Targeted Attitude Segments

You can override the basic attitude profile for a satellite, missile, or launch vehicle and have a selected axis (its Z axis by default) point in the direction of one or more selected targets, subject to applicable access constraints. To use targeted attitude, select Override Basic attitude for selected targets, and click Select Targets....

To create a targeted segment of a multi segment profile, click Add/Edit in the Target Segments frame.

Assigning Targets

Highlight each object that you wish to designate as a target in the Available Targets list and use the right arrow to move it to the Assigned Targets list. To de-assign a target, highlight it in the Assigned Targets list and click the left arrow button. You can also move objects back and forth between the two lists by double-clicking them.

Target Slew

Click Target Slew... to define the time required for the satellite to move from its basic attitude to its target pointing attitude, and to change from the target pointing attitude back to the basic attitude. Select a Slew mode from the drop-down menu; the modes are described in the following table.

Mode Description
Fixed Time The time required to change attitude will always be the same, defined by the Slew time field. Select Match angular velocity to take account of the angular velocity (slope) at the beginning and end of the slew.

The Fixed Time Slew method will slew from the orientation at the stop time of the last target to orientation at the start time of the next target unless that duration is more than 5 times the duration of the Fixed Time value. In that case, a slew will be created of the Fixed Time value in duration from the orientation at the stop time of the last target to the orientation of the basic profile at that time; the orientation will use the basic profile until the next slew; finally, a slew will be created of the Fixed Time value in duration from the orientation of the basic profile at that time to the orientation at the start time of the next target.

Fixed Rate The time required to change attitude is calculated by applying a fixed slew rate, limited to the Maximum slew time.

From the Slew timing between targets drop-down menu, select an event within the window of opportunity to trigger each slew, or select Optimal to change attitude whenever the slew can be performed most efficiently. Define the maximum slew rate by entering a maximum overall Magnitude. You can constrain the slew rate in specific directions by selecting one or more Per Axis rates and defining separate maximum rates for those axes.

Constrained The time required to change attitude will be calculated by applying a constrained slew rate and acceleration, limited to the Maximum slew time.

From the Slew timing between targets drop-down menu, select an event within the window of opportunity to trigger each slew, or select Optimal to change attitude whenever the slew can be performed most efficiently.

From the Slew type menu, select to use a 2nd or 3rd order spline as the interpolation method of the slew's data points. Define the maximum slew rate and slew acceleration by entering maximum overall Magnitude. You can constrain the slew rate or acceleration in specific directions by selecting one or more Per Axis rates and defining separate maximum rates for those axes.

The slew rate and slew acceleration are the inertial angular velocity and inertial angular acceleration, respectively during the slew; the PerAxis rate and acceleration components refer to the body components of these inertially defined quantities (e.g., "Per Axis X" in the maximum slew rate refers to the body X-component of the inertial angular velocity; "Per Axis Y" in the maximum slew acceleration refers to the body Y-component of the inertial angular acceleration).

Target Scheduling

Click Target Times... to open the Target Times Window.

The Target Times window allows for the specification of explicit target pointing intervals or the selection of target pointing deconfliction methods to adjudicate situations where multiple targets are simultaneously available.

Advanced

Click Advanced... to open the Target Advanced Access Window.

Pointing Adjustments

The default pointing attitude of a satellite is defined in such a way that the Z axis is aligned along the line of sight vector to the target, and the X axis is constrained about the relative velocity vector. To change these settings, click Target Pointing... and make the desired changes for the Aligned and/or Constrained Vector.

The Reference for the Aligned Vector is line of sight. For the Constrained Vector, you have the option of using the default Reference (relative velocity) or clicking Select to choose another.

If there are multiple targets, a check box gives you the option to apply this configuration to all targets.