Setting Up a Grid Constraint Object on Terrain for Use With Coverage

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QuestionHow do I set up a Grid Constraint object on terrain for use with Coverage?
Answer
You can set up grid constraint options in a Coverage Definition using the following process:

Assumptions:
You have already loaded in a terrain file and have enabled STK to use it analytically.
You have the Globe Manager open.
  1. Zoom To your *.pdtt terrain file.
  2. Right-click the terrain file in the Globe Manager and select Toggle Extents. This gives you an overlay that you can use to define the Area Target.
  3. Insert a default facility or place.
    1. Go to the Insert menu and select New.
    2. Select Facility or Place on the left and Default on the right. Click the Insert button.
    3. Use 3D Object Editing to shift + click the position of the facility/place somewhere on the terrain.
  4. Ensure that your facility/place considers the terrain height for its altitude:
    1. Open the properties of the object. On the Basic à Position page, select the "Use terrain data" check box for the altitude and set the Altitude Reference to MSL. The facility/place should now be on top of the terrain.
    2. In the BasicàAzElMask page:
      • Select the "Use Mask for Access Constraint" check box.
      • Click Apply or OK.
  5. Create an area target by defining its perimeter points:
    1. Go to the Insert menu and select New.
    2. Select Area Target on the left, and Default on the right.
    3. Rename it accordingly.
    4. Use 3D Object Editing to shift + click out the four perimeter points at the four corners of your terrain file.
    5. Remove the Toggle Extents from the terrain file.
    6. Change the Area Target’s Properties in order to view the boundary wall around the terrain:
      • On the 3D Graphics > Attributes page, select the Show Boundary Wall check box.
      • Change the shortcut menus for both the Upper and Lower Edge to be "Height from Terrain".
      • Change the value to 0.1 km for the Upper Edge.
      • Click OK
  6. Go to the Insert menu and select New. Select Coverage Definition on the left, and Default on the right.
    1. Rename it accordingly.
    2. Open the Coverage Definition Properties.
    3. On the BasicàGrid page:
      • Select Regions = Select your Area Target.  Click OK.
      • Point Granularity: Choose the Distance option and set it to the desired point granularity.
      • Specify Point Altitude as "Altitude above Terrain" at 0 km.
      • Click Grid Constraint Options.
      • Select the check box for "Use Object Instance".
      • Highlight your facility/place.
      Note: You can use the Az-El Mask as a constraint for each grid point. STK will calculate the Az-El Mask for each grid point. You can use the object to associate three types of information with the grid points: access constraints, basic object properties, and the shape of the ellipsoidal obstruction surface used by the Line Of Sight constraint. By selecting a specific object, all of the properties and constraints that apply to that one object, excluding positional information, are also applied to every point in the grid. 
      Note: Do not select the "Use Actual Object on the Grid Points" check box.
    4. On the 2D GraphicsàAttributes page, change your point color, if desired. Choose a color that you can see well so you can see how far out the points are spaced.
    5. On the 3D Graphics > Attributes page, change your Grid Graphics Point Size to 3, if desired. Do this if you want to see larger grid points.
    6. On the Basic > Advanced page, clear the "Automatically Recompute Access" check box.
    7. Click OK to accept all changes.
  7. Right-click the Coverage Definition object in the Object Browser and select Coverage Definition > Compute Accesses.
    Note: The Coverage Definition object is now set up and you can use it for further analysis.
TitleSetting Up a Grid Constraint Object on Terrain for Use With Coverage
URL NameSetting-Up-a-Grid-Constraint-Object-on-Terrain-for-Use-With-Coverage

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