Package com.luciad.tea

Interface ILcdLOSRadarPropagationFunction

All Superinterfaces:
ILcdLOSPropagationFunction
All Known Implementing Classes:
TLcdLOSRadarPropagationFunction, TLcdLOSRadarPropagationFunctionCoverageMatrixWrapper, TLcdLOSRadarPropagationFunctionSkyBackground
public interface ILcdLOSRadarPropagationFunction extends ILcdLOSPropagationFunction
Extension of the interface ILcdLOSPropagationFunction representing a radar line-of-sight propagation function. It adds some property methods that can be used by the propagation functions which are based on a radar line-of-sight computation.

The matrix resulting from this propagation function can contain the following special values:

  • INVISIBLE: for points where the object is invisible.
  • UNKNOWN: for points where the visibility is unknown. For example when no elevation data or invalid data was found at that point.

The following image gives a visual explanation of the parameters of a radar propagation function. The thin black arrows denote the minimum and maximum vertical angles. The red line corresponds to the radar tilt angle. The whole radar is rotated around the rotation axis.

Radar propagation function

Keep in mind that, if the radar tilt angle is not zero, the minimum and maximum viewing angles should be recomputed in the method ILcdLOSPropagationFunction.applyForAzimuthSFCT(double, ILcdLOSCoverageMatrix). In some cases, the computed viewing angle might fall outside the viewing interval [0, 180]. The implementation of this interface should handle these special cases correctly. The viewing angle is usually clipped to 0 or 180.

There are two cases when a viewing angle can fall outside the viewing interval. They are both explained using the image below. Both drawings show on the top-right part the viewing angles as dotted lines for the azimuth aMaxRadarTiltAzimuth and on the bottom-left part for the azimuth aMaxRadarTiltAzimuth + 180. The red lines correspond to the radar tilt angle for the azimuth.

  • case 1: when the maximum viewing angle becomes larger than 180 degrees. In the left drawing, the radar tilt angle is chosen to make the maximum viewing angle fall on the 180 degree line. A larger radar tilt angle makes the maximum viewing angle fall outside the viewing interval [0, 180].
  • case 2: when the minimum viewing angle becomes smaller than 0 degrees. In the right drawing, the radar tilt angle is chosen to make the minimum viewing angle fall on the 0 degree line. Larger radar tilt angles make the minimum viewing angle fall outside the viewing interval [0, 180].
Radar propagation function tilt angle

Note that these cases are only an issue when the corresponding azimuths lies inside the area on which this radar propagation function will be applied. This area is defined by the line-of-sight coverage (TLcdLOSCoverage).

See Also:

  • Field Details

    • INVISIBLE

      static final int INVISIBLE
      The resulting value for points where the object is invisible.
      See Also:

    • UNKNOWN

      static final int UNKNOWN
      The resulting value for points where the visibility is unknown. For example when no elevation data or invalid data was found at that point.
      See Also:

  • Method Details

    • getEarthRepresentationMode

      TLcdEarthRepresentationMode getEarthRepresentationMode()
      Returns the earth representation mode used by this instance.
      Returns:
      the earth representation mode used by this instance.

    • getAltitudeMode

      TLcdCoverageAltitudeMode getAltitudeMode()
      Returns the altitude mode indicating the definition of the resulting line-of-sight values.
      Returns:
      the altitude mode indicating the definition of the resulting line-of-sight values.

    • getKFactor

      double getKFactor()
      Returns the K-factor indicating the reflection of radar waves on the atmosphere. For radar computations, values should be greater than 1, usually 4/3. Setting the value equal to 1 will yield the same results as visual line-of-sight computations.
      Returns:
      the K-factor indicating the reflection of radar waves on the atmosphere.

    • getMaxVerticalAngle

      double getMaxVerticalAngle()
      Returns the maximum angle of the vertical extent in degrees, starting from 0 at the ground to 180 at zenith. It is the maximum vertical angle when the radar tilt angle is set to zero.
      Returns:
      the maximum angle of the vertical extent in degrees.

    • getMinVerticalAngle

      double getMinVerticalAngle()
      Returns the minimum angle of the vertical extent in degrees, starting from 0 at the ground to 180 at zenith. It is the minimum vertical angle when the radar tilt angle is set to zero.
      Returns:
      the minimum angle of the vertical extent in degrees.

    • getMaxRadarTiltAngle

      double getMaxRadarTiltAngle()
      Returns the maximum radar tilt angle in degrees, starting from 0 at the horizontal plane to 90 at zenith.
      Returns:
      the maximum radar tilt angle in degrees.

    • getMaxRadarTiltAzimuth

      double getMaxRadarTiltAzimuth()
      Returns the azimuth in degrees where the maximum radar tilt angle occurs.
      Returns:
      the azimuth in degrees where the maximum radar tilt angle occurs.

    • getTerrainElevationProvider

      ALcdTerrainElevationProvider getTerrainElevationProvider()
      Returns the elevation provider used to retrieve the terrain elevation data.
      Returns:
      the elevation provider used to retrieve the terrain elevation data.