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Though acquisition reform has shaken things up in U.S. government contract work, it has opened more doors for HF/E considerations in improving human-system performance.

This study addressed the development and evaluation of empirically-based helmet-mounted display (HMD) symbology sets. Three attitude formats and three altitude formats were evaluated within a composite tactical aircraft symbology layout. The attitude formats varied in basic shape and symbol compression ratio (SCR = ratio of the angle represented by the symbol to the symbol's subtended visual angle). Symbols which incorporate high SCR represent large angles and have a slow rate-of-motion relative to uncompressed formats. The altitude symbologies were formed of vertical scale and dial formats and included vertical velocity indicators. Subjects performed a flight-path maintenance task within sessions of differing “real” horizon presence and orientation. The formats were evaluated under a task which was designed to require both gross and precise responses. The results showed that performance was influenced by the manipulation of the attitude symbology formats, and suggest that symbol compression may be advantageous.

The helmet-mounted display (HMD) affords continuous availability of critical flight information independent of head orientation. With appropriate information presented on a HMD, aircraft control can be maintained regardless of where the pilot is looking. This research addresses the development of an empirically based HMD symbol set. Three attitude formats and three altitude formats were evaluated within a composite fixed-wing HMD symbology layout. The attitude formats varied in basic form and symbol compression ratio. Symbol compression ratio is the ratio of the angle represented by the symbol to the symbol's subtended visual angle. High symbol compression results in symbols which represent large angles, and therefore have slow rate-of-motion relative to their uncompressed counterparts. The altitude symbologies were formed of both vertical scale and dial formats and included vertical velocity indicators. Subjects performed a flight-path maintenance task within sessions of differing “real” horizon presence and orientation. The formats were evaluated under a task which was designed to require high-accuracy flight-path maintenance. This type of task is traditionally thought to require less symbol compression. The results showed that performance was influenced by the manipulation of the attitude symbology formats. The results also suggest that symbol compression may be advantageous.

The present study evaluated a new aircraft attitude display concept. The new symbology format, or Theta display, was developed by integrating the features of the conventional attitude/direction indicator (ADI) and head-up attitude reference display (HUD) into a single format. Number of trials to reach a specific performance criterion and tracking performance were collected as dependent variables on an attitude maintenance task. The results show that performance and training time were better with both the Theta display and the ADI than with the HUD. The findings support the hypothesis that an attitude display formed of the integration of ADI and HUD symbology will demonstrate a performance benefit over a pure HUD format.

A dive bombing mission was performed in a simulator by 5 experienced USAF pilots. Their view out of the cockpit was provided by an aircraft-fixed or head-steered sensor. Despite significant differences in performance with the two sensors, the mean flight profiles flown with each sensor were similar. However, with the head-steered sensor, some subjects made consistently different head movements. The same subjects also flew different flight profiles. These subjects exploited the mobility of the head-steered sensor to make large amplitude head displacements during ascent. As a result, they sighted the target earlier. It is shown that these early-sighting subjects made changes to their flight profiles during ascent which allowed them, during descent, to aim their aircraft at the target earlier, while higher. Consequently, the early-sighting subjects released their bombs significantly higher than the late-sighting subjects (high bomb release is beneficial to aircraft survival).

The Integrated Helmet Audio-Visual System (IHAVS) project was originated and funded by the JSF Cockpit and Aircrew Systems Integrated Product Team, a joint service sub-team of the JSF Flight Systems IPT. The IHAVS project was conceived as a short-duration technology maturation and flight demonstration program. The JSF Flight Systems IPT provided overall project management, funding, and leadership throughout the entire integration and demonstration effort. The IHAVS project integrated head-mounted aural, verbal, and visual cockpit technologies, previously demonstrated individually, into a single synergistic system in a TAV-8B. A 25-event test operation was conducted to demonstrate the utility of this advanced integrated human systems interface for performing strike missions. IHAVS technologies included a GEC Viper II HMD system, a Polhemus helmet tracker, an Armstrong Laboratory 3-D audio system with ANR, a Smiths Industries IVM, and an LMA NITE Hawk SC TPOD. Three test pilots, one each from the Marine Corps, Air Force, and Navy, were selected to fly similar flight events.

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.

Eight veteran USAF fighter pilots, experienced with AGM-65 Maverick air-to-ground missiles, flew a night, low-level ground attack mission in a flight simulator equipped with a helmet-mounted display (HMD). The mission was performed by delivering five Maverick missiles against ground vehicles using either an aircraft-fixed forward-looking infrared (FLIR) sensor image on a head-up display (HUD) or a head-steered FLIR as the missile aiming device. Additionally, the pilots employed their weapons by two methods: fixing and launching missiles singly or in varying numbers (multiple method). The purpose of the experiment was to determine what, if any, advantage there is to employing the AGM-65 using the HMD FLIR image to slew the missile seeker onto the target versus the conventional method of using the FLIR image displayed on the HUD. With a head-steered sensor (and fixing and launching weapons singly) subjects released their weapons quicker (14.6 second interval between launches vs. 17.1 sec.), at a higher altitude (1739 feet vs. 1603 ft.), and slightly farther from the target (3.42 nautical miles vs. 3.37 nm). Furthermore, data indicated the pilots looked farther off-boresight when searching for and locking the weapon onto a target, thereby more effectively using the full field-of-regard of the missile seeker. The participants also contributed their opinions of the advantages and disadvantages of the two mechanizations.

K. OsgoodUSAF Armstrong Laboratory-Human Engineering Division. WPAFB, OH 45433ABSTRACTThis study was conducted to investigate the effects of different candidate transparent head-coupled helmet-mounted display(HMD) target location symbology orientations on search and intercept performance during an air-to-air task. Orientation, asit refers to HMD symbology, is the method by which the information is referenced and related to the observer. HMDsymbology can be coded so that it responds to ownship maneuvering (within the world coordinate system) as well asobserver head movement (within the ownship coordinate system). Three symbology orientations were compared to thetraditional head-up-display target location symbology: One ofthe candidate symbologies was referenced to ownshipmaneuvering, a second was referenced to head movement, and the last was referenced to both ownship and head movement.The objective and subjective fmdings suggest that HMD target location information is advantageous and that ownshipreferenced information presented via a HMD may be more useful then previously believed.Keywords: helmet-mounted, displays, symbology, target location, visual performance, coordinate reference system1. INTRODUCTION1.1. GeneralIn fixed-wing tactical aircraft, symbology presented on a transparent helmet-mounted display (HMD) provides criticalinformation within the pilot's field-of-view (FOV) regardless of head movement and orientation. Helmet display symbology(HDS) is available continuously and can represent several categories of information. Among the possible categories areaircraft flight status and relative target location information. The objective ofthe HMD concept is to create a wider area ofvisual information availability than is presently possible with the head-up display (HUD). A potential performance benefitstems from affording the pilot better visual search and tracking ability without any associated information decrement. FromBarns, 1989: "The target is outside the HUD FOV during most tactical maneuvers and offsets. The farther offthe target canbe detected and tracked, the more effective the intercept tactics can

This paper is based upon an effort in support of the Armstrong Laboratory, Helmet Mounted Sensory Technology Advanced Development Program (HMST ADP). That effort produced a report which provided the HMST ADP with information to make informed helmet system development decisions. These would be based upon not only crew, but aircraft and mission requirements. Specifically addressed were the following items (portions of them are discussed within this paper): the background of Helmet Display (HD) research and USAF decisions, current aircraft capabilities that support HDs, HD types, aircraft and HD utility, integration with current and future avionics and weapon systems and some analytical conclusions. This work was to project the potential elements which make up those decisions, such as crew, weapons, sensors, aircraft and missions into four HD option descriptions as representative of the technology for examination. These four are discussed throughout this paper as: austere, semi- austere, helmet-mounted head-up display (HUD) and helmet-mounted display (HMD).© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This study evaluated the attitude information conveyance of a new aircraft attitude display concept. The new symbology format, called the THETA symbology, was developed by integrating the shape of the conventional ADI and the transparency of the HUD into a single format. This research addressed whether or not there was a significant performance advantage or decrement incurred by the symbology integration. The THETA symbology, ADI, and HUD were evaluated during an attitude maintenance task and an attitude recovery task. The results of the study suggest few differences between the THETA and ADI formats while performance and training time were better with both the THETA symbology and the ADI than with the HUD format. The findings of the study lend support to the hypothesis that an attitude display formed of the integration of ADI and HUD type symbology will demonstrate a performance benefit over a pure HUD format. Display, Attitude, Symbology, Recovery task.

The role of advanced motion cuing devices as an alternative to platform motion simulation has been debated for several years. The dynamic seat nas been shown to be an effective device for providing task-critical onset motion information on the roll axis, provided that proper attention is given to the drive laws. Since it is difficult to extrapolate the benefit derived from the dynamic seat to an operationally-realistic task environment, the dynamic seat project has initiated a series of studies that lead to motion cuing in a multi-axis aerial refueling task. In this experiment, twelve subjects controlled a compensatory tracking task in roll only, pitch only, and a combined task condition. Operator performance was evaluated between four levels of drive algorithm across axis. Significant differences in tracking performance were found both within axis and between algorithm. In addition, the rank ordering of the treatment means were consistent with previous findings in our laboratory.

Measurements were made of the ability of 20 subjects to acquire 3, 6 or 9 stationary visual targets and then replace them after they had been removed. The targets were viewed with various sized fields-of-view (FOVs) using a Visually Coupled Airborne Systems Simulator (VCASS), which was mounted on the head and which used head position information to provide space-stabilized computer-generated images. Targets were presented with a blank background or a terrain background. Subjects were instructed to use as much time as they required or to be as quick as possible searching for the targets. Mean times to search for the targets were faster with the larger FOVs and faster with fewer targets. Replacement accuracy was not sensitive to the FOV but decreased with increasing number of targets. Search times were slower, but replacement accuracy was greater with a terrain background than with a blank background. In the fast search conditions, the number of guessed target replacements decreased with decreasing numbers of targets and increasing FOV. It is concluded that target replacement performance was sensitive to manipulation of the independent variables and as such is a potentially useful metric of spatial awareness.

Seventeen subjects were presented with stationary targets at random locations in an area 120 left and right and 90 deg upwards from straight ahead. Targets would change shape to indicate that they were threats. Using a head-coupled simulator with 5 different sized fields-of-view (FOVS), subjects had to search for the targets, monitor them for changes in shape, and shoot them. Occasionally, targets which had not changed shape would disappear and subjects had to indicate their last location. There were 9 target conditions which varied in complexity due to the number of targets presented, the number of threats, or the number of targets to be replaced. Decreasing the size of the FOV produced a significant decrement in the percentage of targets hit and a significant increase in the time for which the targets threatened the subjects. In addition, there were significant effects caused by target condition and significant interactions between these two main effects. The data suggest that the effect of FOV size was dependent on task difficulty. An easy task required a 20 deg FOV, whereas a more demanding task required a 60 deg FOV. Target replacement error was unaffected by FOV size, a finding that is consistent with an earlier experiment and which supports the hypothesis thit once the information is acquired, the size of the FOV does not affect its recall.