Research advance in underwater detection of marine status for underwater vehicles

Data of sea-status obtained acoustically by underwater vehicle often have defects of imprecise class with incomplete elements. The class model of underwater-vehicle detected seastatus based on high-pass filter was established by analysing every possible error factor, but the frequency cut-off of the model is difficult to determine in practice for the instance of one acoustic observing point. Acoustic arrays are created on the vehicle, and Hilbert Transform is used to analyse the wave phases observed by each sensor, and then the model-estimated wave direction based on phase difference is presented. In addition, flume experiments were conducted to simulate the processes. The results show that the phase-difference method is effective in determining wave direction, as is helpful in making certain the frequency cut-off of the class model, and the experiments provide a theoretical base for estimating sea-status underwater.