What’s the difference between Plots, Contacts and Centroids?

Sometimes these terms are used interchangeably, but they do have slightly different definitions.

Plot is a generic radar system term that is typically associated with the Tracking Function’s input. Plots are data representations of the raw radar return from a target; they may contain position and shape information.

Contacts and Centroids are SSR’s specific representations of the generic Plot. Both representations are output from the Radar Processor.

Contacts contain only the position of a target, represented in Delta X/Y Coordinates from Ownship X/Y Position. If one was to display plots on a GUI, SSR would recommend using the Contact Messages.

Centroids contain both position and shape data for a target, represented in Range Bins and Azimuth BAMs from Ownship Lat/Lon Position. This information is used by the SSR Tracker to generate Tracks.