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An Underwater Acoustic Doppler Velocity Measurement Method Based on Autocorrelation Estimation and Valid Data Screening

A technology of autocorrelation estimation and Doppler flow velocity, which is applied in the field of underwater acoustic Doppler flow velocity measurement, can solve the problems of echo signal-to-noise ratio decrease, decrease of signal-to-noise ratio, increase, etc., to reduce variance and improve accuracy , Improve the effect of key performance

Active Publication Date: 2021-03-30
NANJING SHIHAI ACOUSTIC TECH CO LTD
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Problems solved by technology

(3) Factors that reduce the signal-to-noise ratio
The small number of scatterers in the water will cause the signal-to-noise ratio of the echo to drop significantly
Conversely, if the concentration of scatterers is too high, it will block the echo of deep water body, thereby reducing its signal-to-noise ratio
(4) Uneven velocity distribution
One is that the faster the flow velocity changes along the beam direction, the greater the velocity difference of scatterers in each water layer will be, and the echo spectrum width will naturally widen, and the standard deviation will increase when estimating stratified flow velocity

Method used

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  • An Underwater Acoustic Doppler Velocity Measurement Method Based on Autocorrelation Estimation and Valid Data Screening
  • An Underwater Acoustic Doppler Velocity Measurement Method Based on Autocorrelation Estimation and Valid Data Screening
  • An Underwater Acoustic Doppler Velocity Measurement Method Based on Autocorrelation Estimation and Valid Data Screening

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Embodiment Construction

[0017] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0018] The underwater acoustic Doppler flow velocity measurement method based on autocorrelation estimation and effective data screening of the present invention, such as figure 1 shown, including the following steps:

[0019] Step 1: Estimate the complex autocorrelation function R(τ) according to formula 1 through the complex echo of the effective water layer, and estimate the value of the total signal power R(0) according to formula 2;

[0020]

[0021] Among them, {x 1 ,x 2 ,...,x m} is the complex data of m current valid water layers, f s is the echo sampling rate, n means that at the sampling rate f s The number of data points corresponding to the time correlation interval τ, the operator Indicates rounding down.

[0022] Step 2, according to the velocity autocorrelation estimation accuracy criterion...

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Abstract

The invention discloses an acoustic Doppler flow velocity measuring method based on autocorrelation estimation and valid data screening, and relates to the technical field of acoustic Doppler measurement. The method includes steps: estimating a complex autocorrelation function value R(tau), estimating a signal total power R(0), calculating a precision eta(v) of a sonar echo sample, and finally determining whether a current sample is reserved through a threshold. According to the method, samples of measurement data are screened through a relation between an autocorrelation estimation precisioncriterion value and the set threshold, the precision of underwater acoustic flow velocity estimation is improved, and it is indicated through analysis of actual measurement data that the method can obviously reduce the variance of flow velocity estimation and improve the key performance of an acoustic velocity-measuring device.

Description

technical field [0001] The invention relates to the technical field of acoustic Doppler measurement, in particular to an underwater acoustic Doppler flow velocity measurement method based on autocorrelation estimation and effective data screening. Background technique [0002] The velocity of water body and the moving velocity of underwater targets are very important measurement objects in underwater acoustic measurement. Most of the common hydroacoustic velocity measurement methods are based on the Doppler principle, and the flow measurement equipment includes acoustic Doppler velocity profiler and acoustic Doppler velocity profiler. The working process of the usual speed measuring sonar is as follows: First, a modulated short pulse with a carrier frequency of tens of kHz to hundreds of kHz is transmitted to the detection water area, and the sound wave encounters a scattering body in the water to produce sound scattering, and the scattered sound wave with extremely small po...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01P5/24
CPCG01P5/241
Inventor 方世良杨永寿孙兆文
Owner NANJING SHIHAI ACOUSTIC TECH CO LTD
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