Definition
A marker on an air traffic control radar display showing the current position of the controller's trackball-controlled cursor. The controller moves the trackball to point this symbol at a specific location on the screen, typically to attach data, measure distances, or designate a target.
Plain English
A small marker on the controller's radar screen that shows where their cursor is pointing, moved by rolling a trackball with their hand.
Context Anchor
Seen in explanations or figures of ARTS III/DBRITE air traffic control radar displays, not as a cockpit instrument indication.
Derivation
A trackball is an input device — like an upside-down mouse — where the user rotates a ball with their fingers or palm to move a cursor. The position symbol is simply the on-screen marker that follows the trackball's movement.
Why Pilots Care
Pilots don't operate the trackball, but understanding what controllers see on their displays helps when interpreting radar services, traffic calls, and the timing of controller responses.
Analogy
It is like a mouse pointer on a computer screen: it shows where the operator is pointing, not where an outside object is located.
Intuition Check
Do not read “position” here as the aircraft’s position. The trackball position symbol shows the controller’s pointer location on the radar display.
Example Sentence 1
The controller moved the trackball position symbol over the target to read out the aircraft's altitude and groundspeed.
Example Sentence 2
A bright trackball position symbol on the DBRITE display allowed quick selection of the arriving aircraft's position for sequencing.