Synthetic Vision Display Research Articles

Pilot Performance Using Head-up and Head-down Synthetic-Vision Displays for SA CAT I Approaches

Thirteen two-person crews flew 39 approaches each to runway 34R at Seattle-Tacoma airport in a 737-800 level D flight simulator using both head-up and head-down synthetic-vision displays. The within-subject design manipulated display type, runway-lighting configuration, ambient illumination, and two combinations of decision height and runway visual range associated with Special Authorization Category I and II approaches. Data collected/analyzed included training trials, instrument landing system tracking, touchdown point and vertical velocity at touchdown, and pilot opinions on the adequacy of the display formats for the specific task. Results indicated that there was a small but reliable difference in touchdown point between day and night approaches (longer in day) and that distance from centerline was also slightly affected by display type. Mean vertical velocity at touchdown was also affected slightly. Data indicated that there appeared to be no operationally significant differences as a function of display type or other variables examined.

An Exploratory Evaluation of General Aviation Pilot Performance and Preferences Using Synthetic Vision Displays for Approaches and Missed Approaches in Flat and Challenging Terrain

Eight instrument-rated General Aviation pilots completed CAT I SA approaches to Oklahoma City (KOKC) and localizer approaches to Aspen (KASE), the latter with missed approaches. Approaches to KOKC were conducted in two levels of runway visual range (RVR) with two decision heights (DH) using a head-up or head-down display with Synthetic Vision (SV) imagery. The lower DH led to significantly more completed approaches while the higher DH regularly caused pilots to execute missed approaches. RVR was not a significant factor for those values examined. Although SV was expected to be more beneficial for missed approaches in mountainous terrain (KASE) than for initial approaches, terrain clearance achieved was not influenced by display format. Cross-track and glide-slope root-mean-square error for the approaches to KOKC did not differ reliably between display conditions. Pilots uniformly believed they could successfully and comfortably complete approaches in lower visibilities if SV equipped as compared with other displays.

Predictive Landing Guidance in Synthetic Vision Displays

In order to improve performance during manual control, synthetic vision displays were augmented with predictive guidance. Little is known on how these predictive guidance concepts can be applied to the landing flare maneuver. This paper discusses the investigation into the applicability of 3D predictive guidance in synthetic vision displays during the final phase of the landing. Two types of predictive guidance were examined, the Flight-Path Predictor that indicates the aircraft’s future position a certain time ahead, and the Flight Trajectory Predictor that presents the future trajectory by interpolating a number of sequential predicted positions. A theoretical investigation and an offline simulation were used to optimize the system for the landing. A pilot-in-the-loop experiment, conducted in a moving-base flight simulator, indicated that predictive guidance supports pilots in manual control. Also, the addition of predictive guidance enhances the pilot’s ability to determine the correct flare initiation time in a way that is comparable to providing a more realistic synthetic vision display with textured surfaces. Even though the flare initiation timing was improved by the addition of predictive guidance, the flare control after initiation was not sufficiently supported and there was no noticeable improvement in landing performance.

Design and Simulator Evaluation of an Ecological Synthetic Vision Display

A synthetic vision display is generally believed to support pilot terrain awareness. Many studies have shown, however, that the bias in perspective views can cause pilots to make judgment errors regarding the relative location, height, and ultimately the avoidance of terrain obstacles. Therefore, alerting systems are required to keep pilots at safe distances from the terrain. These systems provide explicit guidance commands to circumvent terrain conflicts, which is far from optimal regarding pilot terrain awareness as it fails to present the rationale of the terrain separation problem. Consequently, this can affect the trust in and the reliance on these systems and pose a potential safety risk, especially in events or situations unfamiliar to the alerting system. This paper presents the design and evaluation of an extension to a synthetic vision display that aims to make the constraints of the alerting automation more transparent in order to help pilots better understand why, how, and when they should act. A pilot-in-the-loop experiment, using 16 glass-cockpit pilots in a fixed-based flight simulator, showed that the constraint-based overlays indeed improved the overall pilot terrain awareness compared to a command-based display. The decision-making only improved in the unanticipated events introduced in the experiment. The utility of the energy angle was found to be important for recognizing the offnormal events and to prevent terrain crashes. However, the pilot response time, flight safety in terms of low-altitude flying, and pilot workload are better when using the command display. This indicates that a last-resort alerting and advisory system would still be required in operations at the periphery of safe system performance.

Attentional Tunneling and Task Management in Synthetic Vision Displays

This article discusses attentional tunneling as one cause of breakdowns in task management. The phenomenon is defined, and it is shown how it can be induced by head-up display location, and compelling 3-dimensional perspective displays. The results of 6 experiments using a synthetic vision display, with or without a highway in the sky (HITS) display are then summarized, as these reveal the attention tunneling phenomenon manifest in the failure to detect unexpected air hazards. Two factors that enhance this phenomenon are identified: location away from the center of visual scan and the presence of the HITS.

Synthetic Vision Displays for Planetary and Lunar Lander Vehicles

Aviation research has demonstrated that Synthetic Vision (SV) technology can substantially enhance situation awareness, reduce pilot workload, improve aviation safety, and promote flight path control precision. SV, and related flight deck technologies are currently being extended for application in planetary exploration vehicles. SV, in particular, holds significant potential for many planetary missions since the SV presentation provides a computer-generated view for the flight crew of the terrain and other significant environmental characteristics independent of the outside visibility conditions, window locations, or vehicle attributes. SV allows unconstrained control of the computer-generated scene lighting, terrain coloring, and virtual camera angles which may provide invaluable visual cues to pilots/astronauts, not available from other vision technologies. In addition, important vehicle state information may be conformally displayed on the view such as forward and down velocities, altitude, and fuel remaining to enhance trajectory control and vehicle system status. The paper accompanies a conference demonstration that introduced a prototype NASA Synthetic Vision system for lunar lander spacecraft. The paper will describe technical challenges and potential solutions to SV applications for the lunar landing mission, including the requirements for high-resolution lunar terrain maps, accurate positioning and orientation, and lunar cockpit display concepts to support projected mission challenges.

The Opto-Kinetic Cervical Reflex Observed in Pilots Viewing a Synthetic Vision Display and Electronic Attitude Indicator

Prior research indicates that during roll maneuvers in visual meteorological conditions (VMC) pilots exhibit the opto-kinetic cervical reflex (OKCR), an instinctive postural response that humans use to maintain awareness of their spatial orientation. This simulator study was conducted to see if a moving-horizon attitude indicator (AI), electronic attitude indicator (EAI), or Synthetic Vision System (SVS) would elicit the OKCR. The current research found evidence of the OKCR in pilots who viewed both an SVS display and an EAI. Pilots viewing a standard moving-horizon AI produced very little OKCR response.

Synthetic Vision Displays for in-Flight and Surface Navigation with Integrated Notam Information

A synthetic vision display provides the pilot with data regarding terrain, obstacles and traffic. At present, information from NOtices To AirMen (NOTAMs) is available from printouts obtained before the flight, but is not integrated into the synthetic vision display. A study consisting of two experiments was conducted to examine the effect and desirability of integrating electronic NOTAMs in synthetic vision displays. One experiment was concerned with in-flight navigation, the other with navigation on the airport surface. By combining quantitative and qualitative measures, it was established that by integrating NOTAMs in the displays pilots' situation awareness and performance improved, whereas mental workload decreased. Pilots rated the desirability of the integration of NOTAMs very highly.

Human Factors Issues in Synthetic Vision Displays: Government, Academic, Military, and Industry Perspectives

Human Factors Issues in Synthetic Vision Displays: Government, Academic, Military, and Industry Perspectives

Comparison of Head-Up and Head-Down “Highway-in-the-Sky” Tunnel and Guidance Concepts for Synthetic Vision Displays

Comparison of Head-Up and Head-Down “Highway-in-the-Sky” Tunnel and Guidance Concepts for Synthetic Vision Displays

Integration of information in synthetic vision displays: why, to what extent, and how?

Current experimental synthetic vision systems present a spatially integrated presentation of physical constraints such as terrain and obstacles. This paper presents a number of assumptions regarding anticipated procedures and the use of a synthetic vision system, and addresses the desirability of integrating temporary constraints related to the airspace, the airport, and standard procedures. Following this, a number of examples are presented that illustrate a potential approach to integrate such information into a synthetic vision display. The paper ends with an overview of the results from an experiment in which the influence of an integration of temporary constraint information on pilot decision-making was examined.

The Efficacy of Head-Downand Head-Up Synthetic Vision Display Concepts for Retro- and Forward-Fit of Commercial Aircraft

The retrofit question concerns whether useful and effective synthetic vision displays are usable in aircraft that have limited-size display spaces. Two experiments were conducted to examine the efficacy of these displays and develop field-of-view and terrain texture recommendations for design. The first experiment examined issues of field of view and display size using an Asheville, North Carolina, synthetic vision database and fixed-based simulator. The second experiment was conducted on the NASA B-757 aircraft at Dallas/Fort Worth International Airport and investigated the efficacy of both head-down and head-up displays and generic and photorealistic terrain texture. Both experiments confirmed the retrofit capability and that all sizes and texturing methods were found to be viable candidates for synthetic vision displays. These results, future directions, and implications for meeting national aeronautic safety and capacity goals are discussed.