Configure Witness for AGS Long Range Detection

Owned by Guy Avery (Deactivated)
Last updated: Jun 28, 2017

When configuring the tracking settings in Witness to maximise performance with the long range AGS radar, it can help to adjust settings based on the detection range. In simple terms, this means adjusting the settings so the software is more sensitive at longer range and less sensitive closer to the radar. This particularly applies to sites where the terrain or conditions make tracking at long range more challenging, such as detection areas with long grass or uneven ground which can partially obscure targets.

The principal is fairly straight-forward: create two areas, one for close detection and another for long range detection. Then ensure you adjust the tracking parameters for each area to match the level of sensitivity you require. This article outline which parameters should be adjusted and provides some recommended default values.

The example outlined in the article is based around a fictional airfield but it applies to any scenario where the AGS is being used for long range detection.

Step-by-step guide

Given the following scenario at an airfield:


  1. Create a short range detection area - approximately from 0 - 500m from the radar

  2. Create a long range detection area - approximately from 500m out to the desired detection range

    These are detection areas and should not be confused with Alarm Zones. We create detection zone so we can detect and track targets. Alarm Zones are used to generate alarms in response to targets being detected and can be added later once you are happy that the system is tracking correctly.

  3. Setup the correct global settings on the tracker:

    ParameterRecommend ValueNotes
    Clutter Map Time Constant0.9
    Threshold Window8m
    Threshold Delta32AGS 1600 Radar
    Threshold OutputLevel Above
    Minimum Blob Weight1Allow detection of all objects - even the smallest. This is set in the plot extraction settings

      Space              

  4. Create new short range tracking parameters by copying the existing Default settings and renaming to "Short Range" or equivalent:





  5. Repeat these steps and create new long range tracking parameters by copying the existing Default settings
  6. Now configure the appropriate options for short and long range parameters based on the options outlined below
  7. Once you have adjusted your short and long range settings, ensure you add them to the tracking channel

Option 1 - Reduced Weight at Long Range but same Sensitivity

Short Range Detection Area Settings

ParameterRecommend ValueNotes
Min Plot Weight ATI2Filters out very small objects close to the radar
Plot Amplitude ATI6Gives a total threshold for ATI of 38 (32+6)
Plot Amplitude Track2Gives a total threshold for tracking of 34 (32+2)

Long Range Detection Area Settings

ParameterRecommend ValueNotes
Min Plot Weight ATI1Allows small objects to be tracked at range
Plot Amplitude ATI6Gives a total threshold for ATI of 38 (32+6)
Plot Amplitude Track2Gives a total threshold for tracking of 34 (32+2)

Option 2 - Reduced Weight at Range and Increased Sensitivity

Short Range Detection Area Settings (Same as Option 1)

ParameterRecommend ValueNotes
Min Plot Weight ATI2Filters out very small objects close to the radar
Plot Amplitude ATI6Gives a total threshold for ATI of 38 (32+6)
Plot Amplitude Track2Gives a total threshold for tracking of 34 (32+2)

Long Range Detection Area Settings

ParameterRecommend ValueNotes
Min Plot Weight ATI1Allows small objects to be tracked at range
Plot Amplitude ATI2Gives a total threshold for ATI of 34 (32+2)
Plot Amplitude Track0Gives a total threshold for tracking of 32 (32+0)

Summary