The Insert From Satellite Database Tool is used to first query a satellite database for a set of space objects and then create new satellites in STK.
The Insert From Satellite Database tool is available from the Insert menu.
The tool performs two distinct steps:
Note: Both the satellite database file and the corresponding TLE file evolve over time and need to be updated as needed.
The U.S. Strategic Command (USSTRATCOM) currently keeps track of more than 12,000 space objects. These objects constitute the space object catalog. While most of the catalog is made available to the public, some information is restricted. AGI provides the publically released information for use with STK in the form of satellite database files and two-line mean element files (TLEs).
A satellite database file is an ASCII file of a specified format, with file extension .sd, that contains information on space objects. AGI provides four database files:
| Database File | Description |
|---|---|
| stkSatDbAll.sd | Contains information on all non-restricted space objects (both satellites and debris). |
| stkSatDb.sd | Contains information on all non-restricted satellites. |
| stkSatAllComm.sd | Contains information on all non-restricted Communications satellites. |
| stkAllTLE.sd | Contains information on all non-restricted space objects (both satellites and debris) that have a recent TLE (generally, within 30 days of the creation date of the file). |
Each file contains identification information (official name, common name, owner, mission type, etc.) and orbital characteristics (period, inclination, altitude) keyed to the unique identifier for each object, its SSC number. These files are updated daily on the AGI Website. Updated files contain information on newly cataloged objects (new launches and newly found debris) as well as updates to the orbital characteristics for existing objects.
Corresponding to each of the satellite database files are TLE files (files with extension *.tce) that contain ephemeris information for the space objects identified in the *.sd file. For example, stkAllTLE.tce contains TLE information for the space objects listed in stkAllTLE.sd. Because of information restrictions to the public, objects that are restricted for their ephemeris information but not restricted for identification purposes may be listed in a satellite database file even though no TLE is publically available for them and they do not appear in their corresponding *.tce file.
A TLE contains mean elements that are used in conjunction with the SGP4 propagator to produce ephemeris for the space object. The ephemeris produced by SGP4 is generally valid for a few days around the epoch contained in the TLE. (No official validity interval is provided by USSTRATCOM.) New TLEs for space objects are produced on a continual basis. Important objects, such as the International Space Station and Shuttle flights, have TLEs generated several times per day. Some debris objects may have newly generated TLEs only every several days or weeks (or possibly longer if the object is lost for a time). The AGI Website updates its TLE files at least daily.
Enter as many search criteria as possible. If you do not know the exact criteria, you can enter a partial name or use the wildcard character *.
| Search Criteria | Description |
|---|---|
| Common Name | The common name of the object. |
| SSC Number | The SSC number of the object. This is its unique identifier. |
| Advanced Options... | Click this button for additional search options. |
By default, the Common Name, SSC Number, and Status filters are enabled. However, since Common Name and SSC Number are both set to the wildcard character *, the effect is simply to apply the Status filterthus, the default listing is of all space objects marked as Active in the database file.
Click Search to update the list.
The tool searches through a satellite database file, applying the user-specified search filters, and lists those objects meeting all the criteria. The results are sorted by Common Name. To sort the results by a different column, double-click the column heading. To hide or display additional columns, right-click a column heading. If the Propagation TLE Source is Online, "To be retrieved" is displayed in the TLE Epoch column indicating that an appropriately dated set of TLEs will be obtained from the AGI Online Server automatically when satellites are inserted.
The satellite database file that is searched is set on the Scenarios Database properties page. We recommend using stkAllTLE.sd as it contains a listing of both debris and satellites objects that actually have TLE data (and thus can be inserted as a Satellite object).
Note: The search is always performed on the satellite database file selected on the Scenario's Database properties page---the search is not performed online, even if ultimately the TLEs are obtained using the AGI Online Server.
The search process identifies a set of space objects to be considered for insertion as a Satellite. The ephemeris information for a space object consists of a set of TLEs for that object. While there may be many TLEs available for a space object, the most appropriate set of TLEs to use for propagation are those that have an epoch near the Time Period of propagation. By default the Time Period will be the Scenario intervalhowever, you may choose a different interval.
We recommend that the TLE source be set to the AGI Online Server because the correct set of TLEs will be obtained for space objects for the propagation time period. However, you may choose to load TLEs from a file instead if you are unable to connect to the server or you want to use TLEs from a specified file.
To select a different TLE source, click Modify... under Propagation TLE Source.
Note: When using a file as the TLE source, you should insure that the epochs for the TLEs are appropriate for the propagation time period being used.
Select rows from the table (one or more) and click Insert to create a Satellite for each selection. Use the SHIFT or CTRL key to select more than one item. When you click Insert, information for the inserted satellite appears on the satellite's Basic Description properties page.
Note: The same space object may be listed several times in the table, each time with a different common name but with an identical SSC number. If the selected rows contain a duplicate SSC number with different common names, then only one satellite object will be created for that SSC number using the first selected common name.
When using this tool, it is important to use files that are appropriate for the propagation time period being used (which is the Scenario Interval by default).
Within STK, you can update the satellite database and TLE files from the AGI Website using the Data Update Utility or from the Scenarios Database properties page.
Note: Both the satellite database file (*.sd file) and the TLE file (*.tce) will be updated (as well as several database support files), overwriting the existing files.
Satellite database files contain both identification information and orbital characteristics. While the identification information does not change often over time, the orbital characteristics do. Thus, if you are searching for space objects with certain orbital characteristics, you should first obtain an appropriately dated satellite database file. You can do this on the Scenarios Database properties page by clicking Update Database Files. If you are doing an analysis for a past time period, the appropriate file will not be the most current file, but rather an archived database dated near the propagation time period.
Note: The archived database and TLE files simply overwrite any existing files; hence, if you choose another propagation time period, you may need to update the database files once again.
If you are not searching using orbital characteristics, then an appropriately dated satellite database file is less of a concern, unless the most recently available objects are of interest. In that case, the most recent satellite database may suffice.
However, while the date of the satellite database file may be a concern for finding a space object of interest, the epoch for any TLEs used for ephemeris generation for that object is always a concern. Using the AGI Online Server as the TLE source removes the burden of obtaining correctly dated TLEs for objects.
Select the color choice or select Auto Select Color to allow STK to choose colors sequentially.
To propagate ephemeris using a different time period than the scenario time period, click Time Period....
You can group satellites into a single unit called a constellation object. To create a constellation of satellites:
Note: The option to create a constellation is only available with the STKProfessional or STKExpert license.