FY650 Operation and Maintenance Manual

Operation

Multicopter Safety             Page 2

Pre‐Arm Safety Check             Page 4

Arming the Motors             Page 10

3DR Radio Telemetry Manual           Page 12

PixHawk Flight Controller Manual         Page 16

GPS and GCS Failsafes             Page 30

Battery Failsafe               Page 34

Radio Failsafe               Page 37

Geofence Failsafe             Page 46

Maintenance

Installing Mission Planner           Page 51

Frame Type Configuration             Page 54

RC Transmitter Flight Mode Configuration       Page 56

Connect ESC and Motors           Page 62

ESC Calibration             Page 74

Basic Tuning               Page 81

Setting Throttle               Page 84

GPS and Compass Module           Page 88

Accelerometer Calibration           Page 96

Measuring Vibrations             Page 100

Radio Calibration             Page 105

Compass Calibration       Page 111

Appendix 1 Page 1
! Safety - Read Before Flying !

Your first priority must absolutely be the safety of people!

Multicopters are essentially Flying Lawnmowers! 

• ArduCopter is an experimental aircraft running community-created code - Novel and unexpected results 

are NOT uncommon!

• Crashes can happen, because of pilot error or hardware or software malfunction.

• Especially while you are learning, it is recommended that you avoid, stiff, ultra-sharp carbon fiber props.

o Get cheaper more flexible and more breakable plastic ones. 

o Some carbon fiber props cut better than a Ginsu and while they are almost indestructible, you are not. 

• If you are flying anywhere near other people, you are putting them at risk!

• Be sure to maintain safe distances between yourself, and spectators and your copter.

o Circumstances will require that you will need to make your own determination of what is a "safe distance" 

from people and property. 

o At a minimum, consider: at least 10ft (3m) but not further than 30ft (10m) from you. 

o Keep all other people, property and obstacles considerably further away from your copter. 

o Ensure that no one gets between you and your copter. 

o Spectators should always be a safe distance behind the pilot. 

o If people intrude beyond what you have determined to be the "safe" area, land immediately and do not 

take off until they are clear. 

o At full power, an average sized multi-copter can exceed 20 mph (32 km/h), can ascend to hundreds of feet 

and easily travel more than a mile in distance before running out of battery. 

• Always ensure that the battery cable is (NOT) connected to the power distribution board or harness until 

you are ready to fly.

o After landing the first thing you should do is disconnect your battery cable. 

o Always remove your props while you are testing motors. 

o Your hands, arms and face and those of your friends will thank you. 

o When the battery is connected, always assume the motors are armed. 

o Check with a short throttle pulse. 

o Don't pick up the model and the radio at the same time, you may bump the throttle. 

o Do not attempt to fly longer than your batteries safe capacity. 

 At a minimum it is very hard on the battery and at worst you will crash destructively. 

• The APM and PX4 flight controllers we use incorporate a motor arming safety feature.

o Immediately prior to flight after the battery has been connected, the RC transmitters throttle stick needs to 

be held down and to the right for several seconds to arm the motors. 

o After landing your first response should be to hold the throttle down and to the left for several seconds to 

"Disarm" the motors. 

o Disarm condition can be tested by moving the throttle stick up, if the motors do not move it is dis armed. 

o Even when disarmed, the throttle stick should always be kept in the full down position except when flying. 

• Get used to switching back to Stabilize mode from other modes and reassuming full manual control.

o This is the single most important recovery technique (practice it). 

o Stabilize mode can have Simple mode added to it, but if you do, practice with it till you are proficient. 

o Do not use any modes other than Stabilize or Stabilize plus Simple until you are VERY comfortable flying. 

• Important primary response to a crash, inadequate landing or unknown flight controller state.

o The first thing to do is throw a towel over your copters propellers (Propellers may start spinning 

unexpectedly). 

o Then immediately disconnect the battery. 

o A large towel is your most important piece of safety equipment followed by a fire extinguisher and a first 

aid kit. - - Generally better to use the first one than the last one. 

• When testing or flying any of the navigation modes (using GPS):

o Ensure that your GPS has "Lock" before arming and takeoff. 

o Check that your home position on the Mission Planner is in fact correct. 

o Sometimes GPS's do not report the home position accurately, reboot if not accurate and wait for 8 or more 

satellites (not just 3D lock) and check again. 

Appendix 1 Page 2
Keep a safe distance between your Copter and People!

These tips can also help protect your multicopter from damage. 

• Avoid sudden or extreme transmitter control stick deflections

o Move the control sticks in small measured increments and don't "yank" on them. 

o If the copter is properly calibrated and balanced it should require only small stick inputs to control altitude, 

direction and speed. 

o Your copter should be more or less stable on the horizontal plane without any control inputs. 

o If you are "fighting" the copter, land and fix it - something is not right - Hardware adjustment or software 

calibration may be required. 

o Be especially careful of large throttle inputs, as a copter can gain (or lose) altitude very rapidly. 

• Because MultiCopters are symmetrical it is especially easy to lose Visual Orientation.

o For manual flight modes, maintaining a clear vision of the Copters Orientation (direction it is facing) is the 

most critical part of successful flight. 

o Especially while learning it is very important to keep your copter appropriately close to you to aid in 

maintaining visual orientation. 

o Generally: more than 10ft (3m) but not further than 30ft (10m) from you. 

o If the copter gets further than about 100ft (30m) it starts getting difficult to be able to 

maintain orientation and can easily crash. 

o If you lose Yaw orientation while flying in Stabilize mode, try only flying forward and using yaw to steer like 

a car. 

o It is much better to simply descend and land rather than have an orientation-induced crash or fly away. 

 Fly-Aways often happen when the copter is commanded to tilt back towards the pilot but has 

rotated in the meantime and is so far away that orientation is lost. 

 Result: the copter flies further away and crashes or is lost. 

• Always have Stabilize mode as the (Go To) one of your 3 options.

• High or unexpected winds or gusts can make flight considerably more difficult.

o High winds can prevent forward progress or spin the copter around causing you to become disoriented. 

o The higher you are, the more likely high winds will be a problem. 

o Switching to Stabilize mode and landing before you reach your skill limits can help you save your copter. 

• Avoid flying at high speed or high altitude until you have gained considerable confidence in both manual 

and automatic modes.

• When flying around trees or buildings it is very easy to lose visual orientation or even to lose sight of the 

copter completely.

o Gusting winds around objects can also worsen the problem and radio signal loss can also occur. 

o If your copter is approaching a potentially interfering object, immediately switch to stabilize mode and land 

or retrieve the copter to your location. 

• ArduPilot specific safety modes: RTL, FailSafe and GeoFence.

o RTL can provide a safe Return to Launch if it starts to get away from you. 

o FailSafe and GeoFence can assist you with keeping the copter in a safe proximity. 

o Do not rely on the above safety modes, always be ready to take control in stabilize and land the copter. 

o Especially do not rely on the above safety modes to perform maneuvers or training that you would 

otherwise consider dangerous. 

o These modes are a supplement to, not a replacement for sound safety practices. 

• On your first takeoff after tuning or hardware setup

o In stabilize mode advance the throttle very slowly until the copter is almost hovering. 

o If the copter is trying to flip over turn it off and correct the problem, a motor could be turning the wrong 

direction, or a wrong direction prop could be installed. 

o If the copter tries to rotate on it's axis or fly off in some direction the transmitter or RC setup may be 

incorrect, a motor or ESC may not be performing properly or the props may be installed incorrectly. 

o When all problems are fixed it should be fairly easy to get the copter to hover a foot or 2 above the ground. 

o If a stable and stationary hover a foot or 2 above the ground cannot be achieved, land and fix the problem 

• When flying FPV "First Person View" (with a video camera), Set modes to: STABILIZE, SIMPLE, and RTL.

o Ensure RTL is working properly before using FPV, 

o Use Stabilize mode to fly FPV and If you lose FPV video switch to Simple or RTL to get back. 

• Make sure your battery can't fall out, use a Velcro Strap to hold it in place. 

Appendix 1 Page 3
Copter includes a suite of Pre-arm Safety Checks which will prevent the vehicle from arming if

any of a fairly large number of issues are discovered before take-off including missed

calibration, configuration or bad sensor data. These checks help prevent crashes and fly-aways

but they can also be disabled if necessary.

ArduCopter 3.0 Pre-Arm Checks

Contents [hide]

ArduPilot > Copter > Pre-Arm Safety Check

Pre-Arm Safety Check

Copter

English

Appendix 1 Page 4
1 Recognising which Pre-Arm Check has failed using the GCS

2 Failure messages

3 Disabling the Pre-arm Safety Check

Recognising which Pre-Arm Check has failed using

the GCS

The pilot will notice a pre-arm check failure because he/she will be unable to arm the copter

and the LED will be flashing yellow.  To determine exactly which check has failed:

1. Connect the Flight Controller to the ground station using a USB cable or Telemetry.

2. Ensure the GCS is connected to the vehicle (i.e. on Mission Plannerand push the “Connect”

button on the upper right).

3. Turn on your radio transmitter and attempt to arm the vehicle (regular procedure using

throttle down, yaw right)

4. The first cause of the Pre-Arm Check failure will be displayed in red on the HUD window

Failure messages

RC failures (i.e. transmitter/receiver failures):

RC not calibrated : the radio calibration has not been performed.  RC3_MIN and

RC3_MAX must have been changed from their default values (1100 and 1900) and for

channels 1 to 4, the MIN must be less than 1300 and the MAX greater than 1700.

Barometer failures:

Baro not healthy : the barometer sensor is reporting that it is unhealthy which is normally

a sign of a hardware failure.

Alt disparity : the barometer altitude disagrees with the inertial navigation (i.e. Baro +

Accelerometer) altitude estimate by more than 2 meters.  This message is normally shortlived and can occur when the flight controller is first plugged in or if it receives a hard jolt

(i.e. dropped suddenly).  If it does not clear the accelerometers may need to be calibrated

or there may be a barometer hardware issue.

Appendix 1 Page 5
Compass failures:

Compass not healthy : the compass sensor is reporting that it is unhealthy which is a sign

of a hardware failure.

Compass not calibrated : the compass(es) has not been calibrated.  the

COMPASS_OFS_X, Y, Z parameters are zero or the number or type of compasses

connected has been changed since the last compass calibration was performed.

Compass offsets too high : the primary compass’s offsets length (i.e. sqrt(x^2+y^2+z^2))

are larger than 500.  This can be caused by metal objects being placed too close to the

compass.  If only an internal compass is being used (not recommended), it may simply be

the metal in the board that is causing the large offsets and this may not actually be a

problem in which case you may wish to disable the compass check.

Check mag field : the sensed magnetic field in the area is 35% higher or  lower than the

expected value.  The expected length is 530 so it’s > 874 or < 185.  Magnetic field strength

varies around the world but these wide limits mean it’s more likely the compass calibration

has not calculated good offsets and should be repeated.

Compasses inconsistent : the internal and external compasses are pointing in different

directions (off by >45 degrees).  This is normally caused by the external compasses

orientation (i.e. COMPASS_ORIENT parameter) being set incorrectly.

GPS related failures:

GPS Glitch : the GPS is glitching and the vehicle is in a flight mode that requires GPS (i.e.

Loiter, PosHold, etc) and/or the circular fence is enabled.

Need 3D Fix : the GPS does not have a 3D fix and the vehicle is in a flight mode that

requires the GPS and/or the circular fence is enabled.

Bad Velocity : the vehicle’s velocity (according to inertial navigation system) is above

50cm/s.  Issues that could lead to this include the vehicle actually moving or being

dropped, bad accelerometer calibration, GPS updating at below the expected 5hz.

High GPS HDOP : the GPS’s HDOP value (a measure of the position accuracy) is above

2.0 and the vehicle is in a flight mode that requires GPS and/or the circular fence is

Appendix 1 Page 6
enabled.  This may be resolved by simply waiting a few minutes, moving to a location with

a better view of the sky or checking sources of GPS interference (i.e. FPV equipment) are

moved further from the GPS.  Alternatively the check can be relaxed by increasing the

GPS_HDOP_GOOD parameter to 2.2 or 2.5.  Worst case the pilot may disable the fence

and take-off in a mode that does not require the GPS (i.e. Stabilize, AltHold) and switch

into Loiter after arming but this is not recommended.

Note: the GPS HDOP can be readily viewed through the Mission Planner’s Quick tab

as shown below.

INS checks (i.e. Acclerometer and Gyro checks):

INS not calibrated : some or all of the accelerometer’s offsets are zero.  The

accelerometers need to be calibrated.

Accels not healthy : one of the accelerometers is reporting it is not healthy which could be

a hardware issue.  This can also occur immediately after a firmware update before the

board has been restarted.

Accels inconsistent : the accelerometers are reporting accelerations which are different

by at least 1m/s/s.  The accelerometers need to be re-calibrated or there is a hardware

issue.

Gyros not healthy : one of the gyroscopes is reporting it is unhealthy which is likely a

hardware issue.  This can also occur immediately after a firmware update before the board

has been restarted.

Gyro cal failed : the gyro calibration failed to capture offsets.  This is most often caused by

the vehicle being moved during the gyro calibration (when red and blue lights are flashing)

Appendix 1 Page 7
in which case unplugging the battery and plugging it in again while being careful not to

jostle the vehicle will likely resolve the issue.  Sensors hardware failures (i.e. spikes) can

also cause this failure.

Gyros inconsistent : two gyroscopes are reporting vehicle rotation rates that differ by

more than 20deg/sec.  This is likely a hardware failure or caused by a bad gyro calibration.

Board Voltage checks:

Check Board Voltage : the board’s internal voltage is below 4.3 Volts or above 5.8 Volts.

If powered through a USB cable (i.e. while on the bench) this can be caused by the

desktop computer being unable to provide sufficient current to the flight controller – try

replacing the USB cable.

If powered from a battery this is a serious problem and the power system (i.e. Power

Module, battery, etc) should be carefully checked before flying.

Parameter checks:

Ch7&Ch8 Opt cannot be same : Ch7 and Ch8 auxiliary switches are set to the same

option which is not permitted because it could lead to confusion.

Check FS_THR_VALUE : the radio failsafe pwm value has been set too close to the

throttle channels (i.e. ch3) minimum.

Check ANGLE_MAX : the ANGLE_MAX parameter which controls the vehicle’s maximum

lean angle has been set below 10 degrees (i.e. 1000) or above 80 degrees (i.e. 8000).

ACRO_BAL_ROLL/PITCH : the ACRO_BAL_ROLL parameter is higher than the Stabilize

Roll P and/or ACRO_BAL_PITCH parameter is higher than the Stabilize Pitch P value. 

This could lead to the pilot being unable to control the lean angle in ACRO mode because

the Acro Trainer stabilization would overpower the pilot’s input.

Disabling the Pre-arm Safety Check

Appendix 1 Page 8
If you are confident that the pre-arm check failure is not a real problem you can disable the

checks by:

Connecting your Flight Controller to the Mission Planner

Go to Mission Planner’s Config/Tuning >> Standard Params screen

set the Arming Check drop-down to “Disabled” or one of the “Skip” options which more

effectively skips the item causing the failure.

Push the “Write Params” button

Ideally however you should determine the cause of the pre-arm failure and if it can be resolved,

return the Arming Check parameter back to “Enabled”

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 9
Contents [hide]

1 Arming the motors

2 Disarming the motors

Arming the motors

Before arming the motors, make sure all people and objects are clear of the propellers. Then

do the following:

1. Turn on your transmitter

2. Plug in your LiPo battery.  The red and blue lights should flash for a few seconds as the

gyros are calibrated (do not move the copter)

3. The pre-arm checks will run automatically and if any problems are found an APM2.x will

double blink the red arming light, on a Pixhawk the RGB led will blink yellow.  Please refer to

this page .

4. Check that your flight mode switch is set to Stabilize, ACRO, AltHold or Loiter.

5. If using a PX4, press the safety button until the light goes solid.

6. If you are planning on using the autopilot (i.e. Loiter, RTL, Drift, Auto or Guided modes) you

should wait for 30 seconds after the GPS has gotten 3d lock.  This will give the GPS position

time to settle.  On APM2 the GPS lock is indicated by the blue LED going solid.  On an

Pixhawk the RGB LED will blink green.

7. Arm the motors by holding the throttle down, and rudder right for 5 seconds.  It takes

approximately 5 seconds the first time the copter is armed as it re-initialises the gyros and

barometer.  Do not hold the rudder right for too long (>15 seconds) or you will begin the

AutoTrim feature.

ArduPilot > Copter > Arming the motors

Arming the motors

Copter

English

Appendix 1 Page 10
Note:

Note:

8. Once armed, the red arming light should go solid and the propellers will begin to spin

slowly.  The speed they spin can be adjusted with the MOT_SPIN_ARMED parameter.

9. Raise the throttle to take-off.

You can only arm or disarm in Stabilize, ACRO, AltHold and Loiter mode.

If you leave the throttle at minimum for 15 seconds while in any of the above modes

the motors will automatically disarm.

Disarming the motors

To disarm the motors do the following:

1. Check that your flight mode switch is set to Stabilize, ACRO, AltHold or Loiter

2. Hold throttle at minimum and rudder to the left for 2 seconds

3. The red arming light should start flashing on the APM2.  On the Pixhawk the RGB LED will

start flashing green.

4. If using a PX4, press the safety button until the led begins flashing

5. Disconnect the Lipo battery

6. Turn off your transmitter

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 11
3DR RADIOV2

QUICK START GUIDE

PARTS

GETTING STARTED

3DR Radios provide an air-to-ground data link between the autopilot and your ground station laptop or 

tablet. Follow this guide to install the radios on your plane, copter, or rover. 3DR Radios arrive ready to 

use. Just mount and connect to view real-time data from your drone.

Android adapter cable

6-wire Pixhawk connector cable

Micro-USB cable

Two 3DR Radios in 915 or 433 mHz

Attach the antennas, and use either radio as an air or ground module.

6-to-5-position APM and PX4 connector cable

Appendix 1 Page 12
MOUNT

CONNECT TO AUTOPILOT

Connect to the APM 2.5 or 2.6 telemetry port using 

2.6 the 6-to-5-position cable.

Connect to the PX4 I/O telemetry 

port using the 6-to-5-position cable.

Connect to the Pixhawk telemetry 

port using the 6-wire cable.

Mount the air module securely to your vehicle keeping the antenna clear of any propellers or moving 

components. Ensure that the antenna is oriented vertically for maximum range.

CONNECT TO MISSION PLANNER

Use the micro-USB cable to connect the ground module to your laptop. In Mission Planner and APM 

Planner ground station applications, select the communication option that shows COM, set the rate 

to 57600, and select Connect. The radio will not connect unless the vehicle is powered. Use the Flight 

Data screen to view your vehicle’s status and control missions in flight.

LEARN MORE 

about installing a mission planner application for your laptop or tablet and interacting with the 

autopilot using 3DR Radios (including retrieving flight data logs) at planner.ardupilot.com.

Mission Planner

Appendix 1 Page 13
TIPS

Orient the ground radio 

antenna vertically for 

maximum range.

CONNECT TO TABLET

Connect the ground module to your tablet using the Android adapter cable. Connect the colored end 

to the tablet and the black end to the radio. In DroidPlanner or Andropilot, select Connect.

DroidPlanner Flight Data screen

View the strength of the radio signal in the 

mission planner’s flight data screen.

SETTINGS

To change the radio settings in the mission planner, connect the radio to your computer, but do not 

select Connect. Radios can only be configured while unconnected to MAVLink. Select Initial Setup, 

3DR Radio, and Load Settings to configure the radios.

All settings should be the same for both modules. Ensure that the Net ID setting is identical on each 

radio to enable pairing. Select Save Settings to apply settings. For flying with friends, make sure your 

Net IDs do not conflict.

Use the configuration options on this screen to apply the correct airspace regulation requirements 

for your area. You are responsible for complying with all airspace regulations in your area, including 

frequency restrictions, power levels, and licenses. For more information on configuring 3DR Radios to 

comply with local regulations, visit the online documentation at goo.gl/Tsrksf.

Appendix 1 Page 14
SPECIFICATIONS

3DR Radio Guide V1 © 3D Robotics, Inc. 28 October 2013

SUPPORT

For more information about mission planner applications and APM firmware, visit ardupilot.com. For 

online documentation of 3DR Radios, visit goo.gl/Tsrksf. 

For customer support, contact us at help@3drobotics.com or call our support line at +1 (858) 225-1414.

Processing

100 mW maximum output power (adjustable)

-117 dBm receive sensitivity

Based on HopeRF’s HM-TRP module

RP-SMA connector

2-way full-duplex communication through adaptive TDM

UART interface

Transparent serial link

MAVLink protocol framing

Frequency Hopping Spread Spectrum (FHSS)

Configurable duty cycle

Error correction corrects up to 25% of bit errors

Open-source SIK firmware

Configurable through Mission Planner & APM Planner

Features

Interchangeable air and ground modules

915 or 433 mHz

Micro-USB port

6-position DF13 connector

Power

Supply voltage: 3.7-6 VDC (from USB or DF13)

Transmit current: 100 mA at 30 dBm

Receive current: 25 mA

Serial interface: 3.3 V UART

Dimensions

26.7 cm x 55.5 cm x 13.3 cm 

(without antenna)

3

4

5

1 Micro-USB port

2 6-wire cable connector

3 Antenna

4 Frequency

5 LED indicator

1

2

RADIO DESCRIPTION

LED MEANINGS

Solid green

Link established with paired radio

Blinking green

Searching for paired radio

Blinking red

Transmitting data

Solid red

Firmware update mode

Appendix 1 Page 15
AUTOPILOT

QUICK START GUIDE

Appendix 1 Page 16
PARTS

1 Pixhawk

2 Buzzer

3 Safety switch 

4 Micro-SD card and adapter

5 Micro-USB cable

6 Six-wire cable x2 

 7 Power module

 8 I2

C splitter module

 9 Four-position I2

C splitter cable

10 Three-wire servo cable

11 Mounting foam

1 2 3 4 5 7

8 11

 MOUNT

Use the provided foam to mount Pixhawk as close as possible to your vehicle’s center of gravity. 

Make sure to orient the board with the arrow pointing forward.

Vehicle front

Attach the foam squares to the 

corners of the board.

GETTING STARTED

With the help of APM firmware, Pixhawk turns any 

RC plane, copter, or rover into a full-featured personal 

drone. Once you have a fully-assembled frame, follow 

this guide to install Pixhawk.

6

9 10

1 Mount

2 Connect

3 Load firmware

4 Calibrate

1

Appendix 1 Page 17
 CONNECT

(Required) Connect the buzzer 

and safety switch.

(Optional) Connect a 3DR 

Radio to Pixhawk’s Telem 

port using the 6-wire cable 

provided with your 3DR Radio 

Kit to receive data and 

communicate with 

the autopilot in flight. 

(GPS or GPS+Compass required)

Connect a 3DR GPS+Compass to 

provide the autopilot with positioning 

data during flight. This kit includes a 

6-wire cable to connect the GPS ports. 

Connect the MAG to the I2

C port using 

the 4-wire cable provided with the 3DR 

GPS+Compass.

(Required) Connect the 3DR 

Power Module to the Power port 

using the 6-wire cable to direct 

power from your lithium polymer 

(LiPo) battery to the autopilot.

(Optional) The I2C splitter expands the I2C port to allow up 

to four additional peripherals to connect to Pixhawk. Use the 

4-wire cable to connect the I2

C splitter and add a compass 

module, external LED, digital airspeed sensor, or other 

peripherals to your vehicle.

2

Appendix 1 Page 18
Connect the ground (-), power (+), and signal (S) wires to the RC 

pins using the provided 3-wire servo cable.

For a Spektrum DSM, DSM2, or DSM-X Satellite RC receiver, connect to 

the SPKT/DSM port.

CONNECT RADIO CONTROL

FOR PPM RC RECEIVERS AND FUTABA S.BUS RECEIVERS

FOR SPEKTRUM SATELLITE RECEIVERS

FOR PWM RECEIVERS

Purchase a PPM Encoder module to connect a PWM 

RC receiver to Pixhawk at store.3dr.com.

LOAD SD CARD INTO PIXHAWK

If the SD card is not preloaded into Pixhawk, insert the micro-SD card into the slot at the 

bottom end of the board.

For a complete list of RC systems compatible with Pixhawk, visit the APM wiki page here.

Appendix 1 Page 19
 LOAD FIRMWARE 

APM firmware is the brains of your autopilot operation and must be installed before using Pixhawk. 

To load firmware onto Pixhawk, install a mission planner application on your ground station computer. Choose 

either Mission Planner (Windows) or APM Planner for (Windows, OS X, and Linux). 

Both applications are available for free download from ardupilot.com.

For rovers, connect the throttle and steering 

wires to the main output signal pins.

Pin 3 = Throttle

Pin 4 = Steering

Mission planner

firmware

FOR COPTERS

FOR PLANES

FOR ROVERS

Connect each signal wire from the PDB to 

the main output signal (S) pins by motor 

number. Connect one wire for each motor 

to the corresponding pin.

Pin 1 = Motor 1 Pin 5 = Motor 5

Pin 2 = Motor 2 Pin 6 = Motor 6

Pin 3 = Motor 3 Pin 7 = Motor 7

Pin 4 = Motor 4 Pin 8 = Motor 8

For planes, connect the control channel 

wires to the main output signal pins.

Pin 1 = Aileron

Pin 2 = Elevator

Pin 3 = Throttle

Pin 4 = Rudder

CONNECT OUTPUTS

3

Appendix 1 Page 20
Download Mission Planner (Windows)

Mission Planner « Downloads

Sort by: Title | Hits | Date

■ MissionPlanner - Installer Select the installer 

package to download.

Ardupilot.com Downloads Mission Planner

After selecting the correct file, read the safety information and select Download.

Open the file to run the setup wizard. Proceed through any security warnings, and install all 

suggested drivers. When the installation is complete, open the application, and connect Pixhawk to your 

computer using the micro-USB cable. 

Your computer will automatically install the correct drivers. Do not select Connect at this time; Pixhawk can only 

load firmware while unconnected to Mavlink. 

Download APM Planner (Windows, OS X, and Linux)

APM Planner 2.0 « Downloads

Sort by: Title | Hits | Date

■ APM Planner 2.0 Mac

■ APM Planner 2.0 Windows

■ APM Planner 2.0 Linux

Select your platform to 

download.

Ardupilot.com Downloads APM Planner 2.0

INSTALL PLANNER

Appendix 1 Page 21
When prompted, follow the directions to load the firmware. Once the status bar shows that the download is 

complete, power cycle the board by disconnecting and reconnecting the USB.

If you hear a musical tone, your firmware installation is complete. If you hear a series of tones followed by three 

beeps, disconnect the USB and reconnect while holding down the safety button. Upon restart, listen for a series 

of tones followed by two beeps indicating that your firmware has loaded successfully.

beep BEEP beep... 

BEEP BEEP  Pixhawk needs your attention:

beep BEEP beep... BEEP BEEP BEEP

Everything is OK:

musical tone 

Select Initial Setup, Install Firmware, and select your vehicle.

 CALIBRATE

With Pixhawk connected to your computer, select the communication option from the drop-down menu for 

PX4 FMU, set the rate to 115200, and select the Connect icon. Select Initial Setup and Mandatory Hardware to 

access the calibration wizards. 

Remove propellers before performing calibration. !

4

Appendix 1 Page 22
SELECT FRAME TYPE (COPTERS ONLY)

CALIBRATE COMPASS

Select the options to enable the compass; to allow automatic declination 

calculation; and to specify Pixhawk. Select Live Calibration to launch the wizard, 

and follow the prompts.

Show Me

videos demonstrating live calibration techniques at 3dr.com/learn.

For copter, select your frame orientation. 

Appendix 1 Page 23
CALIBRATE ACCELEROMETER

SELECT FLIGHT MODES

4

5

6

RC CALIBRATION

left stick

right stick

Select Accel Calibration, check the box for AC 3.0+, select Calibrate, and 

follow the prompts to calibrate Pixhawk’s accelerometer. Make sure to wait a 

couple of seconds before and after changing the positions of the vehicle.

Select Radio Calibration to teach Pixhawk to work with your RC 

transmitter. Turn on your transmitter, select Calibrate Radio, and move 

all sticks and switches to their extreme positions. Select Click when Done

once the red bars are set for all available channels.

Move each switch on your transmitter to its available positions. The mission 

planner will indicate the currently selected position with green highlighting. Select 

a mode for each switch position, and select Save Modes to assign.

Appendix 1 Page 24
LED MEANINGS

Flashing red and blue: initializing. Please wait.

Double flashing yellow: error. System refuses to arm.

Flashing blue: disarmed, searching for GPS. Autonomous, loiter, and return-to-launch 

modes require GPS lock.

Flashing green: disarmed, GPS lock acquired. Ready to arm. Quick double tone when 

disarming from the armed state.

Solid green plus single long tone: armed and ready to fly!

Flashing yellow: RC failsafe activated.

Flashing yellow plus quick repeating tone: battery failsafe activated.

Flashing yellow and blue plus high-high-high-low tone: GPS glitch or GPS failsafe 

activated.

Quick, constant blinking: performing system check. Please wait.

Solid: ready to arm. Proceed to the arming procedure.

Intermittent blinking: system ready. Press the safety button to activate.

SAFETY SWITCH MEANINGS

Learn more

about LED meanings and buzzer tones at 3dr.com/learn.

Appendix 1 Page 25
1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1 Spektrum DSM receiver

2 Telemetry (radio telemetry)

3 Telemetry (on-screen display)

4 USB

5 SPI (serial peripheral interface) bus

6 Power module

7 Safety switch button

8 Buzzer

 9 Serial

10 GPS module

11 CAN (controller area network) bus

12 I

2

C splitter or compass module

13 Analog to digital converter 6.6 V

14 Analog to digital converter 3.3 V 

15 LED indicator

PORTS

1 2

3 4

1 Input/output reset button

2 SD card

3 Flight management reset button 

4 Micro-USB port

1 2

ground

power

signal

1 Radio control receiver input

2 S.Bus output

3 Main outputs

4 Auxiliary outputs

3 4

Appendix 1 Page 26
Processor

32-bit ARM Cortex M4 core with FPU

168 Mhz/256 KB RAM/2 MB Flash

32-bit failsafe co-processor

Sensors

ST Micro 16-bit gyroscope

ST Micro 14-bit accelerometer/magnetometer

MEAS barometer

MPU6000 accelerometer/magnetometer

Power

Ideal diode controller with automatic failover

Servo rail high-power (7 V) and high-current ready

All peripheral outputs over-current protected, all 

inputs ESC protected

Interfaces

5x UART serial ports, 1 high-power capable, 2x with 

HW flow control

Spektrum DSM/DSM2/DSM-X Satellite input

Futaba S.BUS input and output

PPM sum signal

RSSI (PWM or voltage) input

I

2

C, SPI, 2x CAN, USB

3.3 and 6.6 ADC inputs

Dimensions

Weight 38 g (1.3 oz)

Width 50 mm (2.0”)

Height 15.5 mm (.6”)

Length 81.5 mm (3.2”)

SPECIFICATIONS

IMPORTANT NOTE

SUPPORT

For more information about Pixhawk and other documentation, visit 

3dr.com/learn. For more instruction on using APM firmware and 

planner software, visit ardupilot.com.

For customer support, contact us at help@3dr.com or call our 

support line at +1 (858) 225-1414 Monday through Friday, 8 am to 5 pm, PST.

Please note that these instructions describe basic setup for Pixhawk and do not represent the 

complete set of configuration procedures required to build a copter, plane, or rover. 

For more information on ESC calibration, battery monitoring, failsafes, mode descriptions, 

and more, visit ardupilot.com. Do not operate your vehicle without a complete understanding 

of the online instructions.

Appendix 1 Page 27
Operating a powered vehicle of any kind can be a lot of fun, but it carries certain inherent risks. Regulations 

governing the use of powered vehicles, including aircraft, vary from locale to locale, even within the same country 

or district. It is your responsibility to ensure that you understand and comply with all local laws and regulations.

Safety basics:

•	 Never operate the vehicle or software in a way that could be dangerous to you, other people, or property.

•	 Always keep propeller arcs free of objects and body parts while the vehicle is live.

•	 Keep in mind that software and hardware failures happen. Although we design our products to minimize 

such issues, you should always operate with the understanding that a failure could occur at any time and 

without warning. Accordingly, you should take the appropriate precautions to minimize danger in case of 

product failure.

•	 Never use the software or hardware for manned vehicles.

•	 Always operate within local laws and regulations.

•	 Do not operate the aircraft if you are under the age of 18. 

Additional safety information:

•	 Be sure to maintain safe distances between people and your aircraft. 

•	 Never operate your aircraft if your ability to do so with the utmost attention to safety is impaired in any 

way. Do not operate your aircraft while tired, under the influence of drugs or alcohol, or otherwise unable to 

operate it with the highest attention to safety. 

•	 Environment conditions can change rapidly and can make operation difficult. If this occurs, land your aircraft 

and discontinue use immediately. Do not operate your aircraft if operating conditions are not ideal. This 

includes, but is not limited to, rain, snow or excessive wind.

•	 Always ensure the battery cable is disconnected from the aircraft until you are ready to fly, and ensure that 

your batteries are fully charged prior to use.

•	 Always turn on the transmitter and ensure the throttle stick is all the way down before connecting the 

battery.

•	 After landing, disarm your vehicle immediately and disconnect the battery cable.

•	 Do not turn off the transmitter until after you have disconnected the battery.

•	 Always remove the propellers while testing the motors.

•	 When the battery is connected, always assume the vehicle is live and the motors are armed.

•	 Do not attempt to fly longer than the battery’s safe capacity.

•	 Do not operate the vehicle with excess weight attached.

•	 Ensure that all vehicle components are well maintained before each flight. Ensure that components are 

firmly attached and operating properly. 

•	 Replace any worn or damaged components before each flight. Never operate with any damaged or worn 

components.

•	 SAFETY IS THE FIRST PRIORITY. Take all precautions necessary to ensure your own safety as well as the 

safety of other people and property.

SAFETY

Appendix 1 Page 28
DISCLAIMER

THE LIMITED WARRANTIES APPLICABLE TO 3D ROBOTICS-BRANDED HARDWARE CAN BE FOUND AT 

WWW.3DROBOTICS.COM/TERMS/ AND CAN BE REFERENCED IN FULL AT THAT URL. 3D ROBOTICS 

RESERVES THE RIGHT TO UPDATE THE WARRANTIES AT ANY TIME WITHOUT EXPRESS NOTICE. 3D 

ROBOTICS MAKES NO OTHER WARRANTIES FOR 3D ROBOTICS-BRANDED PRODUCTS, AND MAKES 

NO WARRANTIES WHATSOEVER FOR SERVICE, SOFTWARE, MAINTENANCE OR SUPPORT FOR NON-3D 

ROBOTICS-BRANDED PRODUCTS. SUCH PRODUCTS, SOFTWARE, SERVICES, MAINTENANCE OR SUPPORT 

IS PROVIDED BY 3D ROBOTICS “AS IS” AND ANY THIRD-PARTY WARRANTIES, PRODUCTS, SOFTWARE, 

SERVICES, MAINTENANCE OR SUPPORT ARE PROVIDED BY THE ORIGINAL MANUFACTURER OR 

SUPPLIER, NOT BY 3D ROBOTICS. 3D ROBOTICS MAKES NO EXPRESS WARRANTIES EXCEPT THOSE STATED 

IN 3D ROBOTICS’ APPLICABLE WARRANTY IN EFFECT ON THE DATE OF THE INVOICE, PACKING SLIP OR 

ACKNOWLEDGEMENT.

3D ROBOTICS OFFERS THE HARDWARE AS-IS AND MAKES NO REPRESENTATIONS OR WARRANTIES OF 

ANY KIND CONCERNING THE HARDWARE, EXPRESS, IMPLIED, STATUTORY OR OTHERWISE, 

INCLUDING, WITHOUT LIMITATION, WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A 

PARTICULAR PURPOSE, NON-INFRINGEMENT, OR THE ABSENCE OF LATENT OR OTHER DEFECTS, 

ACCURACY, OR THE PRESENCE OF ABSENCE OF ERRORS, WHETHER OR NOT DISCOVERABLE. SOME 

JURISDICTIONS DO NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES, SO SUCH EXCLUSION MAY 

NOT APPLY TO YOU.

EXCEPT TO THE EXTENT REQUIRED BY APPLICABLE LAW, IN NO EVENT WILL 3D ROBOTICS BE LIABLE TO 

YOU ON ANY LEGAL THEORY FOR ANY SPECIAL, INCIDENTAL, CONSEQUENTIAL, PUNITIVE OR 

EXEMPLARY DAMAGES ARISING OUT OF THE USE OF THE HARDWARE.

3D ROBOTICS ACCEPTS NO LIABILITY FOR DAMAGE(S) OR INJURIES INCURRED DIRECTLY OR INDIRECTLY 

FROM THE USE OF THIS PRODUCT.

SOFTWARE IS SUBJECT TO THE SEPARATE SOFTWARE LICENSE AGREEMENT ACCOMPANYING OR MADE 

AVAILABLE TO YOU IN CONNECTION WITH THE SOFTWARE. A PORTION OF THE SOFTWARE MAY 

CONTAIN OR CONSIST OF OPEN-SOURCE SOFTWARE, WHICH YOU MAY USE UNDER THE TERMS AND 

CONDITIONS OF THE SPECIFIC LICENSE UNDER WHICH THE OPEN-SOURCE SOFTWARE IS DISTRIBUTED. 

YOU AGREE THAT YOU WILL BE BOUND BY ANY AND ALL SUCH LICENSE AGREEMENTS, AND THAT YOUR 

USAGE OF THIS PRODUCT INDICATES YOUR ACCEPTANCE OF THOSE AGREEMENTS. TITLE TO SOFTWARE 

REMAINS WITH THE APPLICABLE LICENSOR(S). IN NO EVENT WILL 3D ROBOTICS BE LIABLE TO YOU FOR 

DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING 

OUT OF THE USE OR INABILITY TO USE THE SOFTWARE.

Pixhawk Kit User Guide V8 © 3D Robotics, Inc. 20 March 2014

Appendix 1 Page 29
This pages covers the set-up and testing of the GPS and Ground Station Control (GCS)

failsafes. Note that Copter has 2 other failsafes : Radio and Battery .

Contents [hide]

1 GPS Failsafe

2 Ground Control Station Failsafe

GPS Failsafe

The GPS Failsafe is enabled by default but you can enable or disable it on the Mission

Planner’s Standard Parameter List, by set the FS_GPS_ENABLE parameter to 0 (Disable)

or 1 (Land) or 2 (switch to AltHold).  It is highly recommended to leave it enabled and no

known reason why it should ever be disabled.

If you lose GPS lock or experience a GPS Glitch for 5 seconds while in a mode that requires

the GPS (Auto, Guided, Loiter, RTL, Circle, Position or Drift) mode it will initiate a Land (or

AltHold if FS_GPS_ENABLE is set to 2).

ArduPilot > Copter > GPS and GCS Failsafes

GPS and GCS Failsafes

Copter

English

Appendix 1 Page 30
Below is a video of a simulated GPS Failure resulting in the copter Landing.

GPS failsafe testing with AC 2.9.2

Additional information on the GPS failsafe and Glitch protection can be found here .

Ground Control Station Failsafe

Appendix 1 Page 31
Note:

Ground Control Station Failsafe

In Mission Planner’s Advanced Parameter List, set the FS_GCS_ENABLE parameter to:

0 to disable the GCS failsafe

1 to enable and always RTL in event of loss of contact

2 to RTL unless in AUTO mode in which case we should continue with the mission

If you have been using the ground station to control the copter (i.e. using a joystick) and then

lose Ground Control Station contact for at least 5 seconds the following will happen:

Disarm motors – if you are in stabilize or acro mode and your throttle is zero

RTL – if you have a GPS lock and are more than 2 meters from your home position

LAND – if you have no GPS lock or are within 2 meters of home

Continue with the mission – if you are in AUTO mode and have set the GCS Failsafe

Options to 2 (Enabled_continue_in_auto_mode).

If the failsafe clears (contact with the ground station is restored) the copter will remain in it’s

current flight mode. It will not automatically return to the flight mode that was active before

the failsafe was triggered. This means that if, for example, you are flying in stabilize mode

when the failsafe is triggered, and this causes the flight mode to change to RTL or LAND, if

you wish to re-take control of the copter you will need to set your flight mode again back to

stabilize.

All Failsafe Parameters can also be observed or set from the Advanced Parameter

List.

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 32
Appendix 1 Page 33
Tip:

This article explains how to setup and test the battery failsafe.

Contents [hide]

1 Overview

2 When the failsafe will trigger

3 What will happen

4 Setting up the battery failsafe

5 Low Battery warning (even with failsafe disabled)

Overview

The battery failsafe can be set-up to automatically trigger an RTL or LAND when the vehicle

battery voltage or estimated remaining power has crossed a configurable threshold. 

To use this failsafe the vehicle must have a Power Module or other voltage and (optionally)

current monitor.

Copter also supports Radio, GPS and Ground Station Control failsafes.

When the failsafe will trigger

If enabled and set-up correctly the battery failsafe will trigger if the main battery:

voltage drops below 10.5 volts (configurable) for more than 10 seconds

ArduPilot > Copter > Battery Failsafe

Battery Failsafe

Copter

English

Appendix 1 Page 34
remaining capacity falls below the configurable Reserved MAH

What will happen

When the failsafe is triggered one of the following will happen:

Nothing if the vehicle is already disarmed

Disarm motors if the vehicle is in Stabilize or Acro mode and the throttle is at zero OR the

vehicle is landed

Return-to-Launch (RTL) if the FS_BATT_ENABLE param is set to “2” (“RTL”) OR the vehicle

is in AUTO mode, has a GPS lock and are at least 2 meters from your home position

Land in all other cases

Setting up the battery failsafe

Setup the power module as described in the Power Modules section of this wiki including

setting the totally battery capacity if using a current monitor

On the INITIAL SETUP | Mandatory Hardware | Failsafe page:

set the “Low Battery” threshold voltage (i.e. 10.5 volts)

set the “Reserved MAH” or leave as “0” if the failsafe should never trigger based on

estimated current consumed.  “600” would be an appropriate number to cause the vehicle

to LAND or RTL when only 20% of a 3000mAH  battery remains.

select the desired behavior as “Land” or “RTL” (Note: the placement of the drop-down is

confusing but this will be corrected in a future version of the mission planner)

Appendix 1 Page 35
Low Battery warning (even with failsafe disabled)

Even if the battery failsafe is not enabled (i.e. FS_BATT_ENABLE = 0) the “Low Battery” voltage

threshold and “Reserved MAH” numbers are used to issue a battery warning. This will result in:

“Low Battery!” message appearing on the ground stations HUD (if using telemetry)

Loud beeping if a buzzer is attached

Flashing LEDs

The only way to disable this warning completely is to set the “Low Battery” voltage and

“Reserved MAH” values to zero.

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 36
Note:

Copter supports Return-To-Launch in cases where contact between the Pilot’s RC transmitter

and the flight controller’s receiver is lost.  This page explains this failsafe’s setup and testing. 

Note the “Radio failsafe” was previously called “Throttle failsafe” because of the way in which

some receivers use the throttle channel to signal the loss of contact.

Copter also support Battery , GPS, Ground Station and EKF/DCM failsafes .

Contents [hide]

1 When the failsafe will trigger

2 What will happen

3 Receiver and flight controller set-up

3.1 Set-up for low-throttle method

3.2 Set-up for No-Signal method

4 Testing

5 Using the receiver to set the flight mode (not recommended)

ArduPilot > Copter > Radio Failsafe

Radio Failsafe

Copter

English

Appendix 1 Page 37
6 Warning to Copter 3.1.5 and FRSky receiver users and users of other receivers that modify

channel 5 during a failsafe event

When the failsafe will trigger

If enabled and set-up correctly the radio failsafe will trigger if:

The pilot turns off the RC transmitter

The vehicle travels outside of RC range (usually at around 500m ~ 700m)

The receiver loses power (unlikely)

The wires connecting the receiver to the flight controller are broken (unlikely).  Note: with

APM2 only the ch3 connection between receiver and flight controller will trigger the failsafe.

What will happen

When a radio failsafe is triggered one of the following will happen:

Nothing if the vehicle is already disarmed

Motors will be immediately disarmed if the vehicle is landed OR in stabilize or acro mode

and the pilot’s throttle is at zero

Return-to-Launch (RTL) if the vehicle has a GPS lock and is more than 2 meters from the

home position

LAND if the vehicle has:

no GPS lock OR

is within 2 meters of home OR

the FS_THR_ENABLE parameter is set to “Enabled Always Land”

Continue with the mission if the vehicle is in AUTO mode and the FS_THR_ENABLE

parameter is set to “Enabled Continue with Mission in Auto Mode”.

If the failsafe clears (i.e. transmitter and receiver regain contact) the copter will remain in its

current flight mode. It will not automatically return to the flight mode that was active before the

failsafe was triggered. This means that if, for example, the vehicle was in Loiter when the

failsafe occured and the flight mode was automatically changed to RTL, even after the

transmitter and receiver regained contact, the vehicle would remain in RTL.  If the pilot wished

to re-take control in Loiter he/she would need to change your flight mode switch to another

position and then back to Loiter.

Receiver and flight controller set-up

Appendix 1 Page 38
Receiver and flight controller set-up

By default, a newly purchased receiver will be set-up to simply hold all channels at their last

known position when the receiver and transmitter lose contact.  This is not good because the

flight controller has no way to know that the Pilot has lost control of the vehicle.  Instead the

receiver must be set-up to signal to the flight controller it has lost contact and there are two

ways that it can do this (the method depends upon the receiver):

“Low-Throttle” method – the receiver pulls the throttle channel (normally channel 3) to a

value below the bottom of it’s normal range (normally below 975).  This method is used by

Futaba systems and many older systems.

“No Signal” method – the receiver stops sending signals to the flight controller.  This is the

preferred method and is how most modern FrSky receivers operate.

Each brand of Transmitter/Receiver is slightly different so please refer to your transmitter’s user

manual to determine which method is available and how to set it up.

Set-up for low-throttle method

Futaba T7C Failsafe Setup

Appendix 1 Page 39
Above is the setup method for a Futaba T7C Transmitter with R617FS or TFR4-B receiver

which uses the “low throttle” method.

With the LiPo battery disconnected:

Connect your flight controller to the mission planner and select Initial Setup >> Mandatory

Hardware >> Failsafe.

Set the Failsafe Options to one of the three options:

“Enabled always RTL” to force the vehicle to always RTL even if flying a mission in

AUTO mode

“Enabled Continue with Mission in AUTO” to allow the vehicle to continue with

missions even if it takes the vehicle outside of RC range (not recommended).  In all

other cases the vehicle will RTL.

“Enable always LAND” to force the vehicle to Land immediately if it loses RC

contact

Set the “FS Pwm” value to be:

at least 10 PWM higher than your Channel 3’s PWM value when the throttle

stick is fully down and the transmitter is off

at least 10 lower than your channel 3’s PWM value when the throttle stick is

fully down and the transmitter is on

above 910

Appendix 1 Page 40
Set-up for No-Signal method

FrSky D4R-II receiver failsafe setup with AC3.1 on Pixhawk

Appendix 1 Page 41
Above is the setup method for a FlySky 9 channel transmitter with FrSky D4R-II receiver which

uses the “No Signal” method.

Similar to the “Low-Throttle” method, with the LiPo battery disconnected:

Connect your flight controller to the mission planner and select Initial Setup >> Mandatory

Hardware >> Failsafe.

Set the Failsafe Options to one of the three options:

“Enabled always RTL” to force the vehicle to always RTL even if flying a mission in

AUTO mode

“Enabled Continue with Mission in AUTO” to allow the vehicle to continue with

missions even if it takes the vehicle outside of RC range (not recommended).  In all

other cases the vehicle will RTL.

“Enable always LAND” to force the vehicle to Land immediately if it loses RC

contact

Because the throttle is not pulled low, there is normally no need to adjust the “FS Pwm” value

from it’s default (975).  Just ensure that it’s well below (i.e. at least 10pwm points below) the

minimum value that channel 3 (throttle) can be.

Testing

You can check your failsafe by performing the following tests with the Pixhawk/APM connected

to the Mission Planner either via a USB cable or telemetry link. You can complete these tests

without plugging in your LiPo battery but if you do connect a battery you should first remove the

propellers.

Test #1 : if using the “Low-Throttle” method, ensure the throttle channel drops with loss

of radio contact

1. Ensure your RC transmitter is on and connected with the throttle all the way down and flight

mode set to Stabilize

2. The throttle (channel 3) PWM value should be approximately as in first illustration below.  It’s

value may be higher or lower but it should definitely be at least 10 higher than the value held

in the FS PWM field

3. Turn the transmitter off and the throttle PWM value should drop to be at least 10 below the

FS PWM field value (as in the second illustration below) below

Appendix 1 Page 42
Test #2 : ensuring motors disarm if in stabilize or acro with throttle at zero

Switch to stabilize mode, arm your motors but keep your throttle at zero. Turn off your

transmitter. The motors should disarm immediately (red led will start flashing, DISARMED

will be displayed in the Mission Planner’s Flight Data screen).

Appendix 1 Page 43
Test #3 : ensuring flight mode changes to RTL or LAND when throttle is above zero

Switch to stabilize mode, arm your motors and raise your throttle to the mid point. Turn off

your transmitter. The Flight Mode should switch to RTL if you have a GPS lock or LAND if

you do not have a GPS lock (the flight mode and GPS lock status are visible in the Mission

Planner’s flight data screen).

Test #4 : retaking control after the failsafe has cleared

continuing on from test #3, turn your transmitter back on

while the flight mode is still in RTL or LAND and armed, change the flight mode switch to

another position and then back to stabilize mode.  Ensure that the flight mode displayed on

the Failsafe page is updating appropriately.

Test #5 (optional) : removing power from the receiver

Switch to stabilize mode, arm your motors and keep your throttle above zero.

Carefully disconnect the power wires connecting the receiver to the APM

The Flight Mode should switch to RTL or LAND as described in Test #3

Warning: unplug the APM so that it is powered down before reattaching the receiver’s power

Using the receiver to set the flight mode (not recommended)

Instead of setting up the receiver and flight controller as described above (i.e. “Low-Throttle”

and “No Signal” methods) the receiver can be set-up to set channel 5 (flight mode channel) to a

flight mode slot that has been set to RTL.  For example the receiver could be setup to move

ch5’s pwm value to 1700 which is “Flight Mode 5” which could then be set to RTL on the

Mission Planner’s Initial Setup >> Mandatory Hardware >> Flight Modes screen.

Although this mostly works it is not recommended because it will not trigger if the receiver loses

power or if the wires between the receiver and flight controller are broken.

Warning to Copter 3.1.5 and FRSky receiver users and users of

other receivers that modify channel 5 during a failsafe event

Some FRSky tx/rx systems receivers can only be set-up to modify all channels including the

Appendix 1 Page 44
flight mode channel (channel 5) when a failsafe event occurs.  For these receivers if using

Copter 3.1.5 (or earlier) it is important to setup the receiver’s channel 5 failsafe value so that

the Pixhawk/APM is switched into RTL, Loiter or LAND.  This is critical because there is a very

short period of time (3/50ths of a second) between when the receiver pulls the throttle low and

when the Pixhawk/APM initiates the RTL or LAND.  During this time, if the receiver also

switches the flight mode channel to stabilize or acro the Pixhawk/APM may switch to stabilize

momentarily and then because the copter is in stabilize with throttle at zero it will disarm the

copter (i.e. Test #2).

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 45
Contents [hide]

1 Overview

2 Enabling the Fence in Mission Planner

3 Enabling the fence with Channel 7 or 8

4 Warnings:

5 Video overview of the Fence setup and Operation

Overview

AC 3.0.1 (and higher) includes a simple “tin can” shaped fence centered on home that will

attempt to stop your copter from flying too far away by initiating an RTL.  The maximum circular

distance and altitude and the vehicle behaviour when the fence is reached can be configured

using Mission Planner.

ArduPilot > Copter > Simple GeoFence

Simple GeoFence

Copter

English

Appendix 1 Page 46
If the vehicle strays outside these borders it will switch into RTL or LAND.  At the moment the

fence is breached a backup fence is erected 20m further out (or up).  If the copter breaches this

backup fence (for example if the the vehicle is not set up correctly or the operator takes

control but is unable to bring the copter back towards home) the copter will be switched into

RTL again (and another backup fence an additional 20m further out will be created).

If the copter eventually flies 100m outside the configured fence distance, the vehicle will switch

into LAND mode.  The idea being that it’s clearly impossible to get the copter home so best to

just bring it down.  The pilot can still retake control of course with the flight mode switches.  Like

with the earlier fences, another fence is erected 20m out which will again switch the copter to

LAND if it continues away from home.

Enabling the Fence in Mission Planner

Appendix 1 Page 47
The Fence can be set-up by doing the following:

Connect your APM/PX4 to the Mission Planner

Go to the Software -> GeoFence screen

Click the “Enable” button

Leave the “Type” as “Altitude and Circle” (unless you want only an Altitude limit or only a

Circular fence in which case you can select “Altitude” or “Circle”)

Leave the Action as “RTL or Land”

Set “Max Alt” to the altitude limit you want (in meters)

Set “Max Radius” to the maximum distance from home you want (in meters).  This should

normally be at least 50m

Enabling the fence with Channel 7 or 8

It is not necessary to set-up a switch to enable or disable the fence but if you wish to control the

fence with a switch please follow these steps:

Go to the Mission Planner’s Software > Copter Pids screen and set either “Ch7 Opt” OR

“Ch8 Opt” to Fence.

holding the switch high (i.e. PWM > 1800) will enable the fence, low (under 1800) will disable

the fence.

Appendix 1 Page 48
Warnings:

The minimum recommended fence radius is 30m

The fence requires the GPS to be functioning well so do not disable the GPS arming check

nor the GPS failsafe while the fence is enabled.  Conversely if you disable either of these

checks, disable the Fence.

For the best results, ensure RTL is working on your vehicle.

With the Fence enabled, the pre-arm checks will require you have GPS lock before arming

the vehicle.

If GPS failsafe is not enabled and the Fence is enabled and you loose GPS lock while

flying the fence will be disabled.

If GPS failsafe is enabled and the Fence is enabled and you lose GPS lock while flying the

vehicle will switch to LAND because we no longer know the vehicle position and we want to

ensure the copter never travels far outside the fence.  This beahviour will occur regardless of

the flight mode.  If a LAND sequence is not desired, the pilot can retake control by moving

the flight mode switch.

The backup fences are created 20m out from the previous breached fence not 20m out from

the vehicle’s position.  This means if you choose to override the fence you may have less

than 20m to regain vehicle control before the fence switches the copter to RTL (or LAND)

again.  If you really want to override the fence, you should be ready to switch the flight mode

twice or alternatively set-up the enable/disable fence switch.

Video overview of the Fence setup and Operation

Appendix 1 Page 49
ArduCopter 3.0 Fence

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 50
Mission Planner is free, open source software available for Windows. These instructions will

guide you through installing Mission Planner on your ground station computer.

Contents [hide]

1 Download the most recent Mission Planner installer file

2 Run the installation utility

3 Open Mission Planner

4 Updating Mission Planner

Download the most recent Mission Planner installer

file

Go to the Mission Planner download page and click on the Download button to get the most

recent Misson Planner installation file.

Run the installation utility

ArduPilot > Copter > common-Installing Mission Planner

Installing Mission Planner

Copter

English

Appendix 1 Page 51
Open the Microsoft installer file (.msi) and select Run to run the installation utility.

Follow the instructions to complete the setup process. The installation utility will automatically

install any necessary software drivers. If you receive a DirectX installation error, please update

your DirectX plug-in from the DirectX Download Center .

If you receive the warning pictured here, select Install this driver software anyway to

continue.

Appendix 1 Page 52
Mission Planner is normally installed in the C:\Program Files (x86)\APM Planner folder or

the C:\Program Files\APM Planner folder. That is where your log files folder is located.  

An icon to open the Mission Planner is created according to your instructions during the

installation.

Open Mission Planner

Once installation is complete, open Mission Planner by clicking on its system icon. 

Then you can either:

Connect Mission Planner to AutoPilot in order to receive telemetry and control the vehicle, or

Load Firmware

Updating Mission Planner

Mission Planner automatically notifies you about available updates (when it is connected to the

Internet).

Please always run the most current version of Mission Planner.

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 53
Note:

On the Mission Planner‘s Initial Setup screen select Mandatory Hardware | Frame Type.

Select the frame for your copter. The default configuration is X. If you want one of the arms to

serve as the exclusive front-facing direction, select the Plus configuration. For Tricopters,

Traditional Helis and Y6s, the frame type is ignored.

Mission Planner: Select Frame Type

For an H-Frame quadcopter use the option to set the frame type to ‘3’ in the

ArduPilot > Copter > Frame Type Configuration in Mission Planner

Frame Type Configuration in Mission

Planner

Copter

English

Appendix 1 Page 54
Advanced Parameter Tab. To apply the H-frame configuration, swap the left rear and right

rear props and reverse the motor direction for each of those motors (by swapping any two

motor wires). Repeat the same process for the front two motors.

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 55
Copter:

This article shows how you can enable up to 6 autopilot control/flight modes to be set from your

RC transmitter.

Contents [hide]

1 Flight modes configuration

2 Setting the flight mode channel

3 Transmitter configuration

3.1 Test transmitter switch settings

3.2 Tutorials for specific RC hardware

3.3 Spektrum DX8 (alternate method)

Flight modes configuration

The mapping between switch position and flight mode is set in the Mission Planner Flight Mode

screen.

ArduPilot > Copter > common-RC Transmitter Flight Mode Configuration

RC Transmitter Flight Mode

Configuration

Copter

English

Appendix 1 Page 56
Note:

Mission Planner: Flight Mode Screen (Copter).

You can set up the flight modes available on the transmitter by doing the following:

Turn on your RC transmitter

Connect the Pixhawk (or other flight controller) to the Mission Planner

Go to the Initial Setup | Mandatory Hardware | Flight Modes screen

As you move your transmitter’s flight mode switch the green highlight bar will

move to a different position.

Use the drop-down on each line to select the flight mode for that switch position.

(Copter) Ensure that at least one switch position is left assigned to STABILISE.

(Copter) Optionally check the Simple Mode check-box for that switch position. If using

AC3.1 or higher you can optionally set Super Simple mode . If both Simple mode and

Super Simple mode checkboxes are checked Super Simple will be used.

When finished press the Save Modes button.

Some modes can also be invoked from the auxiliary switches (a.k.a. ch7, ch8 option

switches). For example, to set a dedicated switch for RTL.

Appendix 1 Page 57
Note:

Setting the flight mode channel

The flight mode channel is the input radio channel that ArduPilot monitors for mode changes.

On Copter this is always channel 5.

Transmitter configuration

The transmitter must emit PWM signals in the correct range to allow us to map a mode to a

switch position.

The correct PWM ranges for selectable modes are shown alongside each mode

selection dropdown in the Mission Planner Flight Mode screen (see screenshot above).

If you want to just support three modes (using a three position switch) then you would configure

the transmitter to produce PWM pulse widths of 1165, 1425, and 1815 microseconds for the

respective switch positions.

If you want to support 6 modes then the transmitter will need to emit PWM widths of around

1165, 1295, 1425, 1555, 1685, and 1815 milliseconds. Typically this is achieved by configuring

the transmitter to mix a two position switch and a three position switch (giving 6 modes in total).

You can also do this with an analog dial if one is available, but it’s hard to reliably turn a dial to

just the right position for six distinct settings.

The sections below provide links showing how to configure transmitters from different

manufactures, and how to test (in Mission Planner) that each switch setting is emitting the

appropriate PWM signal.

Test transmitter switch settings

You can use the Mission Planner Radio Calibration screen to test the PWM pulse widths for

each mode setting.

Simply toggle through the modes on your transmitter and confirm that the PWM for the selected

channel matches the required PWM values. The screenshot below assumes that the flight

mode channel is set to Radio 5.

Appendix 1 Page 58
Tutorials for specific RC hardware

Here are some user-contributed tutorials for doing this (or adding more modes to RC units with

just a two-position toggle) with various RC systems:

JR XG8 DMSS

JR9303

JR X2720

Futaba T8FG

Futaba T8J

Futaba T7CP

Futaba T6EX

Futaba 12fg

Futaba 9ZAP/ZHP

Futaba T10CAG

Futaba T14

Futaba 9C Super

Graupner MX-16

Turnigy 9x (or an even easier way) (Here!)

Turnigy 9x with ER9x firmware

Turnigy 9XR

Appendix 1 Page 59
Hitech Aurora 9

Spektrum DX8   (alternate method below)

Spektrum DX7

Spektrum DX7s

Spektrum DX7 Version 6

Or build your own six-position switch!

Spektrum DX8 (alternate method)

This section describes an alternative way to set 6 modes with the Spektrum DX8. This method

uses the Gear switch and the Flight mode switch. All the other switches can be assigned as

preferred. This method also allows each mode to be set in the middle of each mode’s pulse

width range so small changes will not change modes. Use Mission Planner Flight Modes setup

to monitor the Current PWM for these adjustments.

1. Setup the switches (*required for the 6 modes)

Hold roller bar down, turn on DX8, scroll down to Switch Select, Click roller bar.  Set

switches as follows:

* Gear = Gear (Channel 5)

* FMode = Inh  Not assigned to a channel – Used to mix with Gear Sw (Channel 5) for 6

modes

Others anyway you want. One method is as follows:

Knob to aux1 = channel 6 for camera tilt / tuning

Mix = aux2 = channel 7 to save Way Point or RTL, auto trim or other settings in APM

configuration.

Flap to aux3 = channel 8 for other uses

Click BACK until the normal screen appears, or turn off power, then turn power back on.

2. Set up the non-mixed servo setting for channel 5 (Gear channel controlled by the Gear

Switch)

This will be the values with no mixing – F Mode switch in the 0 position and sets the lowest

pulse width to 1165 ms (mode 1) and highest to 1815 ms (mode 6)

Click the roller bar, scroll down to Servo Setup, Select the Gear channel, Select Sub Trim.

Set sub trim to 0

Select Travel.

Set travel (left, position 0) for 1165 ms pulse  (~90%).

Set travel (right, position 1 for 1815 ms pulse (~74%).

Appendix 1 Page 60
3. Set up Mix 1 to change the Gear Pulse width when F Mode is in position 1

Click roller, scroll down to Mixing, click roller, scroll to first line under Mix (has xxx > xxx,

AIL > RUD, or some other mix set),click roller, Select Mix 1, Click roller.

Set Mix: Gear > Gear. Gear changes Gear depending on Switch F Mode setting

Set Offset = 0, Trim = Inh.

Set SW = FM 1

Set the F Mode switch on the transmitter to position 1.

Set the Gear switch on the transmitter to position 0.

Set top Rate for pulse width of 1290 ms for mode 2  (~-35%)

(change = 400 ms * -90% * -35% = 126 ms. Result = 1165 ms + 126 ms = 1251 ms =

mode 2)

Set the Gear switch on the transmitter to position 1.

Set bottom Rate for pulse width of 1685 ms for mode 5  (~– 45%)

(change = 400 ms * +73% *- 45% = -131 ms. Result = 1815 ms – 131 ms = 1684 ms =

mode 5)

4. Set up a mix 2 to change the Gear Pulse width when F Mode is in position 2

Mix: Gear > Gear.  Gear changes Gear depending on Switch F Mode setting.

Set Offset = 0, Trim = Inh

Set SW = FM2

Set the F Mode switch on the transmitter to position 2

Set the Gear switch on the transmitter to position 0.

Rate top Rate for pulse width of 1425 ms for mode 3  (~–72%) (change = 400 ms * –90%

* – 72% = 259 ms.  Result = 1165 ms + 259 ms = 1424 ms = mode 3)

Set the Gear switch on the transmitter to position 1.

Set bottom Rate for pulse width of 1550 ms for mode 4  (~–89%) (change = 400 ms *

+73% * – 89% = -262 ms.  Result = 1815 ms – 262 ms = 1553 ms = mode 4)

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 61
This article explains how to connect the ESCs, Motors and Propellers for Pixhawk, PX4, and

APM 2.x.

Contents [hide]

1 Connect motor PWM signal outputs (Pixhawk/PX4)

2 Connect motor PWM signal outputs (APM2)

3 Motor order diagrams

3.1 Quad

3.2 Hexa, Octo, Y6

3.3 X8

3.4 Tricopter

4 Attach propellers

4.1 Recognizing clockwise and counterclockwise propellers

5 Choosing propellers

6 Testing motor spin directions

7 Checking the motor numbering with the Mission Planner Motor test

8 KDE (and other) Opto Isolated ESCs

9 Pixhawk ESC issues

Connect motor PWM signal outputs (Pixhawk/PX4)

Connect the power (+), ground (-), and signal (s) wires for each ESC to the controller main

output pins by motor number. Find your frame type below to determine the assigned order of

the motors.

ArduPilot > Copter > Connect ESCs and Motors

Connect ESCs and Motors

Copter

English

Appendix 1 Page 62
Warning:

Note:

Pixhawk Output pins (numbered). First 4 pins are colour-coded for connecting a Quad

frame

The APM PDB described in the following section is not compatible with the

Pixhawk or PX4.

Connect motor PWM signal outputs (APM2)

There are two methods of connecting the motor outputs: connect the electronic speed

controllers (ESCs) to autopilot controller board directly or use a power distribution board (PDB).

When using a PDB, connect the power (+), ground (-), and signal (s) wires for each ESC to the

PDB according to motor number. Find your frame type below to determine the assigned order

of the motors. Then connect the signal wires from the PDB to the main output signal pins on the

flight controller board (ensuring that the motor order numbers match the main output pin

numbers on the controller). If you are using a power module, it is optional to connect the power

and ground wires from the PDB to the flight controller board. If you would like to use these

cables in addition to or instead of the power module or as a common point for low current

servos, connect the ground (-) wire to a main output ground (-) pin and the power (+) wire to a

main output power (+) pin.

Information on assembling PDB is found here for Quad and here for Hexa .

Appendix 1 Page 63
When connecting the ESCs directly to autopilot board, connect the power (+), ground (-), and

signal (s) wires for each ESC to the controller main output pins by motor number. Find your

frame type below to determine the assigned order of the motors.

APM Output Pins (numbered)

Motor order diagrams

The sections below show motor order for each frame type (the numbers indicates the

connected autopilot output pin) and the propeller direction (clockwise (CW) motors are shown

in green and take pusher propellers,counterclockwise motors (CCW) are shown in blue and

take puller propellers.

Use the diagram for your frame type, and wire the motors as shown.

Appendix 1 Page 64
Legend for motor-order diagrams

Quad

Hexa, Octo, Y6

Appendix 1 Page 65
Appendix 1 Page 66
Note: 2014 3DR RTF Y6 uses the Y6B configuration.

X8

Tricopter

Appendix 1 Page 67
Note: If the direction of your tail servo is going the wrong way in response to yaw then

either the RC7_REV or MOT_YAW_SV_REV parameter should be set to -1 (from 1), See

TriCopter setup page for details.)

Attach propellers

Find your frame in the motor order diagrams above. Clockwise motors are shown in green,

marked CW, and take pusher propellers. Counterclockwise motors are shown in blue, marked

CCW, and take puller propellers. Use the diagram for your frame type, and attach propellers to

your vehicle as shown. For copters, attach propellers with the writing facing towards the sky.

For more information on recognizing the different types of propellers, see the next section.

Recognizing clockwise and counterclockwise propellers

Appendix 1 Page 68
Note:

Recognizing clockwise and counterclockwise propellers

The diagrams above show two types of propellers: clockwise (called pushers) and

counterclockwise (called pullers). Pusher propellers are often marked with a P. However not all

propellers are marked and both types are often available in either rotational direction.

Therefore, it is most reliable to recognize the correct propeller type by its shape as shown

below. Note that the propellers below have the edge with the shallow consistent curve at the

leading edge in direction of rotation and the more radical scalloped (and usually thinner edge)

as the trailing edge. You can use these features to recognize propellers of the correct direction

of rotation. 

Choosing propellers

Propellers come in many varieties and are suited to different needs.

Have experience choosing propellers? Help us by editing this section!

Testing motor spin directions

If you have completed the Radio and ESC calibration , you can check that your motors are

spinning in the correction direction:

1. Make sure there are no propellers on your copter!

2. Turn transmitter on and ensure the flight mode switch is set to Stabilize.

Appendix 1 Page 69
Tip:

3. Connect battery.

4. Arm copter by holding the throttle down and rudder right for five seconds.

5. If it fails to Arm with the throttle down and to the right and the motors will not spin, it has

probably failed the  Pre-Arm Safety Check.

Pre-Arm safety check failure is also indicated by the red arming light double flashing and

then repeating.

If the Pre-Arm check fails go to the Prearm Safety Check Page  and correct the problem

or disable the check before continuing.

6. When you can Arm successfully, apply a small amount of throttle, and observe and note spin

direction of each motor. They should match directions shown in the images above for the

frame you’ve chosen.

7. Reverse any motor spinning in the wrong direction.

Motor Direction is reversed simply by interchanging two of the three ESC to motor

power leads.

Checking the motor numbering with the Mission

Planner Motor test

An alternative way to check that the motors have been hooked up correctly is to use the

“Motors” test in the Mission Planner Initial Setup menu.

When connected to the vehicle via MAVLink, you can click on the green buttons shown above

and the corresponding motor should spin for five seconds. Letters correspond to motor

Appendix 1 Page 70
numbers as shown in the example below.

Take off your props first!

If no motors turn, raise the “Throttle %” to 10% and try again. If that doesn’t work, try 15%

The first motor to spin will be the one located directly forward in the case of + configuration, or

the first motor to the right of straight forward in the case of X configuration. The motor test will

then proceed in a clockwise rotation.

In the case of X8, it will spin the top front-right motor first, then the bottom front-right, and

proceed around with the same pattern.

OctoV will spin the front-right motor first, and then again, proceed clock-wise until reaching the

front left motor.

KDE (and other) Opto Isolated ESCs

The KDEXF-UAS and KDEF-UASHV Series are opto-solated and do not provide BEC power

output for the peripheral equipment. They require +5V to power the opto-isolator and while the

Pixhawk can be powered from the servo rail, it does not provide +5V to the servo rail. The

Appendix 1 Page 71
ESCs must be powered by a BEC or with a jumper from an unused connector on the board. It

is strongly recommended that you use a BEC to power the rail rather than a jumper. Do not add

servos or other devices to the servo rail as the power module is not intended to supply power to

them.

The KDE ESCs have fixed PWM ranges so you must manually set the output range of each

PWM signal so that RCx_MIN is 1100 and RCx_MAX is 1900us using the Advanced Parameter

or Full Parameter Settings Page in the planner.

Pixhawk ESC issues

Some ESCs have been reported as not working with Pixhawk.

The Pixhawk should work with every ESC that works with a normal RC receiver (because it

sends the same type of signal) but there is one known exception, the EMAX ESC .

In most cases problems are due to incorrect wiring. Always connect signal and ground. Check

your ESC type to decide how to connect the +5V line. On APM2.x you could get away with

using the power ground as the signal return with the APM but for Pixhawk you must connect

both the signal and the signal ground in order to make the ESC work.

For more information see this page and the video here .

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 72
Appendix 1 Page 73
Note:

Electronic speed controllers are responsible for spinning the motors at the speed requested by

the autopilot. Most ESCs need to be calibrated so that they know the minimum and maximum

pwm values that the flight controller will send.  This page provides instructions for calibrating

ESCs.

Please complete radio calibration before performing ESC calibration.

Contents [hide]

1 About ESC Calibration

2 All at once calibration

3 Manual ESC-by-ESC Calibration

3.1 Calibrating ESCs individually (Currently Untested on PX4)

4 Testing

5 Notes / Troubleshooting

About ESC Calibration

ESC calibration will vary based on what brand of ESC you are using, so always refer to the

documentation for the brand of ESC you are using for specific information (such as tones).  “All

at once” calibration works well for most ESCs, so it is good idea to attempt it first and if that fails

try the “Manual ESC-by-ESC” method.

For 3DR ESCs can use the “All at once” method.

ArduPilot > Copter > Electronic Speed Controller (ESC) Calibration

Electronic Speed Controller (ESC)

Calibration

Copter

English

Appendix 1 Page 74
Warning:

DJI Opto ESCs do not require and do not support calibration, so skip this page completely

Some brands of ESC do not allow calibration and will not arm unless you adjust your radio’s

throttle end-points so that the minimum throttle is around 1000 PWM.  Note that if you

change the end-points on your TX you must re-do the Radio Calibration.

Begin this procedure only after you have completed the radio control calibration and

Connect ESCs and motors part of the Assembly Instructions.  Next follow these steps:

All at once calibration

Safety Check!

Before calibrating ESCs, please ensure that your copter has NO PROPS on it and that the

APM is NOT CONNECTED to your computer via USB and the Lipo battery is disconnected.

1. Turn on your transmitter and put the throttle stick at maximum.

2. Connect the Lipo battery.  The autopilot’s red, blue and yellow LEDs will light up in a cyclical

pattern. This means the it’s ready to go into ESC calibration mode the next time you plug it

in.

Appendix 1 Page 75
3. With the transmitter throttle stick still high, disconnect and reconnect the battery.

4. For PX4 or Pixhawk, press and hold the safety button until it displays solid red.

5. The autopilot is now in ESC calibration mode. (On an APM you may notice the red and blue

LEDs blinking alternatively on and off like a police car).

6. Wait for your ESCs to emit the musical tone, the regular number of beeps indicating your

battery’s cell count (i.e. 3 for 3S, 4 for 4S) and then an additional two beeps to indicate that

the maximum throttle has been captured.

7. Pull the transmitter’s throttle stick down to its minimum position.

8. The ESCs should then emit a long tone indicating that the minimum throttle has been

captured and the calibration is complete.

9. If the long tone indicating successful calibration was heard, the ESCs are “live” now and if

you raise the throttle a bit they should spin. Test that the motors spin by raising the throttle a

bit and then lowering it again.

10. Set the throttle to minimum and disconnect the battery to exit ESC-calibration mode.

Here is a video demonstrating the process:

Appendix 1 Page 76
ESC Calibration "All-at-once" method

Demonstration of ESC calibration process with Pixhawk:

Appendix 1 Page 77
Warning:

3D Robotics IRIS - Calibrate the ESC

Manual ESC-by-ESC Calibration

Safety Check!

Before calibrating ESCs, please ensure that your copter has NO PROPS on it and that the

APM is NOT CONNECTED to your computer via USB.

Calibrating ESCs individually (Currently Untested on PX4)

1. Plug one of your ESC three-wire cables into the throttle channel of the RC receiver. (This is

usually channel 3.)

2. Turn on the transmitter and set throttle stick to maximum (full up).

3. Connect the LiPo battery

4. You will hear a musical tone then two beeps.

Appendix 1 Page 78
5. After the two beeps, lower the throttle stick to full down.

6. You will then hear a number of beeps (one for each battery cell you’re using) and finally a

single long beep indicating the end points have been set and the ESC is calibrated.

7. Disconnect battery. Repeat these steps for all ESCs.

8. If it appears that the ESC’s did not calibrate then the throttle channel on the transmitter

might need to be reversed.

9. If you are still having trouble after trying these methods (for example, ESCs still beep

continuously) try lowering your throttle trim 50%.

10. You can also try powering your APM board via the USB first to boot it up before plugging in

the LiPo.

Testing

Once you have calibrated your ESCs, you can test them by plugging in your LiPo.  Remember:

no propellers!

Ensure your transmitter’s flight mode switch is set to “Stabilize Mode”.

Arm your copter

Give a small amount of throttle.  All motors should spin at about same speed and they

should start at the same time. If the motors do not all start at the same time and spin at the

same speed, the ESC’s are still not properly calibrated.

Disarm your copter

Notes / Troubleshooting

The All-at-once ESC calibration mode simply causes the APM to pass through the pilot’s

throttle directly through to the ESCs. If you power up the APM while in this mode you’ll send the

same PWM signal to all the ESCs. That’s all it does.  Many ESCs use full throttle at startup to

enter programming mode, full throttle postition is then saved as the upper end point and when

you pull the throttle down to zero, that position is saved as the lower end point.

If after calibration your motors do NOT spin same speed nor start at the same time, repeat the

calibration process. If you tried the auto calibration above and it didn’t work or the ESCs do not

drive the motors identically, try the manual calibration method described above. That should

work almost every time. (Rarely after a full manual calibration you will also need to do an

additional final automatic calibration).

Appendix 1 Page 79
Finally, there are a huge number of brands and types of ESCs available and some of them do

not adhere to the normal programming conventions (sometimes even though they claim to) and

they may simply not work with the APM the way it is now. This is an unfortunately necessary

but true disclaimer.

Recommended ESC settings as follows:

1. Brake: OFF

2. Battery Type: Ni-xx(NiMH or NiCd)  (even if you’re using Li-po batteries this setting reduces

the likelihood that the ESC’s low voltage detection will turn off the motors)

3. CutOff Mode: Soft-Cut (Default)

4. CutOff Threshold: Low

5. Start Mode: Normal (Default)

6. Timing: MEDIUM

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 80
This topic covers basic Roll and pitch and throttle tuning.

Contents [hide]

1 Overview

2 Roll and pitch tuning

3 Throttle tuning

Overview

After your first flight, you may notice that you copter doesn’t respond to control inputs the way

you want it to or you may have trouble maintaining control of your copter. If you are familiar with

PID controllers, check out the advanced tuning guide here. If you are an experienced operator,

try out the autotune feature. This page will cover the basic tuning section of Mission Planner

and APM Planner that simplified the complex tuning process into a few simple sliders. This is

the best tuning method for new operators.

Roll and pitch tuning

Tuning is easiest at the field using a telemetry radio. Perform an initial flight with the following

questions in mind:

How does the copter respond to roll and pitch? Is the response more sluggish or twitchy

than you want?

When the copter is hover, what level is the throttle set at? Does it hover at the middle

position of the stick or is it above or below the center position?

ArduPilot > Copter > Basic Tuning

Basic Tuning

Copter

English

Appendix 1 Page 81
When raising the throttle, what rate does the copter accelerate at? Does it gain altitude more

slowly or more quickly than you want?

Connect the telemetry radio ground module to your ground station computer and open either

Mission Planner or APM Planner. Select the correct COM port and select Connect. You should

see live data on the Flight Data screen. To begin tuning, select Config/Tuning and Basic

Tuning.

Start with the Roll/Pitch slider at the top of the page. If you observed that your copter was too

twitchy in response to roll and pitch controls, move the slider one tick mark to the left, or, if you

observed that your copter was too sluggish, move the slider one tick mark to the right. Repeat

your flight to determine if the change was beneficial. Repeat the process until you are satisfied

with the way your copter responds to roll and pitch.

Appendix 1 Page 82
Throttle tuning

The bottom two sliders allows you to tune the throttle control. Adjust the slider marked Throttle

Hover until the copter hovers at the throttle stick’s middle position. If the copter hovers with the

throttle stick above middle position, move the slider to the left by one tick-mark until it hovers at

mid-stick, testing as you go. If the copter hovers with the throttle stick below middle position,

move the slider to the right by single tick-mark increments until it does. Make sure to test each

set of tuning settings as you go.

Move the slider marked Throttle Accel or Climb Sensitivity to the right to have the copter gain

altitude more aggressively or to the left to have the copter gain altitude more gently. Test each

increment after setting to evaluate the tune.

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 83
If you have a slightly overpowered or underpowered copter the throttle required to keep the

vehicle in a stable hover may be under 40% or over 60%.  Although this is fine while flying

purely stabilize mode it can lead to a rough transition to autopilot modes (Alt Hold, Loiter)

where having the throttle outside of the 40% ~ 60% deadzone will be interpreted as meaning

you want the copter to climb or descend.

For this reason it is a good idea to adjust the Throttle Mid parameter (also known as THR_MID)

so that your mid throttle while in stabilize mode is closer to 50%.

Please follow these instructions to adjust your manual throttle to so that your copter hovers at

50% throttle:

Fly your copter in stabilize mode in a stable hover for at least 30 seconds

Disconnect your lipo battery and connect your APM/PX4 to the Mission Planner

Go to the Terminal screen and download your latest dataflash log file (more details on

working with dataflash logs can be found here )

ArduPilot > Copter > Setting Throttle Mid

Setting Throttle Mid

Copter

English

Appendix 1 Page 84
After the download has completed, close the “Log” window and push the “Log Browse”

button and open the latest file in the log directory (it’s last digit will be the Log number you

downloaded so in the example above we downloaded Log #1 so the filename will end in

1.log)

Appendix 1 Page 85
When the Log Browser appears, scroll down until you find any CTUN message.  Click on the

row’s “ThrOut” column and push “Graph this data Left” button.

While referring to the scale on the left of the graph, estimate approximately what the throttle

level was during the hover.  In the example above (which was an unnecessarily long flight)

the mid throttle appears to be about 550.

Note: if the average throttle is below 300 (i.e. 30%) then you have a very

Appendix 1 Page 86
overpowered copter and it would be best to add a some extra weight (i.e. a

bigger battery perhaps) or reduce the power in some other way (smaller motors,

move from a 4S to a 3S battery, etc)

If the average throttle is above 700 (i.e. 70%) then you have a very

underpowered copter.  You should consider increasing the power of the motors

and ESCs or use a higher voltage battery (i.e. switch from a 3S to a 4S battery).

Open the Mission Planner’s Software > Standard Params screen and update the Throttle

Mid Position (THR_MID) to the value estimated above (you’ll find it near the bottom of the

list)

Push the Write Params button

On your next flight you should find the throttle is closer to mid while flying in stabilize mode

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 87
This page covers the installation of the 3DR UBlox GPS + Compass module . 

Contents [hide]

1 Overview

2 Connecting the Autopilot

2.1 Connecting to Pixhawk

2.2 Connecting to APM 2.x

2.3 Connecting to PX4

3 Mounting the GPS Module

4 Setup in Mission Planner

5 LED Indicators

6 Advanced Configuration

Overview

The 3DR UBlox GPS + Compass module is the recommended GPS for Pixhawk, PX4 and

APM2.6 (and above) flight controllers using Plane, Rover and Copter.  These come set-up with

the best known GPS configuration and have been thoroughly tested by thousands of users.

ArduPilot > Copter > common-3DR UBlox GPS + Compass Module

3DR UBlox GPS + Compass Module

Copter

English

Appendix 1 Page 88
Connecting the Autopilot

Connecting to Pixhawk

Connect the GPS’s 6-pin DF13 connector to the Pixhawk’s “GPS” port and the compass’s 4-pin

connector to the I2C port.  Alternatively the compass can be first connected through an I2C

splitter if other I2C devices are to be attached.

Appendix 1 Page 89
As of Copter 3.2 and recent versions of Plane and Rover, a secondary GPS can be connected

to the Pixhawk’s Serial 4/5 port.  Limited testing suggests that a secondary GPS can reduce the

likelihood that GPS glitches will affect the vehicle but can also lead to sudden movements of

the vehicle when the primary GPS switches.

If the parameters are set-up as shown below, the flight controller will use the GPS with the

higher number of satellites (Note: it will switch when one GPS has at least 2 more satellites

than the other).

GPS_AUTO_SWITCH = 1

GPS_TYPE2 = 1

And if using Copter 3.3 or higher or recent versions of Plane/Rover then these parameters

Appendix 1 Page 90
should also be set:

SERIAL4_PROTOCOL = 5

SERIAL4_BAUD = 38

Note that a secondary external compass cannot be attached.

Connecting to APM 2.x

APM 2.6 is compatible with the 3DR UBlox GPS + Compass module.

To connect the GPS module to APM 2.6, attach the GPS port to the APM GPS port using the

included 5-position-to-6-position cable (use the top-entry port, not the side-entry port), and

attach the GPS MAG port to the APM I C port using the included 4-position cable. 2

Appendix 1 Page 91
Note:

APM 2.5 and APM 2.0 have an internal compass (unlike APM 2.6) which must be disabled by

cutting a trace before you can connect the 3DR UBlox GPS + Compass module (the video

here shows how).

Other than disabling the internal compass, connecting the UBlox is the same for

APM2.0/APM2.5 as for APM2.6.

After connecting the external compass you will need to re-calibrate the compass

including Compassmot (if you had run this procedure for the internal compass).

Connecting to PX4

To connect GPS part of the this module to PX4, connect the GPS port to the PX4FMU’s

GPS connector.

Connect the compass lead on the module to the PX4IO’s I2C port.

The PX4IO board I2C port is the 4 pin connector located on the board side opposite the

Servo Out connectors in the second row of connectors in and next to the board mounting

hole.

Appendix 1 Page 92
When the external compass is plugged into the PX4IO boards I2C port, it is automatically

detected and used and the internal compass is disabled.

Next connect with the Mission Planner and go to INITIAL SETUP | Mandatory Hardware |

Compass and set the Orientation to ROTATION_ROLL_180.

Mounting the GPS Module

This module permits the GPS to be mounted separately from the flight control module so that it

can have the best clear (view) of the sky and allows the compass to be distanced from

interfering magnetic fields. When mounting the GPS+Compass module:

Place the module on the outside of your vehicle (in an elevated position if appropriate) with a

clear view of the sky, as far as possible from the motors and ESCs, with the arrow facing

forward.

Distance the module from DC power wiring and the batteries by at least 10cm.  Use of a

mast is highly recommended.

Place the module clear of nearby iron containing metallic objects. (Use nylon or non

magnetic stainless steel hardware and nylon or aluminum standoffs to mount the module).

Twist power and ground wires where possible.

Appendix 1 Page 93
Setup in Mission Planner

Start Mission Planner, connect your autopilot, and select the “Connect” tab. Select the “Initial

Setup” tab, then select the left menu “Mandatory Hardware” tab and select the “Compass” tab.

Select the option to Enable the compass and to allow Auto Dec. To manually input the

declination, select Declination Website and enter the magnetic declination minutes and

seconds for your location.

Next select your autopilot configuration, for Pixhawk and PX4, select the option Pixhawk/PX4

with the image of the Pixhawk. For APM 2.6, select APM with External Compass with the image

of the GPS with Compass module. These options will automatically enter the correct orientation

for the board. Ensure that you have mounted the GPS with Compass with the arrow facing

toward the front of the vehicle and in the same direction as the arrow on the autopilot.

To input a manual orientation for APM, select the Manual option at the bottom of the screen,

and consider the following factors when selecting an orientation. Note: The information below

does not apply to Pixhawk and PX4; for these autopilots, select the Pixhawk/PX4 option to

Appendix 1 Page 94
assign the correct orientation.

If the GPS / compass board is mounted in its correct direction (arrow pointing forward) and

the Flight controller board is also mounted right side up with its arrow pointing forward, the

(COMPASS_ORIENT) parameter will need to be set to (Roll 180) or “8” because the

compass is upside down under the GPS modules antenna.

If the Flight controller board is put in an alternate orientation, the Orientation (i.e.

COMPASS_ORIENT parameter) should be set according to the gps’s attitude to the flight

controller.  So for example if both the Flight controller and the GPS+compass module were

mounted on the bottom of the vehicle (a ridiculous example) then you would leave the

Compass orientation as ROTATION_ROLL_180.  If however you wanted to mount the

GPS+Compass right-side-up you would pick Orientation “ROTATION_NONE” because the

original rotation was Roll 180, then you add the compass rotation which is another roll 180 =

Roll 360 = no rotation.

LED Indicators

The 3DR GPS+Compass module has two LED indicators: one for power (solid red) and one for

GPS lock (flashing blue).

LEDs: Behavior:

Power Solid red when powered

GPS lock Flashing blue when 3D GPS lock acquired

Advanced Configuration

Advanced configuration of the UBlox GPS’s internal settings is documented in UBlox GPS

Configuration .

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 95
Note:

This article shows how to perform basic accelerometer calibration (using Mission Planner).

Accelerometer calibration is mandatory if you’re using EKF to estimate vehicle

position.

Contents [hide]

1 Calibration steps

2 Video demonstration (Copter)

Calibration steps

1. Under Initial Setup | Mandatory Hardware, select Accel Calibration from the left-side

menu.

ArduPilot > Copter > common-Accelerometer Calibration in Mission Planner

Accelerometer Calibration in Mission

Planner

Copter

English

Appendix 1 Page 96
Tip:

Mission Planner: Calibrate Acceleration

2. Click Calibrate Accel to start the calibration.

Mission Planner will prompt you to place the vehicle each calibration position. Press any key

to indicate that the autopilot is in position and then proceed to the next orientation.

The calibration positions are: level, on right side, left side, nose down, nose up and on its

back.

Accelerometer Calibration Positions (Copter)

It is important that the vehicle is kept still immediately after pressing the key for

each step.

You may need to calibrate the board before it is mounted if the size/shape of the

vehicle makes this difficult.

The level position is the most important to get right as this will be the attitude that your

Appendix 1 Page 97
controller considers level while flying.

3. Proceed through the required positions (it is not necessary to use the Click When Done

button).

Mission Planner: Accel Calibration – press any key

4. When you’ve completed the calibration process, Mission Planner will display “Calibration

Successful!” as shown below.

Mission Planner: Calibration Successful

Appendix 1 Page 98
Warning: Do not perform the press the Calibrate Level button. This function will overwrite

your calibration values.

Video demonstration (Copter)

Video demonstration of accelerometer calibration. This is for an older version of

Copter/Mission Planner, but is useful as an example of how you might hold a Copter.

ArduCopter 2.9 Accel Calibration

from Randy Mackay

02:34

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 99
Note:

This article explains how to measure vibration levels and confirm they are acceptable.

Contents [hide]

1 Overview

2 Copter-3.3 and later versions

3 Earlier firmware versions

Overview

Flight controller accelerometers are sensitive to vibration. As accelerometer data is used to

estimate vehicle position (along with barometer and GPS readings), excessive vibration can

lead to poor performance in modes that rely on accurate position calculation. Vibration affects

all vehicle types, but is most critical for the Copter (particularly in AltHold, Loiter, RTL, Guided,

Position and AUTO flight modes).

These instructions explain how to measure the vibration levels. If you find they are out-oftolerance then follow the advice found on the First Time Set-up sections Vibration Damping.

Copter-3.3 and later versions

At time of writing (27 July 2015), Copter-3.3 is still a release candidate. Its changes

are not yet present the official release of Copter, Plane and Rover. The changes here are

expected to be in the next release of Plane and Rover.

ArduPilot > Copter > common-Measuring Vibration

Measuring Vibration

Copter

English

Appendix 1 Page 100
Perform a regular flight (i.e. not just a gentle hover) of at least a few minutes and download

the dataflash logs.

Using the Mission Planner or other GCS graph the VIBE message’s VibeX, VibeY and VibeZ

values.  These show the standard deviation of the primary accelerometer’s output in m/s/s. 

The image below, taken from a 3DR IRIS, shows normal levels which are below 15m/s/s but

occasionally peak to 30m/s/s.  Maximum acceptable values appear to be below 60m/s/s

(see second picture below).

Graph the Clip0, Clip1 and Clip2 values which increase each time one of the accelerometers

reaches it’s maximum limit (16G).  Ideally these should be zero for the whole flight but low

numbers (<100) are likely ok especially if they occur during hard landings.  A regularly

increasing number through the log indicates a serious vibration problem that should be fixed.

This is an example of a vehicle that had position estimate problems due to high vibrations.

Appendix 1 Page 101
The algorithm for calculating the vibration levels can be seen in the AP_InertialSensor.cpp’s

Appendix 1 Page 102
calc_vibration_and_clipping() method but in short it involves calculating the standard

deviation of the accelerometer readings like this:

capture the raw x, y and z accelerometer values from the primary IMU

high-pass filter the raw values at 5hz to remove the vehicle’s movement and create a

“accel_vibe_floor” for x,y and z axis.

calculate the difference between the latest accel values and the accel_vibe_floor.

square the above differences, filter at 2hz and then calculate the square root (for x, y and z). 

These final three values are what appear in the VIBE msg’s VibeX, Y and Z fields.

Earlier firmware versions

Connect your Pixhawk/Flight controller to the Mission Planner

Go to the CONFIG/TUNING | Standard Params screen and set the Log bitmask to

Default+IMU.  This will enable the capture of the accelerometer data to the dataflash logs.

Press the Write Params button

Fly your copter in Stabilize mode and try to maintain a level hover (it doesn’t need to be

perfectly stable or level)

Disconnect the Lipo, reconnect your APM/PX4 to the mission planner

Download the dataflash logs and after the download has completed, use the Mission

Planner’s “Review a Log” buttong to open the latest file in the log directory (it’s last digit will

be the Log number you downloaded so in the example above we downloaded Log #1 so the

Appendix 1 Page 103
filename will end in 1.log)

When the Log Browser appears, scroll down until you find any IMU message.  Click on the

row’s AccX and push Graph this data Left button.  Repeat for the AccY and AccZ columns

to produce a graph like below.

Check the scale on the left and ensure that your vibration levels for the AccX and AccY are

between -3 and +3.  For AccZ the acceptable range is -15 to -5.  If it is very close or over

these limits you should refer back to the Vibration Damping page for possible solutions.

After all the above is complete, go to the Mission Planner’s standard parameters page (you

may need to press the Connect button again) and set the Log Bitmask back to “Default”. 

This is important because especially on the APM logging requires significant CPU resources

and it’s a waste to log these if they’re not really needed.

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 104
This article shows how to perform radio control calibration using Mission Planner.

Contents [hide]

1 Overview

1.1 Transmitter configuration

1.2 Channel mappings

2 Preconditions

2.1 Safety first

2.2 Centre trims

2.3 Connect autopilot and turn on receiver

3 Calibration steps

Overview

RC transmitters are used to control vehicle movement and orientation. Copter and Plane minimally

control throttle, pitch, roll and yaw, while on Rover we just control throttle and roll. Each of these control

signals are mapped to transmitter stick/switch(s) and in turn to autopilot channels from the connected

receiver.

Calibrating each of the transmitter controls/channels is a straightforward process – simply move each of

the enabled sticks/switches through their full range and record the maximum and minimum positions.

Transmitter configuration

There are two main transmitter configurations:

Mode 1: left stick controls pitch and yaw, the right stick will control throttle and roll.

ArduPilot > Copter > common-Radio Control Calibration in Mission Planner

Radio Control Calibration in Mission

Planner

Copter

English

Appendix 1 Page 105
Copter:

Note:

Mode 2: left stick controls throttle and yaw; the right stick will control pitch and roll.

Transmitter (Mode 1): Recommended Channels Transmitter (Mode 2): Recommended Channels

Channel mappings

Copter default channel mappings are:

Channel 1: Roll

Channel 2: Pitch

Channel 3: Throttle

Channel 4: Yaw

Channel 5: Flight modes

Channel 6: (Optional) Inflight tuning or camera mount (mapped to transmitter tuning knob)

Unused channels can be mapped to control additional peripherals.

The default channel mappings can be changed using the instructions in RCMAP Input Channel

Mapping.

Once you’ve calibrated the flight mode you can use the instructions in RC Transmitter Flight Mode

Configuration to specify which vehicle modes are enabled by each switch position.

Appendix 1 Page 106
Note:

Preconditions

Safety first

For safety reasons you should disconnect the battery and/or remove propellers before preforming radio

calibration.

Centre trims

Centre trims in manual RC mode before preforming RC calibration. If trims are not centred you may

need to do the RC calibration again after you have used the vehicle (this is easy to do at the field).

Trims are centred when a moving vehicle does not change direction/speed/orientation when

travelling hands-off with all controls/sticks in neutral positions. If there is any deviation in direction,

speed or orientation, adjust the associated servo to compensate.

Connect autopilot and turn on receiver

Connect the autopilot via USB and turn on your RC transmitter. Verify that the transmitter is bound to

the receiver (the receiver displays a solid green light) and that it is set to use the correct model for your

vehicle.

Open Mission Planner’s INITIAL SETUP | Mandatory Hardware | Radio Calibration screen. If your

RC receiver (Rx) and transmitter (Tx) are bound, you should see the green bars move when you move

the transmitter sticks.

Appendix 1 Page 107
Tip:

Mission Planner: Radio Calibration Screen (Copter)

If the bars are not moving then check what LED lights the receiver is displaying:

no lights – may indicate that it is incorrectly wired to the autopilot (look for connectors that may

have been inserted upside down).

red or a flashing green light – may indicate that your RC transmitter/receiver need be bound (see

the manual that came with your RC equipment for instructions).

a solid green light – recheck the autopilot is connected to the Mission Planner and if the bars are

still not moving, try clicking on the Calibrate Radio button.

Calibration steps

1. Open Mission Planner’s INITIAL SETUP | Mandatory Hardware | Radio Calibration screen.

2. Click on the green Calibrate Radio button in the lower right of the window.

Mission Planner will display a prompt to check radio control equipment is on, battery is not

connected, and propellers are not attached. Select OK.

Appendix 1 Page 108
Tip:

Mission Planner: Select Calibrate Radio and OK to begin calibrating.

3. Move the control sticks and toggle switches on your transmitter to their limits of travel and observe

the results on the radio calibration bars. Red lines will appear across the calibration bars to indicate

maximum and minimum values:

Mission Planner: Input range marked with red lines

The green bars should move in the same direction as the transmitter sticks (except for

Pitch where the bars move opposite to stick movements – low values are forward, high values are

Appendix 1 Page 109
back).  If the green bars move in the wrong direction, reverse them using your RC transmitter’s

channel-reverse function (see your RC gear’s manual for guidance).

You should also calibrate the channel you have selected for controlling vehicle mode, and any other

channels you have connected to the autopilot.

4. Select Click when Done when all required channels are set at the minimum and maximum positions.

Mission Planner will show a summary of the calibration data. Normal values are around 1100 for

minimums and 1900 for maximums.

Mission Planner: Radio Calibration Results

5. Turn off your transmitter and disconnect the battery if it was connected.

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues and

suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 110
This article shows how to perform basic compass calibration.

Contents [hide]

1 Calibration steps

2 Additional information

3 Video demonstration

Calibration steps

1. Under Intial Setup | Mandatory Hardware select Compass. Select the correct orientation

for your setup.

2. Ensure the Enable and AutoDec check boxes are checked

3. Click the Live Calibration button

4. Next select your autopilot configuration:

For Pixhawk and PX4, select the option Pixhawk/PX4 (with the image of the Pixhawk).

For APM 2.6, select APM with External Compass (with the image of the GPS with

compass module).

These options will automatically enter the correct orientation for the board. Ensure that you

have mounted the GPS with Compass with the arrow facing toward the front of the vehicle

and in the same direction as the arrow on the autopilot.

ArduPilot > Copter > Compass Calibration in Mission Planner

Compass Calibration in Mission

Planner

Copter

English

Appendix 1 Page 111
Mission Planner: Compass Calibration

5. A window should pop-up informing you that you have 60 seconds in which to rotate the

APM/PX4 around all axis, press OK

6. A countdown window should appear to show that the Mission Planner is collecting compass

data

7. During these next 60 seconds you should hold the copter in the air and rotate it slowly so

that each side (front, back, left, right, top and bottom) points down towards the earth for a

few seconds in turn.

Compass Calibration Positions (Copter)

8. Upon completion, another window will pop up showing you the new offsets that it calculated.

9. For PX4 and Pixhawk, values may be greater than 150 and less than -150. Press OK.

10. For APM, as long as all three values are between -150 and 150 the offsets are good.  Press

OK.

Additional information

Appendix 1 Page 112
More details on this and other compass set-up procedures “compassmot ” can be found in

Advanced Compass Setup .

General discussion on magnetic interference and ways to reduce it can be found in Magnetic

Interference .

Video demonstration

Video demonstration of compass calibration.

AC 3.0 "Live" Compass Calibration

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 113
This article describes the glitch protection mechanisms used to trigger GPS Failsafe.

Contents [hide]

1 Overview

2 Glitch Protection – Default

3 Glitch Protection – EKF

Overview

GPS Systems can occasionally drop the signal or provide significantly inaccurate position

information (aka “glitches”). While errors are more likely in conditions where the GPS signal can

bounce off multiple paths before reaching the receiver (multipathing), errors can occasionally

occur even with clear sky.

A GPS failsafe event will occur if GPS 3D lock or the position “Glitches” for at least 5 seconds

while Copter is in a mode that requires the GPS (RTL, Auto, Loiter, Circle, Position, Guided or

Drift).  The GPS failsafe response can be set to Land or switch to AltHold mode (in AC3.1 and

higher) so that you can retake manual control.

Without GPS updates, the inertial sensors allow approximately 10 seconds of accurate position

information but after this the horizontal position drift becomes so large that the horizontal

position cannot be maintained at all.  At this point if you still have RC radio control it is

recommended to take back control using Stabilize, Acro or AltHold as soon as possible.

This article describes two forms of GPS glitch logic. The first is used by the default navigation

ArduPilot > Copter > GPS Failsafe and Glitch Protection

GPS Failsafe and Glitch Protection

Copter

English

Appendix 1 Page 114
algorithm for AC3.1 and 3.2. The second (EKF) can be used in AC3.2, and is mandatory in

AC3.3 and later.

Glitch Protection – Default

AC3.1 and AC3.2 include GPS glitch protection which can help alert the pilot to a bad GPS

position, trigger a failsafe and reduce the incidents of fly-aways.  Glitches are detected by

comparing the each new position update received from the GPS with a position projected out

from the previous update’s position and velocity. 

The new position is accepted as “good” if:

1. the two positions are within the GPSGLITCH_RADIUS (defaults to 5m).

2. the new position is within a radius that is 10m/s/s (GPSGLITCH_ACCEL) * dt * dt.  Where “dt”

is the time difference between the two samples.

During a glitch, “Bad Position” will be written on the ground station’s HUD

Glitch Protection – EKF

AC3.2 introduced a new form of glitch protection, the ArduPilot Extended Kalman Filter

(EKF) .

Appendix 1 Page 115
Note: AC3.3 Enables EKF by default, and it cannot be turned off. On AC3.2 EKF is turned

off by default – but you can enable it to run on the faster boards (using 32 bit micros) by

setting AHRS_EKF_USE = 1.

Glitch protection using the EKF works as follows:

1. When new GPS position measurements are received, they are compared to a position

predicted using IMU measurements.

2. If the difference exceeds a statistical confidence level set by EKF_POS_GATE, then the

measurement won’t be used.

3. While GPS measurements aren’t being used, a circle defined by an uncertainty radius grows

around the predicted position. The rate at which this radius grows is controlled by

EKF_GLITCH_ACCEL. This is similar to the circle defined by GPSGLITCH_ACCEL, the

difference being it is centered around the trajectory predicted by the IMU rather than

previous GPS measurements. Because this allows for deviations in trajectory due to

maneuvers, the default value for EKF_GLTCH_ACCEL is smaller at 1.5 m/s/s. The acceleration

growth of the circle is also increased when the vehicle is accelerating or turning to allow for

the increase in IMU errors during maneuvers.

4. If subsequent GPS measurements fall inside the circle, they will be accepted and the circle

is reset back to the minimum radius controlled by EKF_POS_GATE.

5. If the GPS glitch is large enough and lasts long enough, the GPS measurements will

continue to be rejected until the circle radius exceeds a value set by EKF_GLITCH_RAD.

When this happens, an offset is applied to the GPS position so that it matches the estimated

vehicle position and the GPS positions are used again. The GPS offset is then reduced to

zero at 1 m/s. This means that large long duration glitches will cause the vehicle to drift at a

1 m/s rate. This is slow enough to give the operator plenty of time to react.

Questions, issues, and suggestions about this page can be raised on the APM Forum. Issues

and suggestions may be posted on the forums or the Github Issue Tracker.

Appendix 1 Page 116