Environmental Engineering Reference
In-Depth Information
be added to the community; it also provides to the agents the address of the
other agents (so agents can pass messages to each other). The following is a
spacecraft contact scenario that illustrates how the agents worked with the
GCC manager agent:
•
Agents register with the GCC Manager Agent at system startup.
•
The GCC Planner/Scheduler Agent communicates with the spacecraft
Proxy Agents to obtain spacecraft communications-view data. It then cre-
ates a contact schedule for all orbiting spacecraft.
•
The GCC Manager Agent receives the schedule from the GCC Planner/
Scheduler Agent.
•
The GCC Manager Agent informs the CMA about the next contact (when
and with which spacecraft).
•
The CMA receives notification of an acquisition of signal (AOS) from a
spacecraft. The MOCC is now in contact with the spacecraft.
•
The CMA executes the contact schedule to download data, delete data, or
save data for a future pass.
•
The CMA analyzes the downloaded telemetry data. If the telemetry indi-
cates a problem, the CMA may alter the current contact schedule to deal
with the problem.
•
The CMA performs any necessary commanding in parallel with any data
downloads.
•
The CMA sends the telemetry to the appropriate spacecraft Proxy Agent
for processing.
•
The spacecraft Proxy Agent processes the telemetry data and updates the
state of its model of the spacecraft from the telemetry received.
•
If the spacecraft Proxy determines that a problem exists with the space-
craft and an extended or extra contact is needed, a message is sent to the
GCC Planner/Scheduler Agent which will re-plan its contact schedule and
redistribute it to the GCC Manager.
•
The spacecraft Proxy Agent sends to the Contact Manager any commands
that need to be uploaded.
•
The Mission Manager Agent ends contact when scheduled.
4.3.5 Verification and Correctness
Whereas AFLOAT and LOGOS demonstrated that typical control center ac-
tivities could be emulated by a multiagent system, the major objective of the
ACT project was to demonstrate that ground-based surrogate agents, each
representing a spacecraft in a group of spacecraft, could control the overall
dynamic behaviors of the group of spacecraft in the realization of some global
objective. The ultimate objective of ACT was to help in the understanding of
the idea of progressive autonomy (see Sect.
9.6
), which would, as a final goal,
allow the surrogate agents to migrate to their respective spacecraft and then
allow the group of autonomous spacecraft to have control of their dynamic
behaviors independent of relying on ground control.
