Radar Sensitivity Time Control (STC)

Radars use range (or pulse travel time) based attenuation to reduce the strong returns from the nearby clutter objects.

You can enable STC at Radio Frequency (RF) and/or Intermediate Frequency (IF) signal levels, and select a computation based STC type or an external file based STC type.

Descriptions of the STC types are provided below.

Computation Based STC Types

The computation based STC types are:

Decay Factor. STC is a factor of range. It is computed as an inverse power (decay factor) of the range to the cell of interest. For example, attenuation is decreased as a function of R^-2, where R is the range and 2 is the attenuation factor. The STC attenuation set at the STC start value at the minimum range. The attenuation is decreased as a function of the factor of the range to the cell of interest. The STC application is stopped once the attenuation value is decreased to zero dB.
Decay Slope. STC attenuation is stated as a decay slope, e.g. 6 dB/Octave. The STC attenuation set at the STC start value at the minimum range. The attenuation is decreased using the decay slope values till the value is zero.

The parameters for these two types follow.

STC Parameter	Description
Max Value (dB)	Maximum value of STC attenuation.
Start Value (dB)	STC attenuation value at the minimum range.
Atten. Step Size (dB)	Attenuation step size.
Decay Factor	Attenuation decay factor. For example, R^-3, where R is the range and 3 is the decay factor.
Decay Slope / Octave (dB/octave)	Decay slope of the STC attenuation.
Start Range	Minimum range when STC is applied.
Stop Range	Range at which STC is cut off. Note that the STC attenuation value may decay to zero (dB) before the stop range depending on the decay factor or the decay slope values.

External File Based STC Types

The STC attenuation tables are provided by the user in an external STC file. Attenuation values are in dBs.

Select one of the following STC types and enter the name of the STC file in the Filename field.

Map Range. Table of range vs. attenuation is provided by the user. If the range to the cell of interest is within the minimum and maximum limits of the table range then the attenuation value is read from the table and applied. Please note that the attenuation values are NOT interpolated.
Map Azimuth Range. A two dimensional table of Azimuth vs. Range. Rows contain the azimuth data and the columns extend over the range. The STC attenuation is applied for all elevation angles. Please note that the attenuation values are NOT interpolated. A same attenuation value is applied over the range cells till the next range is reached in the data table.
Map Elevation Range. A two dimensional table of Elevation vs. Range. Rows contain the Elevation data and the columns extend over the range. The STC attenuation is applied for all Azimuth angles.

The external file is not automatically reloaded after you make changes to it. To reload the file, click Reload.