What type of scanning indicator do surveillance radars primarily use?

What type of scanning indicator do surveillance radars primarily use?

• A. A-scan
• B. Plan Position Indicator (PPI)
• C. Raster
• D. C-scan

Answer: (B)

Surveillance radars need a two‑dimensional view of airspace in the horizontal plane. A Plan Position Indicator provides exactly that: a circular, plan‑view display with the radar at the center, showing range as the radial distance and bearing around the circle. As the antenna sweeps through azimuth, each target’s plot appears at its true angle and distance from the radar, giving operators a clear, intuitive picture of where every target is and how they relate to one another. The other display types serve different purposes: an A‑scan shows peak signal versus range for a single beam and lacks directional context; a C‑scan or raster-type display presents other dimensions or slices and isn’t the standard way to monitor full 360‑degree airspace in real time. Because the Plan Position Indicator mirrors the actual scanning geometry and provides immediate situational awareness of position, it is the primary scanning indicator used in surveillance radar.

Surveillance radars need a two‑dimensional view of airspace in the horizontal plane. A Plan Position Indicator provides exactly that: a circular, plan‑view display with the radar at the center, showing range as the radial distance and bearing around the circle. As the antenna sweeps through azimuth, each target’s plot appears at its true angle and distance from the radar, giving operators a clear, intuitive picture of where every target is and how they relate to one another. The other display types serve different purposes: an A‑scan shows peak signal versus range for a single beam and lacks directional context; a C‑scan or raster-type display presents other dimensions or slices and isn’t the standard way to monitor full 360‑degree airspace in real time. Because the Plan Position Indicator mirrors the actual scanning geometry and provides immediate situational awareness of position, it is the primary scanning indicator used in surveillance radar.