Filtering access gaps with Analysis Workbench
- Aug 13, 2018
- Tech Tip
- STK Analysis Workbench
The Filtered Interval List is a useful component in Analysis Workbench that allows you to filter Time Intervals.
Click STKFilteredIntervalList.vdf to download the scenario that shows how to analyze blackout periods, or periods of time for when a ground facility does not have access to any satellite in a constellation. To do so, the scenario contains a chain from a constellation object to a ground facility. The constellation uses the “None Of” Logical Restriction, such that the chain is only considered to have complete chain access when none of the satellites in the constellation have individual access to the ground facility. A report of Complete Chain Access yields the following times:
Note that the duration of the gaps vary rather wildly, where some of the blackout periods are around 5-7 min and most linger around the 20 minute mark. In this case, you may want a closer look at some statistics on just the blackout periods that are under 10 minutes. Lets go ahead and get those results using the Filtered Interval List.
What you can do is open Analysis Workbench for the chain object. In the Time tab, create a new Time Inerval List. Set the type to Filtered and select CompleteChainAccessIntervals for the Original Interval List. Set the Filter to Intervals and interval to 600 sec. Here are the settings below:
Now once you click Ok, the component you created will appear in Analysis Workbench. Right-click on the component and select Report. A report of all of the blackout periods that are under 10 minutes will appear. We’re almost there!
Right click on Duration and select Properties. Under statistics select Min, Mean, and Max and click Ok. Scroll down to the botton of the report to see the statistics!