STK Coverage

STK Professional and Coverage.

The results of the tutorial may vary depending on the user settings and data enabled (online operations, terrain server, dynamic Earth data, etc.). It is acceptable to have different results.

In this exercise you will learn to use two objects from STK Coverage - the coverage definition object and the Figure Of Merit - to define and evaluate the coverage of a region, using available coverage assets.

Define the Coverage Region and Assign Assets

You want to define a coverage region in the tropics and compute the coverage using two satellites.

Create a Scenario

  1. Click the Create a New Scenario () button.
  2. Enter the following in the New Scenario Wizard:
    3. Option Value
    Name Coverage
    Location C:\Documents and Settings\<user>\My Documents\STK 11\
    Start 1 Jul 2016 16:00:00.000 UTCG (Note: accept defaults if you are completing the L3 quiz)
    Stop + 1 day (Note: accept default if you are completing the L3 quiz)
  3. When you finish, click OK.
  4. Rename the scenario Coverage.
  5. When the scenario loads, click Save (). A folder with the same name as your scenario is created for you in the location specified above.
  6. Verify the scenario name and location and click Save.

Create the Two Satellites

  1. Using the Orbit Wizard, create a satellite with the following settings:
    2. Option Value
    Type Circular
    Altitude 400 km
    Inclination 97.3
    Name PolarSat
  2. Create a second satellite with the following settings:
    3. Option Value
    Type Circular
    RAAN 340 deg
    Name Shuttle
  3. Click OK.

Create a Coverage Definition

  1. Go to the Insert menu and select Default Object and insert a Coverage Definition () object.
  2. Rename the new Coverage Definition object Tropics.
  3. Open the Basic - Grid page for the coverage definition.
  4. Set the following:
    5. Option Value
    Grid Area of Interest Type Latitude Bounds
    Min Latitude -23.5 deg
    Max Latitude 23.5 deg
    Point Granularity Lat/Lon
    Point Granularity Value 3.0 deg

Assign the Assets

  1. Open the Assets page.
  2. Multi-select the two satellites.
  3. Click the Assign button. Make sure that Status is set to Active.
  4. Click Apply.

    5. To multi-select the satellites, click one satellite, hold down the Ctrl key, and click the other satellite.

Set the 2D Graphics Attibutes

  1. Open the 2D Graphics - Attributes page.
  2. Set the following options:
    3. Option Value
    Show Regions On
    Show Region Labels On
    Show Points On
    Points - Fill On
    Progress of Computations On
    Show Satisfaction Off
  3. Click OK.

Compute Coverage

  1. Right-click on the Coverage Definition () in the Object Browser.
  2. Select Compute Accesses from the CoverageDefinition Tools menu.
  3. Take a look at the results in the 2D and 3D Graphics windows.

Create a Report

  1. Open the Report & Graph Manager () for the coverage definition.
  2. Create a Coverage by Asset report.
    • Which satellite achieved a higher average coverage of the tropics region?
  3. Create a Coverage by Latitude graph.
    • Was coverage better or worse near the Equator?

Assess the Quality of Coverage with a Figure of Merit

Determine opportunities for dual coverage of the tropics region:

  1. On the 2D Graphics - Attributes page for the coverage definition ().
  2. Disable the Show Regions and Show Points options.
  3. Click OK. The Figure of Merit object has its own graphics, and we do not want the Coverage Definition graphics to interfere.

Create a Figure of Merit

  1. Select the CoverageDefinition () in the Object Browser.
  2. Extend the Insert menu again and select Default Object and insert a FigureOfMerit () object.
  3. Name it TwoEyes.

Define the Coverage

  1. Open the Definition page for the Figure of Merit.
  2. Select N Asset Coverage as the Type.
  3. Set the Compute field To Maximum.
  4. Click Apply.

Set the Graphics

  1. On the 2D Graphics - Animation page, set the following options:
    2. Option Value
    Show Animation Graphics On
    Accumulation Current Time
    Show Points Markers
    Marker Style Star

Set the Static Graphics

  1. On the 2D Graphics - Static page, set the following options:
    2. Option Value
    Static Graphics On
    Show Points As Markers
    Markers Circle
  2. Click OK.
  3. Animate the scenario.

The points that are highlighted with stars at any time during the animation are the points that have access to either or both of the satellites at that time. The points marked by circles have access to at least one satellite at some point during the scenario analysis period.

Define the Coverage for the Figure of Merit

  1. Open the Definition page for the Figure Of Merit again.
  2. Enable the Satisfaction option.
  3. Set tje Satisfiedif option to At Least.
  4. Set the threshold to two (2).
  5. Click OK.

The 2D Graphics window will immediately reflect the reduction in the amount of the coverage region that satisfies the 'at least 2' criterion. Animate the scenario, and note that points are highlighted only where the coverage of the two satellites overlaps.

Set the Animation Graphics

  1. Open the 2D Graphics - Static page for the Figure Of Merit.
  2. Disable the Show Static Graphics option.
  3. Click Apply.
  4. Open the Animation page.
  5. Enable the Show Contours option.
  6. >Ensure the Color Method is set to Explicit.
  7. Assign colors to each of the two levels in the Level Attributes list.
  8. Click OK.
  9. Animate the scenario.

Note that points are highlighted in one color when they are covered by only one satellite, and in the second color when covered by both satellites.

Create a Satisfied by Time Report

  1. Open the Report & Graph Manager () for the Figure Of Merit ().
  2. Create a Satisfied by Time report.

The Satisfied by Time report summarizes the percentage and true area of the grid that satisfies the Figure Of Merit at each time step.

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