Introduction to sonar

SONAR is the acronym for SOund Navigation And Ranging. Sonar techology is similar to other technologies such as: RADAR = RAdio Detection And Ranging; ultrasound, which typically is used with higher frequencies in medical applications; seismics, which typically uses lower frequencies in the sediments. The knowledge and understanding of underwater sound is not new. Leonardo Da Vinci discovered in 1490 that acoustics propagate well in the ocean: