This document is intended to aid the reader in deciphering the numerous technical terms, acronyms, and abbreviations found in virtually all literature about drones and their associated technology (and especially those encountered in reading FAA rules and NPRM, as well as terms used in Part 107 study guides).

It covers terms from avionics, computer systems, electronics, FAA documents, general aviation, meteorology, and UAS components, technology, and operations. Brief definitions are provided to help the reader understand the basic concept (with occasional links to more detailed descriptions). This is a ‘living document’ and will be updated based on reader feedback, development of new terms, and identification of relevant terms not found in the current version of the document.

A Amperes Commonly called ‘amps’, this term describes the current flowing in a circuit (e.g., the amount of ‘work’ an electrical circuit can provide/accept/require)

AAC Airworthiness Advisory Circular FAA-generated information regarding the ‘airworthiness’ of specific aircraft

AAD Assigned Altitude Deviation Record of deviation from ATC-assigned altitude (typically greater than 300 feet)

AAR After-Action Review A review of flight operations after the fact; lessons learned

ABAC Attribute-Based Access Control Type of access control for USS providers and users; access is granted based on pre-defined ‘attributes’

AAF Army Air-Field US Army airfield and base

ABUAS Amateur-Built UAS (see also AUAS) Privately-built UAS (not commercial off-the-shelf (COTS) or ready-to-fly (RTF) from a manufacturer). Built from a kit or discrete components

A/C Aircraft A vehicle that flies in the atmosphere (as opposed to spacecraft)

AC Advisory Circular FAA-provided information regarding aviation issues (2) Alternating Current: Electric current which periodically changes phase (direction)

ACAS Airborne Collision Avoidance System A system to detect and avoid collisions, now mandated for all fixed-wing, manned aircraft in the U.S. (but NOT for UAS)

ACC Accelerometer Device measuring ‘proper’ acceleration (referenced to A/C)

AD Airworthiness Directive FAA-generated instructions re: airworthiness of A/C

ADC Analog-Digital Converter Device converting analog signal input to binary data

ADF Automatic Direction Finder Radio-navigation device that displays bearing (azimuth) to a known, fixed-position radio beacon

ADIZ Air Defense Identification Zone Special zones requiring military IFF

ADM Aeronautical Decision Making Term referring to pilot judgement while flying; per FAA, ADM is a “systematic approach to the mental process used by pilots to consistently determine the best course of action in response to a given set of circumstances. It is what a pilot intends to do based on the latest information he or she has”

ADS-B Automatic Dependent Surveillance-Broadcast Broadcast system wherein the aircraft determines its position by satellite navigation and broadcasts it, enabling (manned) aircraft to be tracked in flight. Not approved for UAS

AESA Active Electronically-Steered Array A type of phased array antenna (a computer-controlled array antenna -the beam of radio waves can be electronically ‘steered’ to point in different directions without moving the antenna). AESA is Gen-2 phased array technology, and uses a separate transmitter and receiver for each antenna element (each controlled by computer), for improved performance

AFB Air Force Base A military aerodrome and support base (typically USAF)

AFCS Automatic Flight Control System ‘Auto-pilot’ system allowing flight without direct pilot commands

AFM Aircraft Flight Manual Manual for safe flight of a specific aircraft

AGL Above Ground Level Altitude above the earth, from point of aircraft

AH Altitude Hold Flight mode which maintains altitude via use of barometric pressure sensor, ultrasonic sensor, and/or video-IR sensors

AI Artificial Intelligence Decision-making matrix without specific software program code or instructions (typically associated with ‘software’). Instead, the AI uses machine learning (ML) to accomplish generally stated results, leaving the computer to decide how best to accomplish them

AIA Aerospace Industries Association Collaborative group of aerospace org’s

AKA Also Known As Common acronym for alternate identities or nomenclatures

ALT Altitude The height of an aircraft or device, above ground or sea level

AM Amplitude Modulation Legacy modulation scheme where an analog input signal modulates the amplitude of an RF carrier

AMA Academy of Model Aeronautics Community-based organization for unmanned aircraft such as RC airplanes and unmanned aircraft systems

AMSL Above Mean Sea Level Altitude referenced to average sea level

ANSI American National Standards Institute US standards & specifications org.

ANSP Air Navigation Service Provider Organization managing air traffic on behalf of the contracting entity (FAA for US applications)

ANT Antenna Device to couple RF energy to and from the atmosphere

AOA Angle of Attack (1) Angle between blade pitch angle and helix angle (the angle of relative velocity to direction of propeller rotation) (2) Angle at which an aircraft approaches a given point in space (AKA angle of arrival)

AOB Angle of Bank Angle at which an aircraft ‘banks’ during a turn

APAR Active Phased-Array Radar Radar technology using Gen-2 imaging (see AESA)

AR Augmented Reality Technology which adds computer-generated displays of information to a visual display (‘smart’ glasses, HUD, etc.) of actual reality (the visual display of the world)

ARC Aviation Rule-making Committee FAA-designated committee of aviation stakeholders, convened to recommend technologies to implement FAA rules

ARM Architecture Reference Manual Abstract framework for developing CPU functionality

ARRL American Radio Relay League Membership organization for amateur radio enthusiasts (‘ham operators’); the largest in the U.S.

ARTCC Air Regional Traffic Control Center FAA-run facility to establish air traffic control for aircraft flying on IFR (Instrument Flight Rules)

ARTF Almost Ready to Fly A UAS parts kit requiring minimal assembly (AKA ARF)

ASR Automatic Speech Recognition The ability of machines to understand and process natural speech

ASTM American Society for Testing Materials International standards organization that develops consensus-based standards (for aviation and other industries)

ATC Air Traffic Control(ler) Ground-based service providing control of aircraft

ATIS Automated Terminal Information Service A recording of the local weather conditions and other pertinent non-control information broadcast on a local frequency (played in a ‘looped’ format)

ATM Air Traffic Management Comprehensive flight services including air traffic control, airspace management, and other flight services

ATTI Attitude DJI flight mode with no position sensing enabled (manual positioning)

AUAS Amateur-built UAS UAS built by individual, from COTS or home-made parts

AUW All-Up Weight UAS weight including LiPo battery, memory card, and payload

AUX Auxillary Systems or power separate from primary system (often backup)

AWG American Wire Gauge Standard for measuring wire diameter; higher numbers are smaller gauges, for example 20 AWG is considerably smaller than 10 AWG. As current only flows on the surface of the wire, larger diameters (smaller AWG) are needed for higher-current applications

AWOS Automated Weather Observation System Automated METAR reporting system

AZ Azimuth Angular measurement from a spherical coordinate system, typically measured from a reference point (North), and measured in mils (6400 per circle) or degrees (360 per circle) Also designated as ‘AZM’ in some cases

BAP Battery-Assisted Passive Type of passive RFID chip using on-board battery

BARO Barometric Altimeter A meter that derives altitude from barometric pressure

BCN Beacon Device sending signal for tracking and identification

BDC Brushless Direct Current Type of quiet motor where magnets in fixed case rotate inside fixed coils (or vice versa)

BEC Battery Eliminator Circuit PCB which provides various power connectors or multiple outputs from battery cable

BLE Bluetooth Low-Energy Bluetooth version of wireless protocol for communication with nearby devices

BNF Bind and Fly Type of drone kit where completed drone must be ‘bound’ to a separate remote controller

BPS Barometric Pressure Sensor A type of altitude sensor, to provide stable hovering capabilities

BPSK Bi-Phase Shift Keying Modulation method where an input signal causes an RF carrier to switch between one of two phases (0 degrees and 180 degrees)

BTS Base Transceiver Station Transmission and signal-processing equipment for local ‘cell’ of a wireless network

BVLOS Beyond Visual Line of Sight Range where visual line of sight is not possible

C (1) Capacitance is the measure of the ratio of the rate of change (‘charge’) a device can accept to the electrical potential applied. Capacitors store electrical potential (for a time) and are described as ‘C’ (for example, in an LC -Inductive-Capacitive- filter). (2) Charge is A) the rate of charge a LiPo battery can accept. For example, a 1000mAh (1A) battery with a 1C rating can accept a charge of 1A maximum. A 1000mAh battery with a 3C rating can accept a 3A charge maximum. Thus, C is a multiplier by which the maximum charging current is determined B) C also is used to define the current-delivering capacity of a LiPo battery. For example, if a 1000mAh battery is rated at 40C (burst), it can momentarily deliver 40A of current. If it rated at 10C (continuous), it can deliver 10A of current for the length of the battery charge.

CAA Civil Aviation Authority UK-based organization that manages civil aviation

CAIG Chengdu Aircraft Industry Group Makers of Chinese ‘Wing Loong’ military UAV

CAR Certificate of Aircraft Registration FAA-generated certificate of aircraft registration, including applicable information and compliance with (as applicable) Remote ID requirements

C-B C-Band Defined as the portion of the RF spectrum between 4 and 8 GHz (Some UAS remote controls operate at these frequencies)

CB Cumulo-nimbus Aeronautical abbreviation for a dense, towering vertical cloud, forming from water vapor carried by powerful upward air currents

CBO Community-Based Organization An FAA-recognized organization theoretically representing the recreational UAS and aircraft community. They typically exist on a fee membership basis, and are limited to the AMA and few others

CDA Commercial Drone Alliance Consortium of commercial UAS manufacturers and users, promoting various UAS-based commercial enterprises

CDMA Code Division Multiple Access Method to share frequency spectrum by using carriers modulated with specific pseudo-random ‘code’ (see SSMA)

CF Carbon Fiber Strong, lightweight material commonly used in UAV frames

CFA Controlled Firing Area Areas within MOA where weapons firing may take place, but which allows for civilian flight routes

CFR Code of Federal Regulations Codification of rules and regulations passed by federal agencies and published in the Federal Register

C/KT Carrier to Noise Density Ratio A normalized signal to noise ratio of an RF signal (noise ‘normalized’ using Boltzmann’s Constant

CMOS Complementary Metal Oxide Semiconductor A type of MOSFET technology used to manufacture integrated circuits and (for analog applications) optical sensors used in most UAS cameras and digital cameras

CNAV Civil Navigation Feature added to GPS to allow civil navigation capabilities

CNN Convolutional Neural Network A type of deep neural network often used for computer vision tasks, such as facial recognition, medical image analysis, identifying flight path obstacles, etc.

C/No Carrier to NOise ratio A ‘raw’ measurement (or ratio) of RF carrier power to noise power (not normalized)

COA Certificate of Authorization FAA-issued document allowing UAS operators to operate in missions typically not authorized by FAA rules. For example, the FAA had to issue COA to allow USAF Reaper drones to fly over civilian US airspace (on disaster-relief missions)

COG Center of Gravity An aircraft’s point of balance, at a point on the fuselage, also known as (AKA) CG

COP Center of Pressure The point where the total sum of a pressure field acts on an object, causing a force to act through that point (AKA CP)

COTS Commercial Off The Shelf Systems/parts purchased from major manufacturers

CP-ISR Cargo-Pocket Intelligence, Surveillance, and Reconnaissance US Army program to develop MAV and other small sensors that conceivably fit into a cargo pocket of a soldier’s battle gear

CPS Cyber Physical System Control system for drone swarms

CPU Central Processing Unit Core processor of a computer where performance of most instructions and operations occur (the ‘brains’ of the computer)

CRC Cyclic Redundancy Check Simple type of in-signal error detection and correction; provides an estimated error rate for a circuit without requiring direct testing

CRM Crew Resource Management Concept and practices regarding optimal management of flight crew

CSC Combination Stick Command UAS command from the controller, using two levers or joysticks to effect a command

CSL Control Station Location Location of person manipulating the controls of a UAS; FAA proposed rules would require this location to be broadcast

CSTC Commerce, Science, and Transportation Committee Congressional committee

CTA Consumer Technology Association Standards and trade organization representing many US consumer technology companies

CTAF Common Traffic Advisory Frequency Frequency designated for the purpose of carrying out airport advisory practices while operating to or from an airport without an operating control tower.

CUAS Commercial UAS UAS flown for commercial (as opposed to recreational or military) uses

C-UAS Counter-Unmanned Aerial Systems Technology aimed at detecting and stopping aerial drones, and locating the remote pilots (see C-UAV)

C-UAV Counter-Unmanned Aerial Vehicle Technology aimed at detecting and stopping unmanned aerial vehicles (AKA counter-drone systems/technologies)

CW Continuous Wave Type of RF transmission with a continuous, un-modulated, single-frequency ‘carrier’ (typically used for beacons, legacy radar, signal conversion, radio altimeters, and proximity sensors)

C2 Command and Control The signals and protocol used to control aircraft

dB Decibel Comparative measurement used to determine the power of one signal to another, on a logarithmic scale

dBi Decibels (isotropic) Decibels referenced to isotropic noise power

dBm Decibels (milliwatt) Decibels referenced to one milliwatt of power; the typical power measurement

dBrn Decibels Relative to Noise Decibels referenced to noise power

DC Direct Current Unidirectional flow of electric current, typically used for low-voltage applications. Solar cells and batteries produce DC

DHS Department of Homeland Security US cabinet-level agency created by ‘Patriot Act’ and responsible for coordinating national security actions between various national security agencies

DIY Do-It-Yourself Drone building without a kit, from discrete components

DJI Da-Jiang Innovations World’s largest recreational UAS manufacturer, based in Shenzen, People’s Republic of (communist) China

DL Deep Learning  Refers to machine learning (ML) tasks that use neural networks containing multiple layers

DOF Degree of Freedom Unofficial term for amount of relative flight variability and response an Intertial Management Unit (IMU) provides. For example,  6 DOF = 3 axis gyroscope + 3 axis accelerometer; 9 DOF = 3 axis gyroscope + 3 axis accelerometer + 3 axis magnetometer; 10 DOF = same as 9 DOF and adds a Barometric Altimeter

DREAD Damage, Reproducibility, Exploitability, Affected users, Discoverability Type of hacking threat definition (NASA)

DSMX Type of common DSSS/FHSS chipset for use in UAV and controller

DSSS Direct Sequence Spread Spectrum Modulation technique where a communications signal is ‘mixed’ with a pseudo-random sequence to ‘spread’ the signal across a wide bandwidth (the signal is then effectively in the noise floor)

DVR Digital Video Recorder Device used to record digital video. In UAs terms, this refers to an integrated circuit located either in the FPV goggles, on-board vTX (‘air unit’), or a combination. Can also refer to payload-mounted ‘action cameras’, such as GoPro or equivalent

ECM Electronic Counter-Measures Systems designed to ‘jam’ (or otherwise inhibit) operations of aircraft radar, C2, and telemetry systems

ECCM Electronic Counter Counter-Measures Systems designed to combat ECM

EHF Extremely High Frequency RF Frequency range from 30 to 300 GHz

EIRP Effective Isotropic Radiated Power Measure of the effective RF power radiated into space (measured in dBi)

EL Elevation (1) Height of a geographic feature (2) vertical axis pointing position of an antenna (typically measured in degrees)

EMI Electro-Magnetic Interference Signal interference caused by electro-magnetic fields, typically from motors, transformers, etc

EMP Electro-Magnetic Pulse A short burst of electromagnetic energy (whether from the sun, a radar, a ‘jamming source’, or from the effects of a thermonuclear explosion)

EMS Emergency Medical Services Emergency medical services such as fire, ambulance, and rescue operations.

EPT Effective Performance Time The amount of time an individual is able to perform flying duties efficiently in an environment of inadequate oxygen supply (AKA TUC- Time of Useful Consciousness)

ESA European Space Agency The European equivalent to NASA

ESC Electronic Speed Controller PCB used to control electric motor speed in UAS

ESN Electronic Serial Number Virtual serial number used to uniquely identify mobile communications devices

EXA Unit prefix denoting 10 E18 (1,000,000,000,000,000,000) Ex: Exa-bytes

FAA Federal Aviation Administration US government organization responsible for regulation of all civil aviation in the United States

FANET Flying Ad-hoc Network Network architecture for drone swarms

FCB Flight Control Board UAS component that typically includes CPU, inertial management unit (IMU) accelerometer and magnetometer, compass, GPS receiver, or some combination thereof

FCC Federal Communications Commission U.S. agency responsible for regulating interstate communications in the United States

FCS Flight Control System Complete system which allows control of an aircraft. The FCS consists of the FCB (Flight Control Board), the ESC (Electronic Speed Controller), propellers, radio link and remote controller (and its associated controls). Also includes any software or software-based control devices (such as flying by ‘smartphone’)

FDC Flight Data Center Center issuing NOTAM and other flight data for airmen

FDMA Frequency Division Multiple Access Scheme allowing multiple RF signals to be transmitted at the same time, each in a dedicated frequency ‘slot’

FEC Forward Error Correction A technique for detecting errors in data transmission over unreliable or noisy communication channels (such as a UAS radio path)

FESSA FAA Extension, Safety, and Security Act (2018) AKA ‘FAA Re-authorization Act An act of US Congress extending the FAA charter and funding until 2023

FHSS Frequency-Hopping Spread-Spectrum Modulation type using a carrier ‘spread’ with a pseudo-random bit sequence (PRBS), and frequency-hopping to maintain a clear channel. Typically used on UAS remote controllers

FL Flight Level Altitude designated for a specific flight

FLIR Forward Looking Infrared Radar Thermographic camera that senses infrared radiation, and detects range to target

FM Frequency Modulation Modulation scheme in which an analog signal input causes a radio-frequency (RF) carrier signal to vary in frequency

FOD Foreign Object Damage Damage to an aircraft or its components caused by unintentional entrance of objects (debris, equipment, etc.) into air vents or engine turbines

FOV Field Of View Extent of the physical world seen at a given moment. For optical sensors, it is the angular field of ‘vision’ in which the sensor can detect light.

FPV First Person View View from a subjective perspective. FPV goggles provide a view from the UAS camera’s ‘point of view’

FRIA FAA-Recognized Identification Area An FAA-proposed ‘drone park’, where legacy drones without Remote ID capabilities (or UAS with limited Remote ID capability) would be allowed to fly

FRP Fiber-Reinforced Polymer A type of polymer strengthened with addition of fibers; used for stronger propellers in drones and RC aircraft

FRZ Flight Restricted Zones Areas around White House and US Capitol (and other specially-designated areas) where all civilian flights are restricted

FSS Flight Service Station Office at smaller airports without a control tower that provides basic flight services, such as weather info, advisories, etc.

GB Giga (billion) bytes

Gb/s Giga (billion) bits per second

GCS Ground Control Station Control station or device to allow human control of UAS (e.g., control facility or discrete ‘remote controller’)

GEA Ground Effect Area Region where ‘ground effect’ is experienced by aircraft. (Ground effect is the increased lift and decreased aerodynamic ‘drag’ that an aircraft’s wings generate when they are close to a fixed surface. When taking off or landing, this ‘ground effect’ can give the pilot the feeling that the aircraft is “floating”)

GFSK Gaussian Frequency-Shift Keying filters the signal data pulses with a Gaussian filter to make the transitions smoother. It also reduces side-band power and interference with neighboring channels, but increases likelihood of inter-symbol interference (ISI). Used in some UAS remote controllers

GIS Geographic Information Systems Software program (and associated hardware) that allow aerial mapping (and land-based mapping) and the analysis and management of geographical mapping data

GJ-1 Gong-Ji Wu-Ren Ji (‘attack drone’) Designation for ChiCom PLAAF Wing-Loong MALE UCAV. US Air Force designates this craft the ‘Pterodactyl’

GMT Greenwich Mean Time Mean solar time as measured from a reference point of the Royal Naval Observatory in Greenwich, UK (on the ‘prime meridian’)

GNSS Global Navigation Satellite System (AKA GLONASS) A postioning system implemented by Russia to allow GPS-like functions at latitudes closer to the Earth’s poles. As GPS uses equatorial orbits, many extreme northern and southern latitudes cannot use it (no satellite visibility). GNSS satellites use a circular orbit, which can be ‘seen’ near the poles (and elsewhere on the Earth).

GSM Global System for Mobile (communications) European standard defining operations of second-generation (2-G) mobile communications devices

GPS Global Positioning System Satellite constellation operated by the US, providing navigation and position-finding capabilities to military and civilian users

HALE High Altitude, Long Endurance Type of military drone (ex: Global Star)

HF High Frequency RF frequencies between 3 and 30 MHz

HUD Heads-Up Display Type of visual display where computer information provides an On-Screen Display (OSD) in addition to the visual view of the world (see also AR)

IAS Indicated Air Speed Air speed as indicated by meter or telemetry

ICAO International Civil Aviation Organization United Nations standards organization, seeking to regulate aviation worlwide

ID Identification Some trait or information that provides positive knowledge of an individual, entity, or object. In regards to UAS, an ID is a mechanism to identify an aircraft or component of an aircraft

IEC International Electrotechnical Commission An international standards organization promoting international standards for electrical, electronic, and related technologies

IEEE Institute of Electrical and Electronic Engineers World’s largest  technical professional organization “dedicated to advancing technology for the benefit of humanity”

IFB Intelligent Flight BatteryLiPo battery with memory, recording charge count, etc

IFR Instrument Flight Rules Set of aviation regulations governing flight under instrument, and beyond the range of visual flight rules (VFR)

IMEI International Mobile Equipment Identity Standard ID format for individual mobile communications devices

IMU Inertial Management Unit Component in UAS (and other) applications that measures an object’s specific force, angular rate, and orientation. Typically accomplished using a combination of accelerometers, gyroscopes, and sometimes magnetometers. IMU is often integrated into the CPU, but may be a separate device or PCB (Printed Circuit Board)

INS Inertial Navigation System System which uses position calculation (and ‘dead reckoning’ navigation) based on an initial GPS location. Used when GPS services are no longer available for navigation after initial pre-flight (or in-flight) position fix by GPS

IOC Intelligent Orientation Control Feature which allows ‘headless’ mode of flight, where the orientation between remote pilot (RP) and the aircraft is irrelevant

IP Internet Protocol Transmission Protocol which establishes internetworking. Typically defined as a protocol ‘suite’ (e.g., TCP/IP)

ISA International Standard Atmosphere A reference atmospheric model of how the pressure, temperature, density, and viscosity of the Earth’s atmosphere change over a wide range of altitudes or elevations, and provide a common reference for temperature and pressure.

ISO International Standards Organization International organization defining standards for a number of applications

ITU International Telecommunications Union International Standards organization for telecommunications and related technologies

JITDO Joint Improvised Threat Defeat Organization A counter-drone group

JPEG Joint Photographic Experts Group Type of variable compression algorithm for digital ‘still’ images. Reduced quality and reduced file size

KB Kilo (thousand) bytes One thousand 8-bit digital ‘words’ (bytes)

Kb/s Kilo (thousand) bits per second One thousand binary digits (bits) per second

Ku-B Ku-Band Defined as the portion of the RF spectrum between 12 and 18 GHz

KV Kilo-Volts (1) Voltage potential measured in KV (thousands of volts). For example, 14KV is 14,000 volts (the electrical potential, or amount of potential force) (2) DC motor efficiency rating; rotation speed at a given voltage

LAA Local Airport Advisory Advisory notices and services in area near local airport as presenting possible flight hazards, weather conditions, etc.

LAANC Low Altitude Authorization and Notification Capability  FAA -mandated third party interface between FAA and UAS pilots. It provides access to controlled airspace near airports through NRT (Near Real-Time) processing of airspace authorizations below approved altitudes in controlled airspace

LED Light-Emitting Diode A PN diode ‘doped’ to emit light when forward biased

LEO Law Enforcement Organization Organization dedicated to enforcement of local or international laws

LHCP Left Hand Circular Polarization Radio wave propagation mode in which the electric field (and thus the magnetic field as well) rotate in a ‘left-hand’ direction (as visualized from the direction of propagation).Provides a method of discriminating between similar RF signals (for example one’s own transmit and receive signals)

LIDAR Light Detection and Ranging Pulsed laser light used to measure distance. often used for aerial 3-D mapping of ground-based objects or terrain

LiPo Lithium Polymer Common battery type used in UAS applications

LKP Last Known Position Last position of aircraft indicated by telemetry or radar

LNA Low-Noise Amplifier Amplifies low-power signal (like an RF signal from a distance) and amplifies the signal without amplifying noise (maintains received signal-to-noise ratio)

LOCUST LOw-Cost UAV Swarming Technology One of the emerging architectures for military drone swarms

LOS Loss of Signal/Line of Sight (1) Communications equipment alarm state (2) path between observer/pilot and UAS (or other object)

LRID Limited Remote ID FAA-proposed UAS type which would broadcast remote ID information by internet to a USS, and be limited to flying within 400′ of the control station

LSTM Long Short-Term Memory  A variant of recurrent neural networks; the LSTM key functionality is their ability to ‘remember’ information for a long period of time and apply it to the present (AI) task

mAh Milli-Amp Hour Measure of battery capacity in terms of milli (thousandths of) amp per hour output

MAG Magnetometer Electronic compass that aligns to the Earth’s magnetic field

MALE Medium Altitude, Long Endurance Type of military UAV (ex: Predator)

MAV Micro Air Vehicle Series of small UAV, ranging from hummingbird-size, to Mavic Mini (250g) size. Used for various roles in military forces across the globe

MB Mega (million or 10E6) bytes

Mb/s Mega (million or 10E6) bits per second

MCAS Marine Corps Air Station USMC aerodrome and air base

Mega Unit prefix denoting 10 E6 (1,000,000) Ex: Mega-bytes (1 million bytes)

METAR Meteorological Aerodrome Report Regularly-scheduled local weather report from airport, providing observation of current surface weather and reported in a standard international format.

MOA Military Operation Area/Memorandum of Agreement (1) Airspace designated and reserved for military operations (2) Document defining formal agreement between parties (ex: between FAA and contracted organizations)

MOCA Minimum Obstacle Clearing Altitude Altitude required to clear nearby obstacles in flight path

MPEG Motion Picture Experts Group Standards group (and associated technique/algorithm) for encoding digital video film and multimedia. Like JPEG, MPEG provides reduced-quality images and reduced file size (as compared to ‘raw’ unprocessed digital images)

MQ-n Armed Unmanned Department of Defense nomenclature for an attack UAV, wherein M initially defined as armed with military weapons and Q designates unmanned aircraft. For example, the Predator (in a attack configuration) is termed MQ-1B. (see also RQ). Currently, the M designation defines multi-role aircraft (both reconnaissance and attack capabilities)

MQ-1B USAF designation for the General Atomics ‘Predator’ UCAV (Retired in March 2018 from active service). US Army still uses a MALE version called the ‘Gray Eagle’

MQ-4C Designation for naval version of HALE UAV RQ-4C ‘Global Star’. New designation for former RQ-4C, to indicate multi-purpose payload and operational capability

MQ-8B Designation for ‘Fire Scout’ UAV, a carrier-landing capable UAV used by all branches of the US military

MQ-9B USAF designation for the General Atomics ‘Reaper’ UCAV

MQ-25 Military designation for Boeing ‘Sting Ray’ – an air-refueled, carrier-launched UAV designed for naval operations

MSL Mean Sea Level/Master Station Log (1) Average elevation (zero) of sea level (2) The master log describing station operations, typically for communications and radar sites

MTI Moving Target Indication Legacy radar mode used to discriminate between a target and noise or ‘ground clutter’. Generally replaced by stationary target indicator (STI) technique, which uses return properties to determine targets, moving or not

MTOW Maximum Take Off Weight Maximum weight an aircraft can take off with

MTR Military Training Route Airspace corridors where military training flights are common (at all altitudes)

MUAS Military UAS UAS designed for military use

mW Milli-watt One one-thousandth of a watt (1E-3)

MW Mega-Watt One million watts (1E6)

NACG National Aeronautical Charting Group FAA’s aeronautical charting authority for the development, publication, and dissemination of aeronautical charts and products to support aviation

NAS National Air Space System National system integrating all components of aviation; facilities, airports, rules and regulations, etc. (2) Naval Air Station

NASA National Aeronautic and Space Administration An independent agency of the United States government responsible for the civilian space program, as well as aeronautics and aerospace research

NAV Nano Air Vehicle Series of very small UAV, ranging from bee and dragonfly-size, to hummingbird (MAV) size.

NBS National Bureau of Standards (see NIST)

NIST National Institute for Standards and Technology A US physical sciences laboratory, and a (non-regulatory) agency of the United States Department of Commerce. Its mission is to promote innovation and industrial competitiveness

NM Nautical Miles/Nanometer (1) Term used in air and marine navigation; international nautical mile is defined as exactly 1852 meters (2) Billionth (10E-9) of a meter; term used to define optical wavelengths

NRID No Remote ID FAA-proposed UAS type which would not broadcast remote ID information, and which would be limited to flying within FAA-approved flying areas

NOAA National Oceanographic and Atmospheric Administration A US scientific agency (within the United States Department of Commerce) responsible for studying the conditions of the oceans, major waterways, and the atmosphere

NOC Network Operations Center Center from which network operations are monitored and controlled; also called NOCC – Network operations and Control Center (see also FOC and TOC)

NOTAM Notice to Airmen One of three types of time-critical aeronautical notification filed to inform pilots of conditions that could provide an impediment to flight in the area (For acronyms and abbreviations specific to NOTAM, see https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/systemops/fs/alaskan/alaska/fai/notam/media/cntrns.pdf )

NPRM Notice of Proposed Rule Making FAA notice of intent to create an aviation rule. Thia allows time for comment from stakeholders and committees, and for FAA to consider responses and (potentially) adjust the proposed rule accordingly Ex: UAS Remote ID NPRM became effective 1 January 2020

NSA National Security Agency/National Security Area (1) A US national security agency responsible for global monitoring, collection, and processing of information and data for foreign and domestic intelligence and counterintelligence purposes, through signals intelligence (SIGINT) (2) Airspace reserved for military aircraft, designated critical to national security

NWS National Weather Service Agency of the United States government which provides weather forecasts, warnings of hazardous weather, and other weather-related ‘products’. For NWS list of meteorological acronyms, see https://www.weather.gov/mdl/about_acronyms

OAS Obstacle Avoidance System System used to detect obstacles in the flight path and provide input by which flight controls can automatically maneuver to avoid the detected obstacles. These systems range from simple IR/CMOS cameras to AI systems

OBE Overcome By Events Category for flight accident causes – pilot lost control when the number of unexpected in-flight events exceeded the pilot’s ability to deal with them effectively

OBU On-Board Unit A component on-board a UAV, for example a CPU or IMU

OEM Original Equipment Manufacturer The original manufacturer of a piece of equipment or device (as opposed to ‘after-market’ manufacturers which make compatible parts). Manufactured to original specifications and tolerances (which after-market equipment often is not, either failing or exceeding original standards)

OFDM Orthogonal Frequency Division Multiplexing Modulation scheme where a wide-bandwidth carrier is divided into a series of narrower-bandwidth carriers, to provide immunity to interference

OLED Organic Light-Emitting Diode Component which uses a thin film of organic compound (sandwiched between two electrodes) to produce light. Thinner than an LCD (Liquid Crystal Display), it has found numerous applications in video display systems

OSD On-Screen Display Standalone or integrated module which provides an on-screen display of UAS video on the remote controller (or to a separate board), and allows overlay of various telemetry data over the FPV or on-board video feed

OSI Open Systems Interconnect ISO-specified protocol model for data interchange, which defines networking functionality in seven layers, in order to allow transparent interchange of information between various devices, using various operating systems and software

OW Operational Weight Weight of aircraft under current operational configuration

PAR Precision Approach Radar Type of radar guidance system designed to provide approach (lateral and vertical) guidance to an aircraft pilot for landing

PD-100 Prox Dynamics, model 100 ‘Black Hornet’ micro air vehicle (MAV) helicopter, with three cameras. Used by various western military forces. Provides night vision, long-wave infrared and standard video sensors.

PDB Power Distribution Board Printed circuit board that provides regulated power for electronic speed controllers, CPU, etc. Sometimes integrated with other functions, such as OSD (on-screen display) module

PCB Printed Circuit Board Non-conductive ‘board’ on which electronic circuits and components are ‘printed’. Can be composed of multiple layers

PESA Passive Electronically-Scanned Array AKA passive phased array; an antenna in which the beam of radio waves can be electronically ‘steered’ to point in different directions (that is, a phased array antenna), in which all the antenna elements are connected to a single transmitter. Gen-1 phased array radar (see AESA)

PID Proportional Integral Derivative Type of controller programming which allows user to change (‘tune’) flight characteristics

PII Personally Identifiable Information Information within an FAA-proposed flight-monitoring and surveillance scheme which would directly link an individual to mandated UAS ID information

PIC Pilot In Command Individual actually (and directly) in command of an aircraft (UAS or manned)

PKI Public Key Infrastructure A type of ‘public’ security coding algorithm

PLA Peoples’ Liberation Army (Chinese communist) Military organization effectively in control of communist China (they are both a semi-autonomous military and financial/political entity)

PNF Plug and Fly Type of drone kit requiring minimal assembly

PNP Plug and Play (see PNF)

PNR Point of No Return Point after which commands no longer control aircraft

PRAT Passive Read – Active Tag A type of RFID tag with an ‘onboard’ battery

PRBS Pseudo Random Bit Sequence A finite length shift register bit sequence used for SSMA and bit error detection

PRC Peoples’ Republic of China Communist, totalitarian regime in control of mainland China (as opposed to the democratic Republic of Taiwan). Both entities claim to be the rightful (and only) ‘true China’. PRC can demand all UAS data from any UAS made in China, with no legal recourse to the manufacturer

PRF Pulse Repetition Frequency The frequency at which radar pulses are transmitted

PRM Payload Release Mechanism A radio-controlled mechanism to hold a (typically small) payload, and release it on remote command

PRR Pulse Repetition Rate The rate at which radar pulses are transmitted

PSK Phase Shift Keying Modulation technique where an input signal is used to modulate an RF carrier in (n) phase states, for increased data throughput

PSR Point of Safe Return Point in flight where pilot commands can affect aircraft, and facilitate a safe return flight to ‘home’ (or destination)

PUAS Police UAS/Public UAS UAS used by law enforcement (2) UAS used by public

PWM Pulse Width Modulation Analog control signals affect pulse width of command pulses, used in some UAS to control motor speed

QAM Quadrature Amplitude Modulation Modulation technique in which an input signal causes amplitude and phase changes to an RF carrier, providing improved throughput when compared to traditional QPSK

QPSK Quadra Phase Shift Keying Modulation technique where binary data input is split into ‘di-bits’ which modulate carrier into one of four phase states

RC Radio-Controlled Term for UAV (drone and ‘model aircraft’) controlled by a radio link between aircraft and a remote controller (also written R/C)

RF Radio Frequency Transmission at radio wave frequencies. RF field in space has E (electrical) and H (magnetic) field components in quadrature (90 degree)

RFI Radio Frequency Interference Signal interference from a radio source, such as a co-located transmitter or nearby broadcast source

RFID Radio Frequency Identification Technology used to identify and track items, via RF interrogation from a local or remote ‘reader’. ID chip is fixed on device/object, and can be tracked via interrogator (reader). Ex: NFL players’ speed and distance can be tracked accurately via RFID, and their position determined accurately within six inches. Potential (but not considered) methods for UAS remote ID

RHCP Right Hand Circular Polarization Radio wave propagation mode in which the electric field (and thus the magnetic field as well) rotate in a ‘right-hand’ direction (as visualized from the direction of propagation).Provides a method of discriminating between similar RF signals (for example one’s own transmit and receive signals)

RLOS Radio Line of Sight Traditionally defined as simply LOS; the existence of a clear and unimpeded direct line of sight between two radio stations (note a virtual LOS exists between radio stations that do not have a direct LOS, but use propagation techniques such as tropospheric scatter, etc.)

RNN Recurrent Neural Network  A type of neural network which has ‘loops’. It is designed to allow previously processed information to effect how the AI system interprets new information

ROT Rate of Turn Rate at which an aircraft is executing a turn

RP Remote Pilot Individual actually in control of the aircraft

RPA Remotely-Piloted Aircraft Alternate military designation for UAV

RPIC Remote Pilot In Command FAA-defined individual in a notional UAS flight crew who has ultimate command of (and responsibility for) the UAS flight and ‘actions’

RQ-n Reconnaissance Unmanned (UAV) Department of Defense nomenclature for a reconnaissance UAV, wherein R defines reconnaissance and Q designates unmanned aircraft. For example, the Predator (in a recon configuration) is termed RQ-1B. (see also MQ)

RQ-2B Reconnaissance Unmanned (UAV)-2 ‘Pioneer’ UAV, first used in 1986 to provide gunnery support for Iowa-class battleships. The first widely-used military UAV

RQ-3 Reconnaissance Unmanned (UAV)-3 Lockheed-Martin high-altitude, long-endurance (HALE) UAV, discontinued in favor of RQ-4 (which had longer range)

RQ-4A Reconnaissance, Unmanned (UAV)-4 Northrop-Grumann ‘Global Hawk’, a high-altitude, long-endurance (HALE) UAV equipped with Synthetic Aperture Radar (SAR), long-range Electro-Optical/infrared (EO/IR) sensors. USAF owns most versions, but the US Navy and NASA also own versions of this primary HALE UAV in the US fleet

RQ-4N Reconnaissance, Unmanned (UAV)-4 (Naval Variant) Northrop-Grumann ‘Global Hawk’, a high-altitude, long-endurance (HALE) UAV, with wings modified to stand rapid deceleration for use as a medium-altitude, long-endurance (MALE) UAV.

RQ-5A Reconnaissance, Unmanned (UAV)-5 ‘Hunter’ UAV was originally manufactured in Israel, but Northrop Grumman acquired the design in 2002. It first deployed in 1995, and it was retired in 2015

RQ-7B Reconnaissance, Unmanned (UAV) -7 ‘Shadow’ is a trailer-launched (catapult) military UAV used for reconnaissance, surveillance, and field assessment

RQ-11 Reconnaissance, Unmanned (UAV)-11 ‘Raven’ UAV is a smal;l, hand-launched UAV which was originally developed for the US military by AeroVironment, but is now primarily used by many allied military forces

RQ-12 Reconnaissance, Unmanned (UAV)-12 ‘Wasp’ UAV is a miniature, hand-launched airplane designed for USAF Special Operations Command

RQ-16 Reconnaissance, Unmanned (UAV)-16 ‘T-Hawk’ UAV

RQ-20 Reconnaissance, Unmanned (UAV)-20 AeroVironment ‘Puma’ UAV is a small, battery-powered, hand-launched airplane

RQ-21 Reconnaissance, Unmanned (UAV)-21 ‘Blackjack’ UAV is a Boeing/Insitu-designed, US Navy-operated, single-engine ‘monoplane’

RQ-X Reconnaissance, Unmanned (UAV)-X Lockheed-Martin ‘Stalker’ is a hand-launched XE (Extended Endurance) UAV reportedly developed for US SOC (Special Operations Command), which is (according to Lockheed-Martin) used by special forces units worldwide. No official military designation exists for this unmanned, reconnaissance aircraft (thus RQ-X is used here for classification purposes)

RQ-170 Reconnaissance, Unmanned (UAV)-170 ‘Sentinel’ is a CIA-operated UAV

RQ-180 Reconnaissance, Unmanned (UAV)-180 Not currently (officially) adopted UAV, designed by Northrop-Grumman for contested airspace. Rumored to be in field operations

RSSI Received Signal Strength Indication ‘Bars’ or display indicating signal strength at a receiver (also RSL-Receive Signal Level)

RTF Ready to Fly A pre-assembled UAS which requires (little or) nothing to fly. Also known as commercial off the shelf (COTS) RTF

RTH Return To Home Automatic function programmed in some UAS which commands the UAS to return to the launch point, either under command, due to remaining flight time considerations (typically low battery), or loss of command and control signal

RUAS Recreational UAS UAS intended for recreational use. Note same drone types can be used as either commercial UAS (CUAS) or recreational UAS (RUAS)

RUSS Remote ID UAS Service Supplier Third-party, FAA-designated organization to track and identify UAS, report results to FAA and/or the public, on demand

RX Receiver A device intended to receive a communications signal. In the case of UAS, it is designed to receive a radio signal.

SAE Society of Automotive Engineers Standards organization, originally dedicated to automotive engineering, but expanded to international scope and areas of interest. Active in defining potential standards for the FAA in regards to UAS

SAO Special Area of Operations Geographic areas having unique characteristics that require the use of special equipment, procedures, and/or techniques to safely conduct flight operations

SAR Synthetic Aperture Radar  Form of coherent radar (typically space-borne/side-looking) used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes. SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional beam-scanning radars; the flight path of the radar platform simulates an extremely large antenna ‘aperture’ electronically, which generates high-resolution remote sensing imagery

SATCOM Satellite Communications Communications via geosynchronous or low-earth-orbit satellites. The satellite acts as an in-space transponder for communications signals. Distinct from satellite mapping imagery, etc., but all types of satellite sensor and telemetry data are sent and received by satellite communications.

S-B S-Band Defined as the portion of the RF spectrum between 2 and 4 GHz (Many UAS remote controllers operate in this band)

SBS Soldier-Borne Sensor US Army program to develop MAV and NAV capabilities to provide squad-level series of sensors carried by soldiers (including portable UAV/MAV/NAV)

SD Secure Digital Common type of flash memory card

SDXC Secure Digital Extended Capacity Flash memory card of 128 GB or greater

SHF Super-High Frequency RF Frequencies between 3 and 30 GHz

SIGMET Significant Meteorological Information Weather advisory that contains meteorological information concerning the safety of all aircraft, such as sever storms and weather events

SIM Subscriber Identification Module Integrated circuit that intended to securely store the international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate ‘subscribers’ (users) of mobile communications networks. Typically a mini circuit card that is inserted in the phone

SMA Sub-Miniature-type A Connector type used for RF signal interconnection

SMS Safety Management System Management system (SW-based) used to manage safety in a workplace or environment.

SNPRM Supplemental Notice of Proposed Rule Making FAA addendum to NPRM

SNR Signal to Noise Ratio Ratio (in dB) of difference between signal power to noise power in a specific signal bandwidth

SRAM Static Random-Access Memory Type of computer memory which stores data as long as power is being supplied. Unlike dynamic RAM (DRAM), which stores bits in cells consisting of a capacitor and a transistor, SRAM does not have to be periodically refreshed.

SRID Standard Remote ID FAA-proposed UAS type which would broadcast remote ID information by internet to a USS, and by RF broadcast

SOC Satellite Operations Center Center where satellite (single or constellation) is ‘flown’ (remotely monitored and controlled)

SOP Standard Operating Procedures Formalized procedures to be followed; a set of step-by-step instructions compiled to help aviators (or others) carry out complex routine operations

SRM Single-pilot Resource Management A systematic approach to the mental process used by pilots (to consistently determine the best course of action in response to a given set of circumstances). It is what a pilot intends to do based on the latest information he or she has. Effects same principles as CRM, but for a single pilot.

SSD Solid State Drive Memory drive with no moving parts – all electronic

SSL Secure Socket Layer Cryptographic protocols designed to provide communications security over a computer or communications network.

SSMA Spread Spectrum Multiple Access Scheme allowing different RF signals to share same frequency band, as each is ‘spread’ with a different bit sequence.

STI Stationary Target Indicator Radar technique using properties of return signal to discriminate moving and stationary target from noise or ‘ground clutter’

STRIDE Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service,
Elevation of Privilege Hacking threat definition type (NASA)

SUAV Small Unmanned Aerial Vehicle Miniature drones for use in swarms

SS-7 Signalling System Seven Signalling protocol used to set up and tear down ‘calls’ between devices. Foundation for AIN implementations.

SW Soft Ware Set of computer instructions (‘code’) that tells a computer or intelligent device how to work.

TAF Terminal Aerodrome Forecast A report established for the five statute mile radius around an airport

TB Tera (trillion) bytes. 10E12 (8-bit) bytes of data

Tb/s Tera (trillion) bits per second 10E12 binary digits (bits) of data per second

TCG Time Code Generator Devices providing very stable time and date information (in UTC). Provides high accuracy and chronography (low decay) of time

TCL Technical Capability Levels NASA term to define flight area density and technical flight support capabilities

TCP Transmission Control Protocol Protocol (layer 3 in OSI model) which defines how to establish a network connection over a datalink. Typically used in conjunction with internet protocol (IP), thus TCP/IP

TCU Towering Cumulus A form of cumulus cloud that can be based in the low or middle altitudes. They achieve considerable vertical development in areas of deep, moist convection

TDM Time-Division Multiplexing A system used to multiplex (combine) a variety of ‘tributary’ signals into a composite aggregate, by dedicating ‘time slots’ to each tributary, and combining them

TDMA Time-Division Multiple Access Scheme allowing multiple RF signals to share same frequency band by assigning each carrier a dedicated time slot in which to transmit. Also a method of combining multiple bit streams, by sampling each input and sending each channel out in a dedicated time slot.

TFR Temporary Flight Restriction Temporary restriction of flight in a normally clear (unreserved) airspace

TIP Technical Implementation Procedures Specific, FAA-defined procedures to implement technical solutions and capabilities in aircraft

TLM Telemetry Info from an aircraft/spacecraft regarding its status and operations

TOC Tactical Operations Center/Technical Operations Center Center where ongoing operations are monitored and controlled, similar to Flight Operations Center (FOC) or Network Operations Center (NOC)

TPP Third-Party Providers Private corporations which (through contracts with the FAA) are tasked to manage various flight information, on behalf of the FAA

TRSA Terminal Radar Service Area Area where pilots can receive additional radar services (in surrounding space where terminal radars exist and RF interference from radar could cause hazard to flights) allows radar approach services to participating pilots flying under VFR

TSO Technical Standard Order Minimum performance standard issued by the FAA for specified parts, materials, processes, and appliances used on civil aircraft.

TUAV Tactical Unmanned Aerial Vehicle Tactical military drone

TUC Time of Useful Consciousness AKA effective performance time (EPT); the amount of time an individual is able to perform flying duties efficiently in an environment of inadequate oxygen supply

TX Transmitter System which provides amplification and signal conditioning required to send a signal

UART Universal Asynchronous Receiver-Transmitter A computer hardware device for asynchronous serial communication in which the data format and transmission speeds are configurable. Concerts from parallel data inputs to serial.

UAS Unmanned Aircraft System A system (controller and UAV, for example) used to command and control UAVs in flight

UAV Unmanned Aerial Vehicle An aircraft (‘drone’) piloted by a remote pilot

UCAV Unmanned Combat Aerial Vehicle Military attack drone, designed or equipped for combat operations (as opposed to monitoring or other functions)

UFAA UTM Framework for Authentication and Authorization Basic architecture for UTM access and services authorization

UHF Ultra-High Frequency RF frequencies between 300 MHz and 3 GHz

UMTS Universal Mobile Telephone System Third-generation (3-G) broadband, packet-based transmission of text, digitized voice, video, and multimedia at data rates up to 2 ‘megabits’ (million bits) per second (Mb/s)

UPA Universal Payload Adaptor Device allowing military UAV to accept a variety of payloads. Implementations for commercial applications being developed and standardized

URTCC UAS Regional Traffic Control Center Functional equivalent of governmental Air Traffic Control Center, dedicated to UAS traffic, recreational and commercial

USAF United States Air Force Military forces of the U.S., dedicated to air operations (note some air operations are also performed by other military branches of the US military, but the USAF has primary responsibility for air and space operations)

USB Universal Serial Bus Modern serial data connector and bus architecture

USS UAS Service Supplier FAA-defined third party provider for UAS traffic monitoring, tracking, and reporting functions. A government-specified interface between the UAS pilot, the FAA, and the public

UTC Universal Coordinated Time Standard for coordinated time across the planet. UTC is within one second of solar time, and is adjusted for sidereal variations. UTC is distributed through a hierarchy of ‘time servers’ to synchronize all backbone, internet, and wireless communications (and thus virtually all communications devices)

UTM UAS Traffic Management/Universal Transverse Mercator (1) FAA-defined traffic management ‘ecosystem’ for UAS operations that is “separate from, but complementary to”, the FAA’s Air Traffic Management (ATM) system (2) A mapping method that uses 60 zones and x, y coordinates within the zone to determine position. Most accurate position determination for extreme latitudes (near the poles)

VCSEL Vertical-Cavity Surface-Emitting Laser Type of LED laser which emits a light signal vertically from its surface (as opposed to common edge-emitting lasers). Provides low-power applications for technologies such as HUD (Heads-Up Displays and ‘smart glasses’

VFR Visual Flight Rules Set of regulations under which a pilot operates an aircraft in weather conditions clear enough to allow the pilot to see where the aircraft is going

VLE Visual Light Encoding Proposed method for UAS Remote ID and Tracking whereby UAS ID is detected by broadcast of specific light ‘codes’ to identify the UAS

VLOS Visual Line of Sight (1) Distance at which an object (e.g., aircraft or UAS) can be clearly seen from a remote control position (2) the existence of a clear visual path between observer and object observed

VO Visual Observer Individual in the FAA-defined flight crew who maintains visual contact with the aircraft (while the pilot is perhaps flying the UAS via FPV goggles and has no direct visual contact with the aircraft)

VPP Variable-Pitch Propeller A variable-pitch aircraft/UAV propeller that automatically changes its blade pitch in order to maintain a chosen rotational speed. AKA Constant-speed propeller (CSP) or Controllable-Pitch Propeller

VPS Visual Position System Method for position location via camera, without GPS

VR Virtual Reality Computer-generated display which displays a simulation of reality; the view looks almost real. For example, FPV (First-Person View) goggles can be used for Augmented Reality (AR) when flying UAS (they combine visual and computer information), or they can be used for VR, for example to view video games, in which the display is all computer-generated information, and no actual visual information about the world around an observer.

VSI Vertical Speed Indicator Indication of vertical speed, by telemetry or meter

VTX Video Transmitter Module to transmit UAS FPV (first person view) camera video to remote controller

VSWR Voltage to Standing Wave Ratio A measure of impedance-matching between source and load (transmission source or wave-guide). High VSWR indicates a poor impedance match, and high reflected power.

VTOL Vertical Takeoff and Landing Flight configuration which allows a vertical (‘straight up’) takeoff; not requiring a runway. This mode is inherent in quad-copters. For airplanes, the engine nacelles (housings) are rotated vertically, effectively turning the propellers into rotors. Term initially used to described this feature in airplanes.

WORM Write Once, Read Many Type of RFID (Radio Frequency Identification) chip, which can be field-programmed once, but read may times

X-B X-Band Frequency band commonly used by military radars. Defined as the portion of the RF spectrum between 7 and 11 GHz

XMT Transmit Sending out information (typically by radio); emitting radio waves into space, signals down a transmission line, or otherwise sending information

XPDR Transponder A device which receives a signal (in one format or frequency) and converts the outgoing signal to another format or frequency

Y Yaw Sideways motion of an aircraft (as referenced to a vertical plane)

Yotta Unit prefix denoting 10 E24 (1,000,000,000,000,000,000,000,000) Ex: Yotta-bytes (currently the highest designated prefix)

Z Zulu (1) Alphanumeric time zone corresponding to Greenwich Mean Time (GMT). (2) International aviation (as well as military and scientific) phonetic pronunciation for the letter Z.

ZB Zigbee  A low-power, low data rate, close-proximity ad-hoc wireless network, based on IEEE 802.15.4 specification defining Personal Area Networks (PAN)

Zed UK-based term for letter Z (as opposed to international phonetic pronunciation, in which the letter Z is described as ‘Zulu’)

Zeta Unit prefix denoting 10 E21 (1,000,000,000,000,000,000,000) Ex: Zeta-bytes (one million zillion, in non-scientific vernacular)

5-G Fifth Generation Term used to describe (current latest) modern wireless communications technology. 5-G offers increased bandwidth and services, but requires smaller ‘cells’ with higher power outputs and more closely spaced towers

Excerpted from Drone Dictionary (c) 2020 Mark F. Mullen, Mullen Enterprizes