A comparison of task-related physiological responses in operators using EO/IR sensors or Night Vision Goggles to carry out air-to-ground search

The Advanced Integrated Multi-Sensor Surveillance (AIMS) System was developed by Defense Research and Development Canada – Valcartier to examine issues associated with airborne search and rescue operations using an... [ view full abstract ]

The Advanced Integrated Multi-Sensor Surveillance (AIMS) System was developed by Defense Research and Development Canada – Valcartier to examine issues associated with airborne search and rescue operations using an electro-optical/infrared (EO/IR) sensor. The infrared imaging on the AIMS system can help detect objects (such as downed aircraft) in a wide variety of lighting and weather conditions. An assessment of the overall usefulness of an EO/IR system in a search and rescue context required a comparison of the operator’s effectiveness at using the AIMS system or Night Vision Goggles (NVGs). In addition to our assessment of detection performance with each system, operator physiological parameters were used along with the traditional self-report metrics in order to gauge operator workload, fatigue and stress. Using a case-study methodology, an experienced and an inexperienced operator were monitored across 11 flights. The operators were tasked with manning the AIMs system or NVGs on alternate flights on board the National Research Council’s (NRC) DHC-6 Twin Otter. Each search task was approximately two hours in duration. The experiment was designed to simulate night-time search and rescue under ideal conditions (highly visible targets, level terrain, and minimal natural distractors). Both operators were outfitted with the EquivitalTM EQ02 LifeMonitor, a mobile monitor which recorded a variety of physiological metrics including continuous electrocardiography (ECG) and respiration. Heart rate variability (HRV) metrics were derived from the ECG data as an indicator of physiological arousal, and thus stress states. These metrics were complimented through the use of a pre- and post-flight Psychomotor Vigilance Task (PVT), subjective fatigue and sleepiness ratings, and an abbreviated version of the Dundee Stress State Questionnaire (DSSQ). A difference was observed in HRV metrics such that operators showed signs of greater stress when operating the AIMS system as compared with the use of NVGs. In addition, the operators demonstrated evidence of post-flight fatigue based on PVT performance and questionnaire responses. Operating an airborne sensor system imposed different requirements on the participants than did the use of NVGs. As a result, contrasting physiological responses and differential levels of reported wakefulness and fatigue were evident.