Sonar mapping is a technique used to detect and navigate objects mostly underwater. It uses the principle of propagation of sound. Sonar is an acronym for Sound Navigation and Ranging. Sonar was initially used to track objects located in air before the invention of radar. At present, sonar is mostly used to detect under water objects or vessels. The use of sonar traces way back to the early 19th century during the World War I. This was used to track the under water submarines of enemies. There are two kinds of sonar namely, active and passive. Active sonar uses both transmitting and receiving whereas, passive sonar uses only receiving and not transmitting.
Sonar mapping is the process of studying the shapes, sizes and distances of the ocean floor. They are also used to study the distances between desired objects. They use sound waves to study the shapes of ocean floors. A sound is created using a loudspeaker underwater, which penetrates the water and hits the desired object or the ocean floor directly if there is no obstacle in between. Once it hits the desired object it is reflected back to its originated source. There are instruments which measure the reflected sound. The time taken for the sound to travel back is directly proportional to the distance of the desired object. This is calculated by numerous mathematical calculations. Studying the ocean floor is more complicated because of the uneven surfaces of the ocean bed. Sound reflects from various places when it hits the ocean floor which makes it difficult for calculation.
Studying the ocean floor makes travel easier for ships. Side scan sonar mapping is another method where a tow fish is used that accompanies the vessel and emits sound which gives multiple images of ocean floor making it easier for the vessel to travel. Sonar mapping is also used to calculate habitat information. If one needs to know the number of a particular species present in a habitat, sonar mapping can help them. It uses multi beam sonar mapping technique to find habitat information. This serves as an important means of identifying endangered species in a particular area. With this data we can take steps to preserve the endangered species.
Sonar mapping has its own limitations in studying about habitat information. The high power emitted by the transmitters, results in harming the whales and dolphins. They use similar mechanism as that of the sonar to catch their prey. Due to sonar mapping, whales get confused resulting in them not feeding themselves or mating.
Sonar mapping is mainly used during under water study. Scientists carry out research on various species of whales and other distinct animals under water. Due to the huge ocean floor, it is difficult to identify the location of these animals. Sonar mapping helps scientists to locate these creatures thereby setting traps to catch them for scientific study. Sonar mapping, as we have seen has wide ranging use in the fields of marine navigation, scientific studies, habitat research and so on.
References:
http://www.ri.cmu.edu/research_project_detail.html?project_id=336&menu_id=261.
http://earthguide.ucsd.edu/earthguide/diagrams/sonar/sonar.html
http://www.accessmylibrary.com/coms2/summary_0286-29383485_ITM
