On the Basic Attitude properties page of a vehicle object, select Multi Segment to view and change sequences of Basic, Targeted, and File-based attitude profiles. Selecting this option enables you to view a list of the attitude segments already defined for the object, and the page provides methods to add and change segments. See the sections below for listing and changing of attitude segments.
The attitude segment source (Basic, Targeted, or File) sets its level in the segment prioritization scheme: File-based supersedes Targeted, which supersedes Basic. In the absence of both Target and File-based segments, Basic segments (the bottom level) are continuous without gaps, so that a valid attitude definition is available at any time. All of the Targeted segments come from the ones you build through the Standard Target Pointing profile, and File-based segments are from external files you select to include. Both Targeted and File-based segments have start and stop times already defined, coming either from the targeting logic or from the time tags of the data in the files.
The GUI listing will show which segment will be active at which times, based on segment start and stop times as well as the prioritization. Thus, while a Basic segment may extend from Time A to the end of the scenario, the view on the panel (list) may be different if, for example, some targeted or file-based segments overlap parts of that Basic segment. If you want the Basic segment attitude profile for your object from Time A to Time B, then you must make sure that no Targeted or File-based segments overlap that interval and supersede it.
Attitude segments list
The object's attitude segments appear in a list with the following information:
| Parameter | Description |
|---|---|
| Name | The name of the segment, which depends on the source of the segment |
| Source | The source of the attitude segment: Basic, Targeted, or File |
| Number | A sequential identifier indicating the order in which the segments are applied |
| Start Time | The time at which STK begins using the segment to define the vehicle's attitude |
| Stop Time | The time at which STK stops using the segment to define the vehicle's attitude |
You can control the display of segments by selecting View Basic segments, View Target segments, and View File segments. Basic segments are always applied to the overall attitude profile. You must select Target segments and File segments to apply them to the attitude profile.
- The View segments selections only affect the appearance of attitude segments in the list. For example, if you do not selectView Target segments, targeted profiles in the sequence still apply. To prevent them from applying, you must clear the Target Segments check box.
- Astrogator Maneuver segments can create attitude segments that override the attitude settings of the vehicle that you see on the Attitude page.
Adding, removing, and modifying segments
Editing options for an attitude profile in a multisegment sequence depend on the source of the profile: Basic, Targeted, or File.
Basic segments
Editing options for basic attitude segments appear in the Basic Segments frame. To add a new basic attitude segment to the sequence, click . To edit, copy, or remove a basic attitude segment, highlight it in the list and click , , or .
In the window that appears when you click Add segment..., Edit segment..., or Copy segment..., provide the following information:
| Parameter | Description |
|---|---|
| Name | This is the name of the segment. You can replace the default name. |
| Start Time | This is the time at which the segment begins. If the Start Time for a segment precedes that of another segment, then its Stop Time coincides with the Start time for the later segment. Otherwise, the Stop Time for a segment is the end of the vehicle time frame. For more information on the options for start and stop times, see Time Options. |
| Type | Select a predefined attitude profile from the drop-down menu and specify applicable parameters. |
Target segments
To add or edit a targeted attitude segment, click and proceed as you would for a Standard Target Pointing profile.
Attitude targets defined by latitude, longitude, and altitude points are displayed on the Basic Attitude properties page, but you can only add and edit them using Connect.
File segments
Editing options for attitude segments from an external file appear in the File Segments frame. To add a file segment, click . In the window, enter the path and name of the attitude file or click the ellipsis (
) button and browse for a file. After you select a file, the start and stop times appear. For more information on the options for start and stop times, see Time Options. Select one of the following save options:
| Option | Description |
|---|---|
| Always read data from attitude file | STK does not save the attitude data as part of the vehicle profile. AGI recommends this option because STK updates the vehicle's attitude data automatically if the data in the external attitude file changes. |
| Import and save attitude data | STK saves the attitude data as part of the vehicle profile. This option is convenient in some circumstances (e.g., when sharing vehicle files). |
To overwrite the CoordinateAxes parameter from the attitude file header, clear the Use Default check box, click , and choose one.
Click to add the file segment to the Multi Segment sequence or to return to the Attitude page without adding a segment.
To remove a file segment from the sequence, select it in the list and click .