Which scanning method provides separate instantaneous azimuth and elevation corrections on each received pulse?

Which scanning method provides separate instantaneous azimuth and elevation corrections on each received pulse?

• A. Circular
• B. Conical Scan
• C. Phase
• D. Monopulse scan

Answer: (D)

Monopulse scanning is designed to extract exact angular position from the very next pulse by using multiple beams formed simultaneously. It splits the received signal into a sum beam and two difference beams (typically corresponding to azimuth and elevation). The sum beam provides the overall received energy, while the difference beams compare neighboring beam channels to produce error signals. Taking the ratio of each difference signal to the sum gives immediate azimuth and elevation error indications for that pulse, so you get separate corrections on every pulse. This on-pulse, cross-beam comparison is what sets monopulse apart. Other methods rely on the beam moving or rotating to infer angle—the information is built up over time as the beam scans, not from the instantaneous pulse alone. Circular scanning sweeps the target around in a circle; conical scanning modulates the beam around the target, producing a single modulation-based error metric rather than two independent on-pulse corrections. Phase scanning relies on changing the phase pattern rather than forming true simultaneous beams for separate axes.

Monopulse scanning is designed to extract exact angular position from the very next pulse by using multiple beams formed simultaneously. It splits the received signal into a sum beam and two difference beams (typically corresponding to azimuth and elevation). The sum beam provides the overall received energy, while the difference beams compare neighboring beam channels to produce error signals. Taking the ratio of each difference signal to the sum gives immediate azimuth and elevation error indications for that pulse, so you get separate corrections on every pulse.

This on-pulse, cross-beam comparison is what sets monopulse apart. Other methods rely on the beam moving or rotating to infer angle—the information is built up over time as the beam scans, not from the instantaneous pulse alone. Circular scanning sweeps the target around in a circle; conical scanning modulates the beam around the target, producing a single modulation-based error metric rather than two independent on-pulse corrections. Phase scanning relies on changing the phase pattern rather than forming true simultaneous beams for separate axes.