The Chinese Coastal Acoustic Tomography system and its application to the Luotou Channel, China

The Chinese Coastal Acoustic Tomography (CAT) system was developed for measurement of currents in the coastal sea. The CAT system was composed of two stations and each station was equipped with a GPS and a transducer. The operating frequency range of CAT system was 3-7.5 kHz. The reciprocal sound transmission experiment was carried out in March 25-26, 2009 in the Luotou Channel, near the Zhoushan Island, China. The sound signals using a carrier of 5 kHz modulated with M sequence of 9^th order, were successful received at two stations. The mean signal to noise ratio reached about 19-21 dB. The range-averaged current velocity obtained along the transmission line measured by CAT was in good agreement with that measured by the lowed acoustic Doppler current profiler, producing the root-mean-square difference of 0.095 m/s. The above field experiment results indicated that the CAT system operated correctly.