. 
24 Ground Control Software setup and Debugging | Zero UAV (Beijing) Intelligence Technology 

Co., Ltd.

8.1.2.5 Inspection of Flight Controller and GPS Installation 

The flight controller and GPS installation should be inspected as follows: 

1. Check that the arrows of Gemini M, Gemini S and GPS are all pointing to the aircraft 

nose.

2. Check Gemini M and Gemini S are installed horizontally and GPS is elevated and 

installed horizontally; 

3. Check Gemini M, Gemini S and GPS are fixed firmly. 

8.2 PC Ground Station Setup and Debugging

8.2.1 Ground Station Software Auxiliary Setting (Installation Guideline)

The ground station software should be set up as follows: 

1. Connect the PC to the Wi-Fi

module, or directly to the 

COM1 on the auto pilot 

using the USB adaptor, and 

run “ZERO-GCS rotor 

ground station.exe” to enter 

the initial interface, as

shown in Figure 25.

Figure 25

2. Select “File”→ “Open Wi-Fi”, the flight data information bar will pop up at the bottom of 

the ground station window, indicating controller data, as shown in Figure 26.

3. Now select “Settings”→“Installation guide”, to pop up the installation debugging window, 

as shown in Figure 27.

Figure 26 Figure 27

4. Click “Next” for the installation operation stage. Complete the required information as 

indicated below: 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Ground Control Software setup and 

Debugging 25

Step 1 Set the aircraft type, battery cell number

and required alarm voltage from a single cell.

Step 2 Check channel settings, and failsafe 

setting (F/S)

Step 3 Select transmitter Stick Mode and 

direction of stick movement.

Step 4 Calibrate ESCs

Step 5 Unlock (using the CSC operation) and 

check channel mixing.

Step 6 Examination of flight controller and GPS 

installation 

5. Click “Finish” to exit the installation guide after software debugging. 
26 Ground Control Software setup and Debugging | Zero UAV (Beijing) Intelligence Technology 

Co., Ltd.

8.2.2 Manual Settings

8.2.2.1 Calibration of Transmitter 

The power supply should be disconnected from the motors or propellers removed before continuing.

The transmitter is calibrated as follows: 

1. Select correct stick mode; 

a) Run “ZERO-GCS rotor 

ground station.exe” 

and open Wi-Fi; 

b) Select your TX stick 

mode from the 

pull-down menu, as 

shown in Figure 28.

(Mode 2 – American 

standard is shown)

Figure 28

2. Calibrate Stick Movement

a) Click “Setting(S)”→“Transmitter (T)”→“Adjust Transmitter (C)”, the calibration prompt 

dialogue will open, as shown in Figure 29

b) Click “Yes”, within 5 seconds rotate the left and right transmitter sticks to their 

extremes in all directions, as shown in Figure 30. The flight controller automatically 

record the maximum and minimum values for each control axis and also the neutral 

values.

Figure 29 Figure 30

3. Check the stick movement is consistent with the directions indicated in the GCS; 

a) Check display positions: 

– In the flight data interface, stick positions are shown as per the diagram below. 

Mode 2 is indicated where the throttle and rudder are on the left stick, the aileron 

and elevator are on the right stick, as shown in Figure 31.
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Ground Control Software setup and 

Debugging 27

– When the sticks are in their 

neutral position they are 

shown in green. When 

moving they are shown in 

red. At their full extent they 

are shown in yellow.

Figure 31

b) Select “Setting”→ “Transmitter”→“Capture Transmitter Centre point (N)”, to 

make sure the flight controller records the correct neutral position if this has not 

already been done in fine tuning.

8.2.2.2 Checking CH5 and CH6 Switching and F/S (failsafe)

 Check operation mode switching

Check whether the switching of operation mode is correct after connecting GCS module. 

For example, the flight state 

on the “Flight status” 

interface on the right side of

the GCS should display 

“Manual” when CH5 is at

position 1 and CH6 in any 

position and so on, as shown 

in Figure 32. If not, examine 

the firmware connection or 

your transmitter settings. Figure 32

 Check F/S protection

Switch off your transmitter, flight state should display “Back landing” and the throttle slider

should be near the neutral position in green in the “Manual servo” in the flight data 

interface. This is not the case recheck your failsafe setup.

8.2.2.3 Setting up Aircraft Parameters

The steps of setting up aircraft parameters are as follows:

1. Select “Setting(S)”→“ Parameters (P)”, the parameter setting window will pop up, as 

shown in Figure 33.

2. Click “Get” to obtain the existing parameters of the aircraft; 
28 Ground Control Software setup and Debugging | Zero UAV (Beijing) Intelligence Technology 

Co., Ltd.

3. Click “Send” after 

parameter adjustment 

to send the modified 

parameters to the 

aircraft.

An explanation of 

parameters can be

found in “8.1.2.3

Setting up Aircraft 

Parameters”.

Figure 33

Note: 

 Click Get or Send multiple times to avoid failure in obtaining or sending parameters; 

 Click “Default” to recover factory setting values. 

4. Customized parameter setup (Users of common standard aircraft patterns may skip 

this bit) If you are using a non-standard multirotor with an irregular flight configuration 

you may set up the parameters according to your own requirements, customizing the 

speed increase and decrease ratios of the roll, pitch and yaw channels of each axis. 

The specific definitions are as follows:

Channel Aircraft activity Required parameter values

Throttle Climb or descent 100 for all 

Yaw Rotate to the right Decrease to -100 or increase to 100 

Pitching Pitch down Decrease to -100 or increase to 100

Rolling Roll to the right Decrease to -100 or increase to 100

An example of flight parameter set up is shown in Figure 34, using a 4-axis X-type quad 

copter as an example.

Setting up procedure is as follows: 

a) Click “Setting ”→“Other (O) ”→“ Mixing 

Define (E)” in the GCS.

b) Fill in required parameters and click 

“Send” to send these values to the flight 

controller; click “Get” to download latest 

parameters to the GCS to check 

whether parameters have been 

uploaded successfully.

Figure 34
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Ground Control Software setup and 

Debugging 29

c) In the “Parameters(P)” dialogue enter your correct “Aircraft Type”, for example 

“Quad-Rotor Cross”

d) Power the flight controller after confirming successful modification of parameters and

apply a small amount of throttle to check the motors are spinning in the correct 

directions. If this is successful you are all set to make a trial flight. 

NB 

Because the motors might immediately rotate at high speed after the aircraft type has been 

modified, it is strongly recommended to remove propellers to make sure of safety.

8.2.2.4 ESC Stroke Calibration

Please remove propellers before ESC stroke calibration.

Some ESCs which have been designed specifically for multi-rotors do not need to be 

calibrated. Here we take the Hobbywing ESC as an example.

1. Connect the autopilot power 

only, pull the throttle to the 

bottom and put CH5 to 

position 1.

2. Click "Init Setup" in 

"Setting" page. Click 

"Confirm" button in the 

dialog box. Now the "Flight 

Mode" should be displaying 

as "Settings" in the Data 

screen of the GCS, as 

shown in Figure 35.

Figure 35

3. After arming the motors with CSC (Section 9.3 Unlocking and Arming the Motors), push the 

throttle all the way to the top and then connect power on (No propellers!)

4. Pull the throttle to its lowest position after two confirmatory sound signals from the ESCs 

and the gimbal controller will also sound a number of beeps to indicate the number of 

cells in the battery. This will complete ESC calibration. 

5. Click “Quit Setup” and confirm in the dialog box that pops up. 

6. To check whether verification is successful, push the throttle after unlocking and all 

motors should work simultaneously. 
30 Ground Control Software setup and Debugging | Zero UAV (Beijing) Intelligence Technology 

Co., Ltd.

8.2.2.5 Examination of flight controller and GPS installation 

The flight controller and GPS installation should be inspected as follows:

1. Check that the arrows of Gemini M, Gemini S and GPS are all pointing to the aircraft 

nose. 

2. Check Gemini M and Gemini S are installed horizontally and GPS is elevated and 

installed horizontally; 

3. Check Gemini M, Gemini S and GPS are fixed firmly.
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Pre Flight Inspection 31

9 Pre Flight Inspection

9.1 Test Parachute Opening/Closing

The PAR output channel on the Gemini 

flight controller is a PWM square wave 

signal, to control the operation of the 

parachute servo. The parachute opening

servo must be powered separately from the 

flight controller. 

The mobile ground station can be used to 

test the operation of the parachute.

Battery

PAR port on Flight Control

Parachute Servo GND

VCC

Signal

NB 

 Press the parachute capsule cover to prevent the parachute from deploying during 

debugging, if you do this there is not a problem checking the operation of the servo.

 The parachute must be folded in accordance with the parachute folding video. It is the 

responsibility of the user the parachute does not open because it has been improperly 

folded.

Parachute folding video: http://v.youku.com/v_show/id_XNjgxNTQ1OTU2.html

The parachute operation can be tested as follows:

1. Click “Test Open Parachute” 

in the “Settings” interface to 

pop up the confirmation 

dialogue box, as shown in 

Figure 36.

2. Click “OK”, to open the 

parachute capsule.

3. Click “Test Close Parachute” 

and click “OK”, as shown in 

Figure 37.

Figure 36 Figure 37

Note: 

The Gimbal controller does not support the parachute. 
32 Pre Flight Inspection | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

9.2 Calibrating the Magnetic Compass

9.2.1 Using the Android GCS

NB

 The magnetic compass must be calibrated before the first flight after installation of the 

Gemini flight controller.

 Calibration should be carried out in a clear space outside; calibration should not be done 

indoors or in an environment with strong magnetic fields, such as in the presence of cars 

or shipping containers. 

 You should also calibrate after re-arranging components in your aircraft or if you find it 

flies in circles. 

 Compass calibration does not need to be done every time you fly, or if you upgrade 

firmware without changing hardware position. However it should be done when 

components are moved or if the aircraft flies in unexpected ways.

Compass calibration is carried out in three steps: horizontal calibration, vertical calibration and 

storage of magnetic compass data. Instructions for each stage can be found in the status bar 

at the top “Settings” interface, as follows:

1. Switch the transmitter to manual mode 

and pull the throttle to minimum.

Figure 38

2. Click “Settings” to enter the settings 

interface, as shown in Figure 38.

3. Click “Magnetic compass” to open the 

calibration dialog box, as shown in 

Figure 39.

Figure 39

4. Select “Horizontal Alignment” and to click “OK” to start horizontal calibration.

5. Hold the aircraft horizontally (within a status error of 5°which can be maintained if you 

hold the aircraft with both hands, as shown in Figure 40),turn around two or three times 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Pre Flight Inspection 33

slowly making sure that the blue LED stays lit. If the blue LED goes off, stop and adjust 

the aircraft, before continuing.

6. Now select “Vertical Alignment” and click “OK” for vertical calibration.

7. Hold the aircraft with the nose vertically down(within a status error of 5°, as shown in 

Figure 41) turn around two or three times slowly making sure that the blue LED stays lit. If 

the blue LED goes off, stop and adjust the aircraft, before continuing.

Figure 40 Figure 41

8. Select “Save Alignment” in the dialogue box and click “OK”.

9. You will need to wait for the flight controller to process the recorded magnetic data. A 

purple LED will show during the processing. When the purple light goes out, calibration is 

complete.

10. The ground station will switch to the remote control interface automatically and spend a 

few seconds calculating. Then it will display two circles, one blue and the other red, as 

indicated in the following figures: The superposition of two circles, red and blue indicates 

successful calibration. If this is not the case you need to start again with a new calibration 

operation.

 

Calibration excellent Calibration okay Calibration unsuccessful

9.2.2 Compass Calibration Using a PC Ground Station

NB

 The magnetic compass must be calibrated before the first flight after installation of the 

Gemini flight controller. 

Direction of

aircraft nose
34 Pre Flight Inspection | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

 Calibration should be carried out in a clear space outside; calibration should not be done 

indoors or in an environment with strong magnetic fields, such as in the presence of cars 

or shipping containers. 

 You should also calibrate after re-arranging components in your aircraft or if you find it 

flies in circles. 

 Compass calibration does not need to be done every time you fly, or if you upgrade 

firmware without changing hardware position. However it should be done when 

components are moved or if the aircraft flies in unexpected ways. 

Compass calibration is carried out in three steps: horizontal calibration, vertical calibration and 

storage of magnetic compass data. Instructions for each stage can be found in the status bar 

at the top “Settings” interface, as follows:

1. Switch the transmitter to manual mode and pull the throttle to minimum; 

2. Select“Settings(S)”→“Magnetic Compass (M)”for the “Magnetic Compass Alignment”

window as shown in Figure 42.

3. Click “Horizontal Alignment” for horizontal calibration, as shown in Figure 43.

Figure 42 Figure 43

4. Hold the aircraft horizontally (within a status error of 5°which can be maintained if you 

hold the aircraft with both hands, as shown in Figure 44),turn around two or three times 

slowly making sure that the blue LED stays lit. If the blue LED goes off, stop and adjust 

the aircraft, before continuing.

5. Now select “Vertical Alignment” and click “OK” for vertical calibration.
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Pre Flight Inspection 35

6. Hold the aircraft with the nose vertically down(within a status error of 5°,as shown in 

Figure 45) turn around two or three times slowly making sure that the blue LED stays lit. If 

the blue LED goes off, stop and adjust the aircraft, before continuing.

Figure 44 Figure 45

7. Select “Save Alignment” in the dialogue box and click “OK”; 

8. You will need to wait for the flight controller to process the recorded magnetic data. A 

purple LED will show during the processing. When the purple light goes out, calibration is 

complete.

9. The ground station will switch to the remote control interface automatically and spend a 

few seconds calculating. Then it will display two circles, one blue and the other red, as 

indicated in the following figures: The superposition of two circles, red and blue indicates 

successful calibration. If this is not the case you need to start again with a new calibration 

operation.

 

Calibration Excellent Calibration okay Calibration unsuccessful

9.3 Unlocking and Arming the Motors

NB

 The controller cannot be unlocked and motors armed near large airports, or within Beijing 

5th ring. 

 The controller cannot be unlocked without GPS.

 Magnetic compass calibration must be carried out before the first time you unlock the 

motors. 

Direction of

aircraft nose
36 Pre Flight Inspection | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

 The flight controller will lock the motor again if no throttle has been applied within five 

seconds. In this instance you should perform the unlocking operation again. 

 Checking F/S protection is intended to reduce the possibility of accidents in the flight. 

Failsafe check should be made each time the system is powered.

 The motor will run when applying throttle after unlocking. It’s normal for some motors to 

slow down or even stop if there has been no take off. The aircraft will take off normally 

only by increasing the throttle.

Motors are locked by the Gemini flight controller for the purpose of safety. Motors will run 

normally only after unlocking. The unlocking procedure, also known as arming or applying 

CSC, is as follows: using a FUTABA transmitter as an example (in Japanese stick mode, mode 

1).

1. Check F/S protection by shutting off the transmitter, the flight status bar on the ground 

station should display “Returning and landing”, before attempting to unlock. If it does not 

you should reset failsafe. 

2. Unlock by pushing the rudder stick to the extreme left, and pull it fully down. Now push the 

aileron stick to the extreme right and pull it down. 

Note:

When unlocking, the reverse V-type ( /\ ) is required for the left-hand pattern (Japanese and 

American, or Mode 1 and Mode 2) while the V-type ( \/ ) is required for the right-hand pattern 

(Chinese and European, or Mode 3 and Mode 4). 

 

9.4 Inspecting Motor Rotational Direction

You must inspect the direction of rotation of each motor before the aircraft takes off, in the 

same way that you would inspect the control surfaces of a fixed wing aircraft before takeoff.

Switch to manual mode and check F/S setting to allow unlocking; 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Pre Flight Inspection 37

Using a four axis cross- type multirotor as an example; rotor direction inspection is carried out 

as follows. The diagrams that follow give the conditions required for other types of aircraft: 

1. Check motor balance by making sure that all four motors rotate at the same speed when 

gently applying throttle.

2. Check the aileron channel. Push the aileron stick slightly to the left and the M4 motor

should run immediately (Figure 46) while the other three motors remain static. Push the 

aileron stick slightly to the right and the M2 motor should rotate immediately (Figure 47) 

while the other three motors remain static. 

Figure 46 Figure 47

3. Inspect the climb and descent channel (Elevator) in the same way as the aileron channel. 

Push the elevator stick up and M3 should rotate (Figure 48). Pull the stick down to make 

M1 rotate (Figure 49). 

Figure 48 Figure 49

4-axis X-type: 

 Push aileron stick to left Push aileron stick to right Push elevator stick up Push elevator stick up 
38 Pre Flight Inspection | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

6-axis cross type: 

Push aileron stick to left Push aileron stick to right Push elevator stick up Push elevator stick up 

6-axis X- type: 

Push aileron stick to left Push aileron stick to right Push elevator stick up Push elevator stick up
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 39

10 Flying at the Field

10.1 Flight Status 

10.1.1 LED Status Indications

 GPS 

The red light, blue light and green light indicate the current operational state of the aircraft 

as indicated the table below: 

Light colour Light status Operational status

Red light (for all modes)

3 flashes ••• No GPS

2 flashes •• GPS 5 satellites

1 flash • GPS 6 satellites

Red light out GPS 7 or more satellites

Blue light (GPS mode, non-positioning)

1 flash • User in operation

2 flashes •• Hovering at fixed height

Green light (GPS mode, in positioning)

1 flash • User in operation

2 flashes •• Hovering at fixed point

Note:

 Only take off after 7 or more GPS satellites are in view. 

 The flight controller will use the take-off position as the home location when the GPS 

first locks in to seven satellites. 

 White LED

(1) The LED white light indicates a large status error or a loose connection to the GPS

module.

(2) Action required when the white light comes on: 

– If the light comes on when the aircraft is suffering violent movement but goes out 

when it retains stability than you can continue the flight normally.

– Land the aircraft as soon as possible if the white light shows continuously and

check the GPS connection. Zero the gyro in the GCS if there is a status error.

 Low voltage alarm
40 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

The red light will flash quickly as a low battery voltage alarm. It shows as a solid light in an 

emergency situation of extreme low voltage.

 Barometer initialization failure

A continuous red light showing when the aircraft is on the ground, indicates the failure of 

the barometer to initialize. You must restart the flight controller. 

 Magnetic field verification

When calibrating, a continuous blue light indicates a magnetic compass calibration error

less than 5° and indicates a successful calibration. However, if the blue light goes off with

a status error more than 5° this indicates that adjustment is needed. The purple light will 

be on continuously when storing the data after calibration of the magnetic data. The 

purple light will go out completely when data storage is complete. 

10.1.2 Motor Balance and Real Throttle Position

The two parameters of motor balance and real throttle position are shown as follows in the 

ground station: 

 Mobile ground station: open the mobile ground station and click “Data”, as shown in 

Figure 50.

 PC ground station: Open Wi-Fi and the “Flight data” section will open at the bottom or 

select “View”→“Flight data” to check. The parameters are indicated in Figure 51.

Figure 50 Figure 51

10.1.2.1 Motor Balance

"Motor balance” will display an imbalance between the clockwise propellers or counter

clockwise propellers when the aircraft is in a static hovering position. The propellers need to be 

balanced or replaced with higher quality units.
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 41

To ensure stable flight, accurate examination must be made of the balance and horizontal 

symmetry of the motors and propellers until the motor balance parameter displays “Good”

when hovering the aircraft. 

10.1.2.2 Real Throttle Position

The throttle position of the aircraft when hovering is usually at 40-65, which is considered 

normal (in green). Any position lower than 40 (shown in yellow) indicates the aircraft is 

maintaining a light load on the ESCs while higher than 65 (in red) indicates that the aircraft is 

heavy or the battery is delivering a low voltage. This situation requires a load adjustment or 

battery replacement. 

10.1.3 Adjusting Aircraft Vibration Parameters

The following factors affect the flight stability of the aircraft and corresponding adjustment 

measures need to be carried out: 

1. Shaking, vibration or poor installation of the IMU will affect flight stability. Therefore 

attention should be paid to the following: 

– Make sure the host and slave controllers are in the correction direction (facing the 

aircraft nose) and firmly fixed in a position of as little resonance as possible on the 

aircraft.

– The coefficients of shake and vibrate on the ground station indicate the amount of 

vibration of the IMU. Therefore, when installing the flight controller make sure the 

motors and propellers are installed in balance to reduce the shake and vibration state 

to lower than 10 (use smaller propellers to reduce the amount of vibration in the trial).

An airframe structure of higher rigidity is recommended as a softer frame will cause 

additional vibration. 

Note: 

The Shake state and Vibrate state can be checked as follows: 

 Mobile ground station: open the mobile ground station and click “Data”, as shown 

in Figure 52.

 PC ground station: Open Wi-Fi and the “Flight data” section will open at the 

bottom or select “View”→“Flight data” to check. The parameters are indicated in 

Figure 53.
42 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

Figure 52 Figure 53

2. The orientation of multiple axis aircraft is adjusted by adjusting speed of the motors. The 

sensitivity of the axis control will make a direct impact on the accuracy of the aircraft 

response. Adjust the match between the aircraft weight and the screw pitch of the 

propeller to make sure the motor can generate an adequate rotation speed, producing 

enough control response. The lightest propeller possible, should be selected to reduce 

inertia and to improve command response. There should be a proper balance between 

flight efficiency and stability. 

3. The symmetry of multiple axis aircraft has a vital influence on flight stability. 

The symmetry of the motor and propeller can be evaluated in horizontal flight by referring 

to “10.1.2.1 Motor Balance”. 

4. Further improvements can be made to the stability of the aircraft by adjusting “Roll 

sensitivity”, “Pitch sensitivity” and “Sway Compensation” after completing the above three 

steps. 

Note: 

“Roll sensitivity”, “Pitch sensitivity” and “Sway Compensation” can be checked as follows:

 Mobile ground station: open the mobile ground station and click “Parameter”, as 

shown in Figure 54.

 On the PC ground station select “Settings” →“Parameters” to check, as shown in 

Figure 55.
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 43

Figure 54 Figure 55

10.2 Flight Functions 

10.2.1 Basic Flight Operation

10.2.1.1 Using Your Mobile Device for Remote Control of the Aircraft

In automatic hovering 

status, click the menu key 

on the mobile ground 

station to select “Enable 

Control” to enter mobile 

remote control mode, as 

shown in the figures on the 

right: The button will 

change to “Disable 

Control”.

 

Non-remote control mode Remote control mode

The transmitter sticks cannot be used in mobile remote control mode. Remote control 

using your mobile device is explained in the following table:

After Enable Control Remote control interface operation Aircraft status

Dot status Red: non-positioning Green: positioning -

Hovering operation Do not touch any area of the screen Hovering

Advance operation

1. Touch the central circle and drag up or 

and down

2. Touch the central circle and drag left or 

right

1. move forwards 

or backwards

2. move left or right 

3. move forward 
44 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

After Enable Control Remote control interface operation Aircraft status

3. Touch the central circle and drag 

diagonally

left, backward 

left, forward right 

or backward 

right

Climb / descend / 

rotate

1. Touch the area above the circle (on the 

cross)

2. Touch the area under the circle (on the 

cross)

3. Touch the left side of the circle (on the 

cross)

4. Touch the right side of the circle (on the 

cross)

Note: 

 The distance between the click position 

and the center of a circle is equivalent to 

the change of speed of the aircraft, 

meaning the farther from the center, the

higher speed of the aircraft.

 The touch time is equivalent to the 

moving time of the aircraft.

1. Climb

2. Descend

3. Rotate left

4. Rotate right

Note: 

Mobile remote control mode cannot be used without GPS positioning. (Indoors for example)

10.2.1.2 Mobile Attitude Control Mode

NB

 Please keep the aircraft horizontal before starting attitude control mode. Otherwise, the 

aircraft will fly off in the direction that the mobile dips, after switching to this mode. 

 Mobile attitude control mode can only be used in mobile remote control mode. 

 Control mode will automatically switch immediately to mobile remote control mode after 

exiting from the mobile attitude control mode. However exiting mobile remote control 

mode will revert to transmitter control. 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 45

Click the mobile device

menu key and click “Enable 

Attitude Control” to open the 

attitude option, the remote 

control interface will switch

to a blue cross, indicating

that mobile attitude control 

mode is started as shown 

the figures on the right.

 

Non-attitude control mode Attitude Control mode

The status of attitude control mode can be seen in the following table: 

After Enable Control Remote control interface operation Aircraft status

Dot status Red: non-positioning Green: positioning -

Hovering operation 

Hold the mobile device horizontally and do 

not touch the screen

Hovering 

Advanced operation

1. Tilt the mobile device forwards and 

backwards 

2. Tilt the mobile device from left to right 

3. Tilt the mobile device from upper left to 

bottom left or upper right to bottom 

right 

1. Move forwards 

and backwards

2. Move left and 

right 

3. Move forward left, 

backward left, 

forward right and 

backward right 

Climb / descend / 

rotate

1. Click any area on the screen and drag 

upwards 

2. Click any area on the screen and drag 

downwards 

3. Click any area on the screen and drag 

to the left 

4. Click any area on the screen and drag 

to the right 

Note: 

 Dragging distance is proportional to 

the speed of the aircraft, meaning that 

1. Climb

2. Descend

3. Rotate left

4. Rotate right
46 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

After Enable Control Remote control interface operation Aircraft status

the longer the dragging distance, the 

higher the speed of the aircraft. 

 The time spent touching the screen is 

equivalent to the move duration of the 

aircraft. 

10.2.1.3 Semi-automatic Take Off

The flight status will display “Auto hover” when seven or more satellites are in view and CH5 is 

in position 3 and CH6 in position 1. Now push the throttle after arming and the aircraft will take 

off after the throttle is in mid position and will hover automatically at a height of approximately 

2-3 metres. 

10.2.1.4 Return and Land

NB

For safety reasons it is not recommended to switch to return and land mode if the aircraft is 

too near to people.

Return and land is achieved as follows: 

1. The aircraft will record automatically the starting position, after having attained GPS lock 

with seven or more satellites.

2. Carry out any of the following operations to hand over control to the aircraft to return and 

land. The aircraft will not respond to the flight control sticks on the transmitter during this 

time:

– Switch CH5 and CH6 to position 3 on the transmitter.

– On the mobile ground station: click “Map”→“SPC”→“Auto Landing”; 

– On the PC ground station: select “View”→“Panel” and open the instrument panel and 

click “Auto landing”. 

3. The aircraft will land slowly after reaching the take-off point and at this stage you can 

adjust the position of the aircraft if you need to find a better landing position. 

The flight controller automatically applies throttle at this time and the throttle stick of the 

transmitter is inactive. 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 47

4. The motors will gradually stop rotation when the aircraft is fully on the ground and the 

throttle stick reduced to minimum. The motors will be locked after 5 seconds and a CSC 

operation is required before restarting. 

Note: 

 If the aircraft is 25m or more away from the return point and less than 20m in height, the 

aircraft will climb to 20m before returning when switched to auto land mode. The Aircraft will 

return to its original height after switching to auto land mode if the aircraft is higher than 

20m. The aircraft will return at its current height if the aircraft is less than 25m away from 

the return point.

 The aircraft will exit from return and land mode only after switching CH5 to position 1. 

10.2.1.5 Fly to Point on the Map (FlyToPP)

10.2.1.5.1 Mobile Ground Station Fly to Point

NB

Take care when using FlyToPP that the aircraft does not fly out of sight.

FlyToPP can only be carried out in GPS automatic hover mode. The procedure is as follows: 

1. Switch CH5 to position 3 and CH6 to position 1 on the transmitter.

2. Select a point on the map 

interface, a yellow smiley 

will appear at that point, 

as shown in Figure 56.

3. Click "SWP” then “OK” 

the smiley will change 

into a purple star, as 

shown in Figure 57.

4. Perform the same 

procedure to fly to the 

next target point. 

Figure 56 Figure 57

Note:

The aircraft will fly without turning if the distance between two target points is less than 10m; 

the nose of the aircraft will turn towards the next target point if the distance is larger than 10m.
48 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

10.2.1.5.2 PC Ground Station Fly to Point (FlyToPP)

Fly to point can only be achieved in GPS automatic hovering mode. The procedure is as 

follows: 

1. Switch CH5 to position 3 and CH6 to position 1 on the transmitter.

2. Open the ground 

station and select 

“File”→“Open Wi-Fi”, 

a yellow smiley will 

display on the map, as 

shown in Figure 58: a 

purple star is beneath 

the yellow smiley.

Figure 58

3. Click a target point, the 

yellow round smiling 

face will move to the

point and the covered 

purple star will be 

exposed, as shown in 

Figure 59.

Figure 59

4. Click “Fly to PP”, the 

purple star will move to 

the position of the yellow 

smiley, as shown in 

Figure 60.

5. The aircraft will fly to this 

point and to the next 

target point if the same 

procedure is followed. Figure 60

10.2.1.6 Way Point Flight

10.2.1.6.1 Mobile Ground Station Waypoint Flight 

Waypoint flying is carried out as follows: 

1. Route design: Click “Map”→“Tool”→“Add Waypoints” then “OK” to open the route design 

interface; complete waypoint the design clicking each point on the route.
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 49

Route design can be made by adding single points consecutively (manual generation of 

route) or automatic route generation.

 Editing single points: each waypoint contains the key parameters of “Height”, 

“Hovering time” and “Speed”. To edit waypoints, click on the waypoint and then select 

“Edit waypoint” from the pop-up window.

– “Height”: means the altitude of the aircraft relative to the takeoff point at that 

waypoint. The aircraft will gain or lose altitude between waypoints if they are of 

different heights. The default altitude of a waypoint is the current height of the 

aircraft when switching to navigation mode.

– “Hovering time”: is the 

time spent stationery at 

each waypoint. The default 

setting for the first waypoint 

is 65535. 

– “Speed”: is the speed of 

the aircraft to the next 

waypoint.

Single point editing (manual generation of route)

– “Photography setting”: sets up the ability to take a photograph at intervals or 

at each waypoint indicated along a route. The initial point, where the first 

photograph is taken should be set up according to the “Start photograph” routine 

described below.

 Automatic generation of route: at least 4

waypoints should be set up with the same 

height and flight speed at each waypoint.

After setting up the waypoints, click “Tool”

→“Auto Make Waypoints” and edit the 

correct settings for“Delay”, “Interval”, 

“Altitude” and “Speed”. The software 

will now automatically generate a waypoint 

route. Automatic waypoint route generation 

2. Uploading a route: after drawing a route, it must be uploaded to the flight controller. Click 

“Upload Waypoints” in the Tools menu. The route can also be stored as a file for use in the 

future. Click “Save Waypoints”

To examine whether each waypoint has been uploaded successfully, the color of the 

waypoint will change to blue indicating success or change to orange to indicate failure. 

Uploading should be done again in case of failure. 
50 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

3. Route verification: Click “remove route points” to change blue points into orange points 

and click “verify waypoints”, to download the currently uploaded waypoints into the ground 

station for comparison. If all waypoints change to blue, the route stored in the flight 

controller is consistent with that in the ground station, indicating no errors. If this is not the 

case the route should be uploaded again.

4. Waypoint flight 

 Automatic flight

1) Switch CH5 to position 3 and CH6 to the position 2 on the transmitter.

2) Click “Map”→“SPC”→“Enable Skyway”, the aircraft will fly automatically 

to the first waypoint and hover.

3) Enter 2 in the text box “Target” in “Map”→“SPC”, and click “Target”

now push the elevator stick up and the aircraft will fly to waypoints in the order 2, 

3, 4„ Until the route is complete when it will fly to the first waypoint and hover.

 Semi-automatic flight 

1) Switch CH5 of the RC control TX to position 3 and CH6 to position 2. 

2) On the Android GCS select “Map ”→“SPC ”→“Enable Skyway ”→“Semi-Auto 

Skyway” and click “OK”, the aircraft will stay in its current position; 

3) Push the elevator stick on your TX and the aircraft will fly in the order 1, 2, 3, 

4...etc. until completion of all waypoints. 

Throttle and rudder can be used as normal during the flight. 

2. Exit: Switch CH5 to position 1 (in manual mode) or CH6 to position one (auto hover mode) 

to exit waypoint flying. 

Note:

 If you have not set up a waypoint route the aircraft may fly away if you switch to auto 

navigation mode. After starting the motors, the flight status of the aircraft will change

to automatic navigation 3 seconds after switching to automatic navigation mode. 

 The nose of the aircraft aligned to the next waypoint during waypoint route navigation.

 If you want to control the direction of the nose, click “Map”→“SPC”→“Disable course 

locked” during waypoint flight. The aircraft will fly the route is normal but the nose will not 

point to the flight direction. It will be controlled by the rudder stick on the transmitter. Click 

“Enable course locked”, and the nose of the aircraft will point towards the flight direction 

again. 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 51

10.2.1.6.2 PC Ground Station Waypoint Flight

Waypoint route flying is carried out as follows: 

1. Connect the PC via Wi-Fi and open the ground station. Select “File”→“Open Wi-Fi”; 

2. Route design: Click “ ” to open waypoint route design, click on each waypoint in turn, 

then click “ ” to exit waypoint generation.

Waypoint route design can be single point editing (manual generation of route) and 

automatic route generation. 

 Single point editing: each waypoint contains key parameters of “Height”, “Cycle

time” and “Speed”. Right click on the waypoint and select “Edit” to change these 

parameters.

– “Height”: is the altitude of the aircraft relative to the takeoff point at that

waypoint. The aircraft will gain or lose altitude between waypoints if they are of 

different heights. The default altitude of a waypoint is the current height of the 

aircraft when switching to navigation mode.

– “Cycle time”: is the 

time spent stationery at 

each waypoint. The 

default setting for the 

first waypoint is 65535.

– “Speed”: is the speed 

of the aircraft to the next 

waypoint. Single point edition (manual generation of route)

– “Snapshot config”: sets up 

the ability to take a photograph 

at intervals or at each 

waypoint indicated along a 

route. The initial point, where 

the first photograph is taken 

should be set up according to 

the “Start photograph” routine 

described below. Route edition window

Note:

 Clicking the right button on a selected waypoint will give you the option of uploading 

editing or deleting.

 Left click on the waypoint to display the waypoint properties.
52 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

 Automatic generation of route: at least 4 waypoints should be set up with the same 

height and flight speed at each waypoint. 

1) Select “Path Settings” “Edit Current Path” after setting up route points and the 

“Edit Waypoint” window will pop up.

2) Click “Pattern Waypoints” and the “Pattern Waypoints” window will pop up.

3) Select a waypoint and click LPT1 and enter a setting for “Pattern Delay”, “Pattern 

Interval” and “Pattern Speed”, then click “Make” and the software will

automatically generate a flight route for the aircraft. 

1. Setting up waypoints 2. Route edition window

3. Setting of automatic generation of route 

parameters

4. Automatic generation of route

3. Uploading the route to the aircraft: right 

click a waypoint and click“Upload”or select 

“Path Settings”→“Upload Path to AP”

after setting up the route. The route can also 

be stored as a file for use in the future. To 

examine whether each waypoint has been 

uploaded successfully, the waypoint color

will change to blue indicating success, any 

other color would indicate failure, as shown 

in Figure 61.

Figure 61

4. Route verification: select “Path Settings”→“Download and Check Path”, to download 

the waypoints from the aircraft to the ground station for comparison. All route points will 

change into orange and then blue. All route points in blue indicate that the route stored in 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 53

the flight controller is consistent with that in the ground station, indicating no error in the 

route. If not, the route should be uploaded again.

5. Waypoint flight

 Automatic flight

1) Switch CH5 to position 3 and CH6 to position 2.

2) Click “Enable Skyway” 

on the right hand panel 

and a confirmation will 

pop up, as shown in 

Figure 62, click

“Enable” and the 

aircraft will fly to the 

first waypoint and 

hover.

Figure 62

3) Enter 2 in the textbox “Target Waypoint” in the instrument panel and click 

“Change Target” Now push the elevator stick and the aircraft will fly between 

waypoints in the order 2, 3, 4...etc. until the route is complete when it will hover 

at the first waypoint.

 Semi-automatic flight 

1) Switch CH5 of the RC control TX to position 3 and CH6 to position 2. 

2) On the Android GCS select “Map ”→“SPC ”→“Enable Skyway ”→

“Semi-Auto Skyway” and click “OK”, the aircraft will stay in its current 

position; 

3) Push the elevator stick on your TX and the aircraft will fly in the order 1, 2, 3, 

4...etc. until completion of all waypoints. 

Throttle and rudder can be used as normal during the flight. 

6. Exit: Switch CH5 to position 1 (in manual mode) or switch CH6 to position 1 (auto hover 

mode) to exit the function. 

Note:

 If you have not set up a waypoint route the aircraft may fly away if you switch to auto 

navigation mode. After starting the motors, the flight status of the aircraft will change

to automatic navigation 3 seconds after switching to automatic navigation mode. 

 The nose of the aircraft aligned to the next waypoint during waypoint route navigation.

 If you want to control the direction of the nose, click “Map”→“SPC”→“Disable course 

locked” during waypoint flight. The aircraft will fly the route as normal but the nose will not 
54 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

point to the flight direction. It will be controlled by the rudder stick on the transmitter. Click 

“Enable course locked”, and the nose of the aircraft will point towards the flight direction 

again. 

10.2.1.7 Tracking Mode (Heading Hold)

This function can only be used in GPS mode and when seven or more satellites are in view.

In tracking mode the aircraft flies along the waypoint route with the aircraft nose direction 

locked. 

Tracking mode is carried out as follows: 

1. Switch CH5 to position 3 (GPS hover mode) and move the transmitter sticks to as near 

neutral as possible.

2. On the ground station, click “Enable Course Locked” on the instrument panel to start.

3. Click “Disable Course Locked ” on the instrument panel to exit. 

10.2.2 Professional Flight Operation

The following flight modes are designed for professional photographic work using the Zero 

UAV „Z‟ series brushless direct drive gimbals

 Air rocker 

 FPV aerial photography

 Carefree

Aerial Photography can be carried out using a single transmitter, however most professionals 

would prefer to use two transmitters, one to control the aircraft and the other to control the 

gimbal. Both operational modes will be described: 

10.2.2.1 Dual Controller Operation 

10.2.2.1.1 Aerial Rocker 

The default waypoint flying value, when using a Zero UAV Z series brushless gimbal, is 

the aerial rocker function. Rocking the elevator stick backwards and forwards controls 

the speed of waypoint flight.

When in the aerial rocker function, the gimbal remote control controls the direction of gimbal, 

the aircraft head tracks the gimbal direction. Pushing the elevator stick will make the aircraft fly 

according to the scheduled way point route; the greater the degree of elevator input the higher 

the flight speed. Releasing the stick to center will make the aircraft return to hover. After 

completing all way points, releasing the stick to the center will cause the aircraft to return to the 

first way point and hover. 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 55

Enter the Aerial Rocker function as follows: 

1. Setup your waypoint route on the GCS map interface, upload the route to the autopilot 

and verify.

2. After takeoff, switch to GPS mode on the aircraft controller and hover.

3. Switch CH6 on the aircraft controller from position 1 to position 2. Pause for five 

seconds and the aerial rocker function will enable.

4. To exit, return CH5 to position one (manual mode) or CH6 to position one (GPS mode).

The status of all parameters in aerial rocker mode is shown in following table.

Flight 

mode

Flight 

course

Aircraft 

head

Remote 

controlling 

instruction

Aircraft 

remote 

control

Gimbal remote 

control

Aerial 

rocker 

(waypoint 

route)

Direction of 

planned 

route

Head 

direction 

always 

follows the 

direction of 

the camera 

lens.

Rudder Not controlled Direction is 

controlled

Aileron 

rudder Not controlled Roll is controlled

Elevator

Regulates 

speed of 

waypoint flight

Pitch is 

controlled

Accelerator 

rudder Not controlled

Push throttle 

stick to increase 

stability

CH5 Position three Position one

CH6 Position two X

10.2.2.1.2 FPV Mode

FPV mode (first person view) the aircraft remote control controls the direction of the gimbal. 

The aircraft heading automatically follows the direction of the gimbal so as to avoid the landing 

gear from blocking the view of the camera. The pitch and roll of the aircraft will follow the video 

direction as reference. For example, when circling a point of interest, the pilot can always 

focus on the target by just using the rudder. The autopilot will control aileron, elevator, height 

and distance.

A schematic diagram of FPV mode is shown below: 
56 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

 FPV operation in GPS flight mode

1. Switch CH5 of the gimbal remote control to position 1, the gimbal will not be in 

tracking mode.

2. After the aircraft enters hover in GPS mode, switch CH5 on the aircraft controller 

from position 3 to position 2, after a 2 second pause the aircraft will enter FPV mode 

with a high level of stability. The aircraft will remain hovering in GPS mode.

3. To leave FPV mode switch CH5 on the aircraft controller back to the first position for 

manual mode or 3rd position for GPS hover.

The status of all parameters in FPV mode is shown in following table.

Flight 

mode

Flight 

course

Aircraft 

head

Remote 

controlling 

instruction

Aircraft 

remote 

control

Gimbal remote 

control

Highly 

stable 

FPV 

mode

Takes 

gimbal 

direction as 

reference

The aircraft 

head 

direction 

always 

follows the 

direction of 

the camera 

lens.

Rudder Controlled Not controlled

Aileron 

rudder Controlled Roll is controlled

Elevator Controlled Pitching is 

controlled

Accelerator 

rudder Controlled

Push throttle 

stick to increase 

stability

CH5 Position two Position one

CH6 Position one X

NB: When CH6 is shown as X changing the sensitivity of the gimbal will be invalid.

 FPV operation in manual flight mode

1. Switch CH5 of the gimbal remote control to position one; the gimbal will not be in 

tracking mode.

2. After the aircraft takes off in manual, place CH5 from position 1 to position two. After 

a 2 second pause the aircraft will enter manual FPV mode with a high level of stability. 

Unlike when in GPS automatic hover status, the aircraft will remain in manual mode.

3. To leave FPV mode switch CH5 back to the first position for manual mode.

The status of all parameters in manual mode is shown in following table.

Flight 

mode

Flight 

course

Aircraft 

head

Remote 

controlling 

instruction

Aircraft 

remote 

control

Gimbal remote 

control

Highly 

stable 

FPV 

mode

Take 

gimbal 

direction as 

reference

The aircraft 

head 

direction 

always 

follows the 

Rudder Controlled Not Controlled

Aileron 

rudder Controlled Roll is Controlled

Elevator Controlled Pitch is 

controlled
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 57

Flight 

mode

Flight 

course

Aircraft 

head

Remote 

controlling 

instruction

Aircraft 

remote 

control

Gimbal remote 

control

direction of 

the camera 

lens.

Accelerator 

rudder Controlled

Push throttle 

stick to 

increase stability

CH5 Position two Position one

CH6 X X

10.2.2.1.3 Carefree Mode 

This mode must be used in GPS Hover Status. 

In carefree mode, the navigation direction of the aircraft is locked (i.e. the direction the aircraft 

is heading when entering this mode). Whatever direction faced by the nose of the aircraft, the 

flight direction will remain unchanged. The nose of the aircraft automatically keeps track of the 

gimbal so that the camera avoids the landing gear. The elevator and aileron of the aircraft take 

the navigation direction of the aircraft as reference. 

A schematic diagram of carefree mode is shown below: 

Enter carefree mode as follows:

1. Switch CH5 of the gimbal remote control to position one; the gimbal will not be in tracking 

mode.

2. After takeoff switch to GPS mode and hover

3. After selecting the desired flight direction align the nose of the aircraft in this direction. 

Switch CH5 on the flight controller from position 3 to position 2, switch back to position 3 

then return to position 2. You will now be in carefree mode. 
58 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

4. When you need to exit carefree mode, switch channel 5 to position 1 or position 3 

(manual mode or GPS mode).

The status of all parameters in carefree mode is shown in the following table.

Flight 

mode

Flight 

course

Aircraft 

head

Remote 

controlling 

instruction

Aircraft 

remote 

control

Gimbal remote 

control

Carefree

Take user 

selected 

direction as 

reference

The aircraft 

head 

direction 

always 

follows the 

direction of 

the camera 

lens.

Rudder Controlled Direction is 

Controlled

Aileron 

rudder Controlled Roll Controlled

Elevator Controlled Pitching 

Controlled

Accelerator 

rudder Controlled

Push throttle 

stick to increase 

stability

CH5 Position two Position one

CH6 Position one X

10.2.2.2 Single Transmitter Flight Operation

The default operational mode is dual transmitter control after switch on. Change to single 

transmitter mode as follows: 

1. Toggle the CH7 switch from maximum to 

minimum, 3 times rapidly to change to 

single transmitter control. The gimbal is 

now controlled by the aircraft transmitter 

radio. 

2. In order to check for correct operation, 

gently advance the throttle by around 

5%. If correct, the gimbal will become 

operational and CH7 will control camera 

tilt, as shown in Figure 63.

Figure 63

3. The gimbal will stop stabilization when the throttle is reduced back to zero. 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 59

10.2.2.2.1 Aerial Rocker Function

The default waypoint flying value, when using a Zero UAV Z series brushless gimbal, is 

the “Aerial rocker” function. Rocking the elevator stick backwards and forwards 

controls the speed of waypoint flight.

When in the aerial rocker function, the aircraft remote control controls the direction of gimbal, 

the aircraft head tracks the gimbal direction. Pushing the elevator stick will make the aircraft 

fly according to the scheduled way point route; the greater the degree of elevator input the 

higher the flight speed. Releasing the stick to center will make the aircraft return to hover. After 

complete all way points, releasing the stick to center will cause the aircraft to return to the 1st 

way point and hover. 

Enter the aerial rocker function as follows: 

1. Setup your waypoint route on the GCS map interface, upload the route to the autopilot 

and verify.

2. After takeoff, switch to GPS mode and hover.

3. Switch CH6 from position 1 to position 2. Pause for five seconds and the aerial rocker 

function will enable.

4. To exit, return CH5 to position one (manual mode) or CH6 to position one (GPS mode).

The status of all parameters in aerial rocker mode is shown in following table.

Flight mode Flight 

course

Aircraft 

head

Remote 

controlling 

instruction

Aircraft remote control

Airplane Gimbal

Aerial rocker 

(waypoint 

route)

Direction of 

planned 

route

Head 

direction 

always 

follows the 

direction of 

the camera 

lens.

Rudder Not controlled Controlled

Aileron 

rudder Not controlled Not controlled

Elevator

Regulates 

speed of 

waypoint flight

Not controlled

Throttle 

rudder Not controlled

Push throttle 

stick to 

increase 

stability

CH5 Position three 

CH6 Position two

NB: Gimbal tilt is controlled by CH7.

10.2.2.2.2 Highly Stable FPV Mode 

FPV mode (first person view) the aircraft remote control controls the direction of the gimbal. 

The aircraft heading automatically follows the direction of the gimbal so as to avoid the landing 
60 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

gear from blocking the view of the camera. The pitch and roll of the aircraft will follow the video 

direction as reference. For example, when circling a point of interest, the pilot can always 

focus on the target by just using the rudder. The autopilot will control aileron, elevator, height 

and distance.

A schematic diagram of FPV mode is shown below: 

 FPV operation in GPS flight mode

1. After the aircraft enters hover in GPS mode, switch CH5 from position 3 to position 2, 

after a 2 second pause the aircraft will enter FPV mode with a high level of stability. 

The aircraft will remain hovering in GPS mode.

2. To leave FPV mode switch CH5 back to the first position for manual mode or 3rd 

position for GPS hover.

The status of all parameters in FPV mode is shown in following table.

Flight mode Flight 

course

Aircraft 

head

Remote 

controlling 

instruction

Aircraft remote control

Airplane Gimbal

Highly stable 

FPV mode

Takes 

gimbal 

direction as 

reference

The aircraft 

head 

direction 

always 

follows the 

direction of 

the camera 

lens.

Rudder Not controlled Controlled

Aileron 

rudder Controlled Not controlled

Elevator Controlled Not controlled

Accelerator 

rudder Controlled

Push throttle 

stick to 

increase 

stability 

CH5 Position two 

CH6 Position one 

NB: Gimbal tilt is controlled by CH7.

 FPV operation in manual flight mode

1. After the aircraft takes off in manual, place CH5 from position 1 to position two. After 

a 2 second pause the aircraft will enter FPV mode with a high level of stability. Unlike 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Flying at the Field 61

when in GPS automatic hover status, the aircraft will remain in manual mode.

2. To leave FPV mode, switch CH5 back to the first position for manual mode.

The status of all parameters in manual mode is shown in following table.

Flight mode Flight 

course

Aircraft 

head

Remote 

controlling 

instruction

Aircraft remote control

Airplane Gimbal

Highly stable 

FPV mode

Takes 

gimbal 

direction as 

reference 

The aircraft 

head 

direction 

always 

follows the 

direction of 

the camera 

lens.

Rudder Not controlled Controlled

Aileron 

rudder Controlled Not controlled

Elevator Controlled Not controlled

Accelerator 

rudder Controlled

Push throttle 

stick to 

increase 

stability

CH5 Position two

CH6 X

NB: Gimbal tilt is controlled by CH7.

10.2.2.2.3 Carefree Mode 

This mode must be used in GPS Hover Status.

In carefree mode, the navigation direction of the aircraft is locked (i.e. the direction the aircraft 

is heading when entering this mode). Whatever direction faced by the nose of the aircraft, the 

flight direction will remain unchanged. The nose of the aircraft automatically keeps track of the 

gimbal so that the camera avoids the landing gear. The elevator and aileron of the aircraft take 

the navigation direction of the aircraft as reference. 

A schematic diagram of carefree mode is shown below: 

Enter carefree mode as follows:

1. Switch to GPS mode after take-off, the aircraft will hover as normal. 
62 Flying at the Field | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

2. After selecting the desired flight direction align the nose of the aircraft in this direction. 

Switch CH5 from position 3 to position 2, switch back to position 3 then return to position 2. 

You will now be in carefree mode. 

3. When you need to exit carefree mode, switch channel 5 to position 1 or position 3 (manual 

mode or GPS mode).

The status of all parameters in carefree mode is shown in following table.

Flight mode Flight 

course

Aircraft 

head

Remote 

controlling 

instruction

Aircraft remote control

Airplane Gimbal

carefree

Take user 

selected 

direction as 

reference

The aircraft 

head 

direction 

always 

follows the 

direction of 

the camera 

lens.

Rudder Not controlled Controlled

Aileron 

rudder Controlled Not controlled 

Elevator Controlled Not controlled 

Accelerator 

rudder Controlled

Push throttle 

stick to 

increase 

stability

CH5 Position two

CH6 Position one

NB: Gimbal tilt is controlled by CH7.
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Tasks 63

11 Tasks 

11.1 Gimbal

11.1.1 Servo Driven Gimbal

The PAR/PITCH and PHO/ROLL ports on

the flight controller are connected 

respectively to the gimbal pitch servo and 

the roll servo. You must power the servos 

separately from the flight controller when 

using a servo driven Gimbal.

When using a servo driven gimbal the 

transmitter should have at least seven 

channels. 

Gimbal Battery

Gemini PAR/PHO port Gimbal Servo GND

VCC

Signal

 Gimbal pitch control: assign CH7 to a knob switch on the transmitter. Any adjustment of 

the knob will produce a corresponding tilt on the pitch servo.

 Gimbal roll control: with no initial signal to the roll channel, the roll servo will remain in 

the neutral position to stabilize the roll axis of the gimbal. Adjust the roll channel according 

to the following procedure: 

a) Switch CH5 to position 1 and throttle back to minimum.

b) Click “Settings” in the mobile ground station or the button “Init Setup” on the PC 

ground station. The knob currently assigned to CH7 is changed to control Gimbal roll.

c) Click “Quit Setup” after adjusting the gimbal roll position, the new central position will 

be fixed and stored. CH7 will return to control Gimbal tilt. 

Note:

 PAR/PITCH and PHO/ROLL are set up with the parameter: “PAR+PHO multiplex” which 

can be edited as follows:

On the mobile ground station: click “Parameter”, as shown in Figure 64.

On the PC ground station: select “Setting”→“Parameter Setting”, as shown in Figure 65.

 “PTZ Roll sensitivity” and “PTZ Pitch Sensitivity” on the parameter interface are used to 

adjust the gimbal correction angle. If the correction angle is too small that it should be 

increased and vice versa. A negative value should be entered to indicate reverse PTZ 

sensitivity. The range of PTZ sensitivity is -127 to 127.
64 Tasks | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

Figure 64 Figure 65

11.1.2 Brushless Gimbal

A brushless motor direct drive Gimbal has a much higher 

level of stability than a servo driven Gimbal. The Gemini 

flight controller supports the “Z” Series Brushless Gimbal 

from ZERO UAV. The PTZ1, PTZ2 and PTZ3 ports will 

connect to the corresponding ports on a Z series Gimbal 

controller and it is not necessary to set up any parameters.

The Z 2000 and Z 1400 gimbals are shown on the right 

side.

Zero UAV brushless gimbals are equipped with a 

brushless gimbal controller, a power supply and receiver, 

controlled independently by the gimbal operator. Refer to 

the ZERO Z series brushless Gimbal manual for detailed 

instructions. The manual can be downloaded from the

ZERO UAV official website (www.zerouav.com). 

Z2000 Gimbal

Z1400 Gimbal

11.2 Photography

The PHO/ROLL port on the flight controller outputs an electronic shutter which switches 

between high and low TTL levels. The upper PIN is the signal wire, the middle PIN has no 

connection and the lower PIN is ground. 

The output of the signal is 3.3V. The signal wire will output a temporary low level of 1V for 

400ms approximately and then return to the high level of 3.3V. This output format supports

Canon 550D, 600D and 5D mark II cameras. 

Photographs can be taken in manual or automatic mode. Manual photographs can be taken 

with the RC transmitter or with the ground station, as shown below:
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Tasks 65

NB

 CH8 is set up in the Gimbal R/C TX when using dual transmitters.

 Automatic photography can only be made in waypoint flight. The photographic interval 

must be set up within the range of 5m-255m in automatic mode. Refer to “8.1.2.3 Setting

up Aircraft Parameters”.

 During the photo process, the communication should be kept open.

 Manual photography

 With CH8 of the transmitter.

1. Set up "PAR+PHO multiplex” on the parameter interface of the ground station to

“Parachute + Photo”. You can skip this step if you are using a Zero brushless 

gimbal.y7

2. Toggle CH8 and the camera will take a photograph; 

3. Toggle CH8 again and the camera will take another photograph; 

4. As many photographs as you require can be taken using this method. 

 With Ground Station 

1. Set up the parameter "PAR+PHO multiplex” on the parameter interface of the 

ground station to “Parachute + photo”. You can skip this step if you are using a 

Zero brushless gimbal.y7

2. Take photographs with either of the following operations:
66 Tasks | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

– Open the mobile 

ground station and click 

“Snaps” in the Map 

Section, as shown in 

Figure 66.

– Open the instrument 

panel on the PC ground 

station and click “Take 

Photo”. Each click takes 

one photo, as shown in 

Figure 67.

Figure 66 Figure 67

 Automatic photography: Automatic photography can be carried out when the aircraft is 

in waypoint flight. Refer to “10.2.1.6 Way Point Flight” for waypoint route design. 

 Parameters should be set up in exactly the same way if you are flying to a single 

point. (Fly2PP)

– On the PC ground station set up “Snapshot interval” and photograph 

parameters of each point in the window “Parameter” window.

– On the Mobile ground station set up “Photo spacing” and photograph 

parameters of each route point, as shown in Figure 68 and Figure 69.

 Photographic interval settings can only be made in automatic route generation mode. 

Figure 68 Figure 69 Figure 70

Note: 

 The ground station will record statistics on the number of pictures taken in the photography 

process and the corresponding area on the map will be displayed as a green dot, as shown 

in Figure 70.
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Tasks 67

 The maximum number of pictures recorded is 250. The ground station will restart the count 

if this number is exceeded. 

11.3 POS Info Data Download

11.3.1 Mobile Ground Station Data Download

The text information on pictures taken can be downloaded 

into your phone or tablet including the following information 

(from left to right): number, latitude, longitude, elevation, roll 

angle, tilt angle, heading and GPS elevation. 

1. Open the mobile ground station and connect via Wi-Fi; 

2. Click “pos info” in the “Settings” section, as shown in 

Figure 71. The POS data on the pictures will be 

downloaded automatically to the directory “YShj” in the 

root directory of your mobile device. 

The file is labelled: PIC+time.txt, of which the time 

should be exact to the second, for example: 

PIC20141027181021.

Figure 71

11.3.2 PC Ground Station Data Download

The text information on pictures taken can be downloaded 

into your PC or tablet including the following information 

(from left to right): number, latitude, longitude, elevation, roll 

angle, tilt angle, heading and GPS elevation. 

1. Open the PC ground station and connect via Wi-Fi; 

2. Click “Get Photo Data” on the dashboard. The POS data 

on the pictures will be downloaded automatically to the 

directory “Hj” in the ground station of your PC device.

The download tip will appear in the prompt box under 

the parameter “Fight Mode” during the download 

process, as shown in Figure 72.

The file is labelled: PIC+time.txt, of which the time 

should be exact to the second, for example: 

PIC20141027181021. Figure 72
68 Safety Features | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

12 Safety Features

12.1 Starting and Stopping the Motors

12.1.1 To Start Motors

The motors will be locked after 5 seconds if no throttle is applied before take-off, or after 

landing in manual mode with the pulled back to minimum. The motor will not rotate after it has 

been locked even if throttle is applied. Motors will rotate only after unlocking. Reference can be 

made to “9.3 Unlocking and Arming the Motors”. 

12.1.2 To Stop Motors

The motors will stop when the throttle is pulled back to minimum in manual mode. In GPS 

mode, reducing the throttle to minimum will have the following differing results: 

– The aircraft will reduce altitude but the motors will not stop if the aircraft is in flight; 

– The motors will stop slowly until fully locked if the aircraft is on the ground. 

12.2 F/S Protection

 Loss of Wi-Fi signal 

Full control of the aircraft will be handed to the transmitter if the loss of Wi-Fi signal 

exceeds 1 second when flying the aircraft with the Android mobile device. If the aircraft is 

waypoint flying, it will not be affected and will complete the route where it will hover 

awaiting further commands.

 Loss of R/C transmitter signal 

F/S (failsafe) should be correctly set up. Refer to the RC transmitter manual to set CH5 in 

position 3, CH6 in position 3 and throttle in neutral for correct operation of failsafe.

Failsafe will initialize when there is signal loss from the RC (receiver). 

– The aircraft will switch to auto hover for 5 seconds and then return and land if the 

signal is not recovered within five seconds. 

– The aircraft will keep flying for 5 seconds in automatic waypoint mode and will return 

and land if the signal is not recovered within 5 seconds. 

12.3 Parachute Protection 

NB
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Safety Features 69

 The parachute servo should have its own power supply. It should not be powered from 

the flight controller or the receiver. 

 The weight of the whole aircraft should not exceed the safe protection range of the 

parachute. 

The flight controller will consider the status of the aircraft as abnormal if the angle of deflection 

from horizontal exceeds 70° and will deploy the parachute. The parachute will open 

automatically. The motors have two status when the parachute is opened:

– Motors will be shut off automatically if flying in GPS mode with more than 7 satellites 

locked.

– Motors will not be shut off automatically if flying in manual mode or in GPS mode with less 

than 7 satellites locked.

Note: 

 Manual parachute deployment is not supported, only automatic parachute deployment.

 The parachute will not deploy automatically because of radio interference, control 

instability or low flight battery voltage. 

12.4 Data Record

12.4.1 Flight Data Record - “Black Box Function”

The Gemini flight controller has a flight data record function for fault analysis. It is not 

necessary to have any external memory or to initiate any application for this function to work. A 

record is made automatically during every flight. However, only the data of the last one minute 

before landing is recorded. Therefore if you need to examine this data, please do not make 

another flight or unlock the motors again. 

12.4.1.1 Obtaining Mobile Ground Station Data

The flight data can be obtained from the mobile ground station 

as follows:

1. Connect the power supply to the flight controller, open the 

mobile ground station and connect via Wi-Fi; 

2. Click “One minute data” in the “Setting” interface and a 

confirmation dialog box will pop up, as shown in Figure 73.

3. Click “OK” and the flight controller will upload to the mobile 

device the last minute of recorded flight data. 

Figure 73
70 Safety Features | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

4. It will take 1 minute to obtain the data and then report that completion of 1 minute data 

reading.

5. The file “T-1min. hjext2” can be seen in the directory “YShj” in the root directory of the 

mobile device. You can make your own analysis of this data or email it to the 

manufacturer for debugging. 

12.4.1.2 Obtaining PC Ground Station Data

Flight data can be obtained from the PC ground station as follows: 

1. Connect the power supply to the flight 

controller and to the PC via Wi-Fi.

2. Select “Settings”→“1 Minute Data” and a

confirmation dialog box will pop up, as 

shown in Figure 74.

3. Click “Yes” and the flight controller will 

blow to the PC the last minute of flight 

data. 

Figure 74

4. After 1 minute to obtain the data, the instruction of completion of 1 minute data reading

will pop up on the ground station; 

5. The file “T-1min. hjext2” can be seen in the “Hj” directory of the PC ground station 

software package. You can make your own analysis of this data or email it to the 

manufacturer for debugging. 

12.4.2 GCS Data Record

This function needn't any external device, just keeping the flight controller powering on and 

WIFI connecting, then all of the operation record will be saved by hj files in the related folder of 

GCS for analyzing.

One hj file will be created once closing the GCS and all of data will be in one hj file if not 

closing GCS.

 saved file path

– mobile GCS: root folder in cellphone/YShj catalog

– PC GCS: GCS/Hj catalog

 document format: time.hjext2, for example, 20150506110410.hjext2, 20150506 means 

date,110410 means recording begin time from 11:04:10
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Extending the Range of Capabilities 71

13 Extending the Range of Capabilities

13.1 Radio Connection 

The XB-PRO900 radio can be purchased as an option to extend the control distance,

overcoming the distance limit of Wi-Fi for ground station and mobile device control. 

This radio has an RF power of 100mW on a frequency of 900MHZ and its measured two-way 

communication distance is 1-2 km in open ground. The radio has a RS232 port and the 

communication Baud rate is 115200bps. 

XB-PRO900 consists of two interchangeable radios, one on the aircraft and the other on the 

ground.

13.1.1 Airborne Radio Connection

Remove the Wi-Fi module from the aircraft and install the radio in the aircraft in the same way 

as the Wi-Fi module; connect to the COM port of the flight controller; the radio should be 

powered by a 3S-6S lithium battery. 

13.1.2 Ground Radio Connection

Connect the Wi-Fi module to the other radio 

on the ground with the connection cable 

provided with the radio, which is powered 

separately. The unit on the ground consists of 

the radio and the Wi-Fi module. 

Note:

The radio and Wi-Fi are powered with a 3S-6S lithium battery with the red/black cable, the red 

for anode (+) and the black for cathode (-). 

13.2 Connecting the Power Management Module

Real-time current draw (Amps) and electricity consumption (mAh) can be observed in the 

“Data” interface of the ground station after connecting the optional Power Management 

Module to the Gemini flight controller. 

To use this function connect the power management module (to the A1 port on the Gemini), 

reduce the throttle to minimum and then power the flight controller. The current (A) and 

electricity consumption (mAh) will be displayed, as shown in Figure 75.
72 Extending the Range of Capabilities | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

13.3 OSD Connection

After the OSD (On Screen Display) has been connected to

the Gemini flight controller, flight parameters will be 

overlapped in real time on the video display. This improves 

the quality of the flight experience because the pilot is 

constantly aware of vital flight parameters. Connect the OSD 

COM port to the COM port on the flight controller. Full details 

are available in the ZerOSD manual.

Figure 75
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Upgrading the Firmware 73

14 Upgrading the Firmware 

NB

Make sure the flight controllers not powered, if it is please disconnect.

Before upgrading the firmware, please download the special firmware upgrade tool on the Zero 

UAV official website. 

http://www.zerouav.com/en/service/Download/Firmware/

Upgrading GEMINI firmware is simple! Upgrade the firmware according to the following 

procedure:

1. Download the USB driver from the ZERO official website and install it.

2. Plug the serial converter end of the USB cable into the PC USB port, the other end to the 

COM port on the Flight Controller, white cable upwards.

3. Extract the “YS-X4-X4V2-X4P-Gemini-M-S” 

firmware upgrade archive and double-click 

“UpgradAP(En)-TOOL.exe” and the window 

“AP Firmware upgrade” will pop up, as 

shown in Figure 76.

4. Click “Upgrade” and the window “AP 

Firmware upgrade” will pop up, as shown in 

Figure 77.

Figure 76

Figure 77

5. Select the appropriate COM port for 

upgrading; (if you do not know which COM 

port on your PC is being used, right click “My 

computer”->“Properties”->”Device manager”

->“port”(COM & LPT) to check, as shown in 

Figure 78)

Figure 78
74 Upgrading the Firmware | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

6. Click “Open Com”, if successful, the “Open” button will change from gray to black and 

become clickable; 

7. Click “Open” and to select the firmware file which will have a “.arm” extension from its 

stored location on your PC, as shown in Figure 79.

8. Power up the flight controller and to wait for 

the automatic upgrade process to activate, 

as shown in Figure 80.

9. Power-off the autopilot when it says in red, 

“Please Restart AP!” and then close the 

window, as shown in Figure 81.

Figure 79

Figure 80 Figure 81

Note:

Please close the software and unplug the USB/serial port adapter if the upgrade operation fails. 

Restart the operation from the beginning. 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Appendix 75

Appendix 

Appendix 1 Introduction to Mobile Ground Station (Android)

1. GCS Remote Control Interface 

 

The interface functions are introduced in the following table: 

No. Menu Item Function

1 Remote control Default setting: use the Green Cross to control flight

2 Data Real time flight data

3 Map Cached map or active real time map (Google Earth)

4 Settings Set up aircraft status

5 Parameter Adjust aircraft parameters 

6 Control interface Multiple control modes using mobile device

7 Central button Directs the aircraft in simple control mode

8 Quit Exit GCS software 

9 Set Define system settings

10 Enable attitude control

Click “Enable Attitude control” (red button) to start simple 

mobile device control mode. “Disable Attitude control” 

(green button) 

Click “Disable Attitude control” to exit.

11 Enable control

Click “Enable control” (red button) to start simple mobile 

device control mode. “Disable control” (green button)

Click “Disable control” to exit. 
76 Appendix | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

Note: 

The aircraft serial number and firmware version will display on the remote control interface 

after data connection. 

2. Data Interface 

In the Gemini ground station, continuous monitoring of the statuses of the GPS, magnetic 

compass and IMU of both host and slave controllers is possible. The aircraft will be ready to 

take off if the number of satellites recorded by the GPS is seven or more.

Click the “Data” tab for the data interface to see the screens shown below: the software will 

display communication disconnected in the center if there is no link with the aircraft. 

Descriptions of the parameters are as follows: 

Name Description

Satellites Shows number of GPS satellites in view and locked

GPS velx(cm)

GPS velx(cm) GPS velocity displays a value below 10 when static

Xekf velx

Xekf vely

xekf veld

Speed of the aircraft after Kalman filtering 

A value of 0-10 is displayed when the aircraft is static on the ground. 

Attitude angle Displays real-time attitude angle during flight

Flight mode settings 

state

Displays current craft status: Manual, Manual Altitude Hold, Auto Hover, Auto 

Navigation, Auto Go Home and Land; setup status.

Altitude Barometer altitude of aircraft, units in metres

Course angle 

Aircraft compass heading: Due North= 0°, clockwise direction is positive, 

counterclockwise direction is negative. For example: Due East=+ 90°, Due West=-

90°, Due South=+ 180°. Does not apply in manual mode.

AP voltage Power supply voltage
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Appendix 77

Name Description

GPS longitude 

GPS latitude GPS longitude and latitude 

Motor balance Motor balance performance 

Vibration State

Shake State

Displays the influence of shake and vibration on the IMU from different 

directions: a parameter under 10 indicates normal, larger than 10 indicates

that shake and vibration exceeds the limit, requiring adjustment to the 

airframe to reduce vibration. 

Distance from home The distance of the aircraft from the starting point

Flight time Flight time of the aircraft 

Real throttle Actual position of throttle 

3. Map Interface

A map must be downloaded from 

the Internet before the initial 

opening of the “Map” interface. 

The map will return to its last 

closing position, when reopening 

the map. 

The map interface is shown on 

the right side.

Map parameters are shown in the 

following table:

Name Description

Snaps Manual photography

Show the number of photos.

The maximum number of pictures recorded is 250. The ground station will 

restart the count if this number is exceeded.

Locate My location, Plane location and Search location.

SWP Fly to Point (FlyToPP)

SPC Waypoint and Route flying

Tool Map tools related to the defined waypoint route 

4. Waypoint Editing

The waypoint editing interface are as shown in Figure 82 and Figure 83.
78 Appendix | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

Figure 82 Figure 83 Figure 84

Waypoint editing parameters are shown below: 

Name Description

Single point edit Edit longitude, latitude, height and speed between waypoints

Single point upload Upload waypoint

Single point cancel Cancel waypoint

No. Number of waypoints

Height Waypoint altitude in meters

Longitude Longitude of single waypoint

Latitude Latitude of single way point 

Hovering time Time spent at each waypoint. Zero means no delay at waypoint.

Photograph setting Setup photographic task at waypoint

Target speed Flight speed between waypoints

5. Settings Interface

Please take care with these settings as they are vitally important. 

The settings interface is as shown in Figure 84. The parameters are shown below.

Parameter name Parameter description

Capture Transmitter 

Centre point

With no wind, in manual mode, after flying and trimming, activating this 

will define the neutral point. 

NB: Make sure your TX throttle stick is in the middle position; it does not 

affect the actual throttle position.

Adjust transmitter Used to calibrate the transmitter’s joystick
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Appendix 79

Parameter name Parameter description

Magnetic compass 

Click to enter "Magnetic Compass" Calibration mode, the status bar above 

displays the calibration status.

1 Minute Data 

Used to initiate reading the data saved in the FC within the last minute of 

flight. Please refer to “12.4.1Flight Data Record - “Black Box Function””.

Installation guide The "Installation Guide" will guide you through installation and alignment 

step by step

Init Setup

Used to align channels or enter parameters of craft. Flight status will 

display "Settings" after clicking this button. Once in settings, the control 

channels for each motor on the craft are directly connected to the throttle 

channel of the TX and there is no mix output.

Quit setup

After completing Throttle Alignment and when all parameters have been 

entered, you may click this button to exit from settings.

Zero Gyro Zero the gyro. The aircraft should be perfectly level when you do this.

Snapshot Trigger camera shutter manually

Mixing Define Defines custom mixing of throttle, roll, pitch and yaw.

Follow Me If the Android Ground Station has GPS enabled, the aircraft will follow the 

moving course of the Ground Station.

Test Open Parachute Test parachute open before flight, hold down the container lid to prevent 

deployment.

Test Close Parachute Close parachute after testing.

Appendix 2 Introduction to PC Ground Station 

1. Main Interface 

2. Menu Bar Profile
80 Appendix | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

 File(F) Tab  View (V) Tab

 Path Settings (S) Tab  Tools (T) Tab

 Settings (S) Tab

 Help(H) Tab: software version

Note:

 The correct COM port must be selected when connecting to the flight controller with the 

USB/serial port adaptor cable. 

 When the map is flat mode, you can download offline maps.

The view tab includes the following sections:

 Toolbar 
Zero UAV (Beijing) Intelligence Technology Co., Ltd. | Appendix 81

View Mode Design Route Flag Waypoint Move Route GCS Version

Measure Distance Edit Route Toggle Mode View from Top

 Flight Data (F)  Dashboard

Appendix 3 Installation and Configuration Videos 

 Setting up the Futaba T8FG transmitter radio:

http://www.tudou.com/programs/view/e1ai526Mbt4/

 Wi-Fi configuration: 

http://v.youku.com/v_show/id_XNTE2OTY4MjQ4.html/

 Upgrading firmware:

http://v.youku.com/v_show/id_XNTE3NzEzOTky.html/

 Folding the parachute:

http://v.youku.com/v_show/id_XNjgxNTQ1OTU2.html
82 Appendix | Zero UAV (Beijing) Intelligence Technology Co., Ltd.

Appendix 4 Technical Support 

Please contact ZERO UAV for technical support for any problems arising from actual operation. 

Relevant technical documents can be downloaded in the download section in the official 

website of ZERO UAV. 

 ZERO UAV official website: www.zerouav.com

 ZERO UAV Tel: +8610-82825271

 ZERO UAV QQ Group: 168451730(Group1), 228669705(Group2), 242018689(Group3), 

53371874(Group4)

Appendix 5 Reference Manual Update History

No. Version Modification Modifier Date

1 V1.0 To prepare first version Technical support 1 2014.9.1

2 V1.0 English revision Chris Hornby 2014.12.25

3 V1.1

1. Format Adjustments

2. added functions:

10.2.1.6 Way Point Flight: Semi-automatic 

flight

11.2 Photography

11.3 POS Info Data Download

Technical support 1 2015.1.22

1. Format Adjustments

2. Modify parameters, diagram Technical support 1 2015.5.4

Added function: GCS Data Record Technical support 1 2015.5.14