Which scan type uses a thin beam to cover a rectangular area with horizontal and vertical sweeps, primarily used in air interception?

• A. TWS
• B. Raster
• C. Linear
• D. Circular

Answer: (B)

Raster scanning uses a narrow radar beam that sweeps back and forth across the search volume to form horizontal lines, then steps slightly in the other dimension to fill in the next line. Doing this repeatedly creates a grid that covers a rectangular area. This systematic, line-by-line coverage is ideal for air interception because it provides uniform coverage and good angular and range resolution across the defined airspace, making it easier to detect, locate, and track an approaching aircraft as if painting a picture of the sky in a rectangular zone.

Circular scanning, by contrast, sweeps around a center point, which is great for wide-around surveillance but not for filling a rectangle. Linear scanning tracks a single line of sweep and doesn’t complete a full rectangular grid. Track-While-Scan is about maintaining target tracks while continuing to scan, rather than defining the geometric pattern of the scan itself.