Which is an advantage of passive sonar?

• A. Covert detection of targets
• B. Gathers bearing information poorly
• C. Short detection ranges
• D. Requires active transmissions

Answer: (A)

The advantage of passive sonar is that it detects targets without emitting any sound of its own, keeping the observer covert. Since nothing is transmitted, the target is less likely to detect that it is being listened to, allowing quiet surveillance and tracking, which is crucial for stealthy approaches or screening operations. Bearing information can still be determined using the hydrophone array by analyzing the arrival times of sounds, and with multiple sensors you can triangulate position, though range estimation is more challenging without active pings. The other statements don’t fit this advantage: passive systems don’t require active transmissions, and they can have long detection ranges depending on the target’s noise and ambient conditions, not inherently short ranges.