If the supervisor loses connection, the onboard (supervised) Kuda Core would otherwise keep navigating. The Auto Emergency Stop prevents this.
Set it with the Set Auto Emergency Stop Time button in the Vehicle Control view. If the supervised computer is unsupervised for longer than the set time, it disarms the autopilot and stops the vessel until the supervisor re-arms it with Start Thrusters.
The default is 30 seconds. Adjust it to suit your survey/network environment.