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Scheduling allows a user to schedule any task in the
system for an absolute or relative execution time. The task schedule
contains the time ordered events and tasks for all missions within
the system. Events are simply markers of significant milestones. A
common type of event is an orbital event, but neither the list nor
meanings are constrained by task scheduling. A task may consist of
any combination of the following functions:
- Send an AWE Message
- Execute a procedure
- Launch a client display application
- Terminate a client display application
- Execute a ranging request
- Execute a command
- Reconfigure a hardware interface
- Set a telemetry parameter value
- Modify a parameter’s limit or load a new limit
set
Tasks are user created and can contain any combination
of activities, which can be executed synchronously or concurrently.
Within a task, the user can specify constraint dependencies between
the activities, such as an activity cannot start until the completion
of another activity plus a delay or an activity is to start at the
same time as another activity. In addition activities can further be
constrained by requiring the successful completion of their dependent
activity.
In addition to specifying the activities to be executed, the user can
optionally assign resources and estimated durations for the activity
and a priority value for the task. This is later used during schedule
generation to search for any resource contention and perform deconfliction.
Scheduling of a task may be done manually by a user via a graphical
interface. Relative execution times may be referenced against other tasks
or a defined event, such as “Eclipse Start.” This interface
provides the capability to schedule individual instances of tasks or
periodic occurrences of tasks. For example, a task may be scheduled to
happen at a particular time each week or it may be scheduled to always
take place five minutes prior to any station-keeping event. In addition,
scheduling may be done programmatically based on flight dynamics file
inputs. The scheduler can periodically place events in the schedule,
such as eclipse start/stop times and maneuver start/stop times.
The task execution display allows the user to view the past, present,
and future tasks in the system for all missions to which he is joined.
The display consists of three panes, one for each time frame that may
be resized and scrolled independently.
Select here to learn more about task schedule
generation and task schedule
execution.
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