Contact Scheduling

Contact scheduling is necessary for any inter-satellite or satellite to ground communication. In STK Scheduler, tasks for establishing and conducting this this communication can be made. An example of a real world scenario implementing basic contact scheduling is provided below.

Low Earth Orbit to Ground Station

It is common for LEO sattelites to transmit data to a ground station. The following steps will farmiliarize you with the procedure for scheduling a contact task between several LEO satellites and a ground station.

Prerequisites

File: Contact_Scheduling.vdf Path: C:\Program Files\AGI\STK 11\STKScheduler\Scenarios\Use Cases

Steps

  1. Open STK Scheduler.
  2. Load the associated STK Scenario.
    1. Navigate to Schedule > STK > Load Scenario....
    2. In the Schedule Properties window, click Change Scenario.
    3. Select the file path to Contact_Scheduling.vdf.
    4. Click Open then OK and the STK scenario will be associated with your Scheduler file.
  3. Ingest Resources from STK.
    1. Navigate to Resource > Ingest From STK > All.
    2. In the Select Map Objects for Resource Creation window, click Select All then OK.
  4. Set Resource attributes.
    1. Navigate to Resource > Edit Resource.
    2. On the left side of the Resource Editor window use Ctrl + click to select all Kompsat satellite resources.
    3. In the General tab, locate the New Group field and enter "SAT".
    4. Click the Create button next to New Group.
    5. Select the SAT resource group under Available Groups.
    6. Click the right arrow button to add SAT to the Included Groups.
    7. Click Update then Close.
  5. Set Task definitions.
    1. Navigate to Task > New Task....
    2. In the Task Editor window, type "Ground_Kompsat_Contact" in the Task ID: field.
    3. In the Duration tab, select the radio button next to Variable Duration.
    4. Set the Minimum Duration to 1 minute and the Maximum Duration to Unlimited.
    5. Check the boxes next to Allow Multiple Segments and Allow Resource Changes Between Segments.
    6. Ensure the radio button next to Allow Gaps is selected.
    7. Construct "_1ofSATs' Constraint Group.
      1. In the Resources tab, select "SAT" under Available Resource Groups: and click the right arrow button.
      2. Selcet the radio buttion next to Resources From Group and change the field to 1 resource from group.
      3. Click Create Group/List and enter "_1ofSATs".
      4. Click OK and _1ofSATs will appear under Available Resources.
    8. Click on the Resources tab and create the following Resource Constraints string: <"Ground" AND "_1ofSATs">.
    9. Click Create Possibilities then Update to add the task.
    10. Close the Task Editor window.
  6. Run the desired algorithm.
    1. Navigate to Schedule > Select Algorithm > and select the desired algorithm.
    2. Click Schedule > Go!!! to run the selected algorithm.
    3. Click OK when Done Scheduling to exit the Scheduling Progress window. A Summary Report window will open.

Results

When the above steps are completed you may now review the Summary Report. Note that ground contact has been scheduled for the various Kompsat satellites.

Ingest Command File

A sample ingest command file named Contact_Scheduling.txt is available in the Examples/Use Cases folder. Ingesting that file will replicate the schedule described here.