Enables you to specify the element weights in a text file. Each weight specified in the file is matched to an element by means of the element ID. Thus, the file’s element ID must match the element ID as specified in the antenna’s element configuration. For example, if the antenna is defined to have three enabled elements and their IDs are 5, 7, 8 then the file weights must have IDs of 5, 7, 8. While this beamformer does allow specifying custom time-dynamic gain responses, it can be cumbersome for many adaptations over time. This file format is more appropriate for smaller sized arrays that only have a small set of known responses at determined time intervals. For more robust arrays and a highly time-dynamic custom adaptation, you should use the Beamformer script. Also, if you want to change your custom weights based on the operating frequency, you would need to use the Beamformer script.
Since this is a data file, this beamformer does not use any information from the Direction Providers.
| Parameter | Description |
|---|---|
| AsciiDataBeamformer v1 | Indicates the data format and version of the data format. This is a required keyword and must be the first line in the file. |
| Sampling Mode | Specifies how STK determines element weight 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 file's weight(s) specified by the file's closest time that is less than the current scenario time. STK switches to new weight(s) when the scenario time becomes greater than the next time entry within the file. When there are no future entries, the antenna will continue to hold the last specified weight(s). |
| Number of Elements | Number of enabled elements and thus indicates the number of IDs and weights that must be specified on each line. |
| Weight Data | Time-specified element weights. Each row must include the time step and an element ID and complex weight for each of the Number of Elements specified above. Each complex weight must be a real and imaginary pair separated by a comma and enclosed in parenthesis. |
Beamformer File Sample Format
Following is an example file for a set of weights for a phased array consisting of seven enabled elements with IDs from 2 thru 8, which changes its gain response every five seconds for the first 20 seconds:
# File format is as follows: # If first character of a line is '#' the entire line is treated as a comment line. # First non-comment line is a tag indicating the type of file followed by the file # format version. Tells STK the format of the remaining file. # Second non-comment line is a sampling mode (required). Only "SampleAndHold" is supported # (future will bring more options). # Third non-comment line is a number of elements (required). # Remaining non-comment lines are time specified complex element weights (required) with the # following format: # <time> <elmnt 1 id> <elmnt 1 complex wght> ... <elmnt n id> <elmnt n complex wght> where # element ids MUST correspond to the ENABLED element id specified in the Element Configuration # and the complex weights are specified as a comma separated real and imag values enclosed in # parentheses. AsciiDataBeamformer v1 SampleAndHold 7 -1.0E300 2 (1.0,0.0) 3 (1.0,0.0) 4 (1.0,0.0) 5 (1.0,0.0) 6 (1.0,0.0) 7 (1.0,0.0) 8 (1.0,0.0) 5.0 2 (1.0,0.0) 3 (1.0,0.0) 4 (0.25,0.0) 5 (1.0,0.0) 6 (0.25,0.0) 7 (0.25,0.0) 8 (1.0,0.0) 10.0 2 (1.0,0.0) 3 (0.5,0.0) 4 (1.0,0.0) 5 (0.25,0.0) 6 (1.0,0.0) 7 (0.25,0.0) 8 (0.25,0.0) 20.0 2 (1.0,0.0) 3 (0.25,0.0) 4 (1.0,0.0) 5 (1.0,0.0) 6 (1.0,0.0) 7 (0.25,0.0) 8 (1.0,0.0) 1.0E300 2 (1.0,0.0) 3 (1.0,0.0) 4 (1.0,0.0) 5 (1.0,0.0) 6 (1.0,0.0) 7 (1.0,0.0) 8 (1.0,0.0)