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A helmet-mounted display (HMD) is a device used in aircraft to project information to the pilot's eyes. Its scope is similar to that of head-up displays (HUD) on an aircrew's visor or reticle. An HMD provides the pilot with situation awareness, an enhanced image of the scene, and in military applications cue weapons systems, to the direction their head is pointing. Applications which allow cuing of weapon systems are referred to as helmet-mounted sight and display (HMSD) or helmet-mounted sights (HMS).
Aviation HMD designs serve these purposes:
HMD systems, combined with High Off-Boresight (HOBS) weapons, results in the ability for aircrew to attack and destroy nearly any target seen by the pilot. These systems allow targets to be designated with minimal aircraft maneuvering, minimizing the time spent in the threat environment, and allowing greater lethality, survivability, and pilot situational awareness.
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In 1962, Hughes Aircraft Company revealed the Electrocular, a compact CRT, head-mounted monocular display that reflected a TV signal onto a transparent eyepiece.
The first aircraft with simple HMD devices appeared for experimental purpose in the mid-1970s to aid in targeting heat seeking missiles. These rudimentary devices were better described as Helmet-Mounted Sights. The US Navy's Visual Target Acquisition System (VTAS), made by Honeywell Corporation was a simple mechanical "ring and bead"–style sight fitted to the front of the pilot's helmet that was flown in the 1974–78 ACEVAL/AIMVAL on U.S. F-14 and F-15 fighters. VTAS received praise[ by whom? ] for its effectiveness in targeting off-boresight missiles, but the U.S. did not pursue fielding it except for integration into late-model Navy F-4 Phantoms equipped with the AIM-9 Sidewinder from 1969. HMDs were also introduced in helicopters during this time - examples include the Boeing AH-64 Apache with the Integrated Helmet and Display Sighting System (IHADSS) demonstrated in 1985.
In the 1970s, Mirage F1AZ of the SAAF (South African Air Force) used a locally developed helmet-mounted sight integrated with the Armscor V3A heat seaking missile.This enables the pilot to make off-bore attacks, without having to maneuver to the optimum firing position. After the South African system had been proven in combat, playing a role in downing Soviet aircraft over Angola, the Soviets embarked on a crash program to counter the technology. As a result, the MiG-29 was fielded in 1985 with an HMD and a high off-boresight weapon (R-73), giving them an advantage in close in maneuvering engagements.
Several nations[ which? ] responded with programs to counter the MiG-29/HMD/R-73 (and later Su-27) combination once its effectiveness was known, principally through access to former East German MiG-29s that were operated by the unified German Air Force.
One successful HMD was the Israeli Air Force Elbit DASH series, fielded in conjunction with the Python 4, in the early 1990s. The U.S., UK, and Germany pursued a HMD combined with ASRAAM systems. Technical difficulties led to the U.S. abandoning ASRAAM, instead funding development of the AIM-9X and the Joint Helmet-Mounted Cueing System in 1990. American and European fighter HMDs became widely used in the late 1990s and early 2000s.
The first civilian use of HMD on aircraft was the Elbit SkyLens HMD on ATR 72/42 airplane.
While conceptually simple, implementation of aircraft HMDs is quite complex. There are many variables:
HMD designs must sense the orientation (elevation, azimuth and roll) and in some cases the position (x, y, and z) of the pilot's head relative to the airframe with sufficient precision even under high "g", vibration, and during rapid head movement. Five basic methods are used in current HMD technology – inertial, optical, electromagnetic, sonic, and hybrid.Hybrid trackers use a combination of sensors such as inertial and optical to improve tracking accuracy, update rate, and latency.
Hybrid inertial tracking systems employ a sensitive Inertial Measurement Unit (IMU) and an optical sensor to provide reference to the aircraft. MEMS based IMUs benefit from high update rates such as 1,000 Hz but suffer from precession and drift over time, so they cannot be used alone. In this class of tracker, the optical sensor is used to constrain IMU drift. As a result, hybrid inertial/optical trackers feature low latency and high accuracy. The Thales Visionix Scorpion HMCS and HMIT HMDs utilize a tracker made by InterSense called the Hybrid Optical-based Inertial Tracker (HObIT).
Optical systems employ infrared emitters on the helmet (or flightdeck) infrared detectors in the flightdeck (or helmet), to measure the pilot's head position. The main limitations are restricted fields of regard and sensitivity to sunlight or other heat sources. The MiG-29/AA-11 Archer system uses this technology.The Cobra HMD as used on both the Eurofighter Typhoon and the JAS39 Gripen both employ the optical helmet tracker developed by Denel Optronics (now part of Zeiss Optronics ).
Electromagnetic sensing designs use coils (in the helmet) placed in an alternating field (generated in the flightdeck) to produce alternating electrical voltages based on the movement of the helmet in multiple axes. This technique requires precise magnetic mapping of the flightdeck to account for ferrous and conductive materials in the seat, flightdeck sills and canopy to reduce angular errors in the measurement.
Acoustic sensing designs use ultrasonic sensors to monitor the pilot's head position while being updated by computer software in multiple axes. Typical operating frequencies are in the 50 to 100 kHz range and can be made to carry audio sound information directly to the pilot's ears via subcarrier modulation of the sensong ultrasonic sensing signals. [ failed verification ]
Older HMDs typically employ a compact CRT embedded in the helmet, and suitable optics to display symbology on to the pilot's visor or reticle, focused at infinity. Modern HMDs have dispensed with the CRT in favor of micro-displays such as liquid crystal on silicon (LCOS) or liquid crystal display (LCD) along with an LED illuminator to generate the displayed image. Advanced HMDs can also project FLIR or NVG imagery. A recent improvement is the capability to display color symbols and video.
Systems are presented in rough chronological order of initial operating capability.
In 1985,the U.S. Army fielded the AH-64 Apache and with it the Integrated Helmet and Display Sighting System (IHADSS), a new helmet concept in which the role of the helmet was expanded to provide a visually coupled interface between the aviator and the aircraft. The Honeywell M142 IHADSS is fitted with a 40°-by-30° field of view, video-with-symbology monocular display. IR emitters allow a slewable thermographic camera sensor, mounted on the nose of the aircraft, to be slaved to the aviator's head movements. The display also enables Nap-of-the-earth night navigation. IHADSS is also used on the Italian Agusta A129 Mangusta.
The Russian designed Shchel-3UM HMD design is fit to the ZSh-5 series helmet (and later ZSh-7 helmets), and is used on the MiG-29 and Su-27 in conjunction with the R-73 (missile). The HMD/Archer combination gave the MiG-29 and Su-27 a significantly improved close combat capability and quickly became the most widely deployed HMD in the world.
The Elbit Systems DASH III was the first modern Western HMD to achieve operational service. Development of the DASH began during the mid-1980s, when the IAF issued a requirement for F-15 and F-16 aircraft. The first design entered production around 1986, and the current GEN III helmet entered production during the early to mid-1990s. The current production variant is deployed on IDF F-15, and F-16 aircraft. Additionally, it has been certified on the F/A-18 and F-5. The DASH III has been exported and integrated into various legacy aircraft, including the MiG-21.It also forms the baseline technology for the US JHMCS.
The DASH GEN III is a wholly embedded design, where the complete optical and position sensing coil package is built within the helmet (either USAF standard HGU-55/P or the Israeli standard HGU-22/P) using a spherical visor to provide a collimated image to the pilot. A quick-disconnect wire powers the display and carries video drive signals to the helmet's Cathode Ray Tube (CRT). DASH is closely integrated with the aircraft's weapon system, via a MIL-STD-1553B bus. Latest model DASH IV is currently integrated on India's HAL Tejas.
After the U.S. withdrawal from ASRAAM, the U.S. pursued and fielded JHMCS in conjunction with the Raytheon AIM-9X, in November 2003 with the 12th and 19th Fighter Squadrons at Elmendorf AFB, Alaska. The Navy conducted RDT&E on the F/A-18C as lead platform for JHMCS, but fielded it first on the F/A-18 Super Hornet E and F aircraft in 2003. The USAF is also integrating JHMCS into its F-15E, F-15C, and F-16C aircraft.
JHMCS is a derivative of the DASH III and the Kaiser Agile Eye HMDs, and was developed by Vision Systems International (VSI), a joint venture company formed by Rockwell Collins and Elbit (Kaiser Electronics is now owned by Rockwell Collins). Boeing integrated the system into the F/A-18 and began low-rate initial production delivery in fiscal year 2002. JHMCS is employed in the F/A-18A++/C/D/E/F, F-15C/D/E, and F-16 Block 40/50 with a design that is 95% common to all platforms.
Unlike the DASH, which is integrated into the helmet itself, JHMCS assemblies attach to modified HGU-55/P, HGU-56/P or HGU-68/P helmets. JHMCS employs a newer, faster digital processing package, but retains the same type of electromagnetic position sensing as the DASH. The CRT package is more capable, but remains limited to monochrome presentation of cursive symbology. JHMCS provides support for raster scanned imagery to display FLIR/IRST pictures for night operations and provides collimated symbology and imagery to the pilot. The integration of the night-vision goggles with the JHMCS was a key requirement of the program.
When combined with the AIM-9X, an advanced short-range dogfight weapon that employs a Focal Plane Array seeker and a thrust vectoring tail control package, JHMCS allows effective target designation up to 80 degrees either side of the aircraft's nose. In March 2009, a successful 'Lock on After Launch' firing of an ASRAAM at a target located behind the wing-line of the ‘shooter' aircraft, was demonstrated by a Royal Australian Air Force (RAAF) F/A-18 using JHMCS.
Thales Introduced the Scorpion Head/Helmet-Mounted Display System to the military aviation market in 2008. In 2010 Scorpion was the winner of the USAF/ANG/AFRes Helmet Mounted Integrated Targeting (HMIT) program.The HMIT system was qualified and deployed on both A-10 and F-16 platforms in 2012. Starting in 2018, the installed base of HMIT systems are going through a helmet tracker upgrade. The original AC magnetic tracking sensor is being replaced by an inertial-optical hybrid tracker called Hybrid Optical based Inertial Tracker (HObIT). The HObIT was developed by InterSense and tested by Thales in 2014.
Scorpion has the distinction of being the first HMD introduced and deployed that can display color symbols.It is used along with the aircraft mission system to cue the aircraft targeting pod gimbaled sensor and high off-boresight missile. Unlike most HMDs which require custom helmets, Scorpion was designed to be installed on a standard issue HGU-55/P and HGU-68/P helmets and is fully compatible with standard issue U.S. Pilot Flight Equipment without special fitting. It is also fully compatible with standard unmodified AN/AVS-9 Night Vision Goggles (NVG) and Panoramic Night Vision Goggles (PNVG). Pilots, using Scorpion, can view both the night vision image and the symbols on the display.
Scorpion uses a novel optical system featuring a light-guide optical element (LOE) which provides a compact color collimated image to the pilot. This allows the display to be positioned between the pilot's eyes and NVGs. The display can be positioned as the pilot wishes thereby eliminating the need for precise helmet position on the user's head. Software correction accommodates the display position, providing an accurate image to the pilot and allowing the Scorpion HMCS to be installed onto a pilot's existing helmet with no special fitting. A visor can be deployed in front of the display providing protection during ejection. The visor can be clear, glare, high contrast, gradient, or laser protective. An NVG mount can be installed in place of the visor during flight. Once installed, NVGs can be placed in front of the display, thus allowing the pilot to view both the display symbols as well as the NVG image simultaneously.
Aselsan of Turkey is working to develop a similar system to the French TopOwl Helmet, called the AVCI Helmet Integrated Cueing System. The system will also be utilized into the T-129 Turkish Attack Helicopter.
The French thrust vectoring Matra MICA (missile) for its Dassault Rafale and late-model Mirage 2000 fighters was accompanied by the Topsight HMD by Sextant Avionique. TopSight provides a 20 degree FoV for the pilot's right eye, and cursive symbology generated from target and aircraft parameters. Electromagnetic position sensing is employed. The Topsight helmet uses an integral embedded design, and its contoured shape is designed to provide the pilot with a wholly unobstructed field of view.
TopNight, a Topsight derivative, is designed specifically for adverse weather and night air to ground operations, employing more complex optics to project infrared imagery overlaid with symbology. The most recent version the Topsight has been designated TopOwl-F, and is qualified on the Mirage-2000-5 Mk2 and Mig-29K.
The Eurofighter Typhoon utilizes the Helmet-Mounted Symbology System (HMSS) developed by BAE Systems and Pilkington Optronics. Named the Striker and later version Striker II. It is capable of displaying both raster imagery and cursive symbology, with provisions for embedded NVGs. As with the DASH helmet, the system employs integrated position sensing to ensure that symbols representing outside-world entities move in line with the pilot's head movements.
Vision Systems International (VSI; the Elbit Systems/Rockwell Collins joint venture) along with Helmet Integrated Systems, Ltd. developed the Helmet-Mounted Display System (HMDS) for the F-35 Joint Strike Fighter aircraft. In addition to standard HMD capabilities offered by other systems, HMDS fully utilizes the advanced avionics architecture of the F-35 and provides the pilot video with imagery in day or night conditions. Consequently, the F-35 is the first tactical fighter jet in 50 years to fly without a HUD.A BAE Systems helmet was considered when HMDS development was experiencing significant problems, but these issues were eventually worked out. The Helmet-Mounted Display System was fully operational and ready for delivery in July 2014.
Jedeye is a new system recently introduced by Elbit Systems especially to meet Apache and other rotary wing platform requirements. The system is designed for day, night and brownout flight environments. Jedeye has a 70 x 40 degree FOV and 2250x1200 pixels resolution.
Sweden's JAS 39 Gripen fighter utilizes the Cobra HMD. The helmet is a further development and refinement of the Striker helmet developed for the Eurofighter by BAE Systems. The refinement is done by BAE in partnership with Denel Cumulus.
The Lockheed Martin F-35 Lightning II is an American family of single-seat, single-engine, all-weather stealth multirole combat aircraft that is intended to perform both air superiority and strike missions. It is also able to provide electronic warfare and intelligence, surveillance, and reconnaissance capabilities. Lockheed Martin is the prime F-35 contractor, with principal partners Northrop Grumman and BAE Systems. The aircraft has three main variants: the conventional takeoff and landing (CTOL) F-35A, the short take-off and vertical-landing (STOVL) F-35B, and the carrier-based (CV/CATOBAR) F-35C.
The Rafael Python is a family of air-to-air missiles (AAMs) built by the Israeli weapons manufacturer Rafael Advanced Defense Systems, formerly RAFAEL Armament Development Authority. Originally starting with the Shafrir series, the Shafrir-1 missile was developed in 1959, followed by the Shafrir-2 in early 1970s. Subsequently, the missiles were given the western name of "Python" by the parent company for export purposes, starting with the Python-3 in 1978. Since then, it has been further developed and evolved into the Python-4, Python-5, Derby and also, the SPYDER, an advanced ground-based air-defence system. Currently, the missiles are in service with the armed forces of over fifteen countries from around the world.
Missile guidance refers to a variety of methods of guiding a missile or a guided bomb to its intended target. The missile's target accuracy is a critical factor for its effectiveness. Guidance systems improve missile accuracy by improving its Probability of Guidance (Pg).
A head-up display, also known as a HUD, is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a pilot being able to view information with the head positioned "up" and looking forward, instead of angled down looking at lower instruments. A HUD also has the advantage that the pilot's eyes do not need to refocus to view the outside after looking at the optically nearer instruments.
Low Altitude Navigation and Targeting Infrared for Night, or LANTIRN, is a combined navigation and targeting pod system for use on the United States Air Force fighter aircraft — the F-15E Strike Eagle and F-16 Fighting Falcon. LANTIRN significantly increases the combat effectiveness of these aircraft, allowing them to fly at low altitudes, at night and under-the-weather to attack ground targets with a variety of precision-guided weapons.
HOTAS, an acronym of hands on throttle-and-stick, is the concept of placing buttons and switches on the throttle lever and flight control stick in an aircraft's cockpit. By adopting such an arrangement, pilots are capable of performing all vital functions as well as flying the aircraft without having to remove their hands from the controls.
The Target Acquisition and Designation Sights, Pilot Night Vision System (TADS/PNVS) is the combined sensor and targeting unit fitted to the Boeing AH-64 Apache helicopter. Both systems are independent, but housed together.
A head-mounted display (HMD) is a display device, worn on the head or as part of a helmet, that has a small display optic in front of one or each eye. An HMD has many uses including gaming, aviation, engineering, and medicine. Virtual reality headsets are HMDs combined with IMUs. There is also an optical head-mounted display (OHMD), which is a wearable display that can reflect projected images and allows a user to see through it.
An infrared search and track (IRST) system is a method for detecting and tracking objects which give off infrared radiation such as jet aircraft and helicopters.
The IAR 99 Șoim (Hawk) is an advanced trainer and light attack aircraft capable of performing close air support and reconnaissance missions. The IAR 99 replaced the Aero L-29 Delfin and Aero L-39 Albatros as the jet trainer of the Romanian Air Force. The aircraft is of semi-monocoque design, with tapered wings and a swept-back tail unit. A large blade-type antenna installed beneath the nose on the port side of the fuselage gives the IAR 99 trainer a distinctive appearance.
Pupillary distance (PD) or interpupillary distance (IPD) is the distance measured in millimeters between the centers of the pupils of the eyes. This measurement is different from person to person and also depends on whether they are looking at near objects or far away. Monocular PD refers to the distance between each eye and the bridge of the nose which may be slightly different for each eye due to anatomical variations. For people who need to wear prescription glasses consideration of monocular PD measurement by an optician helps to ensure that the lenses will be located in the optimum position.
The V3E A-Darter is a modern short-range infrared homing air-to-air missile, featuring countermeasures resistance with a 180-degree look angle and 120-degrees per second track rate, developed by South Africa's Denel Dynamics and Brazil's Mectron, Avibras and Opto Eletrônica. It will equip the South African Air Force's Saab JAS 39 Gripen C/D and BAe Hawk 120, and the Brazilian Air Force's A-1M AMX, Northrop F-5BR and Gripen E/F. It was expected to be in production before the end of 2015.
A large number of variants of the General Dynamics F-16 Fighting Falcon have been produced by General Dynamics, Lockheed Martin, and various licensed manufacturers. The details of the F-16 variants, along with major modification programs and derivative designs significantly influenced by the F-16, are described below.
The AN/AAQ-37 Electro-optical Distributed Aperture System (DAS) is the first of a new generation of sensor systems being fielded on the Lockheed Martin F-35 Lightning II Joint Strike Fighter. DAS consists of six high-resolution infrared sensors mounted around the F-35's airframe in such a way as to provide unobstructed spherical coverage and functions around the aircraft without any pilot input or aiming required.
An Enhanced flight vision system is an airborne system which provides an image of the scene and displays it to the pilot, in order to provide an image in which the scene and objects in it can be better detected. In other words, an EFVS is a system which provides the pilot with an image which is better than unaided human vision. An EFVS includes imaging sensors such as a color camera, infrared camera or radar, and typically a display for the pilot, which can be a head-mounted display or head-up display. An EFVS may be combined with a synthetic vision system to create a combined vision system.
Lumus is an Israeli-based Augmented Reality company headquartered in Ness Ziona, Israel. Founded in 2000, Lumus has developed technology for see-through wearable displays, via its patented Light-guide Optical Element (LOE) platform to market producers of smart glasses and augmented reality eyewear. Lumus' technology enables a small natural looking form factor, wide field of view and true see-through performance.
The PL-10 is a short-range, infrared-homing air-to-air missile (AAM) developed by the People's Republic of China. It was designed by Dr. Liang Xiaogeng (梁晓庚) at the Luoyang Electro Optical Center, which is also known as Institute 612 and renamed in 2002 as the China Air-to-Air Guided Missile Research Institute (中国空空导弹研究院). Development of the missile commenced in 2004 for use on stealth fighters such as the J-20.
LifeBEAM, founded in 2011, is an artificial-intelligence wearables technology company. The technology was originally developed for monitoring pilots, astronauts and special forces through sensors in their helmets. It was then expanded to consumer fitness products, including artificially intelligent wearables, such as Vi.
The EuroFirst Passive Infrared Airborne Track Equipment (PIRATE) is the Forward looking infrared (FLIR) / Infra-red search and track (IRST) for the Eurofighter Typhoon. It is produced by the EuroFIRST consortium consisting of Leonardo S.p.A. of Italy, THALES Land & Joint Systems of the UK, and TECNOBIT of Spain. The system is mounted on the port side of the fuselage, forward of the windscreen and provides passive and thus undetectable and unjammable means of long range surveillance. In addition the system has been shown to locate stealth aircraft at a "significant distance" with further improvements in detection through software updates. PIRATE detects heat caused on an aircraft's skin caused by air friction.
TAM Management (TAMM) is a private Georgian military manufacturer which specializes in maintenance, repair, overhaul, design and manufacturing of: military aircraft, civilian aircraft & air to air missiles. It was founded in 2015 on the territory of "Tbilaviamsheni" but is separate entity.
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