CN110244260B - Underwater target high-precision DOA estimation method based on acoustic energy flow vector compensation - Google Patents
Underwater target high-precision DOA estimation method based on acoustic energy flow vector compensation Download PDFInfo
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Abstract
The invention discloses a high-precision DOA estimation method for an underwater target based on acoustic energy flow vector compensation. The method comprises the following steps: firstly, estimating the approximate direction of a target through multi-target DOA estimation; then, calculating the acoustic energy flow component of the anisotropic noise in the target direction; finally, vector subtraction is carried out on the acoustic energy flow in the target direction and the acoustic energy flow component of the noise, so that the target acoustic energy flow after noise interference is suppressed is obtained; and finally, carrying out multi-target DOA estimation again by using the sound energy flow after noise suppression, thereby realizing underwater target high-precision DOA estimation. According to the method, the target acoustic energy flow is reversely compensated by utilizing the sound pressure and particle vibration velocity combined information processing technology according to the anisotropic noise field acoustic energy flow model with the acoustic energy flow as the sum of the acoustic energy flow vectors of all noise sources, and the target acoustic energy flow is combined with the multi-target DOA estimation method of the complex acoustic intensifier, so that the high-precision DOA estimation of the underwater target in the anisotropic noise field is realized by inhibiting the anisotropic noise interference.
Description
Technical Field
The invention belongs to the field of signal processing, and particularly relates to an underwater multi-target DOA estimation method based on a complex sound intensity device by using a single-vector hydrophone.
Background
Orientation estimation is a traditional subject in the field of underwater sound detection, and in recent years, detection and orientation estimation by using a vector hydrophone has become a research hotspot in the field of underwater sound. The sound vector sensor is composed of a traditional nondirectional sound pressure sensor and a dipole directional particle vibration velocity sensor, and can synchronously pick up three orthogonal components of sound pressure P and particle vibration velocity V at one point of a sound field by spatial concurrent. In a remote sound field, the sound pressure and the vibration velocity of a signal source with limited dimension are coherent, and for an isotropic noise field, the sound pressure and the vibration velocity are irrelevant, so that the sound pressure and the particle vibration velocity combined information processing technology using the sound field has strong capability of resisting the isotropic noise. The acoustic vector array coherent signal subspace method and the maximum likelihood DOA estimation method are respectively provided by the Baixingyu and the Sunpuiqing on the aspect of sound pressure and vibration velocity combined processing, the coherence of sound pressure and vibration velocity in an acoustic vector sensor is fully utilized, and a good effect is obtained in an isotropic noise field environment. However, including the above, the existing DOA estimation methods do not consider the influence of the anisotropic noise field on the DOA estimation accuracy. In fact, noise sources generated by factors such as marine dynamic noise and human activities are non-uniformly distributed on a horizontal plane, so that a marine environment noise field presents anisotropy on the horizontal plane, and therefore the average horizontal acoustic energy flow of receiving points in the noise field is not zero, which affects the positioning accuracy of the vector hydrophone.
Disclosure of Invention
In view of the shortcomings of the prior art, the invention aims to provide a high-precision DOA estimation method for an underwater target based on acoustic energy flow vector compensation, which is suitable for a single-vector hydrophone, so as to solve the problem that in the prior art, the DOA estimation generates errors in the underwater target azimuth estimation precision due to noise interference in an anisotropic noise field.
In order to achieve the purpose, the invention provides an underwater target high-precision DOA estimation method based on acoustic energy flow vector compensation, which comprises the following steps:
step 1: and calculating components Ix and Iy of the received acoustic energy flow in the direction of a Cartesian coordinate system X, Y by using sound field information synchronously picked up by the sound pressure P channel, the vibration velocity Vx channel and the vibration velocity Vy channel of the single-vector hydrophone. And calculating to obtain the azimuth angle corresponding to each frequency point according to Ix and Iy.
Step 2: and counting the azimuth angles corresponding to the frequency points by a histogram counting method. Dividing [0 degrees and 360 degrees ] into a plurality of intervals, counting the number of frequency points in each angle interval, and generating a histogram statistical chart, wherein the peak value is the estimated azimuth value.
And step 3: and selecting the azimuth value corresponding to the N peak values with the largest statistical value as the target azimuth angle according to the target estimation number N.
And 4, step 4: calculating the noise energy flow I of each directionn(theta) Acoustic energy flow component I 'in target Direction'n(θ)。
And 5: flow the sound energy of the target direction
And each noise acoustic energy flow component I'nThe average value of (theta) is subjected to vector subtraction operation to obtain a target acoustic energy flow vector I after anisotropic noise suppressions. Suppression of anisotropic noise is achieved.
Step 6: according to IsAnd carrying out multi-target DOA estimation again by using the complex sound intensity device.
The invention has the beneficial effects that: on one hand, the multi-target DOA estimation is based on the single-vector hydrophone, and the sound pressure and particle vibration velocity combined information processing technology has strong isotropic noise resistance and can simultaneously estimate a plurality of target directions; on the other hand, anisotropic noise suppression is performed by using acoustic energy flow vector compensation on the basis of DOA estimation, so that compared with other noise suppression algorithms, the anisotropic noise suppression method has smaller calculation amount and better anisotropic noise suppression effect; finally, the algorithm has no requirements on the bandwidth and the frequency of the received signal, and has good robustness.
Drawings
FIG. 1 is a schematic diagram of a multi-target direction estimation method based on a complex sound intensity machine.
FIG. 2 is a flow chart of an anisotropic noise suppression method in DOA estimation of an underwater target.
Fig. 3 is a beam pattern comparison at SNR of 0 dB.
Fig. 4 is a noise suppression algorithm performance for multiple targets.
Detailed Description
The present invention will be described in further detail below with reference to the accompanying drawings.
The method is based on a multiple acoustic intensity device multi-target Direction of arrival (DOA) estimation method, makes full use of sound field vector information picked up by an acoustic vector sensor, calculates the energy component of target Direction interference noise by using the Direction difference of anisotropic noise energy and the principle that picked-up acoustic energy flow vectors are the sum of acoustic energy flow vectors generated by all noise sources, and further suppresses the anisotropic noise, thereby improving the DOA estimation precision of the target in the anisotropic noise field.
The specific implementation process of the invention is as follows:
data model
The information model picked up by the two-dimensional homodyne vector hydrophone can be represented by the following formula:
wherein x (r, t) is a target sound pressure signal, p (r, t) is a sound pressure signal received by the vector hydrophone, and vx(r, t) is an x-axis vibration velocity signal received by the vector hydrophone, vy(r, t) is a y-axis vibration velocity signal received by the vector hydrophone, an azimuth angle of a theta target in the horizontal direction, and np(r,t)、nvx(r,t)、nvyAnd (r, t) is the sound pressure of the interference noise and the vibration speed in the x and y directions.
Two, initial estimation
According to the sound pressure signal p (r, t) and the vibration number signal v picked up by the vector hydrophonex(r,t)、vy(r, t) calculating the cross-spectrum of the sound pressure and the vibration number, and obtaining the horizontal sound energy flow I in the direction of X, Y by a real partx(f)、Iy(f)
In the formula Re [.]Denotes the real part, f is the frequency, "+" is the conjugate, P (f), Vx(f)、Vy(f) Are respectively divided into p (r, t) and vx(r,t)、vyFourier transform of (r, t), Isx、IsyRespectively the target actual sound energy flow IsComponent in the X and Y directions, Inx、InyRespectively a noise energy flow InThe components in the X and Y directions, K is the number of noise sources.
And calculating to obtain the azimuth angle corresponding to each frequency point according to Ix and Iy. The expression is as follows:
histogram statistics are then performed. If the statistical interval of the azimuth angles is recorded as delta theta degrees, the total interval allowed by the space angles is
The space angle allowable interval obtained by the above formula is: 0 to delta theta, delta theta to 2 delta theta, 2 delta theta to 3 delta theta, … …, (N-1) delta theta to N delta theta, and the number of the estimation directions of each frequency point falling into each statistical angle interval at the moment is assumed to be m1,m2,m3… …, mN, then calculate the following statistic R (θ):
wherein R isr(f) Satisfies the following relation:
the azimuth corresponding to the maximum value of the angle statistic R (theta) of the histogram method reflects the estimated value of the real azimuth of the target. FIG. 1 is a schematic diagram of a multi-target orientation estimation method.
Third, noise suppression method
And estimating the azimuth distribution of each independent noise source by the multi-target DOA estimation algorithm. Because the target radiation noise energy is larger than other interference noise energy under general conditions, the azimuth angle with the largest statistical energy is selected as the target azimuth angle, signals of other azimuths can be all regarded as interference noise, and the component of each azimuth noise acoustic energy flow in the target azimuth is calculated according to the synthetic acoustic energy flow principle, wherein the expression is as follows.
E[·]In order to be expected by the user,
and the rough azimuth angle of the target source, theta is the azimuth estimation angle of the noise source, and K is the number of the noise sources. And carrying out vector subtraction on the target direction acoustic energy flow, namely, restraining the interference noise to obtain the target acoustic energy flow subjected to noise suppression.
The flow chart of the anisotropic noise suppression method is shown in fig. 2.
And fourthly, carrying out DOA estimation again by using the multi-target DOA estimation of the complex sound intensity device.
Fifth, performance analysis
In simulation, three broadband continuous spectrum signals with the center frequencies of 55Hz, 85Hz and 130Hz and the bandwidths of 100Hz are simulated as target signals, the sampling frequency is 1000Hz, the horizontal orientation distribution of the signals is 40 degrees, 90 degrees and 200 degrees, the signals are in a background noise environment formed by superposition of isotropic noise and anisotropic noise, wherein the isotropic noise consists of Gaussian white noise and broadband noise with different directions and different strengths, the horizontal orientation of the anisotropic noise sources is 60 degrees, 140 degrees and 300 degrees, and the noise sources are independent. In order to test the performance of the anisotropic noise suppression algorithm in the DOA estimation of the underwater target, the DOA estimation of a conventional complex sound intensity device and the DOA estimation precision after the algorithm are used for verification.
Fig. 3 is a comparison of a conventional complex tone intensifier DOA estimate to a DOA estimate beampattern based on the algorithm herein, when the SNR is 0 dB. After the noise interference suppression is performed through the vector compensation as shown in fig. 3, the target azimuth angle is compensated to a certain extent, the precision is improved, the statistical peak value in the target direction is greatly enhanced, and the peak is sharp.
Fig. 4 shows the performance of the noise suppression algorithm at multiple targets, which shows that the root mean square error of the multi-target azimuth estimation value based on the anisotropic noise suppression algorithm herein is significantly reduced below SNR 20 dB; the azimuth estimation precision is within 1 degree when the SNR is more than 0 dB; at SNR of 5dB, the azimuth RMSE is significantly reduced compared to the conventional complex acoustic beamformer azimuth estimation.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the scope of the present application shall be subject to the protection scope of the claims.
Claims (5)
1. The underwater target high-precision DOA estimation method based on acoustic energy flow vector compensation is characterized by comprising the following steps of:
step 1, using a single-vector hydrophone to carry out multi-target DOA estimation by utilizing a sound pressure and particle vibration velocity combined information processing technology, and establishing an anisotropic noise source distribution model; the anisotropic noise field acoustic energy flow model is expressed by the following expression:
Isx、Isyrespectively the target actual sound energy flow IsComponent in the X and Y directions, Inx、InyRespectively a noise energy flow InThe components in the X and Y directions, K is the number of noise sources, and f is the frequency;
step 2, estimating the azimuth of a rough target radiation noise source according to the statistical amplitude of the distribution model;
and 3, calculating the acoustic energy flow component of the anisotropic noise acoustic energy flow in the target direction according to the anisotropic noise field acoustic energy flow model, wherein the expression is as follows:
E[·]in order to be expected by the user,
is a rough azimuth angle of a target source, and theta is a noise sourceAn azimuth estimation angle;
and 4, subtracting the acoustic energy flow component of the anisotropic noise acoustic energy flow in the target direction from the acoustic energy flow vector of the target direction, and expressing the following steps:
and 5, using the multi-target DOA estimation of the complex sound intensity device to carry out DOA estimation again.
2. The method for estimating the high-precision DOA of the underwater target based on the acoustic energy flow vector compensation as claimed in claim 1, wherein the used multi-target DOA estimation is a multi-target DOA estimation of a complex acoustic intensity device based on a single-vector hydrophone.
3. The underwater target high-precision DOA estimation method based on acoustic energy flow vector compensation according to claim 1, wherein the estimation of the target radiation noise source rough azimuth is based on the target estimation number N, and N azimuth angles with the highest statistical value in the noise source distribution model are selected as target azimuth angles.
4. The method for estimating the DOA of the underwater target with high precision based on the acoustic energy flow vector compensation as claimed in claim 3, wherein the noise source distribution model is a statistical model obtained by a weighted histogram statistical method based on a complex acoustic intensity device.
5. The underwater target high-precision DOA estimation method based on acoustic energy flow vector compensation as claimed in claim 1, which is characterized in thatCharacterized in that the target actual acoustic energy flow I after noise suppression is utilized to carry out the multi-target DOA estimation by reusing the complex sound intensitysx，IsyAnd (6) performing calculation.
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| CN111596262B (en) * | 2020-05-07 | 2023-03-10 | 武汉敏声新技术有限公司 | Vector hydrophone and multi-target direction estimation method based on vector hydrophone |
| CN115079088A (en) * | 2022-06-10 | 2022-09-20 | 杭州电子科技大学 | Target DOA estimation method based on frequency domain acoustic energy flow instantaneous phase difference weighting |
| CN117350079A (en) * | 2023-11-30 | 2024-01-05 | 汉江国家实验室 | Method and system for calculating horizontal deflection angle of vector acoustic energy flow in submarine mountain environment |
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