Braden McGrath

The Role of Perceptual Modeling in the Understanding of Spatial Disorientation During Flight and Ground-based Simulator Training

When investigators fail to find a materiel cause for a mishap, pilot error may be implicated. Controlled flight into terrain (CFIT), aircraft upset (AU), and loss of control (LOC) are important mishap contributors. Spatial disorientation (SD) is a key causal factor of CFIT and its presence can precipitate or exacerbate LOC. SD typically is inferred based on unusual control inputs by the pilot, insufficient outside visual cues, the presence of factors which would distract the pilot from the primary flight instruments, and the qualitative similarity of the flight circumstances to those known to induce orientation illusions. We recommend that SD analysis should be more quantitative and comprehensive, involving the matching of information from on-board recorders (e.g., acceleration, pilot control inputs) to mathematical models of human orientation functioning that are designed to fit what is known about human perception. We recently combined several established scientific models into one Perception Toolbox which allows comparison of the predictions from each model. We also devised our own model, called the Orientation Modeling System (OMS), which is intended to improve the explanation of mishaps and laboratory perceptual experiments. The OMS and the Perception Toolbox are described briefly in this report. The modeling tool has been used to describe several illusions in laboratory, simulator and flight settings. Two applied examples are highlighted which entailed the successful modeling of a recent SD mishap and some published experimental results relevant to the disorienting effects of head movement during centrifuge-based simulator training. Lessons learned from the model will enhance future aeromedical capabilities by helping investigators determine if SD is a factor in a given mishap, develop educational videos of mishaps to improve mishap evaluation and pilot training, evaluate new instrumentation solutions to prevent AU, LOC, and CFIT, and improve simulation profiles in advanced centrifuge-based simulators.

The neurovestibular challenges of astronauts and balance patients: some past countermeasures and two alternative approaches to elicitation, assessment and mitigation

Astronauts and vestibular patients face analogous challenges to orientation function due to adaptive exogenous (weightlessness-induced) or endogenous (pathology-induced) alterations in the processing of acceleration stimuli. Given some neurovestibular similarities between these challenges, both affected groups may benefit from shared research approaches and adaptation measurement/improvement strategies. This article reviews various past strategies and introduces two plausible ground-based approaches, the first of which is a method for eliciting and assessing vestibular adaptation-induced imbalance. Second, we review a strategy for mitigating imbalance associated with vestibular pathology and fostering readaptation. In discussing the first strategy (for imbalance assessment), we review a pilot study wherein imbalance was elicited (among healthy subjects) via an adaptive challenge that caused a temporary/reversible disruption. The surrogate vestibular deficit was caused by a brief period of movement-induced adaptation to an altered (rotating) gravitoinertial frame of reference. This elicited adaptation and caused imbalance when head movements were made after reentry into the normal (non-rotating) frame of reference. We also review a strategy for fall mitigation, viz., a prototype tactile sway feedback device for aiding balance/recovery after disruptions caused by vestibular pathology. We introduce the device and review a preliminary exploration of its effectiveness in aiding clinical balance rehabilitation (discussing the implications for healthy astronauts). Both strategies reviewed in this article represent cross-disciplinary research spin-offs: the ground-based vestibular challenge and tactile cueing display were derived from aeromedical research to benefit military aviators suffering from flight simulator-relevant aftereffects or inflight spatial disorientation, respectively. These strategies merit further evaluation using clinical and astronaut populations.

Perceptual Modeling as a Tool to Prevent Aircraft Upset Associated with Spatial Disorientation

Controlled flight into terrain (CFIT) and spatial disorientation (SD) constitute the first and second largest categories of loss of control (LOC) mishaps for helicopters. Since SD mishaps tend to result in the death of the pilots, SD is inferred as the primary cause of a mishap via a process of elimination, i.e., it is considered only when a materiel cause cannot be ascertained. In SD mishaps, the information required to maintain control of the aircraft is available to pilots, but they are either not attending to the information or unable to manage or assimilate it rapidly enough to prevent the mishap. For the past 18 years, we have responded to requests from military and civilian aviation accident investigation communities to conduct perceptual analyses of mishaps when SD is inferred as a possible cause. The perceptual models we have employed evaluate data from a variety of sources to predict the orientation and motion perception a pilot will experience when subjected to the physical forces of flight. The algorithm has been developed based on both ground and inflight experimental data and is able to predict the perceived attitude of the pilot which is critical to the pilot’s mental model of the location of the ground prior to a mishap. The model also can make predictions about reflexive gaze control during acceleration. The next step is to incorporate voluntary gaze into the model. When pilots fly in challenging conditions of instrument flight, at least half of the visual attention time is directed to the attitude orienting instruments, as demonstrated by experiments in which the pilots’ gaze direction is monitored using head-mounted cameras. Gaze monitoring technology has improved considerably over the past 25 years so that it is now easy to monitor the gaze of pilots unobtrusively using panel-mounted cameras. It is possible to not only measure which instrument is being monitored, but also whether the pilot is directing gaze away from the panel and for how long. We propose that by using the perceptual model in conjunction with eye gaze, one can predict perception more accurately and determine when the pilot should be alerted to redirect attention to the attitude orienting instruments.

A heterogeneous software defined networking architecture for the tactical edge

The demand for real-time data in a modern battlefield is increasing exponentially. As a result, current military network paradigms and architectures are struggling to cope with increasing capacity demands at the tactical edge. Unfortunately, rescaling existing network architectures will not be a permanent solution to the problem. Therefore, in this paper, we propose a 3- tiered Software Defined Networking (SDN) architecture consisting of heterogeneous Dense Networks (DenseNets), which is a highly condensed deployment of relatively small, lowpowered femtocells, at the tactical edge. The proposed 3-tiered SDN architecture abstracts the Land Tactical Network (LTN) as the Physical Layer, the Battlefield Tactical Network (BTN) as the Control Layer, and the Joint Task Force Headquarters (JTFHQ) as the Management Layer. The simulation and results confirm the architectures capability for providing interoperability between heterogeneous communications equipment and supporting high capacity demands within limited and unreliable networking infrastructure in battlefield environments.

A countermeasure for loss of situation awareness: Transitioning from the laboratory to the aircraft

Loss of situation awareness (SA) is a major contributor to aircraft mishaps. This paper describes a technological (display) countermeasure for loss of situation awareness in flight and considers its key remaining transition challenges. The display countermeasure is a tactile situation awareness system (TSAS) that provides cues concerning aircraft motion. For example, if a helicopter drifts upwards, forwards, or downwards away from its desired hover, the pilot would feel a vibrotactile pulse on top of his/her shoulders, the front of his/her torso, or beneath his/her buttocks, respectively. The key challenge remaining for the TSAS is to transition from the research laboratory science and technology (S&T) setting to routine use aboard manned aircraft, which requires extensive flight testing. We present research evidence supporting the utility of the cues provided by TSAS, the safety benefits of TSAS, and the robustness of TSAS under demanding conditions relevant to flight. However, the research setting differs greatly from the operational setting it serves. Therefore, we conclude by sharing seven practical technology transition lessons we have learned from our efforts to transition TSAS from S&T to the very different world of flight operations. We discuss how the differing procedures, standards, timelines, priorities, incentives, and expectations of scientific versus flight testing raise significant challenges to the efficient transition of new technological inventions to the aircraft. Our hope is that describing our ongoing efforts with TSAS will aid similar display technology transition efforts and provide inventors information that could foster government innovation and implementation.

SDR based through the rubble communications for collapsed mines: A proof-of-concept

The underground communications system is the lifeline of a mine. During a mine emergency, it plays a crucial role in rescue and recovery operations. However, the biggest challenge faced by conventional communications system is its own survivability. Therefore a robust, resilient communications platform plays a crucial role when the safety of the miners is concerned. Hence the motivations for this pilot project for designing a proof-of-concept for a robust, self-organising underground wireless communications system capable of through the rubble communications in the event of an incident. Under this pilot project, the feasibility of using Software Defined Radio (SDR) devices for the creation of an underground heterogeneous wireless communications system is investigated. The primary focus is the use of customised IEEE 802.15.4 implementation for through the rubble transmissions between buried devices and to examine the use of appropriate forward error correction techniques. This work utilized a field programmable gate array (FPGA) based SDR and achieved promising results through extensive laboratory testing, where data was successfully transmitted through a chamber of rubble with a custom IEEE 802.15.4 protocol.