Grex Project

Due to the fact that within GREX the presented solution is one of the first realizations for such kind of
team handling structure and also for vehicle security reasons, only one replanning command is
executed at the same time. Furthermore every order which is send gets a unique identifier that has to
be in the reply message. Depending on the priority of a replanning it is possible that an order will be
denied by the vehicle, e.g. a speed adaptation. A decline of course changes or high priority commands
will end up with a global mission abort realized through an internal message to the Mission
Monitoring component.
Fig.6: Main process diagram of the Team Handler with focus on Mission Replanning
4. Simulation Environment and first results
This external software package provides all data and functionalities which are necessary to simulate
an environment for test purposes from a team handling point of view. It includes e. g. the height above
sea ground, the surrounding sea current or the communication delay as well as data loss as result of
the acoustic underwater communication. Furthermore the Simulation Environment is able to emulate
sensors of a vehicle by calculating the distance to static or dynamic objects like gas concentrations.
Due to the usage of the mentioned data, the GREX simulation software is able to execute missions
with multiple vehicles close to reality.
Fig.7: Simulation Environment
Fig.7 shows the used Simulation Environment with the Environmental Module itself. Every simulated
vehicle needs an interface to the Environment Server to get control relevant data or acoustic messages
from other vehicles. For flexibility reasons it is possible to run the Environment Module and each
simulated vehicle on a separate computer linked by a standard network or the internet. Due to cost
efficiency it is also feasible to run the Environment Module as well as each simulated vehicle on just
one computer.
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