What is the primary purpose of the Plan Position Indicator (PPI) on a naval radar?

• A. To display weather data on a circular chart
• B. To measure target speed
• C. To present radar returns in range and bearing around the own-ship for a real-time situational picture
• D. To filter noise

Answer: (C)

The Plan Position Indicator is a circular, plan-view radar display with your own ship at the center. It shows radar echoes arranged by range from the center and bearing around the circle, so you get a real-time map of where everything is relative to you. This setup gives a quick, intuitive sense of which contacts are to port or starboard, ahead or behind, and how far away they are, forming a continuous situational picture essential for navigation and threat assessment. Weather data would be a separate function or mode on some systems, target speed is determined from tracking history or Doppler processing, and noise filtering comes from signal processing, not the primary purpose of the PPI.