Method for optimizing and selecting transmitting frequency of ADCP (acoustic Doppler current profiler) with environmental adaptability

Abstract

The invention relates to a method for optimizing and selecting transmitting frequency of an ADCP (acoustic Doppler current profiler) with environmental adaptability. The method comprises the followingsteps: S1, according the mathematic relation among a transducer receiving level in an ADCP transducer receiving level as well as a sound source level, one-way propagation loss, a target intensity level and a background noise level, acquiring a sonar equation of the transducer receiving level as well as the sound source level, the one-way propagation loss, the target intensity level and the background noise level; S2, according to the mathematic relation among transmitting frequency, acoustic diameter of a transmitting transducer, the wavelength of transmitting sound wave and the sound sourcelevel, acquiring a calculation formula of the sound source level; S3, according to the mathematic relation among the measuring distance, the attenuation coefficient of water for the sound wave and theone-way propagation loss, acquiring a calculation formula of the one-way propagation loss; and performing other steps to acquire the transmitting frequency. The echo signal-to-noise ratio of the ADCPby using the method can be increased by at most 20 dB compared with that of the ADCP with fixed transmitting frequency.

Description

technical field [0001] The invention relates to the field of underwater monitoring, in particular to an ADCP transmission frequency optimization selection method with environmental adaptability. Background technique [0002] Acoustic Doppler Current Profiler (ADCP) is an active sonar that uses the Doppler principle to measure the stratified flow velocity of water bodies and the flow of sections. ADCP is widely used in many fields such as oil and gas mineral development, biological environment observation, ocean current scientific investigation, underwater submarine operations, long-term wave observation, fishery breeding management, marine traffic safety, underwater pipeline laying, coastal engineering construction and offshore environmental monitoring. [0003] The working process of ADCP is to firstly transmit a short pulse sound wave to the target water layer. After the sound wave is scattered by the scattering body in the water, part of the sound wave returns to the orig...

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Problems solved by technology

[0005] (2) Propagation loss: The propagation loss of sound waves underwater includes distance attenuation, seawater absorption attenuation, viscous attenuation and scattering attenuation

[0010] (3) Target intensity: the logarithm of the ratio of the echo intensity at 1 yard (1 yard = 0.9144 meters) from the target acoustic center to the incident sound intensity. Since the length of the sound wave of the ADCP is much larger than the size of the scatterer, the detection beam is in a certain seawater. The acoustic scattering in the interior belongs to Rayleigh scattering, which is more complicated than the geometric scattering of large-scale targets. At present, there are only approximate empirical formulas to calculate the target intensity

However, there is no way to select the optimal transmission frequency at present, so a scientific and practical method is urgently needed to solve the problems faced

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