What is sonar?

Question

what is it exactly? is it a high or low frequency wave? is it technically sound?

Answer 1

Sonar is underwater radar. A low frequency sound wave, instead of a radio wave is "pinged" into the water, and then the transmitter turns off and the receiver turns on to listen for any return from an object that reflects the sound. You have to use low frequencies to get returns from far away, but the higher the frequency the more accurate you can be. You use different frequencies for different porpoises (sic). Everything is timed very closely. Sonar transmitter and receiving antennas are very directional so you can tell where an object is that reflects the audio wave.

Passive sonar just uses the directive receiving antenna to listen for underwater noises that aren't reflections but energy being emitted from an underwater object.

Some sonar modes will transmit in all directions and then listen in all directions or scan in a tight beam. If you just listen to everything, you can tell how far away it is, but not where it is.

Sonars I installed on tuna boats in the 80s were very sophisticated and could really home in on schools of fish and tell exactly where they were. Navy sonar equipment and methods are very classified and fancy.

Answer 2

Yes, it is sound. Active sonar is a speaker and a microphone -- it sends out sound and times the echo. Passive sonar is just a microphone that picks up sound. Active sonar is better at estimating distance, of course.

Whether it is a high or low frequency wave depends on its intended use.

Sonar intended to used around the home usually relies on ultra high sound, so that people are not bothered by the sound.

Answer 3

SOund NAvigation and Ranging is a low frequency sound wave 'Ping' used underwater and sent out to locate objects by reflecting the sound wave off the object and computing distance and direction to the object.