What type of information does a plan position indicator (PPI) display?

A plan position indicator (PPI) is a type of radar display that visually represents targets on a map-like interface. It presents a two-dimensional view of the airspace around the radar system, allowing radar operators to see the position of aircraft and other objects in real time. The PPI shows the range and bearing of these targets, providing vital information for tracking and navigation purposes.

This presentation style allows for quick and effective situational awareness, enabling operators to monitor the movement of targets relative to the radar system. The use of a circular layout not only enhances visibility but also helps in understanding the geographical context of the targets.

In contrast, other options refer to different functionalities or types of information that aren't typically presented on a PPI. For instance, numeric values and text descriptions are more suited for other types of data displays; real-time weather data would be shown on a different system designed for meteorological information; and audio signals and frequencies relate to sound-based communications, not visual radar information. The PPI's primary role is to provide a visual representation of targets, making it crucial for radar operations.