Compute Access

Now that you have set the stage, it is time to let STK do some work for you. An important tool -- one of many in STK - is Access. Try it out.

1. Select the MEO satellite in the Object Browser.
2. Click to open the Access tool.
3. On the Access page, click the signs to the left of Perth and Wallops facilities to expand the Associated Objects tree and expose the two sensors.
4. Select the two sensors and click Compute....

5. Tip: To multi-select the sensors, select one of the sensors, hold down the Ctrl key, and select the other sensor.

6. Select the 2D Graphics window and observe the thick lines that overlie portions of the satellite's ground track. These lines correspond to periods of access between the satellite and one of the sensors, i.e., times when the sensor can 'see' the satellite.
7. Now animate the scenario and observe that, during periods of access a box is drawn around the satellite and a line is drawn between the satellite and the parent facility.
8. In the 3D Graphics window, during animation, a line appears between the satellite and the associated ground station during access periods.
9. In the Reports area of the Access tool, click Access... to display a list of times during which the satellite has access to each sensor, and also to display global statistics (minimum, maximum, mean, and total duration) for each pair.
10. Close the Access tool, but leave the report open.

Next, impose some constraints on access.