Broad-Band Phased Array Doppler Velocity Measurement Technology

As acoustic Doppler techniques performed outstandingly in the field of measuring ocean velocities, which attracted more attention. The broadband system showed extra performances, those were consistent measurement capability, smaller averaging time and finer depth cell. On the other hand, phased array technology was successfully applied not only to eliminate one of the large error sources, but also reduce the volume of equipment.Two aspects were focused on in the paper, which were broadband phase-coded signal processing techniques and the phased array technology.The principle of using acoustic Doppler techniques on measuring velocities was studied in the paper and the frequency estimation methods especially the complex self-correlation approach algorithm was analyzed in detail, with which the frequency offset estimation was easily obtained. The pulse-to-pulse incoherent and pulse-to-pulse coherent theories were discussed and the signal processing was described. The excellences of using the phase-coded signal were pointed out under the investigation of some computer simulations considering the frequency influence brought by the beam angle.The fundamental theory of the phased array technology employed to the Doppler velocity measurement was studied and the schemes for realizing the transmitting and receiving system were reviewed. After several array radiation patterns were observed carefully, one of the factors that may affect the radiation characteristics was found. Some results were listed in this paper that reveals a better sequel. Two digital ways applied to the receiving phased control were practiced and tested with the relevant experimental data, which were feasible for further work.