Determination of speed of sound using empirical equations and SVP

Acoustic sound, navigation and ranging (SONAR) is commonly used for underwater measurement applications. The most popular underwater applications using acoustic sonar is bathymetry surveying, which echo sounder is used to a measured depth. Depths in acoustic sonar are computed based on sonar equation. In sonar equation, elapsed time from a sensor transmitting sonar wave to the bottom and reflected back to the sensor were measured. The main parameter contributing in computation of depth using acoustic sonar are travel time and speed of sound (SOS). If SOS is accurately known, depth can be accurately determined. However, SOS values are subjected to temperature, salinity and density. There are various equipments and formula can be used to determine SOS accurately. This paper will discuss on field observation of SOS with specific types of water categories (sea water, estuary and fresh water) and compare the value between computed SOS using empirical equations and observed SOS.