CN110703203A - Underwater Pulse Acoustic Localization System Based on Multi-Acoustic Wave Glider - Google Patents

Abstract

An underwater pulse acoustic positioning system based on a multi-acoustic wave glider relates to the technical field of underwater positioning. In order to solve the problem that the buoy method and the long baseline positioning of the surface ship in the prior art are difficult to maintain a good formation for a long time, thus reducing the positioning accuracy, And the problem of high cost, the present invention provides an underwater pulse sound localization system based on the multi-acoustic wave glider by using the acoustic wave glider. The invention can not only obtain the position information of the base station in real time through the satellite, but also can maintain a good formation through the position control, so as to realize the high-precision positioning, and the wave glider can obtain the energy required for the long-term operation of each node through the solar panel, and the cost is relatively low. lower.

Description

Underwater Pulse Acoustic Localization System Based on Multi-Acoustic Wave Glider

technical field

The invention relates to the technical field of underwater positioning, in particular to an underwater pulse sound positioning system based on a multi-acoustic wave glider.

Background technique

Among the existing underwater pulse acoustic positioning systems, the long-baseline positioning system has the highest accuracy.

For the long-baseline positioning based on the submerged beacon method, the transponder and the beacon are anchored on the seabed, and the positions of each site are determined in advance. The advantage is that the location of the base station is fixed, and the formation can be maintained in an optimal state with high positioning accuracy. The problem is that the deployment is difficult and the calibration is time-consuming, especially in the deep sea.

For the buoy method and the long-baseline positioning of the surface ship, the position of the base station can be accurately measured in real time by satellite. Calculate. The disadvantage is that the position of the buoy changes with the current and waves, and it is difficult to maintain a good formation for a long time, which reduces the positioning accuracy; while for surface ships, although the formation of the long baseline base station can be controlled, multiple surface ships work at the same time, and the cost is high. , especially the tonnage requirements of the ship under the conditions of the open sea are large. Therefore, the positioning capability of the surface base station and the cost of the positioning system are mutually restricted, which affects the long-baseline positioning accuracy.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a multi-acoustic wave glider based on the problems that the buoy method and the long baseline positioning of the surface ship in the prior art are difficult to maintain a good formation for a long time, thereby reducing the positioning accuracy and high cost. underwater pulse acoustic positioning system.

The technical scheme adopted by the present invention in order to solve the above technical problems is: an underwater pulse sound positioning system based on a multi-acoustic wave glider, including: a shore station processing center and an AWG node,

The shore station processing center is used to store and solve the target position of the data transmitted by the AWG node, and display the processing results,

The AWG node is used to receive and process the target acoustic signal in the water. After signal detection and direction finding, the GPS location information and time of each AWG node are obtained through GPS, and the data is transmitted to the shore station processing center.

The signal detection adopts energy detection, and the detailed steps of the signal detection are as follows: first, it is assumed that the received signal of any hydrophone of the AWG is S(t), the duration of the execution is T, and the overlapping score, get

Compare E(n) with the set noise threshold C. If E(n)>C, it is considered that there is a pulse signal in this time period, otherwise there is no pulse signal.

Further, the shore station processing center includes a shore station data communication module, a shore station GPS positioning and timing module, a shore station data storage module, a shore station data calculation module and a display and control platform,

The shore station data communication module is used to transmit the target acoustic signal, GPS information and time data received by the AWG node between the AWG node and the shore station processing center;

The shore station GPS positioning and timing module is used to receive GPS signals, and obtain the location information of the AWG node and the time information corresponding to the location information;

The shore station data storage module is used to store the data transmitted by the AWG node and the calculated data;

The display and control platform is used to display the relevant information obtained after the data is processed and solved;

The AWG node includes a node data communication module, a node GPS positioning timing module, a node control module, a node data processing module, a power supply module, an autonomous positioning module and a hydrophone array module;

The node data communication module is used to transmit the target acoustic signal, GPS information, time and other data received by the AWG node between the shore station processing center and the AWG node;

The node GPS positioning and timing module is used to obtain the real-time GPS position information and time of each node of the AWG;

The node control module includes a hull control unit and a data control unit, the hull control unit is used to control the navigation of the AWG, and the data control unit is used to control the transmission of data;

The node data processing module is used for signal detection and outlier elimination processing on the data received by the AWG node;

The power module is used to supply power to each module of the AWG node;

The autonomous positioning module is used to process the detected target signal, and then perform positioning and calculation to obtain the required target position information;

The hydrophone array module is used for receiving acoustic signals in water.

Further, the outlier removal processing includes single node data outlier rejection and multi-node data outlier rejection.

Further, the single-node data outliers are eliminated by estimating whether the azimuth is consistent with the enclosing area. The specific steps are to first perform molecular band azimuth estimation on the target signal, and perform histogram statistics on the azimuth estimation result to obtain the space of the target signal. spectrum, estimate the azimuth of the target and the amplitude-frequency characteristics corresponding to the azimuth, and then obtain the azimuth range of the target relative to each AWG in the enclosed area of multiple AWGs according to the AWG formation. When the azimuth of the estimated target is not within the cross-spectrum range, it is considered as a wild point , to be removed.

Further, the specific steps of the single-node data wild point elimination are: first, the orientation of the pulse signal relative to the i-th AWG is θ(t) _i , if there is a large difference between the orientation of a certain time and the orientation of its adjacent time points. , and does not conform to the change trend of the overall orientation over time, the point is regarded as a wild point, the signal detected at this moment is not the target pulse signal, and the signal detected at this moment is excluded.

Further, the specific steps of removing the multi-node data outliers are as follows: firstly, the correlation coefficient between the characteristic spectrums of the target signal corresponding to each node is obtained. When the correlation coefficient value is less than 0.3, it is considered that the detected outliers are.

Further, the autonomous positioning module adopts hyperbolic intersection positioning, and its specific steps are: first, number m AWGs respectively, and obtain the hydrophone connected to the AWG according to the GPS loaded on the AWG and the depth gauge loaded on the hydrophone array. The positions of the hydrophones are respectively (x ₁ , y ₁ , z ₁ ), (x ₂ , y ₂ , z ₂ )…(x _m , y _m , z _m ), one of the sound pressure hydrophones of m AWGs The received signals are

S ₁₁ (t), S ₂₁ (t)…S _m1 (t), according to the cross-correlation formula

Cross-correlate the received signals of No. 2 to m AWGs with the received signals of No. 1 AWG, respectively, to obtain the time delay difference τ _1j of the received signals between the AWG nodes, j=2, 3...m, j represents the received signal of No. 1 AWG As the relevant node number, τ _1j is the time delay difference between the received signal of AWG No. 1 and the received signal of No. j AWG, and the hyperbolic positioning model is established

where, r _1j =cτ _1j (4)

c is the speed of sound, r _1j is the difference between the distance between the No. 1 AWG node and the target sound source and the distance between the j No. AWG node and the target sound source,

Expand the above equation at position (x ₁ , y ₁ , z ₁ ), we can get:

τ′₁₂和τ′_1m是根据几何关系得到的理论上声源到各基站的时延差，由In the formula, ε ₁ and ε _m-1 are high-order small quantities and can be ignored;

τ′ ₁₂ and τ′ _1m are the theoretical delay difference from the sound source to each base station obtained according to the geometric relationship, which is given by

Obtained, where the sound source position (x, y, z) is the value after each iteration, which is a known quantity,

The initial value of the sound source position (x, y, z) is set to the coordinates (x ₁ , y ₁ , z ₁ ) of the matrix 1, and the initial value of the sound source position is brought into the theoretical delay difference calculation formula to obtain the sound source. The theoretical delay difference τ′ ₁₂ and τ′ _1m at the source location, the difference between the actual measured delay difference τ ₁₂ and τ _1m and the theoretical delay difference, and the difference Δτ ₁₂ and Δτ _1m are brought into the error equation to obtain Sound source position error Δx, Δy and Δz, add the error to the sound source position (x, y, z) to obtain a new sound source position, continue to perform error calculation, and continuously correct the sound source position until the obtained position error Less than C _x meters, the sound source position at this time is the final target sound source position coordinates.

Further, the power module adopts a solar panel.

The beneficial effects of the present invention are as follows: the present invention provides an underwater pulse sound localization system based on the multi-acoustic wave glider by using the acoustic wave glider. The invention can not only obtain the position information of the base station in real time through the satellite, but also can maintain a good formation through the position control, so as to realize the high-precision positioning, and the wave glider can obtain the energy required for the long-term operation of each node through the solar panel, and the cost is relatively low. lower.

Description of drawings

Figure 1 shows the geometric configuration of the underwater pulse acoustic localization system of the multi-acoustic wave glider

Fig. 2 is the system composition of the present invention.

Figure 3 is a single node configuration diagram.

Figure 4 is a flow chart of the positioning algorithm.

Figure 5 shows the four-element cross formation.

FIG. 6 is a flowchart of quaternary cross array orientation estimation.

Figure 7 shows the circular formation.

FIG. 8 is a flow chart of circular array orientation estimation.

Figure 9 shows the geometric relationship of the vibration velocity vector of the vector hydrophone.

Figure 10 is a flow chart of vector hydrophone orientation estimation.

Detailed ways

Embodiment 1: This embodiment is described in detail with reference to FIG. 1 to FIG. 4. The underwater pulse sound localization system based on a multi-acoustic wave glider described in this embodiment includes: a shore station processing center and a plurality of AWG nodes,

The shore station processing center is used to store and solve the target position of the data transmitted by the AWG node, and display the processing results,

The AWG node is used to receive and process the target acoustic signal in the water. After signal detection and direction finding, the GPS location information and time of each AWG node are obtained through GPS, and the data is transmitted to the shore station processing center.

The positioning system of the present invention includes a shore station processing center and a plurality of AWG nodes. The function of the shore station processing center is to store and solve the target position of the data transmitted by the AWG node, and display the processing results. The function of the AWG node is to receive and process the target acoustic signal in the water. After signal detection and direction finding, the GPS location information and time of each node of the AWG are obtained through GPS, and the data is transmitted to the shore station processing center.

的积分，得到The signal detection adopts energy detection, and the detailed steps of the signal detection are as follows: first, it is assumed that the received signal of any hydrophone of the AWG is S(t), the duration of the execution is T, and the overlapping

score, get

Compare E(n) with the set noise threshold C. If E(n)>C, it is considered that there is a pulse signal in this time period, otherwise there is no pulse signal.

As shown in Figure 2, the shore station processing center includes a data communication module, a GPS positioning and timing module, a data storage module, a data calculation module and a display and control platform.

The data communication module of the shore station processing center is used to transmit the target acoustic signal, GPS information and time data received by the AWG node between the AWG node and the shore station processing center;

The GPS positioning and timing module of the shore station processing center receives the GPS signal, and obtains the position information of the AWG node and the time information corresponding to the position information;

The data storage module of the shore station processing center is used to store the data transmitted by the AWG node and the data after the solution;

The display and control platform of the shore station processing center is used to display the relevant information obtained after the data is processed and calculated.

The AWG node includes a data communication module, a GPS positioning timing module, a control module, a data processing module, a power supply module, an autonomous positioning module and a hydrophone array module.

The data communication module of the AWG node is used to transmit the target acoustic signal, GPS information and time data received by the AWG node between the shore station processing center and the AWG node;

The GPS positioning timing module of the described AWG node is used to obtain the real-time GPS position information and time of each node of the AWG;

The control module of the AWG node refers to two aspects of hull control and data control;

The hull control of the AWG node is used to control the navigation of the AWG; data control is used to control the transmission of data;

The data processing module of the AWG node is used to perform signal detection, outlier elimination and other processing on the data received by the AWG node;

The solar panel/power module of the AWG node is used to convert solar energy into electrical energy to supply power to each module of the AWG node;

The autonomous positioning module of the AWG node is used to process the detected target signal, and obtain the required target position information through the positioning solution;

In Fig. 1, reference numerals 1 and 1 acoustic wave glider AWG1; 2, 2 acoustic wave glider AWG2; 3, 3 acoustic wave glider AWG3; 4, 4 acoustic wave glider AWG4; 5, pulse sound source; 6, Seabed; 7. Shore station processing center.

In Figure 3, 1. GPS/radio antenna; 2. Solar panel/power module; 3. Surface pontoon; 4. High-frequency beacon; 5. Umbilical cable; 6. Towing rope; 7. Load-bearing cable; 8. Electronic cabin; 9, hydrophone, pressure sensor.

The working process of the underwater pulse acoustic localization system based on the multi-acoustic wave glider of the present invention is shown in Figure 4:

(1) Obtain the marine environmental parameters of the test sea area;

Obtain historical data of sea depth through charts or other methods or use multi-beam sonar for on-site measurement to obtain the sea depth of the test sea area to ensure that the seabed is relatively flat;

Use historical data or sound speed profile information measured with a sound speed profiler to ensure that the sonar transducer works to avoid the thermocline.

(2) Deploy AWG;

Determine the number of AWGs and design the optimal formation according to the sea depth, sound velocity profile and the positioning area required by the mission; the number of AWGs is greater than 2.

Power on the system with multiple AWGs, and use the GPS second pulse signal to synchronize the time of each AWG;

The AWG is deployed from the ship, and the command is sent by satellite to make the AWG sail to the designated position.

(3) Detecting the pulse signal;

Use the energy detection method to detect the pulse signal:

Segment the received signal according to a certain window length and calculate its signal energy. If the value exceeds the set detection threshold, it is considered that a pulse signal has been detected;

(4) Single node data outlier elimination

Calculate the azimuth of the pulse signal detected in the geodetic coordinate system, and judge whether the azimuth is located in the enclosed area of the AWG. If not, the result is considered to be a wild point and can be eliminated.

(5) Calculation of the position of the AWG underwater array

The two beacons transmit signals at a certain period. After receiving the signals, the underwater acoustic array performs band-pass filtering and correlates with the reference signal respectively. The time delay difference of the signals is calculated, and the horizontal distance of the underwater acoustic array relative to the GPS is obtained. ; At the same time, the underwater acoustic array performs direction finding on the beacon signal to obtain the azimuth of the beacon relative to the acoustic array;

Combine the horizontal distance and the position of the beacon relative to the acoustic array to obtain the relative position of the acoustic array; add the GPS position to obtain the absolute position of the acoustic array.

(6) Return the data signal and position to the processing center;

Through radio backhaul/satellite/drone relay, after the transient acoustic signal is detected, the short segment of the transient acoustic signal will be sent back to the processing center of the shore base station. The content of the returned data includes AWGID, signal detection time, AWG latitude and longitude coordinates, pulse data, target azimuth and corresponding spectrum;

(7) Multi-node data outlier elimination;

Calculate the correlation coefficient between the characteristic spectrums of the target signal received by each node. When the correlation coefficient is less than a certain value, the detected result is considered to be a wild point and is eliminated.

(8) Target hyperbolic positioning solution;

The detected pulse signal is correlated to estimate the time delay difference of the received signal between the base stations, and the position of the target is solved by the hyperbolic positioning method.

The specific embodiments of the present invention are given below in conjunction with the accompanying drawings of the positioning algorithm flow chart: (Note: Here, according to the difference in the form of the hydrophone array of each AWG node of each AWG, which leads to different signal processing methods, a total of four Element cross array, circular array, vector azimuth estimation and monophonic pressure hydrophone 4 ways.)

Example 1:

(1) Obtaining environmental parameters:

Use an echo sounder or side sweep to get the depth of the operating area to ensure that the seabed is as flat as possible. Use the sound speed profiler to measure the sound speed profile information in the operating sea area to ensure that the hydrophone on the AWG avoids the clamshell work.

(2) AWG deployment:

The four AWGs are arranged in corresponding positions according to a certain geometric formation, and the formation can be the four vertices of a square with a side length of 2 kilometers. Each AWG is connected to a hydrophone array. The hydrophone array is located at a depth of approximately 20 meters above the water surface.

(3) Pulse signal detection

的积分，得到Pulse signal detection is performed on the signals received by each AWG hydrophone respectively. The detection method adopts energy detection. Assuming that the signal received by any AWG hydrophone is S(t), the duration of the process is T, and the overlapping

score, get

Compare E(n) with the set noise threshold C. If E(n)>C, it is considered that there is a pulse signal in this time period, otherwise there is no pulse signal. Here, T is generally required to be greater than 2 times the desired pulse width.

(4) Single node data wild point elimination

There are mainly two standards

Criterion 1: Eliminate based on whether the estimated azimuth matches the enclosing area or not.

The molecular band orientation is estimated for the target signal, and the histogram statistics are performed on the orientation estimation result to obtain the spatial spectrum of the target signal, the estimated target orientation and the amplitude-frequency characteristics corresponding to the orientation.

According to the AWG formation, the azimuth range of the target in the enclosed area of the four AWGs relative to each AWG is calculated. When the estimated azimuth of the target is not within the cross-spectrum range, it is considered as a wild point and is eliminated.

Standard two:

The azimuth of the pulse signal relative to the i-th AWG is θ(t) _i , if there is a large difference between the azimuth of a certain time and the azimuth of its adjacent time points, and it does not conform to the trend of the overall azimuth change with time, the point As a wild point, the signal detected at this moment is not the target pulse signal, and the signal detected at this moment is rejected.

(5) Data return

Through radio/satellite/UAV relay backhaul, the backhaul data includes the azimuth spectrum corresponding to the target, the amplitude spectrum corresponding to the target, the ID of the AWG, the timestamp, the location, and the received target signal.

(6) Multi-node data wild point elimination

In order to achieve the purpose of the present invention, the correlation of the characteristic spectrum of the target signal received by each node is used for further wild point elimination.

The specific method is: find out the correlation coefficient between each node corresponding to the characteristic spectrum of the target signal, when the value of the correlation coefficient is less than 0.3, it is considered that the detected point is a wild point.

(7) Hyperbolic intersection positioning

The four AWGs are numbered No. 1, No. 2, No. 3 and No. 4 respectively. According to the GPS loaded on the AWG and the depth gauge loaded on the hydrophone array, the positions of the hydrophones connected to the four AWGs are (x ₁ , y ₁ , z ₁ ), (x ₂ , y ₂ , z ₂ ), (x ₃ , y ₃ , z ₃ ), (x ₄ , y ₄ , z ₄ ).

The signals received by one of the sound pressure hydrophones of the four AWGs numbered 1, 2, 3, and 4 are S ₁₁ (t), S ₂₁ (t), S ₃₁ (t), and S ₄₁ (t), respectively. According to the cross-correlation formula

Cross-correlate the received signals of No. 2, 3, and 4 AWGs with the received signals of No. 1 AWG, respectively, to obtain the time delay difference τ _1j of the received signals between the AWG nodes, j=2, 3, 4, j represents and No. 1 AWG The received signal is the associated node number, and τ _1j is the time delay difference between the received signal of AWG No. 1 and the received signal of No. j AWG.

Build a hyperbolic positioning model

where, r _1j =cτ _1j (4)

c is the speed of sound, and r _1j is the difference between the distance from the No. 1 AWG node to the target sound source and the distance from the j No. AWG node to the target sound source.

Expand the above equation at position (x ₁ , y ₁ , z ₁ ), we can get:

τ′₁₃和τ′₁₄是根据几何关系得到的理论上声源到各基站的时延差，由In the formula, ε ₁ , ε ₂ and ε ₃ are high-order small quantities, which can be ignored;

τ′ ₁₃ and τ′ ₁₄ are the theoretical delay difference from the sound source to each base station obtained according to the geometric relationship, which is represented by

obtained, where the sound source position (x, y, z) is the value after each iteration, which is a known quantity.

The initial value of the sound source position (x, y, z) is set to the coordinates (x ₁ , y ₁ , z ₁ ) of the matrix 1, and the initial value of the sound source position is brought into the theoretical delay difference calculation formula to obtain the sound source. Theoretical delay differences τ′ ₁₂ , τ′ ₁₃ and τ′ ₁₄ at the source location, the actual measured delay differences τ ₁₂ , τ ₁₃ and τ ₁₄ are compared with the theoretical delay differences, and the difference values Δτ ₁₂ , Δτ ₁₃ and Δτ ₁₄ are brought into the error equation to obtain the sound source position error Δx, Δy and Δz, add the error to the sound source position (x, y, z) to obtain a new sound source position, continue the error calculation, and constantly correct The sound source position, until the obtained position error is less than C _x meters, the sound source position at this time is the final target sound source position coordinates.

Embodiment 2: As shown in Figure 5 and Figure 6, the azimuth estimation of the quaternary cross array is implemented as follows:

The quaternary cross array is composed of four hydrophones in the same plane. In this plane, the left-hand rectangular coordinate system is defined with the center of the quaternary cross array as the origin. The positions of the four array elements are: array element 1 (a, 0), array element 2(0,a), array element 3(-a,0), array element 4(0,-a), 2a is the distance of the diagonal array element. A compass is installed directly under the four-element cross array. The north direction of the compass points to array element 1 from the center. The compass is rigidly connected to the four-element cross array.

The signals received by the four hydrophones are s ₁ (t), s ₂ (t), s ₃ (t) and s ₄ (t), respectively, and the signals are sampled to obtain s ₁ (n), s ₂ (n), s ₃ (n), s ₄ (n), after windowing respectively, are

x ₁ (n)=s ₁ (n)w(n) (7)

x ₂ (n)=s ₂ (n)w(n) (8)

x ₃ (n)=s ₃ (n)w(n) (9)

x ₄ (n)=s ₄ (n)w(n) (10)

Find the discrete Fourier transform:

Find the cross-spectrum in the analysis band:

where H represents complex conjugation.

The cross-spectrum is corrected in combination with the compass measurements.

Obtained by integrating P' ₁₃ and P' ₂₄ over the integration time

Find the bearing of the signal at each frequency

进行直方图统计，将相同方位的功率相加。right

Do histogram statistics and add the power of the same azimuth.

S(θ)=∑P ₁₁ (k) (22)

That is, the spatial spectrum characteristics of the target signal are obtained. Assuming that the maximum value is the target, the target azimuth θ is

Embodiment 3: As shown in Figure 7 and Figure 8, the circular array orientation is estimated as follows:

Use a uniform circular array with M elements to estimate the orientation, assuming that the array manifold is (d _x , _dy )

圆阵1的接收到M个阵元的信号表示为[x₁(n) x₂(n) x₃(n) … x_M(n)]。d _x =RcosmΔθ,d _y =RsinmΔθ,

The received signal of M array elements of circular array 1 is expressed as [x ₁ (n) x ₂ (n) x ₃ (n)  … x _M (n)].

First, the Fourier transform is performed on the signals of each channel to obtain

[X ₁ (k) X ₂ (k) X ₃ (k) … X _M (k)]

其中，

为第i个子带的上限频率，为第i个子带的下限频率，分子带滤波后得到Perform sub-band filtering on the Fourier-transformed signals of each array element respectively, the center frequency of the i-th sub-band is k _i , and the filter passband of this sub-band is

in,

is the upper limit frequency of the ith subband, is the lower limit frequency of the ith subband, obtained after molecular band filtering

为阵元1的各子带滤波结果，k_i代表第i个子带的中心频率。in,

is the filtering result of each subband of array element 1, _ki represents the center frequency of the ith subband.

Calculate each subband signal of array element 1 The power P(k _i ) of ,

For the M-element array filtering results of each subband, beamforming is performed once.

Taking the ith subband as an example, the center frequency of the subband signal is _ki at this time, and the phase difference is compensated for the filtered signal of each array element.

Let the center of the circular array be the reference point, and the phase difference of the array element m relative to the center of the array is

where τ _n is the time delay of the signal received by the array element m relative to the center of the array,

m＝0，1…M-1，c为声速。where θ is the signal direction,

m=0, 1...M-1, c is the speed of sound.

The signal direction θ is searched from 0 to 359°, and obtained after phase compensation

After compensating the phase difference of the signals of each array element, the summation obtains the output signal S(k _i , θ) of the array,

in,

Find the output signal power of the array

P=|S( _ki , θ)| ² (30)

The energy P(θ) of each beam is obtained, and the azimuth θ corresponding to the maximum energy is the subband, that is, the azimuth of the signal with frequency _ki .

After beamforming is performed once for each frequency point _ki to obtain the azimuth, the corresponding azimuth θ( _ki ) of each frequency point is obtained.

According to the azimuth θ(k _i ) of each frequency point, perform histogram statistics on the self-spectrum P(k _i ) of each frequency point, that is, accumulate the self-spectrum energy of the frequency points on the same azimuth to obtain

P(α)=∑P(k _i ) (31)

Here P(k _i ) satisfies α-Δα<θ(k _i )<α+Δα, Δα is the angular interval, P _α ( _ki ) represents the self-spectral energy corresponding to the frequency point in the α direction, and P(α) is α The energy sum in the direction. In the histogram statistical result P(α), the direction with the largest energy is the direction of the estimated target signal.

Embodiment 4: As shown in Figure 9 and Figure 10, the azimuth estimation of the vector hydrophone is implemented as follows:

A vector hydrophone is used to collect the acoustic signal radiated by the target to be measured at the same point. The acoustic signal includes one sound pressure signal p(n) and two vibration velocity signals v _x (n) and v _y (n), 0<n<Q, Q is the number of samples of each signal, and the directions of the two vibration velocity signals are located on the same horizontal plane and are perpendicular to each other; the v _x (n) direction is facing the true north, and the v _y (n) direction is facing Due East.

和

First, perform linear phase band-pass filtering on the signal, so that the signal is the working frequency band, the band-pass filter frequency band is [f _L , f _H ], the order is N, and after filtering, the

and

Perform N-point Fourier transform on the signal respectively to obtain P(k), V _x (k), V _y (k) to calculate the cross-spectrum and auto-spectrum, and get

P(k)=P(k) ^PH (k) (34)

Take the real part and find the arctangent to get the azimuth θ(k) of different frequency points,

Wherein, the value range of k is k ₁ <k<k ₂ , and

Among them, f _s is the signal sampling frequency, and f _L and f _H are the lower limit frequency and the upper limit frequency of the working frequency band, respectively.

According to the azimuth θ(k) of each frequency point, the histogram statistics of the self-spectrum P(k) of each frequency point are carried out, that is, the self-spectrum energy of all frequency points in the same azimuth is accumulated to obtain

P(α)=∑P(k) (38)

Here P(k) satisfies α-Δα<θ(k)<α+Δα, Δα is the angular interval, P _α (k) represents the self-spectral energy corresponding to all frequency points in the α direction, and P(α) is the α direction energy and. In the histogram statistical result P(α), the direction with the largest energy is the direction of the estimated target signal.

Embodiment 5:

If the hydrophone of each AWG node is a single hydrophone, the wild point culling in steps 4 and 6 is not required.

It should be noted that the hydrophone array module of the AWG node is used for receiving acoustic signals in water. It should be noted that the specific embodiment is only an explanation and description of the technical solution of the present invention, and the protection scope of the right cannot be limited by this. Any changes made according to the claims and description of the present invention are only partial changes, which should still fall within the protection scope of the present invention.

Claims (8)

1. Pulse sound positioning system under water based on many acoustics wave glider, its characterized in that includes: a shore station processing center and an AWG node,

the shore station processing center is used for storing the data transmitted by the AWG node, resolving the target position and displaying the processing result,

the AWG node is used for receiving and processing target acoustic signals in water, acquiring GPS position information and time of each AWG node through a GPS after signal detection and direction finding, transmitting data to a shore station processing center,

the signal detection adopts energy detection, and the detailed steps of the signal detection are as follows: firstly, suppose that any hydrophone receiving signal of AWG is S (T), the time length is T, and the signals are overlapped

Is integrated to obtain

And E (n) is compared with a set noise threshold C, if E (n) is greater than C, a pulse signal exists in the time period, otherwise, no pulse signal exists.

2. The multi-acoustic wave glider-based underwater impulsive sound positioning system of claim 1, wherein: the shore station processing center comprises a shore station data communication module, a shore station GPS positioning and time service module, a shore station data storage module, a shore station data resolving module and a display control platform,

the shore station data communication module is used for transmitting target acoustic signals, GPS information and time data which are received by the AWG node between the AWG node and the shore station processing center;

the shore station GPS positioning and timing module is used for receiving GPS signals and acquiring position information of the AWG node and time information corresponding to the position information;

the shore station data storage module is used for storing the data transmitted by the AWG node and the resolved data;

the display control platform is used for displaying relevant information obtained after data is processed and resolved;

the AWG node comprises a node data communication module, a node GPS positioning time service module, a node control module, a node data processing module, a power supply module, an autonomous positioning module and a hydrophone array module;

the node data communication module is used for transmitting data such as target acoustic signals, GPS information, time and the like received by the AWG node between the shore station processing center and the AWG node;

the node GPS positioning time service module is used for acquiring real-time GPS position information and time of each node of the AWG;

the node control module comprises a ship body control unit and a data control unit, wherein the ship body control unit is used for controlling navigation of the AWG, and the data control unit is used for controlling data transmission;

the node data processing module is used for carrying out signal detection on the data received by the AWG node and eliminating wild values;

the power supply module is used for supplying power to each module of the AWG node;

the autonomous positioning module is used for processing the detected target signal and then performing positioning calculation to obtain the required target position information;

the hydrophone array module is used for receiving acoustic signals in water.

3. The multi-acoustic wave glider-based underwater pulsed acoustic positioning system of claim 2, wherein: the wild value elimination processing comprises single-node data wild point elimination and multi-node data wild point elimination.

4. The multi-acoustic wave glider-based underwater pulsed acoustic positioning system of claim 3, wherein: the method comprises the specific steps of firstly carrying out molecular band orientation estimation on a target signal, carrying out histogram statistics on an orientation estimation result to obtain a space spectrum of the target signal, an estimated target orientation and amplitude-frequency characteristics corresponding to the orientation, then obtaining the orientation range of targets in a plurality of AWG enclosure regions relative to each AWG according to an AWG array type, and when the orientation of the estimated target is not in a cross-spectrum range, considering the target as a wild point and removing the wild point.

5. The multi-acoustic wave glider-based underwater pulsed acoustic positioning system of claim 3, wherein: the method comprises the following specific steps of: firstly, the orientation of the pulse signal relative to the ith AWG is theta (t)_iIf the difference between the azimuth of a certain time and the azimuth of the adjacent time point is large and the overall azimuth change trend along with the time is not met, the point is regarded as a wild point, the signal detected at the moment is not the target pulse signal, and the signal detected at the moment is rejected.

6. The multi-acoustic wave glider-based underwater pulsed acoustic positioning system of claim 3, wherein: the specific steps of the multi-node data field point elimination are as follows: firstly, the correlation coefficient between the characteristic frequency spectrums of the target signals corresponding to the nodes is calculated, and when the correlation coefficient value is less than 0.3, the detected nodes are considered to be wild points.

7. The multi-acoustic wave glider-based underwater pulsed acoustic positioning system of claim 2, wherein: the autonomous positioning module adopts hyperbolic curve intersection positioning, and the specific steps are as follows: numbering m AWGs respectively, and obtaining the positions of hydrophones connected with the AWGs according to a GPS loaded on the AWGs and a depth meter loaded on a hydrophone array, wherein the positions of the hydrophones are (x)₁，y₁，z₁)、(x₂，y₂，z₂)…(x_m，y_m，z_m) The signals received by one path of sound pressure hydrophone of the m AWG are respectively

S₁₁(t)、S₂₁(t)...S_m1(t) according to the cross-correlation formula

Respectively cross-correlating 2-m AWG receiving signals with 1 AWG receiving signals to obtain the time delay difference tau of the receiving signals among the AWG nodes_1jJ-2, 3.. m, j represents a node number associated with AWG1 received signal, τ_1jEstablishing a hyperbolic positioning model for the time delay difference between the No. 1 AWG receiving signal and the No. j AWG receiving signal

Wherein r is_1j＝cτ_1j(4)

c is the speed of sound, r_1jThe difference value between the distance from the No. 1 AWG node to the target sound source and the distance from the No. j AWG node to the target sound source,

the above formula is positioned at the position (x)₁，y₁，z₁) And (3) expanding to obtain:

in the formula, epsilon₁And ε_m-1Is a high order small quantity, which can be ignored;

τ′₁₂and τ'_1mThe time delay difference from the sound source to each base station is obtained theoretically according to the geometric relation

The position (x, y, z) of the sound source is obtained, where the position (x, y, z) of the sound source is a value after each iteration, is a known quantity,

the initial value of the sound source position (x, y, z) is set as the coordinate (x) of the matrix 1₁，y₁，z₁) Substituting the initial value of the sound source position into a theoretical time delay difference calculation formula to obtain the theoretical time delay difference tau 'at the sound source position'₁₂And τ'_1mThe actually measured time delay difference tau₁₂And τ_1mIs different from theoretical time delay difference by delta tau₁₂And Δ τ_1mIntroducing an error equation to obtain sound source position errors delta x, delta y and delta z, adding the errors to the sound source position (x, y, z) to obtain a new sound source position, continuously calculating the errors, and continuously correcting the sound source position until the obtained position error is less than C_xAnd (3) the sound source position at the moment is the finally obtained target sound source position coordinate.

8. The multi-acoustic wave glider-based underwater pulsed acoustic positioning system of claim 2, wherein: the power module adopts a solar cell panel.

Images