Part 1: Build Scenarios

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

Capabilities covered

This lesson covers the following STK Capabilities:

  • STK Pro

Problem statement

Engineers and operators need an environment to quickly model and simulate their missions both analytically and visually.

Solution

Systems Tool Kit (STK) provides a physics-based simulation environment for digital mission engineering. Your system and component models can interact in STK, enabling you to measure their performance in the context of the complete mission. The NASA Systems Engineering Handbook (see the reference below) refers to this process in chapter four as creating Design Reference Missions (DRMs) to capture the intended concept of operations (ConOps). This approach supports collaboration with distributed, multidisciplinary teams across all of your operational domains and life cycle phases. STK scenarios function as DRMs, and STK was deliberately built to design and evaluate these DRMs quickly. For many missions, two or more DRMs make up a single ConOps. The design and performance analysis leading to the requirements should satisfy all of the DRMs. For more information on DRMs, you can check out AGI's webinar on Design Reference Missions here.

You can access the NASA Systems Engineering Handbook here.

What you will learn

To begin using STK, you need a basic understanding of the STK workflow and layout. You will learn how to:

  • Set up a new scenario
  • Understand the STK windows
  • Understand common tools

Video guidance

Watch the following video. Then follow the steps below, which incorporate the systems and missions you work on (sample inputs provided).

Setting up a new STK scenario

In this section, you will learn to choose a central body for your scenario, create a new scenario, and then save your scenario.

Changing the central body

If enabled, the Central Body drop-down menu appears in the STK: New Scenario Window. Select from the list of planets to designate the scenario's primary central body. Earth is STK's default primary central body. To enable Planetary Options:

  1. Launch STK ().
  2. Extend the View menu when STK opens.
  3. Click Planetary Options so that a check mark appears next to it. This enables the Central Body option on the STK: New Scenario Wizard.

Create a new scenario

Create a new STK Scenario () object using the STK: New Scenario Wizard tool. The Scenario object defines the context in which the properties and behavior of other objects are defined.

For additional information about this tool, visit the New Scenario Wizard help page.

  1. Click Create a Scenario in the Welcome to STK dialog box.
  2. You can use the Central Body: selection, which defaults to Earth, to change the scenario's central body.
  3. Enter the following in the STK: New Scenario Wizard:
    4. Option Description
    Name STK_NewScenario
    Description

    This is my first STK scenario.
    Location

    STK Default Directory (e.g., C:\Users\username\Documents\12). This is the default directory, where the directory, scenario, and associated files are located when you save the scenario. You can choose a different directory or create a new directory by clicking the ellipsis () button.
    Start

    Default Start Time

    The default times are based on the date, time, and time zone set on your computer. The times are in Gregorian Coordinated Universal Time (also called UTCG or ZULU time).
    Stop + 24 hrs

    The default times are based on the date, time, and time zone set on your computer. For instance, if you are opening a scenario on 1 January 2023 and your computer is set to Eastern Time (US & Canada), the analysis Start time defaults to 1 Jan 2023 16:00:00.000 UTCG. UTCG is the Gregorian Coordinated Universal Time Unit of Measure, or ZULU time. Since your computer is using Eastern Time, 1 Jan 2023 16:00:00.000 UTCG is equivalent to 1 Jan 2023 12:00:00.000 LCLG. LCLG is Gregorian Local Time or twelve noon.

    There are other analysis period options available by clicking the drop-down arrow. You can:

    • Set the Start and Stop times to Today, the current date at 12:00 midnight based on your computer's internal clock
    • Set the Start and Stop times to Tomorrow, the next day's date at 12:00 midnight based on your computer's internal clock
    • Select from a calendar interface for the desired date
    • Change the date and time formats

  4. Click OK when you finish.

Saving the scenario

When the scenario first opens or when you complete a set of steps, you should Save () the scenario.

  1. Click Save () when the scenario loads. STK creates a folder with the same name as your scenario for you.
  2. Verify the scenario name and location in the Save As window.
  3. Click Save.
  4. Click Close in the Insert STK Objects tool. You will learn more about STK Objects tool in Lesson 2: Objects and Properties.

Save often during this lesson!

The STK workspace

The STK workspace offers many ways for you to organize and interact with its many varied windows. At the completion of this tutorial, practice workspace customization. Instructions are on the Managing Your STK Workspace Help page.

All windows and toolbars discussed in this lesson are some of the most commonly used defaults you see when you install and open STK for the first time STK.

Menus and tools

Menus and toolbars are at the top of STK. This tutorial covers selected tools. Tools not covered in this tutorial are covered in later lessons. You can display or hide toolbars to customize your STK windows. For extensive information on using STK Toolbars, go to the Using STK Toolbars Help page.

  1. Extend the View menu.
  2. Hover over Toolbars to extend the menu. This is one way to choose the toolbars you require.
  3. Right-click in the empty space to the right of the currently available toolbars. This is another way to quickly enable and disable Menu selections and toolbars.

Object Browser

When you introduce an object into a scenario, it appears in the Object Browser. You can see the Scenario () object (STK_NewScenario) you created. As you create more objects, they appear in the Object Browser in a parent-child relationship. For more information on the Object Browser, go to the Getting started with the Object Browser Help page.

Understanding the STK Graphics windows

The 2D and 3D Graphics windows graphically display information about your scenario. By default, the 2D and 3D Graphics Windows are in the Integrated Workspace. They can be evenly spaced in that area, as well as minimized, maximized, or closed. STK organizes the integrated windows with tabs at the bottom of the Integrated Workspace.

  1. Extend the Window menu.
  2. Select Tile Vertically to evenly space the windows side-by-side in the workspace.

Understanding the 2D Graphics window

The 2D Graphics window graphically displays information about your scenario. The 2D Graphics window gives you one giant advantage: you can see the whole central body at one glance. For more detailed information about the 2D Graphics window, click the 2D Graphics Window Help page.

Properties

You can customize the 2D Graphics Window by modifying its properties, such as colors, geographic features, display formats, and latitude / longitude line spacing. Look at the 2D Graphics window and notice the separation between umbra and direct sun. You can specify this separation in the 2D Graphics Window's Properties:

Grab Globe

When activated, Grab Globe enables you to move or pan the central body in grab mode. Grab Globe is enabled by default.

  1. Click Grab Globe () in the 2D Graphics Defaults toolbar if it's not enabled.
  2. To pan, place your cursor on the 2D Graphics window map.
  3. Hold the left mouse button and drag the mouse around the 2D Graphics window.

Zoom In

Zoom In brings the view closer to the selected area and changes the map center. Each time you zoom in, it adds one zoom level to the zoom stack.

  1. Click Zoom In () in the 2D Graphics Defaults toolbar.
  2. Place your cursor on the 2D Graphics window map.
  3. Hold down the left mouse button.
  4. Drag your mouse cursor across the area of the 2D map window you want to zoom. This draws a box around the area of interest.
  5. Release the left mouse button.

Zoom Out

Zoom Out widens the view of the 2D Graphics window one zoom level per click.

  1. Click Zoom Out () in the 2D Graphics Defaults toolbar to zoom out of the 2D window one zoom level.
  2. You can continue to click Zoom Out () until the 2D map fills the display window.

Mouse scroll wheel

You can zoom in and zoom out using the mouse scroll wheel. Using the mouse scroll wheel does not add any zoom levels to the zoom stack, so after zooming in using the mouse scroll wheel, hitting Zoom Out zooms all the way out to a global view.

  1. Place your cursor on the 2D Graphics window map.
  2. Move the mouse scroll wheel up to zoom in on the 2D Graphics window map.
  3. Move the mouse scroll wheel down to zoom out on the 2D Graphics window map.

Snap Frame

You can save pictures of the 2D Graphics window to a file or to the clipboard using the Snap Frame tool. Use Snap Properties to set the properties of the Snap Frame tool to make high resolution images of a 2D graphics window.

2D Graphics toolbar

The 2D Graphics toolbar provides easy access to the most frequently used options and tools to control the graphical display of your scenario in the 2D Graphics window.

Measure Tool

The Measure tool measures the shortest distance between two points and reports the azimuth bearing.

  1. Click Measure () in the 2D Graphics toolbar.
  2. Place your cursor on the 2D Graphics window map.
  3. Hold down the left mouse button and drag the cursor to another spot on the map.
  4. Release the left mouse button. The distance between the two points and the azimuth bearing display in the lower left-hand corner of the Status Bar and in the Message Viewer.

The data is only as good as where you clicked on the map. In general, this tool is a good way to get an approximate distance measurement between two points. If you require exact distances, you will need to measure the distance between two STK objects using the Report & Graph Manager.

Central Body tool

The Central Body tool enables you to change the central body of the selected 2D Graphics window by selecting a central body from a shortcut menu.

  1. Click the 2D Graphics Window's Central Body () icon in the 2D Graphics toolbar.
  2. Select a planet.
  3. When finished, change the 2D Graphics window's central body back to Earth.

Microsoft Bing™ Maps

The Microsoft Bing™ Maps tool displays a background image (Microsoft Bing™ map or Basic.bmp) in 2D Graphics windows.

  1. Click Microsoft Bing™ Map ().
  2. Try different map styles.
  3. When finished, reset the map style to Aerial.

Understanding the 3D Graphics window

STK enables you to view complex information in a 3D Graphics window. You can observe relationships among space, air, land, and sea objects as they exist in the present as well as in the past and future. Like you did with the 2D Graphics window, you'll practice using selected tools. For detailed information about the 3D Graphics window, click 3D Graphics Window Help page.

Using the Mouse

In addition to tools available in toolbars, the 3D Graphics window has additional mouse controls that manipulate the 3D Graphics window. Get familiar with the mouse controls.

  1. Double-click the left mouse button on any spot on the globe to display the latitude and longitude of the selected spot.
  2. Place your cursor on the 3D Graphics window globe.
  3. Hold down the left mouse button and move the mouse around to rotate the globe.
  4. In one motion, hold down the right mouse button and push the mouse away from you to Zoom out.
  5. While holding down the right mouse button, pull the mouse closer to you to Zoom in.
  6. Hold down the Shift key and left mouse button while moving the mouse around. This will pan and tilt the virtual camera.
  7. After you pan and tilt in the previous step, release the Shift key and left mouse button.
  8. Hold the left mouse button down and move the mouse around to keep the camera in a fixed point in space and change its orientation.

3D Graphics window default tools

You can use the mouse to interact with the 3D Graphics window. Most of the tools have functions similar to the 2D Graphics window Defaults Toolbar. You will focus on the Grab Globe and Zoom In tools, but this toolbar also gives access to Properties, Snap Frame, and Snap Properties.

Zoom In

Zoom In enables you to zoom into a portion of the 3D Graphics window. The camera is then fixed on the center point of the zoomed in area.

  1. Click Home View () in the 3D Graphics window toolbar to reset your view. You will become familiar with Home View () in the 3D Graphics Toolbar section of this lesson.
  2. Rotate the globe by holding down the left mouse button and moving the mouse around to obtain a view of a landmass in the 3D Graphics window, such as North America.

    3. View of North America

  3. Click Zoom In () in the 3D Graphics window Defaults toolbar.
  4. Hold down the left mouse button and drag your mouse cursor across the area of the 3D globe you want to zoom in to, such as the west coast of the United States.
  5. Continue to zoom in using the mouse scroll wheel until you're fairly close to the ground.

View of Los Angeles

Grab Globe

Although it is similar to the Grab Globe tool in the 2D Graphics window, there's one important difference. You need to turn Grab Globe on and use the Shift key along with the left mouse button.

Start with Zoom In prior to using Grab Globe.

  1. Click Grab Globe () in the 3D Graphics Defaults toolbar.
  2. Hold down the Shift key and the left mouse button and drag the mouse around the 3D Graphics window to grab the globe and pan.
  3. Release the Shift key and left mouse button.
  4. Use the mouse scroll wheel to zoom in or out depending on the detail you are trying to obtain.
  5. Hold down the left mouse button and move the mouse around to rotate and tilt the globe. The globe pivots on the center point of the zoomed in area.

3D Graphics toolbar

The 3D Graphics toolbar provides easy access to the most frequently used options and tools used to control the graphical display of your scenario in the 3D visualization windows. You will focus on the Home View, Flashlight, and 3D Measure tools, but you can see descriptions of all the tools on the 3D Graphics Toolbars Help page.

Home View

Home View displays the default view. If you are lost in your view, this is one of your best friends. It will bring you back to your home view with one click.

  1. Use the scroll wheel to zoom in close to the surface of the central body (Earth).
  2. Click Home View () in the 3D Graphics toolbar to reorient the 3D Graphics camera back on the default Earth-centered view.

Flashlight

The Flashlight illuminates the globe and objects when they aren't located in sunlight. This is visual only. Analytically, actual lighting conditions still apply. You define the Flashlight settings in the 3D Graphics window properties.

  1. Rotate the globe until you're viewing the dark side of the Earth.
  2. Click Flashlight () in the 3D Graphics toolbar.
  3. When finished, click Flashlight () again to disable it.

3D Measure tool

Similar to the 2D Measure tool, the 3D Measure tool measures the shortest distance between two points and the azimuth bearing in the 3D Graphics window.

  1. Click 3D Measure () in the 3D Graphics toolbar.
  2. Place your cursor on the 3D Graphics window map.
  3. Hold down the left mouse button and drag the cursor to another spot on the map.
  4. Release the left mouse button. The distance between the two points and the azimuth bearing display in the lower left hand corner of the Status Bar and the Message Viewer.

Remember, the data is only as good as where you clicked on the map. In general, this tool is a good way to get an approximate distance between two points. If you require exact distances, you will need to measure the distance between two STK objects using the Report & Graph Manager. You can learn more about reports and graphs in Lesson 3: Access Reports and Graphs.

Globe Manager

Globe Manager () is a very important visualization tool. You can use it to populate the central body of your 3D Graphics window with imagery, terrain, data sets, and tile sets. Globe Manager is covered in later tutorials; you can focus on Globe Manager by completing the following tutorial: Using Globe Manager in STK.

Microsoft Bing™ Maps

Microsoft Bing™ Maps () display a background image (Microsoft Bing™ map or Basic.bmp) in 3D Graphics windows. This tool works the same in the 3D Graphics window as it does in the 2D Graphics window.

Terrain Server

The Terrain Server distributes Earth terrain data for visualization or analysis. By default, STK connects to the AGI Terrain Server, which is available via an internet connection to all STK users.

  1. Check your internet connection via your status bar. If online operations are available (), continue to the next step. If online operations are not available (), troubleshoot online operations or skip to the next section.
  2. Zoom In () on an area of interest in the 3D Graphics window.
  3. Use the mouse scroll wheel to zoom very close to the Earth's surface.
  4. Hold down the left mouse button and push the mouse away from you to tilt the globe on its side.

    5. You should see terrain features. If you happen to be zoomed into a flat area, readjust your area to a more hilly or mountainous location. If you find yourself under the terrain, zoom out a bit and readjust your view.

Terrain Server Streaming Terrain

Animation toolbar

The animation tool bar helps you control the progression of your scenario. With a few clicks, you can control the start time, stop time, and how quickly the scenario progresses from start to stop. Use the animation controls to play through the scenario.

  1. Select the Window menu.
  2. Select Tile Vertically.
  3. Click Home View () in the 3D Graphics toolbar.
  4. In the Animation toolbar, click Start () to have the scenario animate forward in time from the current point.
  5. Click Pause () to stop the scenario animation.
  6. Click Step Forward () or Step Backward () to progress one step at a time through the scenario.
  7. Click Reverse () to have the scenario animation rewind from the current point.
  8. Experiment with increasing () and decreasing () the speed of the animation, which by default is 10 seconds. This will also affect the time step of Step Forward and Step Backward as well.
  9. At any point, click Reset () to have the scenario return to the start time. This does not reset the speed of the animation.

    10. Besides the buttons that increase and decrease animation speed, you can set a scenario to run at a particular speed using the following yellow clock symbols:

    • Normal Animation Mode (): The scenario animates in accordance with the scenario time you defined when creating the scenario and the defined time steps. Again, by default, the defined time steps are 10 seconds.
    • Real-Time Animation Mode (): The scenario animates in real time in accordance with your computer's internal clock.
    • X Real-Time Animation Mode (): The scenario sets the playback to a sped-up or slowed-down version of real time. For instance, entering a value of 1 will have the scenario run at real time. Entering a value greater than 1 speeds up the animation. A value between 0 and 1 will slow down the animation.

Timeline View

Use Timeline View to visualize a variety of time intervals within your scenario. The user interface of the Timeline View is comprised of a toolbar, three timelines, and rows of time componentsFor detailed information about the Timeline View, go to the Timeline View help page.

Time Display

The Time Display is the largest and most granular of the timelines. Use the gray pointer to adjust the animation time to any point within the Time Display's current boundary to visualize time events.

  1. Click Home View () in the 3D Graphics toolbar to rest the view.
  2. Click Zoom Out () in the 2D Graphics Defaults toolbar to zoom out of the 2D window. Click Zoom Out () as many times as needed until the 2D map fills the display window.
  3. While looking at the 2D Graphics or 3D Graphics window, put your cursor on the Gray Pointer () in the Timeline View.
  4. Hold down the left mouse button and slide the Gray Pointer to the right.
  5. Notice the globe rotating and the day-night shading on the 2D Graphics window moving as you scroll through the scenario time period.
  6. Click Save ().

Summary

You got a thorough introduction of the STK: New Scenario Wizard and a brief outline of STK tools and windows such as the Object Browser and the Timeline View. The bulk of the information in this tutorial helped you to become familiar with the functions and tools of the 2D and 3D Graphics windows. These windows are important for your situational awareness while using STK.

Continue to Lesson Two: Objects and Properties.

On your own

Throughout the tutorial, hyperlinks to STK Help files were provided that pointed to in-depth information of various tools and functions. Now is a good time to go back through this tutorial and view that information. Try rearranging windows and tools. Enable other tools and view their functions.