How Does Sonar Work?

Sonar, short for Sound Navigation and Ranging, operates by emitting sound wave pulses into the water. When these pulses encounter objects such as fish, aquatic plants, or the seabed, they are reflected and bounce back to the surface. The sonar device precisely measures the time it takes for the sound waves to travel from emission, to striking an object, and then returning. This principle closely resembles the echolocation system used by bats and dolphins. Using this time data, the device can accurately determine the depth of the reflecting object.

In addition, sonar equipment measures the strength of the returning pulses—generally, the harder the object, the stronger the reflected pulse. Each time the sonar receives a returning pulse, it immediately emits the next one. Given that sound travels through water at roughly one mile per second, sonar can emit multiple pulses per second.

The returning sound pulses are converted into electrical signals, which are then displayed in an intuitive format. This provides anglers with a clear view of the underwater environment, including depth, bottom hardness, and the presence of various objects between the seabed and the water surface.