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Version: 4.9

Command & Control

The Command & Control subsystem controls the behavior of the spacecraft. Use the Command & Control menu is used to create Conditions and Operational Modes.

Conditions​

Conditions are assigned to operational modes to drive ConOps logic. For example, you can use a condition to require line of sight to your groundstation for entry into downlink operational mode. Additionally, they can be used to filter targets in a Target Group, determine when Sensors produce data, and terminate the simulation. There are four types of conditions.

Compare Conditions​

A compare condition is fulfulled when two parameters (A and B) must satisfy the relationship defined upon the creation of the condition. Parameter A may fall in one of three categories:

  • Satellite - These parameters are related to the satellite itself, for example latitude, battery state of charge, eclipse state, beta angle, etc.
  • Target - These parameters are related to a target or target group, for exmaple line of sight (access), range, satellite elevation, solar elevation, etc.
  • Date and Time

Parameter B may be either a constant value (scalar or boolean) or a satellite or single target parameter.

Finally define the relationship, which is an equality or inequaltiy (for example, <, >=, etc.).

If a Target Group parameter is chosen for Parameter A, you will be prompted to select a group "roller", which is a method to combine the individual target parameters into a single comparable quantity. Available rollers include "all", "any", "count", etc. You can choose to have this Condition filter the Target Group by clicking the checkbox.

Field of View Conditions​

Field of view conditions evaluate whether a Target, Reference Vector, or celestial body lies within a Field of View. Select "Negate" to instead evaluate whether the target/vector/body is outside of the field of view.

The FoV evaluation for targets includes checking for eclipse by the Earth, moon, and other celestial bodies, evaluating to false if the target is blocked.

Evaluation of vector in FoV does not take eclipsing into account.

Compound Conditions​

Compound conditions combine multiple previously defined conditions into one. Using the "and" operator, this can simplify the definition of Operational Modes and any other place where Conditions are selected. The "any" and "count" operators can be used to define more complex logic, since "all" is assumed when assigning Conditions to an Operational Mode, for example.

Same Target Multi-Condition​

This is a variant of Compound Condition that combines conditions associated with a single Target Group. The difference is that these evaluate to "true" only if all of the conditions are "true" for at least one target. For instance, if a ground target can only be imaged during certain local time and satellite elevation conditions, combining the two conditions into a Same Target Multi-Condition will allow ConOps logic to access whether any target can be imaged.

It is recommended to use a Same Target Multi-Condition any time that multiple conditions are imposed on a Target Group (such as in an Operational Mode) since it will assure that the Agent condsiders the Target Group in an intuitive manner.

Operational Modes​

Operational modes are the building blocks of your ConOps. Each operational mode is assigned a pointing mode and - optionally - conditions and timing constraints. Other Sedaro modules will assign mode-dependent factors to these operational modes.

To create an Operational Mode, click the dashed box at the top of the table and give it a name. Next, associate a Pointing Mode to this Operational Mode. Finally assign Conditions and constraints to this operational mode. Constraints limit the duration or frequency of the Operational Mode, such as by max duration or minimum time between seperate occurences.

After creating your Operational Modes, drag and drop them in the table to re-order them by priority. The lowest priority mode is the "default" operational mode. Any conditions attached to a default mode are not evaluated during simulation. An operational mode can only be active if it is the default mode or if all of the conditions assigned to it are satisfied. At each time step in your mission simulation, the highest-priority operational mode with all conditions satisfied will become the active mode.