Gregory Craig

Airborne Optical and Thermal Remote Sensing for Wildfire Detection and Monitoring.

For decades detection and monitoring of forest and other wildland fires has relied heavily on aircraft (and satellites). Technical advances and improved affordability of both sensors and sensor platforms promise to revolutionize the way aircraft detect, monitor and help suppress wildfires. Sensor systems like hyperspectral cameras, image intensifiers and thermal cameras that have previously been limited in use due to cost or technology considerations are now becoming widely available and affordable. Similarly, new airborne sensor platforms, particularly small, unmanned aircraft or drones, are enabling new applications for airborne fire sensing. In this review we outline the state of the art in direct, semi-automated and automated fire detection from both manned and unmanned aerial platforms. We discuss the operational constraints and opportunities provided by these sensor systems including a discussion of the objective evaluation of these systems in a realistic context.

Time Delays in Visually Coupled Systems During Flight Test and Simulation

Increasing control system time delays have well-documented detrimental effects on pilot-in-the-loop performance. With increased use of helmet-mounted displays in aircraft, pilots may soon be exposed to both control system and visual display system time delays. They may be sensitive to both the magnitude and source of the time delay, that is, some pilots may be more sensitive to visual delays than to control delays, or vice versa. In the current study, control and visual delays were examined in two experiments, the first conducted in a helicopter and the second conducted in a flight simulator. A helmet-mounted display was used to present external imagery and symbology in both experiments. Standardized low-level maneuvering tasks were used to examine changes in system handling qualities ratings as a function of time delays in the control and visual display processing loops. The addition of delays in both the control and the visual loops impaired the system handling qualities and increased the magnitude of position maintenance error. Differences between control and visual delays were evident in reports of motion sickness symptoms, which were more frequent for visual delay conditions. Motion sickness symptoms and related physiological effects induced by delays may increase pilot fatigue. Therefore, determination of acceptable latency criteria for design and implementation in systems with visually coupled components is critical.

Detection of motion-defined form under simulated night vision conditions

The influence of Night Vision Goggle-produced noise on the perception of motion-defined form was investigated using synthetic imagery and standard psychophysical procedures. Synthetic image sequences incorporating synthetic noise were generated using a software model developed by our research group. This model is based on the physical properties of the Aviator Night Vision Imaging System (ANVIS-9) image intensification tube. The image sequences either depicted a target that moved at a different speed than the background, or only depicted the background. For each trial, subjects were shown a pair of image sequences and required to indicate which sequence contained the target stimulus. We tested subjects at a series of target speeds at several realistic noise levels resulting from varying simulated illumination. The results showed that subjects had increased difficulty detecting the target with increased noise levels, particularly at slower target speeds. This study suggests that the capacity to detect motion-defined form is degraded at low levels of illumination. Our findings are consistent with anecdotal reports of impaired motion perception in NVGs. Perception of motion-defined form is important in operational tasks such as search and rescue and camouflage breaking. These degradations in performance should be considered in operational planning.

The Impact of Night Vision Goggles on Way-Finding Performance and the Acquisition of Spatial Knowledge

Objective: This study examined the effects of night vision goggles (NVGs) on navigation and way-finding performance and the acquisition of spatial knowledge. Background: Although numerous studies have examined the effects of NVGs on visual perception, few have examined the effects of using NVGs on the acquisition and expression of spatial cognition. Method: Participants learned the environment through active navigation and way finding, searching for targets within a life-sized maze with or without NVGs. Knowledge of the environment was then tested with two spatial memory tests. Results: Findings show that navigation and way finding with NVGs appear to be harder, as indicated by longer navigation times and additional, unnecessary turns, than they are without NVGs. Moreover, change in navigation performance over the course of the way-finding trials varied as a function of group assignment indicating that NVGs influenced the learning process. NVG users demonstrated a significant decrease in navigation times earlier as well as significant decreases in navigational legs compared with the control group. In judging the positions of objects relative to target objects in different rooms in the maze, performance was better for participants without NVGs than for those with NVGs. In a map-drawing task, participants in the NVG group were more likely to position objects incorrectly and to receive worse scores than the controls. Conclusion: These results demonstrate that NVGs affected not only spatial navigation and way-finding performance but also the acquisition of spatial knowledge. Application: These degradations in spatial knowledge should be considered in operational planning and NVG training programs.

Effects of field-of-view on pilot performance in night vision goggles flight trials: preliminary findings

Night vision goggles (NVGs) allow pilots to see and navigate under minimal levels of illumination. While NVGs allow the user to see more than they typically could under these levels of illumination, the visual information provided by NVGs has a limited field-of-view. The size of the field-of- view can diminish the pilots spatial orientation ability in the night flying environment. We examined pilot performance in low level helicopter flight while the pilots were using NVGs with 40 degree(s), and 52 degree(s) fields-of-view. The pilots flew a standardized ADS-33D hover maneuver in a Bell 206 helicopter equipped with an accurate position measurement system. The tests were conducted in simulated night conditions and both subjective and objective measures of task performance were obtained. Pilot Cooper-Harper ratings increased from Level 1 baseline ratings to Level 2 ratings when the NVGs were used, indicating worse performance when using the NVGs. Small rating differences were noticed between the 52 degree(s) and 40 degree(s) field-of-view conditions. Similar trends were noticed in the objective data of altitude, and lateral and longitudinal station keeping errors.

Flight performance using a hyperstereo helmet-mounted display: aircraft handling

A flight study was conducted to assess the impact of hyperstereopsis on helicopter handling proficiency, workload and pilot acceptance. Three pilots with varying levels of night vision goggle and hyperstereo helmet-mounted display experience participated in the test. The pilots carried out a series of flights consisting of low-level maneuvers over a period of two weeks. Four of the test maneuvers, The turn around the tail, the hard surface landing, the hover height estimation and the tree-line following were analysed in detail. At the end of the testing period, no significant difference was observed in the performance data, between maneuvers performed with the TopOwl helmet and maneuvers performed with the standard night vision goggle. This study addressed only the image intensification display aspects of the TopOwl helmet system. The tests did not assess the added benefits of overlaid symbology or head slaved infrared camera imagery. These capabilities need to be taken into account when assessing the overall usefulness of the TopOwl system. Even so, this test showed that pilots can utilize the image intensification imagery displayed on the TopOwl to perform benign night flying tasks to an equivalent level as pilots using ANVIS. The study should be extended to investigate more dynamic and aggressive low level flying, slope landings and ship deck landings. While there may be concerns regarding the effect of hyperstereopsis on piloting, this initial study suggests that pilots can either adapt or compensate for hyperstereo effects with sufficient exposure and training. Further analysis and testing is required to determine the extent of training required.

Flight performance using a hyperstereo helmet-mounted display: post-flight debriefing questionnaire

Helmet-mounted display (HMD) designs have faced persistent head-supported mass and center of mass (CM) problems, especially HMD designs like night vision goggles (NVG) that utilize image intensification (I2) sensors mounted forward in front of the users eyes. Relocating I2 sensors from the front to the sides of the helmet, at or below the transverse plane through the users head CM, can resolve most of the CM problems. However, the resulting increase in the separation between the two I2 channels effectively increases the users interpupillary distance (IPD). This HMD design is referred to as a hyperstero design and introduces the phenomenon of hyperstereopsis, a type of visual distortion where stereoscopic depth perception is exaggerated, particularly at distances under 200 feet (~60 meters). The presence of hyperstereopsis has been a concern regarding implementation of hyperstereo HMDs for rotary-wing aircraft. To address this concern, a flight study was conducted to assess the impact of hyperstereopsis on aircraft handling proficiency and pilot acceptance. Three rated aviators with differing levels of I2 and hyperstereo HMD experience conducted a series of flights that concentrated on low-level maneuvers over a two-week period. Initial and final flights were flown with a standard issue I2 device and a production hyperstereo design HMD. Interim flights were flown only with the hyperstereo HMD. Two aviators accumulated 8 hours of flight time with the hyperstereo HMD, while the third accumulated 6.9 hours. This paper presents data collected via written questionnaires completed by the aviators during the post-flight debriefings. These data are compared to questionnaire data from a previous flight investigation in which aviators in a copilot capacity, hands not on the flight controls, accumulated 8 flight hours of flight time using a hyperstereo HMD.

In-flight study of helmet-mounted symbology system concepts in degraded visual environments

BACKGROUND During approach and departure in rotary wing aircraft, a sudden loss of external visual reference precipitates spatial disorientation. METHODS There were 10 Royal Canadian Air Force (RCAF) Griffon pilots who participated in an in-flight investigation of a 3-dimensional conformal Helmet Display Tracking System (HDTS) and the BrownOut Symbology System (BOSS) aboard an Advanced System Research Aircraft. For each symbology system, pilots performed a two-stage departure followed by a single-stage approach. The presentation order of the two symbology systems was randomized across the pilots. Subjective measurements included situation awareness, mental effort, perceived performance, perceptual cue rating, NASA Task Load Index, and physiological response. Objective performance included aircraft speed, altitude, attitude, and distance from the landing point, control position, and control activity. Repeated measures analysis of variance and planned comparison tests for the subjective and objective responses were performed. RESULTS For both maneuvers, the HDTS system afforded better situation awareness, lower workload, better perceptual cueing in attitude, horizontal and vertical translation, and lower overall workload index. During the two-stage departure, HDTS achieved less lateral drift from initial takeoff and hover, lower root mean square error (RMSE) in altitude during hover, and lower track error during the acceleration to forward flight. During the single-stage approach, HDTS achieved less error in lateral and longitudinal position offset from the landing point and lower RMSE in heading. DISCUSSION In both maneuvers, pilots exhibited higher control activity when using HDTS, which suggested that more pertinent information was available to the pilots. Pilots preferred the HDTS system.

Handling qualities comparison of panoramic night vision goggles and 46-deg. night vision goggles

Night Vision Goggles allow the user to see in extremely low illumination levels but the visual information provided by Night Vision Goggles has a limited field-of-view that diminishes handling-qualities in the night flying environment. Panoramic Night Vision Goggles were designed to correct this problem by providing a 100° horizontal field-of-view which is larger than currently used Night Vision Goggles. However, in the first generation Panoramic Night Vision Goggle, the improved field of view came at the cost of diminished resolution, contrast and central overlap area when compared to conventional Night Vision Goggles. This paper describes an evaluation that was conducted in the variable stability NRC Bell-205 helicopter to examine the influence on system handling qualities of the Panoramic Night Vision Goggles and a 46° field-of-view UK Night Vision Goggle. Five pilots flew the ADS-33D hover, sidestep and pirouette manoeuvres in simulated night conditions with the UK Night Vision Goggle and the Panoramic Night Vision Goggle. Both subjective and objective measures of task performance were obtained. Handling-qualities ratings showed the pirouette was performed better with the Panoramic Night Vision Goggles. This was the only manoeuvre where there was a clear-cut handling qualities improvement when using the Panoramic Night Vision Goggles. Other manoeuvres such as the sidestep and hover did not show definitive handling qualities rating differences between the two Night Vision Goggle types. The flight test results were interpreted in terms of the design trade-offs of the two night vision systems, with regard to the different acuity, binocular overlaps and fields-of-view.

The NRC Bell 412 ASRA safety system: a human factors perspective on lessons learned from an airborne incident

Abstract The National Research Council (NRC) Bell 205 Airborne Simulator is a full authority fly-by-wire (FBW) research helicopter. On 24 May, 1996 this aircraft underwent a failure which drove all four flight control actuators to full extension shortly after engagement of the FBW system, with nearly catastrophic results. The sound design inherent in the original Bell 205 safety system allowed the safety pilot to override the FBW system and prevented the loss of aircraft and crew. This incident, however, led to the realization that the existing safety system configuration in the Bell 205 was only marginally acceptable, and that this same system would be inadequate for the next generation FBW aircraft, the NRC Bell 412 Advanced Systems Research Aircraft (ASRA). Experience gained from the Bell 205 incident, and historical experience, has driven the design process of the safety systems for ASRA, with a particular view toward the capabilities and limitations of the operators.