IntroductionThere are two new controls for editing time quantities in STK; one for time intervals and one for time instances.
Time Interval Control
The Interval Control displays either an interval component (Figure 1) or a pair of time instance controls (Figure 2) depending on your preference as selected from the drop-down menu to the right of the control.
Time Instance Control
The Time Instance Control displays either a time instance component (Figure 3) or a specific date and time (Figure 4) depending on your preference as selected from the drop-down menu to the right of the control.
Time Properties and Options
|Interval||Defines the time period as a single interval component.|
|Start||Defines the start date and time either as a time instance component or a specific date and time.|
|Stop||Defines the stop date and time either as a time instance component or a specific date and time.|
The following time options are set using the drop-down menu accessed by selecting the button to the right of the control.
|Interval Component||Displays the Select Time Interval window. Select an existing time interval or click the Create New Interval button () to create a new time interval using the Add Time Component window.|
|Convert time components to their specific time. This option breaks the link to the time component|
|Start Time||Start date and time defined either as a time instance component or a specific date and time.|
|Stop Time||Stop date and time defined either as a time instance component or a specific date and time.|
|Set to Today||References the current date and time based on your computer's internal clock. The current date and time are updated each time the scenario is opened.|
|Set to Tomorrow||References 24 hours after the current date and time based on your computer's internal clock. The date and time are updated each time the scenario is opened.|
|Use Analysis Start Time||Found in the Epoch Time drop down menu it uses the scenario's analysis start time as the epoch time instance.|
|Time Component...||Displays the Select Time Instance window. Select an existing time instance or click the Create New Time Instant button () to create a new time instance using the Add Time Component window.|
|Select Date||Select a date from the calendar displayed. When selecting or changing dates the associated time does not change.|
|Set Animation Time||Sets the current animation time to the time displayed.|
|Set Animation Start Time||Sets the animation start time to the time displayed.|
|Format...||Displays the Format Dialog window allowing for the selection of different time formats.|
|Units||Select from a list of available date and time unit formats.|
STK recognizes several time keywords that you can type into a time field; each of the keywords references the current date and time based on your computer's internal clock.
If a scenario includes time values of Today, NoonToday, Tomorrow, or NoonTomorrow, the animation time of those fields is updated - each time that the scenario is opened - to correspond to the current time or twelve o'clock (noon) on the current day or the current time or twelve o'clock (noon) on the next day, respectively.
The keyword "Now" does not persist like the other time keywords. Typing "Now" into a time field simply enters the current computer time; that time will not be update when the scenario is reopened.
Default Time Period
The scenario's analysis period is also used as the default time period for operations involving objects that don't have an implicit sense of availability. A vehicle, for example, has an interval of availability that is defined by the span of its ephemeris, while a facility has no such time-oriented restrictions and uses the scenario time period if such an interval is needed. Finally, animation start and stop times are automatically updated to match the time period when a new one is set here.