The Effect of Workload on Performance of Operators Monitoring Unattended Ground Sensors
Final rept. Jan 1974-Feb 1975
HRB-SINGER INC STATE COLLEGE PA
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The objective was to determine the effect of workload target activity level and number of sensors used on unattended ground sensor UGS operators target-detection ability, false-alarm rate, and direction and speed estimation accuracy. Experienced operators monitored activations of UGS used in grids under six workload conditions--two levels of target activity x three levels of number of sensors monitored. Target activity level was defined as either 5 or 14 vehicle groups per 27 sensors per hour. The operators monitored in counterbalanced sequence 27 sensors 3 grids, 54 sensors 6 grids, and 108 sensors 12 grids. Percentage of detections decreased linearly from 85 4 to 6 vehicle groups per hour presented on 27 sensors to 26 about 40 vehicle groups per hour presented on 108 sensors. Without special training, operators should monitor no more than 60 sensors being activated by a maximum of 10 vehicular groups per hour detection completeness for this condition was 76. The number of false alarms and the accuracy of speed estimation did not significantly change over workload. Operator accuracy in direction estimation decreased significantly as a function of workload from true azimuth or - 30 deg. to true azimuth or - 54 deg.
- Human Factors Engineering and Man Machine Systems