sonar pulse http://oceanservice.noaa.gov/facts/sonar.html What is sonar? - National Ocean Service - NOAA NOAA National Ocean Service (NOS) other types of sonar National Ocean Service (NOS) What is sonar? sonar sonar pulse National Ocean Service (NOS) sonar "What is sonar?" http://oceanservice.noaa.gov/facts/sonar.html sonar National Ocean Service (NOS) SONAR NOAA "What is sonar?" SOund Navigation And Ranging http://oceanservice.noaa.gov/facts/sonar.html What is sonar?