Submersible sound speed measurement apparatus and method of submersibly measuring sound speed

摘要

A submersible sound speed measurement apparatus 100 comprises a frame 102 carrying an acoustic transducer 110 and an acoustically reflecting surface 124 at opposite ends. A processor 126 is connected to the acoustic transducer 110 to measure a forward time of flight to the acoustically reflecting surface 124 through a first medium in which the sensor is submerged and a reverse time of flight through a second medium 112 between the transducer and its mounting surface 116 of the frame. The processor measures the forward time of flight to calculate the speed of sound in the first medium and uses the measured reverse time of flight to apply an offset to the calculation of the sound speed value. This compensates for movement between the transducer and the reflecting surface with pressure. The transducer may be piezoelectric. Also disclosed is a method of calibrating the sensor for temperature.