COMPARING DIFFERENT WORKLOAD AND STRESS ASSESSMENT METHODS IN AIR TRAFFIC CONTROL SIMULATIONS

Kurzfassung

Measuring the current level of workload is one of the key indicators to assess the benefit of new supporting tools or new procedures for air traffic controllers. In addition, it is well-known that the current stress level depends on the current level of workload and is furthermore directly related to the current traffic capacity of air traffic control. Different workload assessment techniques are already available, but they are either subjective like the Instantaneous Self-Assessment Technique (ISA) or cannot be used in real-time during simulations like the NASA task load index (NASA-TLX). In the frame of the European 7th framework project GAMMA, a new stress measurement prototype was developed which is based on voice recognition. This prototype uses vocal stress signals to determine the current stress level of any speaker within air-ground voice communication in air traffic control. The advantage of such a system is the availability of objective stress measurements in real-time. In order to verify this new stress measurement prototype, several high-workload ATC simulations were conducted at DLR Braunschweig in January 2017. During this simulation campaign, the prototype was used in parallel with ISA and with an assessment by a third person using a modified Cooper-Harper Scale (MCH). Active air traffic controllers attended the simulation campaign, which contained a total number of 20 air traffic control simulations using DLR's radar simulator ATMOS. The trials showed that even common workload measurement methods (ISA and MCH) showed just a clear correlation between each other in less than 50% of the trials, which underlines the need for a reliable and objective stress measurement technique. The mentioned prototype shows the potential to become such a tool in the midterm future. This paper gives basic information about the used assessment / measurement techniques, describes the setup and the conduction of these trials, illustrates obtained results and provides a discussion and an outlook about enhancements in stress measurement techniques.