The Integrated Helmet Audio Visual System (IHAVS) is a joint advanced strike technology project which integrated previously but separately demonstrated audio and visual cockpit technologies into a single system. These technologies included a helmet mounted display system, a 3-D audio system with active noise reduction, voice control/speech recognition, and an imaging FLIR targeting system. A flight demonstration program on a TAV-8B aircraft is performing mission management and air-to-ground attack functions, demonstrating the operational utility of IHAVS technologies for strike missions. This paper serves to introduce the SPIE conference session and the associated papers that will describe in detail the IHAVS technologies, system development, integration and flight demonstration.
The Integrated Helmet Audio/Visual System (IHAVS) suite is composed of the GEC Helmet Mounted Display (HMD), Armstrong Labs 3-D Audio system, Polhemus Head Tracker (HT) and SMiths Interactive Voice Module (IVM). The LORAL NITE Hawk Targeting Self Cooled IR pod (TFLIR) was added, supplementing the IHAVS for off-boresight target management. The lightweight HMD generates a high resolution visor projected display. Symbology displayed within the binocular and fully overlapped 40 degree field of view presents aircraft moding, navigation, weapon delivery, and threat data to the pilot. The 3-D Audio system generates four audio cues localized to within 10 degrees of the commanded position. THe specialized headset localizes TFLIR position and threat audio cues. The HT system provides helmet position to the aircraft, the HMD and 3-D Audio system. Twelve IVM digital voice output reports aircraft status. The T/AV-8B aircraft and avionics architecture are discussed laying the foundation for the described integration of the IHAVS suite. Integrated together, these systems provide the pilot with greatly increased field of regard for target recognition, designation and attack. Tightly coupled to the IHAVS suite, the TFLIR allows off-boresight target management and the field of regard is well matched and complements the IHAVS.
The Naval Air Warfare Center Weapons Division, China Lake, conducted a flight demonstration program of the Integrated Helmet Audio/Visual System on the TAV-8B (trainer AV-8B) aircraft under the Joint Advanced Strike Technology program. This paper describes the methodology for the testing that was performed and provides some background about the scenarios that were chosen for each of the tests. The flight tests were set up to provide a broad spectrum of the operational environment while minimizing the number of engagements. Also discussed are the data resultant from the testing.
There is a critical need across the Services to improve the effectiveness of aircrew within the crewstation by capitalizing on the natural psycho-motor skills of the pilot through the use of a variety of helmet-mounted visual display and control techniques. This has resulted in considerable interest and significant ongoing research and development efforts on the part of the Navy, as well as the Army and the Air Force, in the technology building blocks associated with this area, such as advanced head position sensing or head tracking technologies, helmet- mounted display optics and electronics, and advanced night vision or image intensification technologies.
A notable effort within the Joint Advanced Strike Technology (JAST) program is the Integrated Helmet Audio-Visual System (IHAVS) project. The objective of the JAST/IHAVS effort is to integrate an off-the-shelf helmet-mounted display, an interactive voice module and three-dimensional sound technology into a T/AV-8B attack aircraft for a flight demonstration program. As part of this effort, the Armstrong Laboratory's Aerospace Vision Laboratory was tasked to participate in the selection and design of the helmet-mounted display visual symbology sets, sensor imagery integration, and overall helmet-resident visual information concept. The Aerospace Visions Laboratory's Visually Coupled Airborne Systems Simulator provides the only dynamic presentation of the IHAVS symbology and was used as a predemonstration tool to familiarize the project's test pilots with the symbologies and imagery in an interactive simulation. Besides providing a symbology and imagery interface representative of the IHAVS demonstration aircraft, additional symbol designs developed by Aerospace Vision Laboratory personnel were made available. The test pilots' subjective feedback from the simulator demonstrations is discussed and recommendations by the Aerospace Vision Laboratory team are presented.
Loral Aeronutronic is supporting the IHAVS project by integrating Navy-furnished NITE Hawk Targeting FLIR Pod (AN/AAS-38B) Weapons Replaceable Assemblies (WRAs) with Loral-furnished aft section and interface module WRAs for flight testing on a TAV-8B. Loral developed an aft section WRA without the conformal fairing required for installation on an F/A-18 and incorporated a self-cooling system. WRAs from the AN/AAS-38B pod are integrated in this aft section to provide a pod which is functionally the same as the F/A-18 system yet can be installed on any aircraft. Loral calls this derivative of the F/A-18 NITE Hawk pod the NITE Hawk Self-Cooled (SC) pod. The NITE Hawk SC has also has also been flight demonstrated on the F-15, F-16 and F-14 platforms and is the baseline laser targeting system on the Spanish Air Force's EF-2000 aircraft. The Loral-developed interface module WRA provides the capability to translate messages from any aircraft mission computer into the particular format design for the F/A-18 controller processor WRA. This maintains maximum commonality to the AN/AAS-38B WRAs. The interface module provides for signal processing of the FLIR video and includes the capability to electronically zoom, freeze, and format the video output into any standard required by the aircraft.
Headgear systems for the dismounted soldier are being developed that will provide an extensive set of new capabilites on the battlefield. These systems provide dramatically enhanced audio and visual information flow to and from the soldier. Integrated/modular headgear components include a miniature helmet mounted high resolution display, an advanced intensified night sensor, a head orientation sensor, advanced signal processing electronics, a helmet mounted radio antenna, in addition to new ballistic protection and helmet suspension and communication components.
This paper describes a demonstration of monocular helmet/head mounted display (HMD) approaches conducted at Fort Benning, Dismounted Battlespace Battle Lab. The objective of the monocular demonstration was to explore soldier impressions of monocular HMD concepts relevant to the Generation II Soldier Systems (GEN II) program, and to do so in realistic field settings. Two monocular HMD prototypes were demonstrated to infantry soldiers in daylight, dusk, and night conditions. In general, soldiers found both see-through and look-around monocular HMD approaches to be acceptable, with perceptual differences in approaches most pronounced in daylight viewing. The look-around approach was associated with the best daylight visibility of the electronic display, while the see-through approach was associated with the best daylight visibility of the natural world. Soldier feedback on the acceptabilty of the various HMD configurations will allow the GEN II team to more adequately evaluate HMD design trades in the future.
The first VGA (640 X 480) electroluminescent display is reported with a 24 micron pixel pitch and over 1000 lines per inch resolution. The display measures 0.71 inches by 0.53 inches and was designed specifically for head mounted applications. The display is fabricated on single crystal silicon-on-insulator wafers which allows the integration of the pixel as well as the peripheral addressing circuitry onto the display. Initial samples have been built utilizing both a green (ZnS:Tb), and an amber (ZnS:Mn) EL phosphor. Luminance, contrast ratio and power dissipation for displays operating at a 4.5 kHz drive frequency with a 60 Hz frame rate will be presented. Results indicate that this VGA display shows ideal characteristics for compact high performance head mounted applications.
The Advanced Image Intensifier Advanced Technology Demonstrator is an Army program to develop and demonstrate the next generation of night vision goggle using revolutionary new technologies to improve system performance and expand the capability of currently fielded image intensifier devices. The Advanced Image Intensifier is a helmet mounted imaging and display system that exploits recent advances in diffractive optics, miniature flat panel displays, image intensifier tube technology and manufacturing processes. The system will demonstrate significantly enhanced operational performance by increasing low-light resolution by greater than 25 percent; increasing field of view from 40 degrees to 60 degrees; improving high light performance; and integrating a display for viewing thermal imagery, computer graphics, and symbology. The results of these improvements will increase the night fighting capability, operational effectiveness, mobilty, versatility, and survivability of the dismounted soldier and aviator.
Demand for color head- and helmet-mounted displays (HMDs) is growing. Interest focuses on full-color systems, but a limited color repertoire is sufficient for some applications and can reduce cost and complexity significantly, especially when implemented using subtractive-color active-matrix liquid-crystal display (AMLCD) technology. Recently, Honeywell completed an extensive series of human factors experiments to answer important questions about the design and merits of two-primary subtractive-color AMLCDs for HMD applications. Our main conclusion is that a subtractive-color AMLCD with high aperture ratio should yield better image quality than a comparable spatially integrative AMLCD. Making use of a two-primary display's ability to produce mixture colors (e.g., yellow and orange) could also prove beneficial. This paper summarizes the experiments and findings that lead to these and other conclusions.
This paper presents a brief overview of the Combat Vehicle Crew Helmet Mounted Display (CVCHMD) enhanced user system which allows M1A2 rank commanders to accesss electronic battlefield information while out of hatch. The system provides the same information as the commanders independent display located in the turret of the M1A2, but provides it on a HMD. This paper describes the development and testing of the prototype CVCHMD symbology and screens. It discusses the design trade-offs of providing a maximum amount of information while keeping the HMD screens clutter free. It describes the systems symbology, screen layout, and functionality. This paper also describes tests conducted with the enhanced user system by integrating it into an M1A2 tank simulator at the Army's Distributed Interactive Simulation (DIS) facility at Fort Knox, Kentucky. The DIS testing showed that the CVCHMD enhanced user system would greatly cut down on the number of times an M1A2 tank commander would have to jump back into the tank turret, thus increasing the amount of time they could spend out of hatch. The testing also showed that the system can improve the fightability and survivability of the M1A2 tank.
The Advanced Flat Panel program is developing high resolution color head mounted display systems for medical and low power applications. The first phase of the program has developed a stereoscopic head-mounted display for arthroscopic and endoscopic surgical applications using high resolution color AMLCDs and 1280 by 1024 spatially colored active matrix electroluminescent image sources. The next phase of the program will target low power color HMD applications with sequentially colored 1280 by 1024 AMEL devices and conclude with the demonstration of a 2560 by 2048 flat panel HMD. The medical HMD design and preliminary user evaluation of the system are discussed here along with a review of the spatially colored AMEL performance and a comparison of system architectures of the three different high resolution color displays that are being demonstrated on this program.
Modern fighter aircraft windscreens are typically made of curved, transparent plastic for improved aero-dynamics and bird-strike protection. Since they are curved these transparencies often refract light in such a way that a pilot looking through the transparency will see a target in a location other than where it really is. This effect has been known for many years and methods to correct the aircraft head-up display (HUD) for these angular deviations have been developed and employed. The same problem will occur for helmet-mounted displays (HMDs) used for target acquisition only worse due to the fact the pilot can look through any part of the transparency instead of being constrained to just the forward section as in the case of the HUD. To determine the potential impact of these windscreen refraction errors two F-15 windscreens were measured; one acrylic and one multilayer acrylic and polycarbonate laminate. The average aiming error measured for the acrylic was 3.6 milliradians with a maximum error of 9.0 milliradians. The laminated windscreen was slightly worse at 4.1 milliradians average error and 10.5 milliradians maximum. These aiming errors were greatly reduced by employing correction algorithms which could be applied to the aiming information on the HMD. Subtleties of coordinate systems and roll correction are also addressed.
Application of technology for head-slaved pointing of imaging and weapons systems has been employed in military cockpits for many years. As the sophistication of the aircraft systems increases and the dynamics of the operational needs of head-slaved systems become more complex, a technology that meets this challenging need is required. A technology that appears to answer this need is magnetic head tracking. However, even magnetic technology with its low latency, high dynamic performance, and solid-state reliability has fundamental issues that complicate its introduction into the challenging environment of the aircraft cockpit. This paper addresses the barriers commonly associated with the technology and discusses the results of a new-generation magnetic-based head tracker that breaks down and removes these barriers.
One of the major advantages of HMDs is the display of information wherever the pilot is looking. These displays, however, raise important human factor issues for the optimal method of presenting attitude information. For example, problems may occur when the pilot looks off- boresight and is provided with information that is based upon the forward view of the aircraft (i.e. aircraft-referenced) and is thus incongruent. An experiment was conducted to examine this issue in which a traditional pitch ladder format was compared against the novel 'cylinder' format in an off-boresight attitude control task on a simulated HMD. This task involved recovery from unusual positions (UPs) which were presented at various off-boresight angles. Subjects' initial response times were faster for the pitch ladder format than for the two formats for total recovery times, error rates, height deviations, situational awareness rating technique or the questionnaire data. It was concluded that the performance on the cylinder format may be explained by the subjects' past experience using the pitch ladder or by the lack of information available when the aircraft was slightly nose-up or nose-down. It was suggested that improvements should be made to the cylinder if it is to be further examined in future research. Finally, the implications of this research for future work are discussed.
The performance of the integrated helmet display sighting system used in the AH-64 Apache hilicopter has been evaluated. Measured parameters included physical and optical eye relief, exit pupil size and position, field-of-view, luminance range, transmittance and reflectance characteristics, and static and temporal response. The purpose of the evaluation was to provide a performance baseline for comparison with future helmet mounted display designs.
In the event that all pilot efforts to recover a serverely disabled aircraft have failed, the pilot may be forced to eject from the aircraft. A pull of the ejection handles launches the pilot into the violent, complicated environment of an aircraft ejection. Aircraft altitude and velocity, pilot physiology and body posture, pilot personal equipment, and helmet/HMD characteristics are just a few broad categories comprising the vast list of variables potentially influencing the pilot's chances of surviving an ejection. The nearly infinite number of permutations of these variables describing any given ejection makes predicting, modeling, and simulating such an environment very difficult. Moreover, developing criteria and designing test and evaluation methodologies for certifying advanced helmet systems as 'safe-to-fly' is an increasingly frustrating process characterized by too many unknowns and too little data. In order to accurately simulate the aircraft ejection environment in performing test and evaluation of advanced helmet systems, especially helmet-mounted displays (HMDs), a better understanding of helmet/HMD dynamics is required. This study attempts to develop a model combining the two major force contributions during aircraft ejection: windblast forces due to canopy jettison and g-forces imparted by rapid acceleration out of the aircraft. By superimposing data collected from windblast tests and from ejection-tower tests, more accurate resultant head/neck loads can be calculated in determining whether a given helmet/HMD design should receive the 'safe-to-fly' certification.
The Covert Night/Day Operations for Rotorcraft (CONDOR) program is a collaborative research and development program between the governments of the United States and the United Kingdom of Great Britain and Northern Ireland to develop and demonstrate an advanced visionics concept coupled with an advanced flight control system to improve rotorcraft mission effectiveness during day, night, and adverse weather conditions in the Nap- of-the-Earth environment. The Advanced Visionics System for CONDOR is the flight- ruggedized head mounted display and computer graphics generator with the intended use of exploring, developing, and evaluating proposed visionic concepts for rotorcraft including; the application of color displays, wide field-of-view, enhanced imagery, virtual displays, mission symbology, stereo imagery, and other graphical interfaces.
The AN/AVS-7 head up display (HUD) system is designed to enhance night vision goggle pilotage by superimposing aircraft, navigation and flight symbology on the aviator's night vision imaging system. The AN/AVS-7 system is produced by AEL Industries Inc., Cross Systems Division under a five year production contract with the Army's Communications and Electronics Command. The program is managed by the Army's Project Manager for Night Vision, Reconnaissance, Surveillance and Target Acquisition.
A dangerous situation is created when the pilot looks inside the cockpit for instrument information when flying combat and low altitude missions. While looking at instruments, a pilot cannot be performing situation analysis; yet not looking at instruments runs such risks as flying into the ground, particularly in low visibility conditions or in relatively featureless terrain where visual cues for altitude and attitude are inadequate or deceptive. The AN/AVS-7 HMD solves this problem for night flight for both helicopters and fixed wing aircraft which must operate in a 'nap of the earth' flight regime. The display unit mounts on the AN/AVS-6 night vision goggles and provides symbology overlaid on the pilot's outside view; cockpit instrument information is thus provided through the goggles. The pilot is immediately aware of changes in either his surroundings or the instrument readings. This minimizes the risk of critical information being missed in one area while the pilot is looking in the other. The 'day' HMD version of the AN/AVS-7 display now carries these advantages into daytime flights. This display unit operates in conditions from full sunlight to dusk, provides the same symbology as the night display, and connects to the night display interface with no aircraft modification. The day HMD mounts to the helmet using the attachment points previously reserved for the night vision goggles. This display improves the safety of daytime operations by keeping the eyes 'out of the cockpit' in difficult situations such as those presented during landings, cargo lifting and flight utilizing terrain masking. It offers the possibility of a less stressful way of familiarizing the pilot with the symbology and of the dynamic relationships it has to the aircraft and background motions. This familiarization is now accomplished during night flights using night vision goggles. The 'day' HMD is also a useful maintenance aid, easing the ground crew's checkout of the aircraft systems during the day.
A rotorcraft guidance and control system designed for real-time detection and avoidance of terrain and obstacles has been developed and evaluated in a moving-base simulation. The system, referred to as pilot-directed guidance (PDG), relies upon forward-looking sensor information along with digital terrain elevation data to perform automated terrain-following and lateral and vertical obstacle avoidance maneuvering in the presence of flight path obstructions. An important aspect of this system is that it does not restrict the pilot to a predefined nominal course but instead allows for complete flight-path autonomy with no prior surveying of the obstacle environment. The pilot interface has been designed to enable the obstacle-avoidance sub-system to be transparent to the pilot except when performing emergency obstacle avoidance. Back-driven cockpit controls provide cueing to the pilot and also facilitate pilot-override of automated maneuvers when necessary, such as in the event of a sensor failure. The pilot interface also includes HMD symbology to provide the pilot with navigation and system performance information. This paper describes the fundamental components of the PDG system; the forward-looking sensor, data processing and fusion, guidance algorithms, controller design, and pilot interface. Important results from a piloted simulation are then presented that describe the overall performance and workload reduction potential of the PDG system.
The helmet resident locator line with a look-to orientation is designed to guide the user's line- of-sight (LOS) to a specific point-of-interest (POI) in space. The locator line is used to indicate the relative position of a POI within the sensor field-of-regard but beyond the display field-of- view (FOV). The distance the LOS must traverse in order to bring the POI within the display FOV is called vector length. The present study was conducted to investigate the effects of different locator line vector length symbology approaches on search and tracking performance. Five candidate symbologies were formed by varying their static and dynamic features. The locator lines were compared using both static interpretation and dynamic tracking tasks. Recommendations for the use of specific symbology features are made.
Sweden is one of the world's smallest countries with a domestic aircraft industry. Since the 1950's Sweden has produced fixed-wing aircraft like the J29 'the flying barrel', J32 Lansen, J35 Draken, JA/AJS 37 Viggen and today the JAS 39 Gripen. The Gripen aircraft is a small lightweight multi-role aircraft adapted to the needs of the Swedish Air Force. The Swedish Defence Material Administration is conducting a study of an integrated helmet system suitable for the specific Swedish conditions. The objective of the study is to define a requirement specification for an integrated helmet system intended for a future version or retrofit of the JAS 39 Gripen aircraft. To meet the technical, tactical and economical requirements the call was for an interdisciplinary approach with participants from the industry, the medical society and the pilot community. This paper will discuss some of these requirements and possible solutions.
A new concept for displaying images to a viewer has been patented. It uses new principles for creating an image on the viewer's retina. An image with a particular resolution can be considered as a distribution of picture elements in two dimensions within the integration time of the human eye. The image production can now be divided between two separated display elements which can combine the generation of pixel information in a number of different ways. Synchronization between the display elements is essential. The first and second display elements are arranged at a distance from one another along a line creating a viewing direction for the viewer, which essentially coincides with the direction from the viewer to the first display element. The second display element is carried by the viewer and as he moves, the image remains in a fixed position in space, different to a conventional head-mounted display. Other features possible are: physically small displays; large image angles and/or high resolution; 'private' image seen only by those using personal equipment; separate images to different viewers (e.g. blank display); stereo and 'real' 3D. Demonstrators have been built using TV sets, LED arrays and laser scanners as the first display element, and low-frequency optomechanical deflectors or FLC switches as the second display element.
The subtractive LCD color display used in the helmet mounted display places technically challenging reuqirements upon the color separation optics when used with a light source emitting broadband light spectra. This is because the bands of blue-green wavelengths and yellow wavelengths must be filtered out to provide good color gamut while retaining extremely high brightness in the display. High brightness is required for use in the outdoor environment. In order to improve the overall helmet performance, metal halide arc lamps with spectra tailored to emit prime colors have been developed for Kopin Corporation under a contract from Natick US Army Research and Development Center (funding from ARPA) for delivery to Honeywell. The metal halide lamps are based upon the concept of limiting the radiation of the lamp as much as possible to only ground state based atomic line spectra and selecting the atomic species involved to minimize radiation in the blue-green and yellow wavelengths. The ideal lamp would consist of a single broad line in each of the red, green and blue regions of the spectrum and was well approximated in the actual lamp. In addition, the use of mercury as a component was eliminated because of its emission at 577 nm in the yellow. The final lamp is krypton based AC operated short arc with separate halides added for each of the prime colors.
The helmet mounted display (HMD) is an important technology for aircraft cockpit information exchange, and is also of advantage for outdoor field use. For both applications, high display luminance is required to maintain acceptable contrast ratio while competing with environmental forward field scene luminance during bright daylight conditions. For the full color HMD, a broad color gamut is required. Notch Polarizers, made from crosslinked cholesteric liquid crystal silicones and utilized to modulate color with high resolution subtractive color twisted nematic diplay image sources, yield substantial improvements in system luminance efficiency, color gamut, and contrast ratio, compared with conventional color polarizers made with dichroic dyes. A TN subtractive color display system design with notch polarizers is presented, resulting in improved luminance, color gamut, contrast ratio, and contrast ratio in the presence of high ambient luminance. Results are given for backlighting with a broad band Xenon arc lamp, as well as with a trichrominance (primary color) lamp. Very substantial improvements in display system luminance efficiency, color gamut and contrast ratio were achieved.