Avionics - AbsoluteAstronomy.com

Avionics are electronic

Electronics

Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...

systems used on aircraft

Aircraft

An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

, artificial satellites and spacecraft.

Avionic systems include communication

Communication

Communication is the activity of conveying meaningful information. Communication requires a sender, a message, and an intended recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication; thus communication can occur across vast...

s, navigation

Navigation

Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...

, the display and management of multiple systems and the hundreds of systems that are fitted to aircraft to meet individual roles. These can be as simple as a searchlight

Searchlight

A searchlight is an apparatus that combines a bright light source with some form of curved reflector or other optics to project a powerful beam of light of approximately parallel rays in a particular direction, usually constructed so that it can be swiveled about.-Military use:The Royal Navy used...

for a police helicopter

Police helicopter

A police aircraft is an airplane, helicopter, powered paraglider, or blimpused in police operations. They are commonly used for traffic control, ground support, search and rescue, high-speed car pursuits, observation, air patrol and riot control...

or as complicated as the tactical system for an Airborne Early Warning

Airborne Early Warning

An airborne early warning and control system is an airborne radar system designed to detect aircraft at long ranges and control and command the battle space in an air engagement by directing fighter and attack plane strikes...

platform.

History

The term avionics is believed to have been coined by journalist Philip J. Klass

Philip J. Klass

Philip Julian Klass was an American journalist and UFO researcher, known for his skepticism regarding UFOs. In the ufological and skeptical communities, Klass tends to inspire strongly polarized appraisals. Klass has been called the "Sherlock Holmes of UFOlogy"...

. Avionics was pioneered in the 1970s, driven by military need rather than civil airliner development. Military aircraft had become flying sensor platforms, and making large amounts of electronic equipment work together had become the new challenge. Today, avionics as used in military aircraft almost always forms the biggest part of any development budget. Aircraft like the F-15E and the now retired F-14 have roughly 80 percent of their budget spent on avionics. Most modern helicopters now have budget splits of 60/40 in favour of avionics.

The civilian market has also seen a growth in cost of avionics. Flight control systems (fly-by-wire

Fly-by-wire

Fly-by-wire is a system that replaces the conventional manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic signals transmitted by wires , and flight control computers determine how to move the actuators at each control...

) and new navigation needs brought on by tighter airspaces, have pushed up development costs. The major change has been the recent boom in consumer flying. As more people begin to use planes as their primary method of transportation, more elaborate methods of controlling aircraft safely in these high restrictive airspaces have been invented.

Aircraft avionics

The cockpit of an aircraft is a major location for avionic equipment, including control, monitoring, communication, navigation, weather, and anti-collision systems. The majority of aircraft power their avionics using 14 or 28 volt DC

Direct current

Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...

electrical systems; however, larger, more sophisticated aircraft (such as airliner

Airliner

An airliner is a large fixed-wing aircraft for transporting passengers and cargo. Such aircraft are operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an aircraft intended for carrying multiple passengers in commercial...

s or military combat aircraft) have AC

Alternating current

In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....

systems operating at 400 Hz and 115 volt rather than the more common 50 and 60 Hz of North American home electrical devices. There are several major vendors of flight avionics, including Honeywell

Honeywell

Honeywell International, Inc. is a major conglomerate company that produces a variety of consumer products, engineering services, and aerospace systems for a wide variety of customers, from private consumers to major corporations and governments....

(which now owns Bendix/King

Bendix Aviation

The Bendix Aviation Corporation, a manufacturer of aircraft parts, was started by inventor Vincent Bendix in 1929 as a continuation of his auto parts company. It was renamed to Bendix Corporation in 1960, and in 1983 was acquired by the Allied Corporation and combined with King Radio company to...

, Baker Electronics, Allied Signal, etc.), Rockwell Collins

Rockwell Collins

Rockwell Collins, Inc. is a large United States-based international company headquartered in Cedar Rapids, Iowa, primarily providing aviation and information technology systems and services to governmental agencies and aircraft manufacturers.- History :...

, Thales Group

Thales Group

The Thales Group is a French electronics company delivering information systems and services for the aerospace, defense, transportation and security markets...

, Garmin

Garmin

Garmin Ltd. , incorporated in Schaffhausen, Switzerland, is the parent company of a group of companies founded in 1989 by Gary Burrell and Min Kao , that develops consumer, aviation, and marine technologies for the Global Positioning System...

, Avidyne Corporation

Avidyne Corporation

Avidyne Corporation is an avionics company based in Lincoln, Massachusetts. Avidyne is developer of Integrated Flight Deck Systems, multi-function displays, and traffic advisory systems for light general aviation aircraft. Headquartered in Lincoln, MA, the company has facilities in Columbus, OH,...

, and Narco Avionics.

Communications

Communications connect the flight deck to the ground and the flight deck to the passengers. On-board communications are provided by public address

Public address

A public address system is an electronic amplification system with a mixer, amplifier and loudspeakers, used to reinforce a sound source, e.g., a person giving a speech, a DJ playing prerecorded music, and distributing the sound throughout a venue or building.Simple PA systems are often used in...

systems and aircraft intercom

Intercom

An intercom , talkback or doorphone is a stand-alone voice communications system for use within a building or small collection of buildings, functioning independently of the public telephone network. Intercoms are generally mounted permanently in buildings and vehicles...

s.

The VHF aviation communication system works on the airband

Airband

Airband or Aircraft band is the name for a group of frequencies in the VHF radio spectrum allocated to radio communication in civil aviation, sometimes also referred to as VHF, or phonetically as "Victor"...

of 118.000 MHz to 136.975 MHz. Each channel is spaced from the adjacent ones by 8.33 kHz. VHF is also used for line of sight communication such as aircraft-to-aircraft and aircraft-to-ATC. Amplitude Modulation

Amplitude modulation

Amplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...

(AM) is used, and the conversation is performed in simplex

Simplex communication

Simplex communication refers to communication that occurs in one direction only. Two definitions have arisen over time: a common definition, which is used in ANSI standard and elsewhere, and an ITU-T definition...

mode. Aircraft communication can also take place using HF (especially for trans-oceanic flights) or satellite communication.

Navigation

Radio navigation

Radio navigation or radionavigation is the application of radio frequencies to determine a position on the Earth. Like radiolocation, it is a type of radiodetermination.The basic principles are measurements from/to electric beacons, especially...

is the determination of position and direction on or above the surface of the Earth. Avionics can use satellite-based systems (such as GPS and WAAS), ground-based systems (such as VOR

Vör

In Norse mythology, Vör is a goddess associated with wisdom. Vör is attested in the Prose Edda, written in the 13th century by Snorri Sturluson; and twice in kennings employed in skaldic poetry...

or LORAN

LORAN

LORAN is a terrestrial radio navigation system using low frequency radio transmitters in multiple deployment to determine the location and speed of the receiver....

), or any combination thereof. Older avionics required a pilot or navigator to plot the intersection of signals on a paper map to determine an aircraft's location; modern systems calculate the position automatically and display it to the flight crew on moving map displays.

Monitoring

Glass cockpit

A glass cockpit is an aircraft cockpit that features electronic instrument displays, typically large LCD screens, as opposed to the traditional style of analog dials and gauges...

s started to come into being with the Gulfstream G-IV private jet in 1985. Display systems provide sensor data that allows the aircraft to fly safely. Much information that previously was displayed on mechanical gauges now appears on electronic displays in newer aircraft.

Aircraft flight control systems

Airplanes and helicopters have means of automatically controlling flight. They reduce pilot workload at important times (like during landing, or in hover), and they make these actions safer by 'removing' pilot error. The first simple auto-pilots were used to control heading and altitude and had limited authority on things like thrust and flight control surfaces. In helicopters, auto stabilization was used in a similar way. The old systems were electromechanical in nature until very recently.

The advent of fly by wire

Fly by Wire

Fly by Wire: The Geese, the Glide, the Miracle on the Hudson is a book written in 2009 by William Langewiesche about US Airways Flight 1549 with emphasis on the role played by the advanced fly-by-wire flight control system of the aircraft....

and electro-actuated flight surfaces (rather than the traditional hydraulic) has increased safety. As with displays and instruments, critical devices which were electro-mechanical had a finite life. With safety critical systems, the software is very strictly tested.

Collision-avoidance systems

To supplement air traffic control

Air traffic control

Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...

, most large transport aircraft and many smaller ones use a TCAS (Traffic Alert and Collision Avoidance System), which can detect the location of nearby aircraft, and provide instructions for avoiding a midair collision. Smaller aircraft may use simpler traffic alerting systems such as TPAS, which are passive (they do not actively interrogate the transponders of other aircraft) and do not provide advisories for conflict resolution.

To help avoid collision with terrain (CFIT), aircraft use systems such as ground-proximity warning systems (GPWS), which use radar altimeters as a key element. One of the major weaknesses of GPWS is the lack of "look-ahead" information, because it only provides altitude above terrain "look-down". In order to overcome this weakness, modern aircraft use the Terrain Awareness Warning System (TAWS).

Weather systems

Weather systems such as weather radar

Weather radar

Weather radar, also called weather surveillance radar and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, estimate its type . Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the...

(typically Arinc 708

ARINC 708

ARINC 708 is a specification for airborne pulse Doppler weather radar systems primarily found on commercial aircraft. ARINC 708 and the Honeywell Picture bus are the predominant avionics data bus for most aircraft today superseding ARINC 453....

on commercial aircraft) and lightning detector

Lightning detector

A lightning detector is a device that detects lightning produced by thunderstorms. There are three primary types of detectors: ground-based systems using multiple antennas, mobile systems using a direction and a sense antenna in the same location , and space-based systems.The device was invented in...

s are important for aircraft flying at night or in instrument meteorological conditions

Instrument meteorological conditions

Instrument meteorological conditions is an aviation flight category that describes weather conditions that require pilots to fly primarily by reference to instruments, and therefore under Instrument Flight Rules , rather than by outside visual references under Visual Flight Rules . Typically, this...

, where it is not possible for pilots to see the weather ahead. Heavy precipitation (as sensed by radar) or severe turbulence (as sensed by lightning activity) are both indications of strong convective activity and severe turbulence, and weather systems allow pilots to deviate around these areas.

Lightning detectors like the Stormscope or Strikefinder have become inexpensive enough that they are practical for light aircraft. In addition to radar and lightning detection, observations and extended radar pictures (such as NEXRAD

NEXRAD

NEXRAD or Nexrad is a network of 159 high-resolution Doppler weather radars operated by the National Weather Service, an agency of the National Oceanic and Atmospheric Administration within the United States Department of Commerce...

) are now available through satellite data connections, allowing pilots to see weather conditions far beyond the range of their own in-flight systems. Modern displays allow weather information to be integrated with moving maps, terrain, traffic, etc. onto a single screen, greatly simplifying navigation.

Aircraft management systems

There has been a progression towards centralized control of the multiple complex systems fitted to aircraft, including engine monitoring and management. Health and Usage Monitoring Systems

Health and Usage Monitoring Systems

Health and Usage Monitoring Systems is a generic term given to activities that utilize data collection and analysis techniques to help ensure availability, reliability and safety of vehicles. Activities similar to, or sometimes used interchangeably with, HUMS include Condition Based Maintenance ...

(HUMS) are integrated with aircraft management computers to give maintainers early warnings of parts that will need replacement.

The Integrated Modular Avionics

Integrated Modular Avionics

Integrated modular avionics represent real-time computer network airborne systems. This network consists of a number of computing modules capable of supporting numerous applications of differing criticality levels....

concept proposes an integrated architecture with application software portable across an assembly of common hardware modules. It has been used in fourth generation jet fighters and the latest generation of airliner

Airliner

Mission or tactical avionics

Military aircraft have been designed either to deliver a weapon or to be the eyes and ears of other weapon systems. The vast array of sensors available to the military is used for whatever tactical means required. As with aircraft management, the bigger sensor platforms (like the E-3D, JSTARS, ASTOR, Nimrod MRA4, Merlin HM Mk 1) have mission management computers.

Police and EMS aircraft also carry sophisticated tactical sensors.

Military communications

While aircraft communications provide the backbone for safe flight, the tactical systems are designed to withstand the rigours of the battle field. UHF

Ultra high frequency

Ultra-High Frequency designates the ITU Radio frequency range of electromagnetic waves between 300 MHz and 3 GHz , also known as the decimetre band or decimetre wave as the wavelengths range from one to ten decimetres...

, VHF Tactical (30-88 MHz) and SatCom systems combined with ECCM methods, and cryptography

Cryptography

Cryptography is the practice and study of techniques for secure communication in the presence of third parties...

secure the communications. Data links like Link 11, 16

Link 16

Link 16 is a military tactical data exchange network created and used by the United States and adopted by some of its Allies and by NATO. Its specification is part of the family of Tactical Data Links....

, 22

Link 22

During the late 1980s, NATO, agreeing on the need to improve the performance of Link 11, produced a mission need statement that became the basis for the establishment of the NATO Improved Link Eleven Program...

and BOWMAN

Bowman (communications system)

Bowman is the name of the tactical communications system used by the British Armed Forces.The Bowman C4I system consists of a range of HF radio, VHF radio and UHF radio sets designed to provide secure integrated voice, data services to dismounted soldiers, individual vehicles and command HQs up to...

, JTRS and even TETRA

Tetra

provide the means of transmitting data (such as images, targeting information etc.).

Radar

Airborne radar

Radar

Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

was one of the first tactical sensors. The benefit of altitude providing range has meant a significant focus on airborne radar technologies. Radars include Airborne Early Warning

Airborne Early Warning

(AEW), Anti-Submarine Warfare

Anti-submarine warfare

Anti-submarine warfare is a branch of naval warfare that uses surface warships, aircraft, or other submarines to find, track and deter, damage or destroy enemy submarines....

(ASW), and even Weather radar

Weather radar

(Arinc 708

ARINC 708

) and ground tracking/proximity radar.

The military uses radar in fast jets to help pilots fly at low levels. While the civil market has had weather radar for a while, there are strict rules about using it to navigate the aircraft.

Sonar

Dipping sonar fitted to a range of military helicopters allows the helicopter

Helicopter

A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...

to protect shipping assets from submarines or surface threats. Maritime support aircraft can drop active and passive sonar devices (Sonobuoy

Sonobuoy

A sonobuoy is a relatively small expendable sonar system that is dropped/ejected from aircraft or ships conducting anti-submarine warfare or underwater acoustic research....

s) and these are also used to determine the location of hostile submarines.

Electro-Optics

Electro-optic systems include devices such as the Head-Up Display

Head-Up Display

A head-up display or heads-up display is any transparent display that presents data without requiring users to look away from their usual viewpoints...

(HUD), Forward Looking Infrared (FLIR), and Passive Infrared Devices (PIDS

Pids

PIDS may refer to:*Passenger Information Display System*Protocol-based intrusion detection system...

). These are all used to provide imagery and information to the flight crew. This imagery is used for everything from navigational aids, Search and Rescue, and target acquisition.

ESM/DAS

Electronic support measures and defensive aids are used extensively to gather information about threats or possible threats. They can be used to launch devices (in some cases automatically) to counter direct threats against the aircraft. They are also used to determine the state of a threat and identify it.

Aircraft Networks

The avionics systems in military, commercial and advanced models of civilian aircraft are interconnected using an avionics databus. Common avionics databus protocols, with their primary application, include:

Aircraft Data Network
Aircraft Data Network
Aircraft Data Network is a concept introduced by the ARINC Airline Electronics Engineering Committee in the ARINC 664 Specification. The specification proposes data networking standards recommended for use in commercial aircraft installations. The standards provide a means to adapt COTS...

(ADN
Aircraft Data Network
Aircraft Data Network is a concept introduced by the ARINC Airline Electronics Engineering Committee in the ARINC 664 Specification. The specification proposes data networking standards recommended for use in commercial aircraft installations. The standards provide a means to adapt COTS...

): Ethernet derivative for Commercial Aircraft
Avionics Full-Duplex Switched Ethernet (AFDX): Specific implementation of ARINC 664 (ADN
Aircraft Data Network
Aircraft Data Network is a concept introduced by the ARINC Airline Electronics Engineering Committee in the ARINC 664 Specification. The specification proposes data networking standards recommended for use in commercial aircraft installations. The standards provide a means to adapt COTS...

) for Commercial Aircraft
ARINC 429
ARINC 429
ARINC 429 is the technical standard for the predominant avionics data bus used on most higher-end commercial and transport aircraft. It defines the physical and electrical interfaces of a two-wire data bus and a data protocol to support an aircraft's avionics local area network.-Messages:ARINC 429...

: Generic Medium-Speed Data Sharing for Private and Commercial Aircraft
ARINC 664
Avionics Full-Duplex Switched Ethernet
Avionics Full-Duplex Switched Ethernet is a data network for safety-critical applications that utilizes dedicated bandwidth while providing deterministic Quality of Service . AFDX is based on IEEE 802.3 Ethernet technology and utilizes commercial off-the-shelf components...

: See ADN above
ARINC 629: Commercial Aircraft (Boeing 777)
ARINC 708
ARINC 708
ARINC 708 is a specification for airborne pulse Doppler weather radar systems primarily found on commercial aircraft. ARINC 708 and the Honeywell Picture bus are the predominant avionics data bus for most aircraft today superseding ARINC 453....

: Weather Radar for Commercial Aircraft
ARINC 717: Flight Data Recorder for Commercial Aircraft
IEEE 1394b: Military Aircraft
MIL-STD-1553
MIL-STD-1553
MIL-STD-1553 is a military standard published by the United States Department of Defense that defines the mechanical, electrical, and functional characteristics of a serial data bus. It was originally designed for use with military avionics, but has also become commonly used in spacecraft on-board...

: Military Aircraft
MIL-STD-1760
MIL-STD-1760
MIL-STD-1760 Aircraft/Store Electrical Interconnection System defines a standardized electrical interface between a military aircraft and its carriage stores. Carriage stores range from weapons, such as GBU-31 JDAM, to pods, such as AN/AAQ-14 LANTIRN, to external fuel tanks...

: Military Aircraft
TTP
TTP
TTP may refer to:* Tehrik-i-Taliban Pakistan , the main Taliban militant umbrella group in Pakistan* Tenderness to palpation, a medical diagnostic such as in Trochleitis...

- Time-Triggered Protocol: Boeing 787 Dreamliner, Airbus A380
Airbus A380
The Airbus A380 is a double-deck, wide-body, four-engine jet airliner manufactured by the European corporation Airbus, a subsidiary of EADS. It is the largest passenger airliner in the world. Due to its size, many airports had to modify and improve facilities to accommodate it...

, Fly-By-Wire Actuation Platforms from Parker Aerospace
TTEthernet
TTEthernet
TTEthernet is a computer network technology marketed by TTTech Computertechnik AG for use in airplanes and other real-time applications.-Description:...

- Time-Triggered Ethernet: NASA Orion Spacecraft

Disaster Relief and Air Ambulance

Disaster Relief and EMS aircraft (mostly helicopters) are now a significant market. Military aircraft are often now built with a role available to assist in civil obedience. Disaster Relief helicopters are almost always fitted with video/FLIR systems to allow them to monitor and co-ordinate realtime relief efforts. They can also be fitted with searchlights and loudspeakers.

EMS and Disaster Relief helicopters will be required to fly in unpleasant conditions, this may require more aircraft sensors, some of which were until recently considered purely for military aircraft.

External links

The Avionic Systems Standardisation Committee
Space Shuttle Avionics
Aviation Today Avionics magazine
RAES Avionics homepage
Vertical Gyroscope Avionics Information
On-Board Electronics related papers (Portuguese)
ISBN 9788536501574 - Book: Eletrônica Embarcada Automotiva (Portuguese)
Repair Factory

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

History

Aircraft avionics

Communications

Navigation

Monitoring

Aircraft flight control systems

Collision-avoidance systems

Weather systems

Aircraft management systems

Mission or tactical avionics

Military communications

Radar

Sonar

Electro-Optics

ESM/DAS

Aircraft Networks

Disaster Relief and Air Ambulance

See also

External links