You can use ASCII Data Direction Provider files within the Phased Array Antenna and HFSS EEP Array Antenna models. These enable you to use ASCII text files to specify the beam direction(s) and, within the Phased Array Antenna only, null direction(s). ASCII Data Direction Providers are convenient for custom fixed pointing in particular direction(s) or when pointing needs to be time dynamic but the number of times it must change direction is few. When the pointing is highly time dynamic, it would be better to use a Script Direction Provider.
Beam ASCII Data Direction Provider file format
Use the following keywords in Beam ASCII Data Direction Provider files:
| Keyword | Description |
|---|---|
| BeamAsciiDataDirectionProvider v2 | Indicates the data format and version of the data format. This is a required keyword and must be the first line in the file. |
| <AntennaCoordinateSystem> | Text string that specifies how the Az/El angles are measured. Valid strings are "SphericalAzEl", "Polar", and “Rectangular”. For more information, see Antenna Coordinate Systems. |
| <Sampling Mode> | Text string that specifies how STK determines direction values for time steps between what is specified in the file. SampleAndHold is the only option available. SampleAndHold causes STK to continue to use the direction(s) specified by the file's time that is less than the current analysis time. STK switches to a new direction when the analysis time becomes greater than the next time entry within the file. When there are no future entries, the antenna continues to hold the last specified direction. |
| <Direction Information> |
Time-specified pointing direction information. The Direction Information consists of many rows of space-separated data sets, one row for each time step. Azimuth and elevation are in degrees. Each row has the following format:
|
Beam ASCII Data Direction Provider file sample format
If first character of a line is "#", the entire line is treated as a comment. Uncommented lines have the following meanings:
- The first uncommented line is a tag indicating the type of file followed by the file format version.
- The second uncommented line is the antenna coordinate system. Valid keywords are "SphericalAzEl", "Polar", or “Rectangular”. SeeAntenna Coordinate Systems.
- The third uncommented line is the sampling mode. The only valid entry is SampleAndHold.
The remaining uncommented lines are time-specified pointing directions with the following format:
<time> <number of directions> <direction 1 Az> <direction 1 El> ... <direction n Az> <direction n El>
where time is in epoch seconds, and Az/El values are in degrees in the antenna's body reference frame.
Following is an example of a Beam ASCII Data Direction Provider file:
# This example has two beam directions and holds one at 0.0 deg azimuth, -26.0 deg elevation and the other beam at 0.0 deg # azimuth, 20.0 deg elevation for all time. Add more rows in between for explicit dynamic beam steering directions. # BeamAsciiDataDirectionProvider v2 SphericalAzEl SampleAndHold -1e300 2 0.0 -26.0 0.0 20.0 1e300 2 0.0 -26.0 0.0 20.0
Null ASCII Data Direction Provider file format
Use the following keywords in Null ASCII Data Direction Provider files:
| Keyword | Description |
|---|---|
| NullAsciiDataDirectionProvider v2 | Indicates the data format and version of the data format. This is a required keyword and must be the first line in the file. |
| <AntennaCoordinateSystem> | Enter a text string that specifies how the Az/El angles are measured. Valid strings are "SphericalAzEl", "Polar",and “Rectangular”. For more information, see Antenna Coordinate Systems. |
| <Sampling Mode> |
Enter a text string that specifies how STK determines direction values for time steps between what is specified in the file. SampleAndHold is the only option available. SampleAndHold causes STK to continue to use the direction(s) specified by the file's time that is less than the current analysis time. STK switches to a new direction when the analysis time becomes greater than the next time entry within the file. When there are no future entries, the antenna continues to hold the last specified direction. |
| <Metric Scale> | Enter a text string that specifies the scale of the <MetricValue> field. Options are Logarithmic and Linear. |
| <Direction Information> |
This is time-specified pointing direction information. The Direction Information consists of many rows of space-separated data sets, one row for each time step. Azimuth and elevation are in degrees. Each row has the following format:
|
Null ASCII Data Direction Provider file sample format
If first character of a line is "#", then the entire line is treated as a comment. Uncommented lines have the following meanings:
- The first uncommented line is a tag indicating the type of file followed by the file format version.
- The second uncommented line is the antenna coordinate system. Valid keywords are "SphericalAzEl", "Polar", or “Rectangular”. See Antenna Coordinate Systems.
- The third uncommented line is the sampling mode. The only valid entry is "SampleAndHold."
- The fourth uncommented line indicates the scale of the metric values, either "Logarithmic" or "Linear".
The remaining uncommented lines are time-specified pointing directions with the following format:
<time> <number of directions> <direction 1 Az> <direction 1 El> <direction 1 metric> ... <direction n Az> <direction n El> <direction n metric>
where time is in epoch seconds, and Az/El values are in degrees in the antenna's body reference frame.
Here is an example of a Null ASCII Data Direction Provider file:
# This example has two null directions and holds one at 0.0 deg azimuth, -46.0 deg elevation with a weight of 10 dB and the # other null at 0.0 deg azimuth, 66.0 deg elevation with a weight of 10 dB for all time. Add more rows in between for # explicit dynamic null steering directions. # NullAsciiDataDirectionProvider v2 SphericalAzEl SampleAndHold Logarithmic -1e300 2 0.0 -46.0 10.0 0.0 66.0 10.0 1e300 2 0.0 -46.0 10.0 0.0 66.0 10.0