What is a reasonable Video Update Rate for Remote Tower Control?

This was questioned when the EUROCAE working Group 100 “Remote and Virtual Tower” looked for a minmium System performance for the “Video update rate”. There are different solutions on the market, ranging from 5 up to 30 Hz. But what is the the minimum the provide remote control safe and efficiently? Are there use cases where lower frame rates can be accepted by the ATCO to get compensated with higher resolution instead to see in the far distance? Does a lower frame rate induce physiological stress? Those questions were not investigated so far. Therefore in 2017 DLR carried our an experimental study with voluntarily Air Traffic Controllers, which tested several frame rate conditions. The results are now public and can be downloaded here: paper presentation