Which method is commonly used to determine a contact's position using sonar?

Which method is commonly used to determine a contact's position using sonar?

• A. Bearings-only triangulation
• B. Single-station range estimation
• C. Visual triangulation from the bridge
• D. Infrared imaging

Answer: (A)

Determining a contact’s position with sonar relies on using bearing information from multiple known locations and finding where the lines of bearing intersect. Each bearing measurement from a fixed position defines a line that extends from that position toward the contact. When you have two or more of these lines, their intersection pinpoints the contact’s location. This is why bearings-only triangulation is the preferred method: you don’t need exact range data from a single sensor to fix where the contact is—angle data from several known positions is enough to locate it. In practice, passive sonar networks or dispersed hydrophones provide bearings to a contact. Plotting each bearing on a chart as a line from its known position allows the navigator to determine where those lines cross, giving the contact’s position. The more bearings you have, and the more accurately they’re measured, the more reliable the fix becomes, because you can reduce error from misalignments or noise. Single-station range estimation cannot fix a two-dimensional position on its own, since it gives distance to the target from one point but not direction. Visual triangulation from the bridge and infrared imaging are not sonar-based position fixes; they may aid in detection or tracking, but they do not provide the pure bearing-based geometry used for locating with sonar.

Determining a contact’s position with sonar relies on using bearing information from multiple known locations and finding where the lines of bearing intersect. Each bearing measurement from a fixed position defines a line that extends from that position toward the contact. When you have two or more of these lines, their intersection pinpoints the contact’s location. This is why bearings-only triangulation is the preferred method: you don’t need exact range data from a single sensor to fix where the contact is—angle data from several known positions is enough to locate it.

In practice, passive sonar networks or dispersed hydrophones provide bearings to a contact. Plotting each bearing on a chart as a line from its known position allows the navigator to determine where those lines cross, giving the contact’s position. The more bearings you have, and the more accurately they’re measured, the more reliable the fix becomes, because you can reduce error from misalignments or noise.

Single-station range estimation cannot fix a two-dimensional position on its own, since it gives distance to the target from one point but not direction. Visual triangulation from the bridge and infrared imaging are not sonar-based position fixes; they may aid in detection or tracking, but they do not provide the pure bearing-based geometry used for locating with sonar.