FPV Acronyms and Technical Terms Explained

FPV is full of acronyms which is confusing (even the name of the hobby is the acronym of “first person view”). Here is a glossary of most if not all of the technical terms and acronyms used in FPV, or the RC hobby in general. Let me know if I am missing any!

AcronymsStands ForDescription
2.4GHz, 5.8GHz, 900MHzHz = Hertz
MHz = Mega Hertz
GHz = Giga Hertz
Frequencies used in RC and FPV.
1S, 2S, 3S, 4S, 5S, 6S...S = number of cellsThese numbers indicate how many cells in a LiPo battery. The higher the cell count, the higher the nominal voltage. More Info.
2", 2.5", 3", 4", 5", 6", 7"2-inch, 2.5-inch, 3-inch, 4-inch, 5-inch, 6-inch, 7-inchThese are propeller sizes, often also used to described the size of a quadcopter (as the biggest prop it can support)More info
31mm, 40mm, 65mmThese are common propeller sizes used in micro drones such as Tiny Whoop
ACAlternating CurrentThe type of electricity that comes from your wall socket. Uses Live and Neutral, as opposed to positive and negative (+ & -)
ACCAccelerometerA device that measures acceleration forces in a specific direction.
AcroAcrobaticIt means Acrobatic, or when referring to flight mode, it's means "rate mode". More info
Active BrakingAKA "Damped Light", it's a feature in BLHeli that improves throttle responsiveness.
ADCAnalogue to Digital ConverterA type of circuit to convert analogue signal to digital signal; OpenTX has an "ADC Filter" option to reduce stick jitters
AHAltitude holdA flight mode that maintains height of the drone using a barometric sensor (BARO), or ultrasonic sensor
AILAileronsAlso known as roll (It's the letter "A" in channel map, TAER1234)
Air ModeFC firmware feature that keeps PID controller working even when throttle is at zero, what is air mode.More info
ALAuto LevellingA flight mode that allows the copter to stay level. It uses "ACC" sensor
ALTAltitudeThe vertical distance you are from ground
Angle ModeA stabilized flight mode using both gyroscope and accelerometer sensors; See Self-level mode vs. Acro mode
APAerial PhotographyUsing a multirotor to take aerial videos and photos.
APMArdu Pilot MegaA type of flight controller board
ArducopterA type of flight controller software. More info
ARTF (ARF)Almost Ready to FlyAn ARTF or ARF model is a pre-built model that usually includes everything you need to fly, except the radio transmitter and receiver.
AUWAll up weightThe total weight of a copter including LiPo Battery and necessary parts in order to take off, and any other peripherals
AUXAuxiliary ChannelsChannels in addition to those used for the control sticks - for example, the switches, rotary controls and sliders. These can be used for changing flight modes & controlling peripherals
AWGAmerican wire gaugeAn electrical wire size measurement, the larger the number, the smaller the wire. More info
BandThere are a number of VTX frequencies which are split into bands, there are 8 channels per band. More info
BAROBarometric AltimeterIt measures altitude by using barometric pressure
BECBattery Eliminator CircuitA voltage regulator found in some PDB, ESC, FC and VTX. They are designed to provide constant voltage, e.g. 5V and 12V, for other RC equipment such as FPV camera and radio receiver
BFBetaflightBetaflight is a popular fc firmware for racing drones. More info
BNFBind and FlyA BNF model is a pre-built model similar to an RTF, but minus the radio transmitter. You have to have your own radio and bind to it.
BindThe process of pairing radio transmitter and receiver when first setting them up to work together
BLDCBrushless Direct Current MotorDespite your quadcopter using a DC battery, BLDC motors are not to be confused with the brushless motors on a quad, which actually run on 3 Phase AC.
BootloaderSpecial code stored in non-volatile memory in a microprocessor that can interface with a PC to download a user's program.
Brushed MotorA type of motor that is commonly used in small multirotors, they are generally powered by 1S batteries, and weaker than brushless motors
Brushless MotorA type of electrical motor that is commonly used in multirotors. They have a wide range of voltage input, more durable and powerful than brushed motors. How to choose mini quad motors
BuFButterflightA fc firmware for racing drones
BuzzerA very loud speaker commonly used in drones, for the purpose of low voltage and lost model alarms. More info
CC3DCopterControl 3DA type of flight controller
CellLiPo battery consists of one or multiple cells. Each cell has a nominal voltage of 3.7V. In order to obtain higher voltage, cells can be connected in series inside a battery. For example, a 4S1P LiPo has 4 cells.
CF- Carbon Fiber
- Cleanflight
It can mean 2 things in this hobby: carbon fibre, the material used in quadcopter frames; or Cleanflight, a flight controller firmware
ChannelVideo transmitters broadcast signals on a particular frequency, and this frequency is a channel, each VTX can support multiple channels; Channel can also refer to the controls on a radio transmitter
COG or CGCenter of GravityThe average location of the weight of a copter. It's important to make sure the COG of your copter is right in the middle (or close enough)
CriusA type of flight controller board
CW / CCWClockwise / Counter-ClockwiseDescribing the rotational direction of motors or propellers
DCDirect CurrentDC is the type of electricity that comes from power source with Positive and Negative (+ and -), such as a battery. In DC circuitry Negative is often referred to as GND, Ground or common.
DDDirect DriveA type of prop designed to go straight on a motor shaft without a gear reduction.
DFUDevice Firmware UpdateFor some FC, firmware can be flashed by putting it in DFU mode
Diversity ReceiverA multiple receiver FPV system picks the strongest signal from multiple video receivers and antennas to display the best picture
DMASome pins on a flight controllers have dedicated DMA channels, some don't. Certain features in Betaflight require dedicated DMA channel to work, such as DShot motor output. For example, you might be able to remap motor output to some other pins that don't have DMA channels, multishot might work but DShot does not work properly, this is also known as DMA channel conflict.
DOFDegree of FreedomOften used in FC marketing back in 2013, it gives clues as to what sensors are available on the flight controller.
For example 6DOF = 3 axis gyroscope (gyro) + 3 axis accelerometer (ACC);
9DOF = 3 axis Gyro + 3 axis ACC+ 3 axis magnetometer (compass);
10DOF = same as 9DOF but with an additional barometer
DroneAn unmanned aircraft that is guided remotely by a pilot. For military use, these aircraft have weapons and/or surveillance gear. For personal/recreational use, these aircraft often have HD cameras. The term is popular in the media and can be misleading sometimes. More info
DShotDigital ShotA type of ESC protocol, what is DShot. More info
DSM / DSM2 / DSMXThese are the proprietary technology of an RC equipment maker, Spectrum, and DSM stands for "Digital Spectrum Modulation".
DSSSDirect-Sequence Spread SpectrumDSM uses Direct-Sequence Spread Spectrum (DSSS) modulation technique. As with other spread spectrum technologies, the transmitted signal takes up more bandwidth than the information signal that modulates the carrier or broadcast frequency. The name 'spread spectrum' comes from the fact that the carrier signals occur over the full bandwidth (spectrum) of a device's transmitting frequency.
Dry WeightThe weight of a multirotor including everything necessary to take off except the battery.
EEPROMElectronically Erasable Programmable Read Only MemoryA type of non-volatile memory used in computers and other electronic devices to store small amounts of data that must be saved when power is removed, e.g.,static calibration/reference tables. Unlike bytes in most other kinds of non-volatile memory, individual bytes in a traditional EEPROM can be independently read, erased, and rewritten.
ELEVElevatorAlso known as pitch, it's the letter "E" in channel map, TAER1234)
EMIElectro-Magnetic InterferenceEMI is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source.
ESCElectronic Speed ControlESC is used to convert signals from a flight controller or radio receiver, and apply the right amount of power to the electric motors. It also turns DC voltage into AC in order to spin up the 3-phase brushless motor. More info
FAAFederal Aviation AdministrationA United States Department of Transportation Agency, it has authority to regulate and oversee all aspects of civil aviation in the USA
FailsafeA mechanism to minimize the damage to the multirotor, and nearby objects in case of system failure. More info
F1, F3, F4, F7These are the different processors in flight controllers. More info
FCFlight ControllerFlight Controller is the brain of your multirotor. More info
FETField-effect transistorFET is a device which enables us to use one smaller electrical signal to control another bigger one.
FlowA word often used in the FPV hobby to describe fast and smooth flying with style
FOVField of ViewA measurement how much environment you can see through a camera lens. Usually measured in degrees.
FPVFirst Person ViewUtilizing an onboard FPV camera and wireless connection, to allow a pilot on the ground to see live video stream from an RC aircraft while flying, through FPV goggles or monitor, More info
FTDIFuture Technology Devices InternationalThe name of the company that makes the electronic chip standard, to convert USB to serial communications. Available as a chip for boards that have a USB connector, or in a cable to connected to breakout pins.
FWFirmwareFirmware is an application specific software designed for a specific piece of hardware / equipment.
GCSGround Control StationSoftware used to monitor a Flight Controller Board. The OpenPilot GCS for example.
GimbalIt can mean two things: 1. a motorized camera stabilizer; 2. the entire stick control assembly within a radio transmitter
GITA version control system for software developers.
GPSGlobal Positioning SystemUsed to track movement or hold position at pre-defined coordinates
GNDGroundGround or Negative of a DC electrical circuit
Ground EffectAir turbulence from propellers bouncing off the ground when the copter is hovering at low altitude
GYROGyroscopeIt's a sensor on the flight controller that measures the angular velocity around 3 axes of space in degrees (basically, how fast the drone is rotating).
This is one of the most important sensors, as the data is used in PID controller to keep the drone afloat and to fly smoothly.
There are many types of gyros, some are faster while some are noisier. More info
HEXAHexacopterA type of multicopter, that has 6 motors, no servos, all motors on same level.
HKHobbykingOne of the biggest RC Vendors in the world with warehouses in EU, US, AU, RU and China.
Horizon ModeThis is a stabilized flight mode, similar to Angle mode, but it allows the pilot to do roll and flip.
I2CInter-Integrated CircuitA serial bus that allows multiple low speed peripherals, such as sensors, to be connected to a microprocessor.
IMUInertial Measurement UnitA Break Out Board containing sensors that reads and sends data to the flight controller
IntoFPVOne of the most popular forums for FPV Multirotor: http://intofpv.com/
JelloUndesirable high frequency vibration in flight footage
JSTA type of battery connector for lower power micro drones
JST-SHA type of small connector for lower current applications, such as signals
Kalman FilterThe algorithm used in Multicopter Flight controllers. It is primarily used to combine accelerometer and gyro data to provide an accurate description of aircraft attitude and movement in real time.
KKKaptein KukMulticopter controller by Rolf Bakke
LC FILTERL = Inductor
C = Capacitor
An LC filter is a circuit that reduces unwanted frequencies (noise) from a power supply. A video feed needs stable power to operate optimally and an LC filter smooths the input power.
LEDLight Emitting DiodeOne of the most efficient forms of lighting.
LiPoLithium Polymer BatteryAka LiPoly. It's the most commonly used power source for the RC hobby these days because of its high energy storage density-to-weight and high discharge rate. More info
LOSLine of SightWhen you are flying your aircraft by watching your aircraft directly, you are flying LOS. Another way of flying is FPV.
Locked inA positive description of a multirotor's stable and on-rail flying performance
LPFLow-pass FilterA type of digital filter that reduces high frequency signal. More info
LQLink QualityLink quality is a measurement of how good/reliable the radio link is in Crossfire. It's different from RSSI. More info
mAhmilli-amp per hourAn unit that measures the capacity of a LiPo battery
MAGMagnetometerAn electronic compass - used to let our FC ( Flight Controller ) know which direction it is pointed in, compared to the Earth's Magnetic field
MegaPirateA cloned flight controller software of the Arducopter
Mode1 / Mode2These are the different transmitter stick configurations: mode 1, throttle stick on the right; mode 2, throttle stick on the left (more widely used). See RC Transmitter Basics. More info
MTOWMaximum take-off weight
MultishotA type of analogue ESC protocol to replace Oneshot
MWCMultiWii CopterMultiWii is a general purpose software to control a multirotor RC model. It can use various sensors but was initially developed to support Nintendo Wii console gyroscopes and accelerometers
OCTOOctocopterA type of multicopter, that has 8 motors, no servos, all motors on same level.
OneshotOneshot125A type of analogue ESC protocol to replace PWM
Opto ESCOpto ESC is a common saying for ESC without BEC
OSDOn Screen DisplayA piece of hardware that overlays flight data in text or graphical form over an existing live stream video.
PBattery cells in parallelFor example, a LiPo battery of 4S2P, has two 4S batteries connected in parallel.
PayloadWhat the drone can carry/lift, such as a camera, or package
PAL / NTSCThese are video formats in FPV cameras and your video display. More info
PCBPrinted Circuit BoardSilicon board with copper traces and components soldered onto it. Most electronics in this hobby are built on PCB's, such as FC, VTX, TX, RX....
PDBPower distribution boardA board designed to carry high current, it's built with copper traces used to connect various electronic components such as LiPo battery, ESCs, Video transmitter, LEDs etc
PIDProportional Integral DerivativeThe three parameters that you can adjust to change the copter's flight performance. In theory PID is a control loop that attempts to minimize the difference between a measured process value and its desired value by adjusting the control input of a process.More info
PNPPlug and PlayA PNP quadcopter kit usually comes without the receiver, transmitter, battery and FPV Goggles.
PPM SUM (CPPM)Pulse Position ModulationA way of sending sequence of multiple signals down one signal wire. More info
PropPropellerShort for propeller.
PunchSudden burst of thrust.
Punch outAscending vertically at 100% throttle.
PWMPulse Width ModulationThe square-wave signals used in RC control to drive servos and speed controllers.
QuadQuadcopterShort for quadcopter, which is a type of multicopter that has 4 motors on the same level
RateRate changes how fast your copter rotates with the sticks. More info
Rate ModeA.K.A. Acro Mode, and Manual mode. It's a flight mode that only uses the gyro sensor. More info
RCRadio ControlThe foundation of our hobby, it's also used to refer to the hobby as a whole, radio controlled cars, multirotor, planes boats and more.
RCGRCGroupsOne of the most popular RC forums in the world.
RevoRevolutionThe 3rd generation of OpenPilot Controllers
RFRadio FrequencyCommon radio frequency in the FPV hobby are 2.4gHz, 900mHz and 433mHz. More info
RPMRevolutions Per MinuteThe number of motor rotations in 60 seconds.
RSSIReceived Signal Strength IndicationRSSI is a measurement of how good your radio signal is. More info
RTFReady to FlyAn RTF model is a pre-built model that's sold with everything you will need in order to fly right out of the box.
RTHReturn to HomeA GPS feature that when enabled, it returns the aircraft to the "home" position where it took off.
RTLReturn To LaunchSame as RTH.
RUDRudderAlso known as yaw, it's the letter "R" in channel map, (TAER1234)
RX"Radio Receiver" or the "RX pin in a UART"A device that receives commands from the radio transmitter, and sends them directly to the servos or flight Controller. More info.
RX can also mean the receiving pin in a serial connection on a flight controller. More info
SCell Count - "Cells connected in series"For example, a 4S LiPo is a LiPo battery with 4 cells connected in series, nominal voltage is 14.8V (4x3.7).
SASmart AudioSmart Audio is a protocol for VTX Control. More info
SBUSSBUS is a type of serial communication protocol used by Futaba and FrSky. It supports up to 16 channels using only one signal cable. More info
SFSlow flyA type of propellers that are designed to go on a motor using a gear reduction to lower rotational speed
SimonKAn ESC firmware designed for multirotors, but no longer updated and now obsolete
SMA / RP-SMASub-Miniature Version A
Reverse Polarity SMA
Connectors for FPV equipment. More info
TAER1234A type of radio channel mapping. It means mapping throttle as channel 1, Aileron as channel 2, Elevator as channel 3, and Rudder as channel 4
TelemetryA feature that allows you to receive real time flight data from the aircraft back to you; It's commonly seen in radio TX and RX, there are also standalone devices for telemetry
ThrottleOne of the controls on your radio transmitter, it changes the speed of all the motors in a drone. It's the letter "T" in channel map, (TAER1234)
ThrustThe force generated by the propellers and motor, measured in grams
Tiny WhoopA class of ultra small quadcopters with ducts (propeller guards). More info
ToothpickA class of small quadcopters, aka ultra-light micro quad, usually equipped with 2.5" or More info3" propellers.
TOWTake off weightSimilar to AUW
TRITricopterA type of multicopter that has 3 motors and a servo for yaw control.
TVLTV LineTVL (TV Lines) is basically a measure of how good the FPV camera resolution is. The number is based on how many alternating black and white lines can be displayed in its image horizontally.
TX"Transmitter" or the "TX pin in a UART"TX, or radio transmitter, is a device that sends user commands to the Receiver. More info.
TX can also mean the transmitting pin in a serial connection.
UARTUniversal Asynchronous Receiver/TransmitterSerial communication port. A piece of computer hardware that translates data between parallel and serial form.More info
UAVUnmanned Aerial VehicleAircraft without a human pilot onboard. Control is provided by an onboard computer, remote control or combination of both.
UBECUniversal Battery Elimination CircuitBasically just a DC voltage regulator.
VccVccPositive power supply input
VRXVideo ReceiverA device that receives video signal from our video Transmitter, and display the live footage on our FPV goggle or screen.
V-tailA type of multirotor that has 4 motors, 2 tail motors form a V shape, it has no servo.
VTOLVertical take off and landing
VTXVideo TransmitterA device that sends video signal from the FPV camera, to video receiver / FPV goggles. More info
WOTWide Open Throttle100% throttle
X8A type of multirotor that has 8 motors and of a shape of X, 4 motors on top, 4 motors at bottom, no servo
XT30A type of battery connector for micro FPV drones. It's smaller than XT60.
XT60The most common type of battery connector for FPV drones. The number indicates current rating and size, it's larger than XT30 but smaller than XT90. More info
XT90A type of battery connector for large FPV drones. It's larger than XT60.
Y4A type of multirotor that has 4 motors, 2 tail motors one on top of the other, it looks like a tricopter but has no servo

Edit History

  • Feb 2015 – Post created
  • Apr 2018 – Updated list with lots of new technical terms
  • Jan 2020 – Added DMA, props sizes, toothpick and tiny whoop
  • Jun 2020 – Added “search” feature

32 thoughts on “FPV Acronyms and Technical Terms Explained

  1. Theboatpirate

    On flight controllers they use F3, F4, F7. What do those numbers mean? Is that the number of UARTs? If so, that would increase functionality of the FC?

    Reply
  2. Alastair

    Would it be possible to add the terms used to describe all the different sizes of drones like whoop and 40mm, I keep coming across them but I get confused about whether terms overlap, especially now as I’m buying new props.

    Reply
  3. Barry Moore

    I am new to Quads since first of year, still learning jargon. Last night 7hatguy said to turn ADC off on your Frsky radios in the new BetaFlight 4.0. What does ADC stand for? I don’t see it in Quad glossary here.

    Thanks in advance

    Reply
    1. Oscar Post author

      OpenTX has an “ADC Filter” option to reduce stick jitters.
      Long press Enter button, and scroll over to “hardware” page. the option of at the very bottom.

      Reply
  4. Jacob Felix

    I have one abbreviation that have not seen or heard of. Maybe one you could help with. “KG” abbreviated on flight board I salvaged off a old SJRC toy drone. Anyone? Anyone?

    Reply
  5. David Schick

    Here’s another one I came across not in your list: DFU. I think it means Device Firmware Update, but not sure.

    github.com/betaflight/betaflight/wiki/Installing-Betaflight

    Thanks for the great work on your site!

    Reply
    1. Matt

      DFU… It’s easy that one, it obviously stands for ‘Don’t F**k UP!’

      Sorry, very puerile of me, but I just could not resist hehehe

      Reply
  6. voodoo

    Missing a few important one. I know you have CF for Cleanflight which is all the rage these days. But what about the lesser known FW like Betaflight. :)

    BF – Betaflight
    BFC – Betaflight configurator
    RF – Raceflight
    RFC – RF configurator
    BUF – ButterFlight
    RX and TX – confusing but often also referred to UART RX and TX
    FKF – Fast Kalman Filter
    # eg. 3S, 4S etc?

    Reply
  7. Nobody In Particular

    One of the best list’s i’ve seen, Thank you. Let’s make it better with A few more ACRONYMS If I may suggest.
    1. CW/CCW- ClockWise / Counter ClockWise rotation.

    2.Add to Diversity: To read
    Diversity Tracking- An FPV setup that uses a dual receiver system that picks between multiple
    antennas to display the best picture.

    3. FW- Firmware, software designed specifically for a piece of equipment.

    4. LED- Light Emitting Diode.

    5. Mode 1- Tx throttle position – stick on the right.
    6. Mode 2- Tx throttle position – stick on the left (the more widely used configuration).
    7. MTOW- Maximum Take Off Weight.
    8. (n)S count- Series on a LiPo battery represents the number of cells that are connected in
    series. For example, a 3S LiPo has 3 cells connected in series. Each cell generally has around
    4V, so a 3S would have around 12V.
    9. Pal / NTSC- Both are video formats.
    10. PNP- Plug and Play.
    11. Polarization- A subject related to FPV antennas.
    12.RTF- Ready To Fly. A multicopter that’s sold with a radio transmitter. It can be flown right out
    of the box.
    13. TOW- Take Off Weight.

    14. VTOL- Vertical take off and landing.

    14. XT-60- battery connector type.
    .
    Hope these help,
    Nobodyinparticular

    Reply
  8. Claudio Costerni

    Hi Oscar,

    nice work here, it helps a lot, thanks.
    I have found a typo:

    SimonK A famous ESC firmware optomised for multirotors

    Reply
  9. Edwin Brandt

    Quadcopter Acronyms – Terminology – Glossary – Vocabulary – Drone Multirotors RC
    Ground Effect :- The effect ( back Wash or impact induced ) on the flight characteristics of the crafts own Propellers on Air induced BOUNCE when hovering or at the Take-Off & Landing of Craft from surounding Solid Obstacles ( i.e. Ground , Walls etc. ) usualy seen as Dust Cloud .

    Ermmm yea i think thats what i mean , I saw it missing so im kinda being presumtuious
    Sorry
    Edwin

    Reply
    1. robert

      I am in same position low blow. I’m so happy i finally found this info. It would have been expensive to learn by experimentation, which is what I had been doing.

      Reply

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