STK Aviator: UAV Flight Path Tutorial

STK Premium (Air) or STK Enterprise
You can obtain the necessary licenses for this tutorial by contacting AGI Support at support@agi.com or 1-800-924-7244.

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.

Capabilities covered

This lesson covers the following STK Capabilities:

  • STK Pro
  • Aviator

Solution

Use STK's Aviator capability to create a flight path using the STK Basic UAV model.

Creating a new scenario

First, you must create a new STK scenario.

  1. Launch STK ().
  2. Click Create a Scenario in the Welcome to STK dialog box.
  3. Enter the scenario name AMM and leave all other settings as default values.
  4. Click OK when you finish.
  5. Click Save () when the scenario loads. STK creates a folder with the same name as your scenario for you.
  6. Verify the scenario name and location in the Save As dialog box.
  7. Click Save.

Save () often during this lesson!

Adding terrain

If you have an internet connection, you only need to add analytical terrain. Microsoft Bing Maps can be used for imagery. However, imagery is not required.

  • If you have previously created a *.pdtt file from the hoquiam-e.dem terrain data file during STK Comprehensive training, you can enable it for analysis.
  • If you have not already created the *.pdtt file, you can use a provided one.

Use these steps to add a PDTT file.

  1. Launch the Globe Manager () from the 3D Graphics window toolbar.
  2. Use the Add Terrain/Imagery () option in the Globe Manager () to load your terrain file (*.pdtt) to the globe in the 3D Graphics window.
  3. If you haven't created a terrain file, go to <STK install folder>\Data\Resources\stktraining and select StHelens_Training.pdtt.
  4. When prompted Use Terrain for Analysis:
    1. If you are already using the hoquiam-e.dem terrain data file for analysis, do not enable terrain for analysis.
    2. If you haven't loaded the hoquiam-e.dem terrain data file for analysis, enable terrain for analysis.

Setting Scenario object properties

Besides analytical terrain, your scenario will require other properties to be set for your analysis.

Setting an altitude reference

Aviator performs best in the 3D Graphics window when the surface reference of the globe is set to Mean Sea Level. You will receive a warning message when you apply changes or click OK to close the properties window of an Aviator object with the surface reference set to WGS84.

It is highly recommended that you set the surface reference as indicated before working with Aviator.

  1. Open the scenario's () properties ().
  2. Go to the 3D Graphics - Global Attributes page.
  3. In the Surface At field, under Surface Reference of Earth Globes, select Mean Sea Level from the drop-down menu.
  4. Click OK.

Creating waypoints

Enter waypoints into the scenario. Then, insert the airport from where the UAV will take off and land. Use the 3D Aviator Editing tool to build the mission.

There are multiple ways to design waypoints in STK. For this scenario, the UAV will fly direct to waypoints that you can easily insert into the scenario using the Place object and the From City Database method and the Search by Address method.

  1. To better see all the place objects' labels, open the 3D Graphics window's properties.
  2. In the Label Declutter field, select the Enable check box.
  3. Click OK.
  4. Using the Insert STK Objects tool (), insert two Place () objects using the From City Database method:
    • Eatonville (Washington)
    • Kelso (Washington)

    If you don't have an internet connection, move to No Internet Connection Steps. Otherwise, continue.

  5. Using the Insert STK Objects tool, insert a Place () object using the Search by Address method:
    • Mount St Helens, WA
  6. Go to the Object Browser.
  7. Using the Shift key, select all three place () objects and open their properties ().
  8. On the Basic - Position page, enable the Use terrain data check box.
  9. Click OK.

This puts the Place objects on top of the terrain.

Creating the airport

Insert a local airport. This is where the UAV will begin and end its mission.

  1. Using the Insert STK Objects tool, insert a Place () object using the Search by Address method:
    • Chehalis-Centralia Airport, WA
  2. Open Chehalis_Centralia_Airport_WA's () properties ().
  3. On the Basic - Position page, select the Use terrain data check box.

You now have all the required place objects. Begin building the flight route.

Internet connection steps

If you have an internet connection, use this section to build the aircraft and its flight route.

Adding an Aviator aircraft

Add an Aircraft object to the scenario and then edit its performance models using the Aviator Editing toolbar. This toolbar enables you to define an aircraft and its procedures directly in the 3D Graphics window. Since you're going to use the Basic UAV model, this procedure will be the fastest way to build the aircraft object.

  1. Using the Insert STK Objects tool, insert an Aircraft () object into the scenario using the Insert Default method.
  2. In the Object Browser, rename the Aircraft object "UAV".
  3. Extend the View menu.
  4. Extend the Toolbars menu and select the 3D Aviator Editing tool.
  5. Move the 3D Object Editing and 3D Aviator Editing tools next to each other for easier use.

    6. 3D Object Editing and 3D Aviator Editing tools

  6. Zoom To Chehalis_Centralia_Airport_WA ().
  7. Center on the runway.

    8. Centered Runway

  8. Select the Aircraft/UAV from the 3D Object Editing toolbar Object Selection drop-down list.
  9. Click the Object Edit Start/Accept () button to start the 3D Object Editing tool.
  10. Click the Switch to Aviator () icon on the 3D Aviator Editing tool.
  11. Click OK when the warning window pops up.

Clicking OK enables the 3D Aviator Editing tool.

Selecting the aircraft type

First you will select the aircraft type and then edit its performance models.

  1. In the 3D Aviator Editing tool, click the Select Aircraft () button.
  2. When the Select Aircraft dialog box appears, right-click Basic UAV and select Duplicate.
  3. Select Copy of Basic UAV and rename it "MyUAV".
  4. Click OK.

Changing the performance model

Change one performance model for familiarization of the GUI.

  1. Click the Aircraft Catalog for Current Aircraft () button.
  2. You can browse through the Basic Performance models to familiarize yourself with these Built-in Models.

    3. There are Advanced Performance models that you can add to the scenario. However, in this tutorial, use Basic Performance Models.

  3. Select Acceleration - Built-in Model.
  4. Enable Bank Angle and change the value to 10 deg.
  5. Click Save and then Close.

Adjusting the position of the aircraft

Line the aircraft up with the runway for the Takeoff procedure.

Use the 3D Object Editing and 3D Aviator Editing toolbars to create a flight route to include takeoff and landing. STK can utilize DAFIF or the Digital Aeronautical Flight Information Files.

  1. Choose Runway in the Aviator site drop-down menu.
  2. Choose Takeoff in the Aviator Procedure drop-down menu.
  3. Using the mouse, shift-click on the center of the runway.
  4. Scroll out far enough to see one red ball at both ends of the Takeoff procedure.
  5. Place the cursor on the Takeoff @ Runway - WheelsRelease red ball, hold down the left mouse button, and drag and drop the red ball at the runway threshold for runway 16.

    6. Wheels Release

  6. Click the Object Edit Start/Accept () button on the 3D Object Editing tool to accept your changes.
  7. Zoom to the Aircraft object.

Modifying the aircraft's runway placement

Depending on how precise your clicks were in the 3D Graphics window, the Aircraft object's model could be above or below the surface of the map. Either way, instruct the Aircraft object to follow the terrain during the takeoff roll. Furthermore, compensate for the wheels to ensure, visually, that the wheels are touching the runway.

  1. Click the Object Edit Start/Accept () button to start the 3D Object Editing tool.
  2. Click the Modify Procedure () button in the 3D Aviator Editing tool.
  3. Make the following changes in the Takeoff Properties dialog box:
    4. Option Value
    Runway Altitude Offset 5 ft
    Use Terrain for Runway Altitude Enabled
  4. Click OK.
  5. Click the Object Edit Start/Accept () button to accept the changes.
  6. Zoom to the Aircraft object.
  7. Once satisfied with the UAV's alignment, move to Continue Building the Flight Route.

If required, using the 3D Object Editing tool and the 3D Aviator Editing tool, continue to adjust the takeoff procedure until satisfied with the Aircraft object's alignment.

Aircraft Alignment

No internet connection steps

If you don't have an internet connection, use an airfield model to simulate the runway at Chehalis-Centralia Airport. First, create the Mount Saint Helens waypoint.

If you have internet access, skip to the next section.

  1. Using the Insert STK Objects () tool, insert a Place () object using the Insert Default method.
  2. In the Object Browser, rename the Place object "MountSaintHelens."
  3. Open MountSaintHelen's () properties ().
  4. On the Basic - Position page, make the following changes:
    5. Option Value
    Latitude 46.1913 deg
    Longitude -122.193 deg
    Use terrain data Enabled
  5. Click OK.

Creating the Airfield

Now create the airfield.

  1. Insert a Facility () object using the Insert Default method
  2. In the Object Browser, rename the Facility object "Chehalis.
  3. Open the Chehalis's () properties ().
  4. On the Basic - Position page, make the following changes:
    5. Option Value
    Latitude 46.677 deg
    Longitude -122.983 deg
    Use terrain data Enabled
  5. Click Apply.
  6. Go to the 3D Graphics - Model page.
  7. In the Model field, click the Model File ellipsis () button.
  8. When the Select File window opens, select airport.glb and then click Open.
  9. Click Apply.
  10. Bring the 3D Graphics window to the front.
  11. In the Object Browser, Zoom To Chehalis ().

Raising the runway

You can see that the runway model is partially buried in the terrain. You can use offsets to move the model to better represent the actual runway at the airport.

  1. Return to Chehalis's properties and go to the 3D Graphics - Offsets page.
  2. In the Rotational Offset field, select the Use check box.
  3. Change Z to 90 deg.
  4. In the Translational Offset field, select the Use check box.
  5. Change Z to -15ft.
  6. Click OK.

Rotational offset visually shifts the runway to a north/south direction, which is similar to the actual runway. Translational offset visually raises the runway model up 15 feet, which places the model above the terrain.

Making sure Place objects sit on terrain

Put Eatonville and Kelso on top of the terrain.

  1. Return to the Object Browser.
  2. Using the Ctrl key, select Eatonville () and Kelso ().
  3. Open their properties ().
  4. Select the Use terrain data check box.
  5. Click OK.

Adding and editing an Aviator aircraft

Add an Aircraft object to the scenario and then edit the aircraft type and its performance models using the Aviator Editing toolbar. This toolbar enables you to define an aircraft and its procedures directly in the 3D Graphics window. Since you're going to use the Basic UAV model, this procedure will be the fastest way to build the aircraft object.

  1. Using the Insert STK Objects () tool, insert an Aircraft () object into the scenario using the Insert Default method.
  2. In the Object Browser, rename the Aircraft object "UAV".
  3. Extend the View menu.
  4. Extend the Toolbar menu and select the 3D Aviator Editing toolbar.
  5. Position the 3D Object Editing and 3D Aviator Editing tools beside each other for easier use.

    6. 3D Object Editing and 3D Aviator Editing tools

  6. Zoom To Chehalis.
  7. Center on the runway.

    8. Alternate Runway Centered

    In the above image, the north end of the runway is to the left.

  8. Select the Aircraft from the 3D Object Editing toolbar Object Selection drop-down list.
  9. Click the Object Edit Start/Accept () icon to start the 3D Object Editing tool.
  10. Click the Switch to Aviator () icon on the 3D Aviator Editing tool.
  11. Click OK when the warning window pops up.

Clicking OK enables the 3D Aviator Editing tool.

Editing the aircraft model

First select the aircraft type, and then edit its performance models.

  1. In the 3D Aviator Editing tool, click the Select Aircraft () button.
  2. When the Select Aircraft dialog box appears, right-click Basic UAV and select Duplicate.
  3. Select Copy of Basic UAV and rename it "MyUAV."
  4. Click OK.

Changing the performance model

Change one performance model for familiarization of the GUI. There are Advanced Performance models that you can add to the scenario. However, in this tutorial, use Basic Performance models.

  1. Click the Aircraft Catalog for Current Aircraft () button.
  2. Select Acceleration - Built-in Model.
  3. Select the Bank Angle check box and change the value to 10 deg.
  4. Click Save and then Close.

Align the aircraft on the runway

Line the aircraft up with the runway for the Takeoff procedure.

You'll be using the 3D Object Editing and 3D Aviator Editing toolbars to create your flight route to include takeoff and landing. STK can utilize DAFIF or the Digital Aeronautical Flight Information Files.

  1. Choose Runway in the Aviator site drop-down menu.
  2. Choose Takeoff in the Aviator Procedure drop-down menu.
  3. Using the mouse, shift-click on the center of the runway.
  4. Scroll out far enough to see one red ball at both ends of the Takeoff procedure.
  5. Place the cursor on the Takeoff @ Runway - WheelsRelease red ball, hold down the left mouse button and drag and drop the red ball at the runway threshold (North End).
  6. Click the Object Edit Start/Accept () button to accept the changes.
  7. Zoom to the Aircraft () object.

Modifying the aircraft's runway placement

Depending on how precise your clicks were in the 3D Graphics window, the Aircraft object's model could be above or below the surface of the map. Either way, instruct the Aircraft object to follow the terrain during the takeoff roll. Furthermore, compensate for the wheels to ensure, visually, that the wheels are touching the runway.

  1. Click the Object Edit Start/Accept () button to start the 3D Object Editing tool.
  2. Click the Modify Procedure () button in the 3D Aviator Editing tool.
  3. Make the following changes in the Takeoff Properties dialog box:
    4. Option Value
    Runway Altitude Offset 10
    Use Terrain for Runway Altitude Enabled
  4. Click OK.
  5. Click the 3D Object Editing tool's Object Edit Start/Accept () button to start the 3D Object Editing tool to accept the your changes.
  6. Zoom to the Aircraft object.

If required, using the 3D Object Editing tool and the 3D Aviator Editing tool, continue to adjust the takeoff procedure until satisfied with the Aircraft object's alignment and wheel placement. You may be required to increase or decrease Runway Altitude Offset in the Takeoff Properties window using the Modify Procedure button.

Alternate UAV Alignment

Continuing to build the flight route

Once you are satisfied with the takeoff procedure, save the runway to a catalog. You can use the cataloged runway when creating the landing procedure.

  1. Click the Object Edit Start/Accept () button to start the 3D Object Editing tool.
  2. Click the Modify Site () button in the 3D Aviator Editing tool.
  3. When the Runway Properties window opens, change Name to "Chehalis."
  4. Click Add To Catalog and then click OK to close the Add Successful dialog box.

Building the aircraft route

  1. Adjust the 3D Graphics window view so that you are looking straight down at the map and zoom out far enough so that you can see all the waypoints and the airport.
  2. Select STK Static Object in the Aviator Site pull down menu.
  3. Ensure Basic Point to Point is selected in the Aviator Procedure window.
  4. Shift-click the waypoints in the 3D Graphics window in the following order:
    • Kelso
    • Mount_St_Helens_WA
    • Eatonville
  5. Change the Aviator Site to Runway from Catalog and the Aviator Procedure to Landing.
  6. Shift-click on Chehalis_Centralia_Airport_WA or Chehalis (if you used the Insert Default method).
  7. If you don't have an internet connection, accept your changes and zoom to the aircraft. Otherwise, continue with steps below.
  8. Select the Modify Procedure () button.
  9. In the Landing Properties window, make the following changes:.
    10. Option Value
    Runway Altitude Offset 5 ft (internet) 10 ft (if using the airport model)
    Use Terrain for Runway Altitude Enabled
    Delay enroute climbs and descents Enabled
  10. Click the Object Edit Start/Accept () button in the 3D Object Editing tool to accept your changes.
  11. Zoom to the Aircraft object.

The aircraft is lined up for a takeoff roll, flies to the selected waypoints, and lands back at the airport.

Use the Animation toolbar to view the flight. Remember to decrease the Time Step.

Viewing the Help

You used the 3D Object Editing and the 3D Aviator Editing tools to create the mission. You could have built the mission inside the UAV's properties.

On the Basic - Route page, two fields stand out that are not visible when building the mission in the 3D Graphics window; The Mission Window and Phases of Flight.

  1. Open UAV's () properties ().
  2. At the bottom of the Basic - Route page, click Help.
  3. Take some time to look at the Help file and the Basic - Route page.
  4. When you're done, close the Help page.
  5. Click Cancel to close UAV's () properties ().

Generating a report of the flight profile

Create a report of the UAV's flight profile. The Flight Profile by Time report is a good report that provides important data such as down-range distances and how much fuel the aircraft has consumed. As with all reports, you can customize the report with your own data.

  1. In the Object Browser, right-click UAV () and select the Report & Graph Manager.
  2. In the Styles list, select Flight Profile by Time report and click Generate.
  3. Close the report.
  4. Close the Report & Graph Manager.

Embedding the report in the 3D Graphics window

You can embed the Flight Profile by Time data in the 3D Graphics window. This is a great technique to use for briefings and making movies.

  1. Open UAV's () properties ().
  2. Go to the 3D Graphics - Data Display page.
  3. Click Add....
  4. In the Add a Data Display dialog box, select Flight Profile by Time and click OK.
  5. In the Appearance field, change Font Size to Large.
  6. Click OK.
  7. Return to the 3D Graphics window.

In the upper-left corner of the 3D Graphics window, you can see a dynamic display of UAV's flight profile.

  1. Click Play () in the Animation toolbar.
  2. When you are finished, click Reset ().
  3. Save () the scenario.