Helmet-mounted display

A helmet-mounted display (HMD) is a display system built into or attached to a helmet that places an image, usually symbology or sensor video, in front of one or both of the wearer's eyes. Helmet-mounted displays were developed mainly for military aviation, where they let a pilot see flight and targeting information while looking in any direction and aim sensors or weapons by turning the head.

The abbreviation HMD is shared with the head-mounted display, and the U.S. Army's reference work on the subject treats the two together as "helmet-/head-mounted displays (HMDs)". Military helmet displays and head trackers are an important part of the prehistory of virtual reality and augmented reality: Thomas Furness built helmet displays and visually coupled simulators for the U.S. Air Force from 1966 before founding the Human Interface Technology Laboratory at the University of Washington, and the U.S. Army's Integrated Visual Augmentation System (IVAS) program developed a soldier head-up display originally based on the Microsoft HoloLens.

Reviewed 27 September 2026. All history, specification, program and date claims checked against the 2009 USAARL helmet-mounted display book, Li et al. (2013), and the CRS, Microsoft, DefenseScoop, RTX, Road to VR, Defense News and University of Washington sources. About review dates.

Definition and components

Melzer and Moffitt described an HMD as minimally consisting of "an image source and collimating optics in a head mount". Writing from the perspective of U.S. Army rotary-wing aviation, Rash extended this in 2000 to include a coupling system that uses head or eye position to slave one or more aircraft systems, typically a head-directed sensor. That gives four basic elements: an image source with its drive electronics, display optics, the helmet, and a head or eye tracker. Li and colleagues use the same four-element description in their 2013 review of avionic HMDs.

Element	Role
Image source	A display device on which sensor imagery or symbology is reproduced. Early systems used miniature cathode-ray tubes (CRTs) or image-intensifier tubes; later designs use miniature flat-panel displays such as a microdisplay.
Display optics	Magnify and focus the display image and couple it to the eye, usually ending in a partially reflective element called a combiner that merges the see-through view of the real world with the displayed image.
Helmet	Still provides the impact, visual and acoustic protection it was designed for, and also acts as the mounting platform for the image source and optics.
Head tracker	Measures the direction of the wearer's head so that sensors and weapons can be pointed along the same line of sight; optional when the display only shows status information that is not tied to directions in the outside world.

In a more general description by Manning and Rash (2007), which also covers commercial systems that are increasingly called head-worn displays, the mounting platform can range from a simple headband to a full flight helmet, and the relay optics usually end in a beam-splitter or combiner. When the display presents imagery tied to the outside scene, a preflight calibration called boresighting aligns the sensor's line of sight with the user's.

Fielded helmet-mounted displays present a virtual image. According to the Army reference, a virtual image near optical infinity lets the eye relax, allows more users to see the image without corrective optics, and reduces retinal blur caused by vibration.

Visually coupled systems

A head tracker without a full display is sometimes called a helmet-mounted sight. Combined with a helmet-mounted display, it forms what the military calls a visually coupled system (VCS): the tracker is the control input that points sensors, weapons or avionics, and the display gives back symbology or imagery. The authors of the Army reference describe the result as a "look-and-shoot" rather than a "point-the-vehicle-and-shoot" capability. Li and colleagues call HMD applications that cue weapon systems helmet-mounted sights (HMS).

Classification

Shontz and Trumm (1969) sorted HMDs by how imagery reaches the eyes into three types: one-eye occluded, one-eye see-through, and two-eye see-through. A parallel scheme uses the terms monocular, biocular and binocular:

Type	Meaning	Example given in the Army reference
Monocular	Imagery is seen by one eye only	Integrated Helmet and Display Sighting System (IHADSS) on the AH-64 Apache
Biocular	Two optical channels, but both eyes see exactly the same image from the same perspective	Not named
Binocular	Two images, one per eye, from sensors (or a manipulated sensor) displaced in space, giving a perspective difference	Aviator's Night Vision Imaging System (ANVIS), with 100% overlap

Binocular HMDs usually overlap the two images fully, which limits the field of view to that of the optics. To widen it, some designs overlap the channels only partially, giving a central binocular region flanked by two monocular regions; the Kaiser Electronics Helmet Integrated Display Sight System (HIDSS) designed for the Comanche helicopter overlapped about 17 degrees of a 52 degree horizontal field.

Optical designs vary. Most use refractive and reflective lens elements that relay the image to a combiner in front of the eye. Visor-projection designs reflect the image off the helmet visor, which reduces weight, improves the center of mass and increases eye relief, but can suffer from ghost images and vibration. Other approaches use holographic optical elements as powered combiners, lasers that scan an image directly onto the retina (the retinal scanning display), and, in BAE Systems' Q-Sight, a waveguide with embedded holographic optics. Li and colleagues identify weight, field of view, modulation transfer function, exit pupil size and eye relief as the five main optical parameters in avionic HMD design.

History

Early concepts and sights

Both the Army reference and Li and colleagues trace the history of the helmet-mounted display to Albert Bacon Pratt of Lyndon, Vermont, who received a series of U.S. and U.K. patents between 1915 and 1917 for an "integrated helmet mounted aiming and weapon delivery system" for a marksman, in which a helmet-linked gun was aimed by turning the head.

In the 1970s the U.S. Army fielded an electro-mechanical linkage head-tracked sight in the AH-1G Huey Cobra attack helicopter; the pilot aimed the gimbaled gun by placing a helmet-mounted reticle over the target. The U.S. Navy then fitted an electro-optical head-tracking system, the Visual Target Acquisition System (VTAS), to late F-4J and F-4N Phantoms, coupled with the radar and AIM-9H Sidewinder missiles. VTAS used photodiodes on a "halo" assembly on the standard flight helmet and a visor-projected reticle for daytime off-boresight air-to-air targeting. It was discontinued in the 1970s because of technological limitations. Li and colleagues attribute VTAS to Honeywell and give its field of view as 3 to 6 degrees.

In the Soviet Union, a helmet-mounted sight with a flip-down monocle and an LED reticle was developed for the R-73 (AA-11 Archer) high off-boresight missile carried by the MiG-29 and Su-27. The Army reference credits this combination with giving Soviet pilots a greatly improved close-combat capability, and says that Soviet helmet sights paired with missiles of this generation caused a surge in Western HMD development programs.

Computer graphics and simulation

In the late 1960s Ivan Sutherland built a head-tracked display for computer-generated three-dimensional images, which he described in the 1968 paper "A head-mounted three dimensional display". The Army reference credits Sutherland's HMD with opening the way to "computer-generated 3-D stroke images coupled with head trackers", which it calls "the same basic principles applied today".

Thomas Furness began working on visual displays in the U.S. Air Force in 1966, and his work included some of the first helmet-mounted displays and visually coupled systems. In 1982 he presented the Air Force with his first virtual flight simulator, the Visually Coupled Airborne Systems Simulator (VCASS), which he described in an email to Defense News as "a fully immersive three dimensional circumambience of graphical information superimposed over the real world". Pilots wore the helmet while sitting in a cockpit mockup; it used a Polhemus sensor for six-degree-of-freedom head tracking and one-inch CRTs with 2,000 scan lines. VCASS led to the Super Cockpit program in 1986, whose described features included head-aimed and voice-actuated control, a virtual hand controller and an eye control system. Furness directed the Super Cockpit until he joined the University of Washington in 1989.

Simulation and training remained a major use. The Army reference notes that the military and NASA pursued visually coupled systems as an alternative to large domed flight simulators, concentrating resolution and graphics power into the pilot's instantaneous field of view.

Operational systems

The first complete visually coupled system in operational service was the Integrated Helmet and Display Sighting System (IHADSS), introduced by the U.S. Army on the AH-64 Apache attack helicopter; Li and colleagues date it to 1984. IHADSS was also the first HMD in which the helmet and display optics were developed as one system. It is monocular and uses a miniature one-inch CRT with relay optics. The pilot's unit is slaved to a nose-mounted thermal sensor with a 30 by 40 degree field of view, giving one-to-one head-coupled pilotage imagery, while the copilot/gunner's unit is linked to a thermal targeting sensor and to the head-slaved gun and missiles. Flight or fire-control symbology is mixed electronically with the thermal image.

Elbit Systems of Israel developed the Display and Sight Helmet (DASH) series for Israeli Air Force F-15s and F-16s. DASH 3 entered production in the early 1990s together with the Rafael Python 4 missile; it projects stroke symbology onto a spherical visor with a 20 degree field of view and a 15 mm exit pupil and weighs 1.65 kg in the larger helmet size. The Army reference, published in 2009, calls it the first of the new generation of Western HMDs to reach operational service and reports more than 1,000 DASH systems delivered.

DASH technology fed into the Joint Helmet-Mounted Cueing System (JHMCS), built by Vision Systems International, a joint venture of Rockwell Collins and Elbit, for the F-15, F-16 and F/A-18. JHMCS is a monocular visor-projected display for the right eye, driven by a half-inch CRT, with an electromagnetic tracker and a 20 degree field of view. Its main purpose was to slave the AIM-9X Sidewinder missile to the pilot's line of sight. Production deliveries began in 2000, and by early 2007 more than 1,400 units had been delivered to 14 nations.

Helicopter systems followed a different path, since they do not face high-g maneuvering or ejection but need wider fields of view for low-level flight. The Thales TopOwl, fielded on the Eurocopter Tiger and Denel Rooivalk, is a binocular visor-projection helmet with more than 70 mm of eye relief. Its two sensors sit on the sides of the helmet about 286 mm apart, more than four times the normal eye separation. The Army reference notes that side-mounted sensors spaced wider than the eyes can cause hyperstereopsis, in which nearby objects appear closer than they are; on the Eurofighter Typhoon helmet, flight tests found this perceptible below about 1,000 feet.

F-35

The F-35 Lightning II was designed without a dedicated head-up display, with the helmet taking over that role. The Helmet Mounted Display System first flew on 10 April 2007 on the tenth F-35 test flight; the Army reference describes it as replacing the JHMCS CRT with two 0.7-inch SXGA active-matrix LCDs and providing a 40 by 30 degree field of view. The current production version, the F-35 Gen III HMDS, is built by Collins Elbit Vision Systems, a joint venture of Collins Aerospace and Elbit Systems of America. The company describes it as the pilot's "primary display system" and delivered the 3,000th Gen III unit in February 2024; it said it had then provided more than 20,000 systems and logged more than 1 million flight hours on 40 fighter aircraft platforms. The same announcement described Zero-G HMDS+, unveiled about five months earlier, as "the lightest, most capable and safest helmet mounted display system ever developed"; the company said it was designed for next-generation fighter aircraft and can also support fourth- and fifth-generation aircraft.

Human factors

The Army reference lists head-supported weight, center-of-mass offset, changes to head movement, image quality and legibility, and display jitter and lag as the main factors in whether users accept an HMD. Military helmet-based HMDs weighed more than 4 lb (1.8 kg), and because the optics sit in front of the eyes, the extra weight is usually above and forward of the head's natural center of mass, which can cause muscle fatigue over a flight.

When a head-slaved sensor supplies the image, total system latency includes tracking the head, slewing the sensor, capturing the scene and displaying it. The same source reports latencies of hundreds of milliseconds, cites studies finding totals near 300 ms unacceptable, and notes a goal of less than one display frame (typically 33 ms). Such latency has been blamed for motion sickness. Other problems carried over from head-up displays include attention capture (fixating on the symbology rather than the outside scene) and symbology hiding objects in the scene. The 2009 book also discusses binocular rivalry and other perceptual conflicts.

Soldier-worn displays

The concept has also moved from the cockpit to the infantry soldier. In November 2018 the U.S. Army awarded Microsoft an Other Transaction Agreement worth up to $22 billion over 10 years to develop IVAS, whose head-up display was "originally based on Microsoft's commercially available HoloLens". The Army procured 5,000 IVAS 1.0 systems in 2022 and 5,000 IVAS 1.1 systems in 2023. These early versions reportedly caused "mission-affecting physical impairments", including headaches, eyestrain and nausea, and the IVAS 1.2 prototype redesign reduced the field of view from 70 to 60 degrees.

Microsoft and Anduril announced in February 2025 that Anduril would take over production, hardware and software development and delivery timelines, pending Department of Defense approval, with Microsoft Azure as the preferred cloud. The Army reportedly approved the contract novation on 10 April 2025. It renamed the follow-on IVAS Next effort the Soldier Borne Mission Command (SBMC) in March 2025 and awarded prototype contracts to Anduril ($159 million) and the start-up Rivet ($195 million). The Congressional Research Service's July 2026 update cites the Government Accountability Office as reporting that "none of [the 10,000] developed [IVAS] units will be fielded". In August 2026, DefenseScoop reported that Anduril's phase-two SBMC design uses digital night vision with 4K displays; according to an Anduril executive, the full head-up display weighs about 110 grams and a production award could come in fiscal 2028.

Relationship to VR and AR headsets

The Army reference places HMDs on the reality-virtuality continuum: a see-through helmet display overlays computer-generated information on the real world, as in augmented reality, while an opaque one replaces the view, as in virtual reality. It notes that virtual reality spurred interest in HMDs in industry and among the general public, and that HMD use in military and industrial simulation and training "served as a precursor to consumer gaming". Its list of commercial and consumer applications includes computer-aided design, surgery, maintenance and gaming.

See also

• Head-mounted display
• Head-up display
• Thomas Furness
• Sword of Damocles
• Optical combiner
• Head tracking
• Microsoft HoloLens