A sonar device that measures water depth by emitting a downward acoustic pulse and timing the return of its echo from the seafloor. The system calculates depth by multiplying the sound’s travel time by the velocity of sound in water and dividing by two. Echosounders are central to hydrographic surveying, dredging control, fishery studies, and underwater navigation. Compact echosounders are also used on drones and unmanned vessels for quick deployment in shallow or remote locations.
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Core Acoustic Concepts
The Most Important Sonar Terms Explained
Acoustic Image
A visual rendering created by plotting sonar echoes by their intensity and time delay. Acoustic images resemble photographs but are generated by sound, revealing underwater scenes even in zero visibility.Acoustic Shadow
A dark or signal-void region behind an object that blocks the sonar beam. The length and shape of acoustic shadows help infer object dimensions and orientation, enhancing target interpretation.AUV (Autonomous Underwater Vehicle)
A self-navigating underwater robot that executes pre-programmed missions to collect sonar, imaging, or environmental data. It is used in deep-sea mapping, military reconnaissance, and oceanographic research where endurance and autonomy are required.