Sustaining Performance and Vigilance during Extended Unmanned Aerial System Operations

Current scheduling of unmanned aerial system (UAS) operators often allows for 8 hour shifts, where operators are typically exposed to low event rate tasks, thus leading to the occurrence of underload. While a long, rich history of vigilance research exists, few studies have examined the threshold at which performance decrements occur in UAS operators in operational settings and the utility of strategies to mitigate vigilance and performance decrements. This study evaluated the performance thresholds relative to time-on-task during a 4 hour simulated UAS mission. Additionally, this study evaluated the effectiveness of countermeasure strategies (secondary task and ambient lighting) on sustaining performance and vigilance during simulated UAS missions. Finally, the study demonstrated patterns of psychophysiological indicators of operator states (comparing high and low workload). Findings suggest that performance begins to decline after 15 minutes on task and plateaus by 45 minutes on task for both workload conditions. There was insufficient evidence to support any of the countermeasures, yet patterns in EEG are consistent with past findings regarding shifts in perceived workload.