Creating and Using Attitude Files

If you import and use an external attitude (*.a) file, it overrides any target pointing or basic attitude profile that you have set in STK during the imported file's time frame.

For information on how STK performs differentiation calculations, see Attitude Interpolation and Differentiation in STK .

Importing external attitude files

To import a file:

  • Right-click a vehicle and select Properties.

  • Under Basic, select Attitude.

  • At the top left, select Standard.

  • Under Precomputed, select Override Basic & Target Pointing Attitude for specified times.

  • Click the ellipsis () button and browse for a file.

The name of the file and its Start and Stop times appear on the Attitude page. To change these times, select Override the times contained in the file, select an option from the box menu below it, and change the Time of the first attitude point. For more information on the options for start and stop times, see STK Time.

The Reload File option under Precomputed enables you to edit the external file and update the attitude profile without closing the scenario. Edit the attitude file, save it, and click Reload File.

Creating an attitude file

You can generate an external attitude file for a satellite by numerically integrating Euler's equations for it. In the Basic Attitude window, select Standard at the top left. Under Precomputed, click Generate New File... and enter the Integrated Attitude window parameters as described below.

Time period and epoch

You can edit the Start and Stop times to define a period shorter than that defined for the satellite. The Epoch is the time of the initial condition attitude and normally coincides with the Start time. If the Epoch is not the Start time, STK integrates (forward or backward, as appropriate) without saving until it reaches the Start time; from there it integrates forward to the Stop time and saves. For more information on the options for start and stop times, see STK Time.

Initial conditions

The Initial Conditions frame defines the initial orientation of the satellite in the Earth Inertial (ECI) frame. The orientation can be in any of three forms:

In the Body Fixed Rates fields, enter the initial angular velocity rates, if any, about the satellite's X, Y, and Z axes.

Click Initialize from Current Attitude to set initial conditions on the basis of the settings on the Attitude page of a satellite's Basic properties.

Importing torque files

To import an external torque file (*.tq), select Torque File and click the ellipsis () button to browse for a file.


In the Output frame, enter the file name for the Integrated Attitude file.

Message Reporting

Within your external attitude file, you can designate the level of message feedback provided by STK concerning its reading of the file. See "MessageLevel" in the Keyword table of the topic Attitude File Format.

Exporting the file

When all integration parameters are set, click the Export button and select a path for the file location.