Radar SAR Constraints
Use the Radar SAR constraint category to impose one or more of the following constraints on a radar object set tosynthetic aperture radar (SAR) configuration.
You can extend the STK Radar SAR computation and constraints with the SAR User Plugin constraint.
Except for Sigma N (below), Radar SAR constraints are available only if SAR mode is enabled in the radar's Basic properties (SAR page).
| Option | Description |
|---|---|
| Area Rate | The coverage rate of the SAR; Min and/or Max area rate as the ratio of the selected distance unit squared to the selected time unit |
| Azimuth Resolution | The fixed azimuth resolution or the resolution achievable within the desired integration time, depending on the setting of the analysis mode when defining the radar; mutually exclusive with the Integration Time constraint |
| CNR | Clutter-to-noise ratio for the SAR radar |
| Image Area | The image area of the SAR |
| Integration Time | The fixed integration time or time to achieve the desired azimuth resolution, depending on the setting of the analysis mode when defining the radar; mutually exclusive with Azimuth Resolution constraint |
| OrthoPol CNR | Clutter-to-noise ratio for the orthogonal polarization channel of a SAR radar |
| OrthoPol PTCR | The point target-to-clutter ratio for the orthogonal polarization channel of a SAR radar |
| OrthoPol SCR | Signal-to-clutter ratio for the orthogonal polarization channel of a SAR radar |
| OrthoPol SNR | Signal-to-noise ratio for the orthogonal polarization channel of a SAR radar |
| PTCR | The point target-to-clutter ratio for the SAR radar |
| SAR User Plugin | See the SAR user plugin section |
| SCR | Signal-to-clutter ratio for the SAR radar |
| Sigma N | The effective backscatter coefficient of the additive noise |
| SNR | Signal-to-noise ratio for the SAR radar |
SAR user plugin
The SAR User Plugin constraint extends STK Radar performance computations. You can create a SAR plugin script using MATLAB or VB. STK interfaces with the script and provides updated object geometry, Vector Geometry Tool (VGT) data, and radar performance data at each time step of the scenario execution. The script uses the STK-supplied data to compute a new parameter and return the value to STK. For more information, see Custom Plugins for Radar Search/Track and SAR Constraints.
When you select to apply the SAR User Plugin constraint, address the following options in the Constraint Properties area:
| Option | Description |
|---|---|
| File | Type the file path or click the ellipsis ( ) to select your plugin file. A fully functional template (VB_RadarSARNIIRSConstraint.vbs) is provided for your use. All STK inputs to the script and the output from the script are already programmed in the template. A simple data model is programmed as an example. You can replace the template example model with your own model equations. The radar-target geometry data and VGT data is independent of the radar's operational mode and is supplied to the SAR plugin script. |
| Min/Max | If the constraint data needs to limit the access visibility intervals, enter the appropriate minimum and/or maximum values. |
| Exclude Time Intervals | When you select this check box, STK excludes the time intervals during which the constraint is satisfied. |