Attitude Data File Options | STK Ephemeris and STK Binary Ephemeris Data File Options | SPICE Ephemeris Data File Options | CCSDS Data File Options | PropDef Data File Options

Export Ephemeris/Attitude Data

You can create vehicle attitude or ephemeris data for all types of vehicles using the Export Ephemeris/Attitude tool. To open the Export Ephemeris/Attitude tool, select Export Ephemeris/Attitude... from the Utilities menu.

To create vehicle attitude or ephemeris data, click Select Object... to select the vehicle from which you are creating the data file and select one of the following combinations:

External STK File Type Option Ephemeris Type Option Click the Export File button to create...
Attitude n/a

An attitude profile ASCII text file (.a) for the vehicle.

For descriptions of settable file parameters, see Attitude Data File Options.
Ephemeris STK Ephemeris

An ephemeris ASCII text file(.e) that contains ephemeris points for the vehicle.

For descriptions of settable file parameters, see STK Ephemeris and STK Binary Ephemeris Data File Options.
Ephemeris SpiceEphemeris

An ASCII text file (.bsp) that contains ephemeris points for the vehicle in a format compatible with the SPICE Toolkit. For information on how SPICE files are automatically loaded by STK, click here.

For descriptions of settable file parameters, see SPICE Ephemeris Data File Options.
Ephemeris CCSDS Ephemeris

An ASCII text file (*.oem or *.xml) that contains ephemeris points for the vehicle in the CCSDS Orbit Ephemeris Message version 1.0 format.

For descriptions of settable file parameters, see CCSDS Data File Options.
Ephemeris CCSDS v2.0 Ephemeris

An ASCII text file (*.oem or *.xml) that contains ephemeris points for the vehicle in the CCSDS Orbit Ephemeris Message 2.0 format.

For descriptions of settable file parameters, see CCSDS Data File Options.
Ephemeris STK Binary Ephemeris

A binary text file (.be) that contains ephemeris points for the vehicle.

For descriptions of settable file parameters, see STK Ephemeris and STK Binary Ephemeris Data File Options.
PropDef n/a

An ASCII text file (.pg) that contains an element set and path definition for a vehicle.

For descriptions of settable file parameters, see PropDef Data File Options.

Attitude data file options

Option Value
Coordinate Axes Select from the drop-down menu the coordinate axes for STK to use in the file. The choices are dependent on the selected format. The Current format supports Fixed, J2000, ICRF, or Custom for the Earth, and Fixed, J2000, ICRF, Inertial, or Custom for all other central bodies. For Custom coordinate axes, click Select... to define the coordinate system.
Include Choose the details to include in the data file: either Quaternions or Quaternions and Angular Velocity.
FormatProvides the option to generate files compatible with prior versions of STK. Choose from the following options: Current, 8.0 Format, 6.0 Format, and 4.3 Format.

All supported formats may be read into the current version of STK.

Time Period Select one of the following:
  • Use Entire Ephemeris. STK creates a data file using the Start and Stop Time specified in the vehicle's Orbit page.
  • Specify Time Period. STK creates a data file using the Start and Stop Time specified here. For more information on the options available for start and stop times, see Time Options.
Steps

Select one of the following:

  • Use Ephemeris Steps. STK uses the Step Size specified in the vehicle's Basic properties.
  • Use Step Size. Enter a Step Size for STK to use for the vehicle.
  • Use Time Array. STK uses a time array component that defines the time steps.
  • Use Native Times. STK uses the Step Size specified in the vehicle's Basic properties, plus any additional times at which the vehicle's attitude changes abruptly. This creates a more complete attitude file without requiring the use of a very small, performance-reducing step size.
Output File Enter the name of the file you are creating. The default is the name of the object.

STK Ephemeris and STK Binary Ephemeris data file options

Option Value
Coordinate This is the coordinate system in which to export the ephemeris. The choices provided depend on the selection of the central body. When the central body is Earth or Moon, there are choices in addition to the standard set of Fixed, J2000, ICRF, TrueOfDate, and Inertial: TEMEOfDate and several ITRFYYYY frames for Earth, and MeanEarth for Moon. When the central body is Earth or Sun, Inertial is not available because the inertial frame for these bodies is simply ICRF, which is already there.
Central Body The location of the selected central body serves as the origin of the coordinate system in which to export the ephemeris. Choosing Use Vehicle Central Body sets the central body selector to the vehicle's central body.
Include Interpolation Boundaries Select this check box to include interpolation boundaries.
Version Format

Provides the option to generate files compatible with prior versions of STK. Choose from the following options: Current, 8.0 Format, 6.2 Format, 4.3 Format, 4.2 Format, and 4.1.0 Format.


  • The 4.1.0 and 4.2 formats only allow a J2000 coordinate system when the central body is the Earth, Moon, or Sun.
  • The export of covariance information is not compatible with the 4.1.0 version format.
  • All supported formats may be read into the current version of STK.
  • The STK Binary Ephemeris format is not compatible with a version of STK prior to STK 10.
Export CovarianceChoose to export no covariance information, position covariance (3x3), or — for STK 6.2 or greater format — position/velocity covariance (6x6). If the requested covariance information is not available from the selected object, STK will still create the ephemeris file but will display a warning in the Message Viewer window. Covariance information may be available for objects with paths defined using the HPOP or STK External propagators.
Time Period Select one of the following:
  • Use Entire Ephemeris. STK creates a data file using the Start and Stop Time specified in the vehicle's Orbit page.
  • Specify Time Period. STK creates a data file using the Start and Stop Time specified here. For more information on the options available for start and stop times, see Time Options.
Steps

Select one of the following:

  • Use Ephemeris Steps. STK uses the Step Size specified in the vehicle's Basic properties.
  • Use Step Size. Enter a Step Size for STK to use for the vehicle.
  • Use Time Array. STK uses a time array component that defines the time steps.
Output File Enter the name of the file you are creating. The default is the name of the object.

SPICE Ephemeris data file options

Option Value
Coordinate You may not edit the coordinate system for a SPICE propagator.
Central Body Select Use Vehicle Central Body or choose a central body from the drop-down menu.
Satellite ID Enter the identifying number for the satellite ephemeris being created.
Interpolation Type Choose the interpolation type: Type 9 (LaGrangian) or Type 13 (Hermitian).
Interpolation Enter an interpolation order value between 1 and 15. If the interpolation type is Type 13 (Hermitian), and then you are required to enter an odd interpolation order value.
Time Period Select one of the following:
  • Use Entire Ephemeris. STK creates a data file using the Start and Stop Time specified in the vehicle's Orbit page.
  • Specify Time Period. STK creates a data file using the Start and Stop Time specified here. For more information on the options available for start and stop times, see Time Options.
Steps

Select one of the following:

  • Use Ephemeris Steps. STK uses the Step Size specified in the vehicle's Basic properties.
  • Use Step Size. Enter a Step Size for STK to use for the vehicle.
  • Use Time Array. STK uses a time array component that defines the time steps.
Output File Enter the name of the file you are creating. The default is the name of the object.

CCSDS data file version 1.0 and 2.0 options

OptionValue
OriginatorEnter a string that specifies an identifier of the organization producing the data file.
Object IDEnter a string defining the Object ID, specified as the international spacecraft designator, also known as an NSSDC identifier, which follows a YYYY-NNNA format, where YYYY is the year of the launch, NNN is the sequential launch number within that year, and A is a letter designating the specific piece from the launch.
Object NameEnter a name for the Object. By recommendation of the CCSDS standard, you should use the name from the SPACEWARN Bulletin.
Use Satellite Center and FrameSelect to use the central body and reference frame of the selected satellite object.
CenterThis is the location of the selected central body that serves as the origin of the coordinate system in which to export the ephemeris.
Reference Frame

Select from the following reference frames:

  • ICRF
  • GCRF (valid for Earth only)
  • EME2000 (i.e., Earth Mean Equator and Equinox 2000, also called J2000)
  • TOD (i.e., True of Date)

  • TEMEOfDate (valid for Earth only)

  • MeanEarth (valid for Moon only)
  • ITRF, ITRF2020, ITRF2014, ITRF2008, ITRF2005, and ITRF2000 (valid for Earth only)
  • Fixed (not valid for Earth or Moon)
Time PrecisionSpecify the number of digits past the decimal point used in the expression of seconds in the selected date format. Enter an integer between 0 and 10.
Time SystemSelect the desired time system. For descriptions of the available selections, see the Units of Measure page.
Date FormatSelect a date format. YMD format is YYYY-MM-DDT:HH:mm:SS.SSS, where YYYY is the four-digit year, MM is the two-digit month, DD is the two-digit day of the month, HH is the two-digit hour, mm is the two-digit minute, and SS.SSS is a floating point representation of seconds into the minute where the precision is specified via the time precision setting. YDOY is similar except that the day of the year, DDD, replaces the month and day of month: YYYY-DDD:THH:mm:SS.SSS.
Ephemeris FormatSelect a format, SciNotation or FloatingPoint, for representing the position and velocity information as either scientific notation or floating point notation, respectively. Scientific notation is recommended when possible, since it guarantees the number of significant digits which will be represented.
File FormatSelect the format of the exported file, either Keyword-Value or XML.
Include Covariance Include covariance data in the exported file. (Not valid for CCSDS v1.0.)
Include Acceleration Include acceleration data in the exported file. (Not valid for CCSDS v1.0.)
Time Period Select one of the following:
  • Use Entire Ephemeris. STK creates a data file using the Start and Stop Time specified in the vehicle's Orbit page.
  • Specify Time Period. STK creates a data file using the Start and Stop Time specified here. For more information on the options available for start and stop times, see Time Options.
Steps

Select one of the following:

  • Use Ephemeris Steps. STK uses the Step Size specified in the vehicle's Basic properties.
  • Use Step Size. Enter a Step Size for STK to use for the vehicle.
  • Use Time Array. STK uses a time array component that defines the time steps.

About the CCSDS Ephemeris

The Consultative Committee on Space Data Systems (CCSDS) orbit ephemeris message format is defined by the CCSDS Blue Book, Orbit Data Messages, CCSDS 502.0-B-1. You can download this document from https://public.ccsds.org/publications/MOIMS.aspx. The role of the CCSDS is to develop recommendations for data and information sharing standards.

Generation of CCSDS orbit ephemeris messages using STK:

  • Center names are restricted to central bodies known to STK.
  • Time tags will be referred to the UTC time system.
  • The interpolation method and degree will be that used by STK.
  • Separate metadata / ephemeris data sections are created to prevent interpolation across maneuvers.

PropDef Data file options

Option Value
Output File Enter the name of the file to be created. The default is the name of the object.