CN112924933B - An Omnidirectional Split Beam Measurement Method for a Cylindrical Array Transducer Array - Google Patents

Abstract

The invention belongs to the technical field of ocean information measurement, and particularly relates to an omnibearing split beam measurement method of a cylindrical surface array transducer array, which comprises the following steps: dividing a certain part of array elements in a P multiplied by Q array element in a cylindrical surface array transducer array into 4 continuous areas which are connected end to form a logic quadrant I, a logic quadrant II, a logic quadrant III and a logic quadrant IV, sequentially and circularly rotating the four logic quadrants, and obtaining four independent equivalent wave beams by adopting a wave beam forming method for all the array elements in each logic quadrant to obtain virtual split wave beams; the array elements receive the sound wave signals, determine a vertical offset angle phi of the target to be detected through the phase difference between the upper half wave beam of the virtual split wave beam and the lower half wave beam of the virtual split wave beam, determine a horizontal offset angle theta of the target to be detected through the phase difference between the left half wave beam of the virtual split wave beam and the right half wave beam of the virtual split wave beam, and determine the position of the target to be detected in the virtual split wave beam.

Description

An Omnidirectional Split Beam Measurement Method for Cylindrical Array Transducer Arrays

technical field

The invention belongs to the technical fields of marine information measurement and acoustic measurement, and in particular relates to a method for measuring omnidirectional split beams of a cylindrical surface array transducer array.

Background technique

Acoustic measurement technology is widely used in the assessment of marine biological resources. The split beam mode can realize the detection and measurement of target strength of marine biological targets, as well as the accurate position of marine biological target monomers in the beam. It is often used in marine marine Survey and assessment of biological/fishery resources.

Existing split-beam devices are often used in walk-through surveys to obtain the amount of biological resources in the survey area. Due to the small beam coverage angle and the limitation of sampling volume, it does not have all-round monitoring capabilities, and its application in fixed monitoring of marine biological resources is severely limited. The need for long-term, real-time online monitoring of fishery resources. With the increasing demand for monitoring biological resources in oceans, rivers and lakes, online monitoring and evaluation of marine biological resources has become a necessary means. It is necessary to obtain long-term changes in the amount and density of resources in the monitoring area to study the temporal and spatial evolution of important organisms. Single-split beam systems are not up to the task.

Contents of the invention

In order to solve the above-mentioned defects existing in the prior art, the present invention proposes an omni-directional split-beam measurement device for a cylindrical array transducer array, the method comprising:

Divide a certain part of the P×Q array elements in the cylindrical surface array transducer array into 4 continuous areas connected end to end to form I logical quadrant, II logical quadrant, III logical quadrant and IV logical quadrant. The four logical quadrants are sequentially rotated in order, and for all array elements in each logical quadrant, the beamforming method is used to obtain independent beams, and then four independent equivalent beams are formed to obtain virtual split beams;

Logical quadrant I and quadrant II form the upper half beam of the virtual split beam, logical quadrant II and logical quadrant III form the left half beam of the virtual split beam, logical quadrant III and logical quadrant IV form the lower half beam of the virtual split beam, 1V logic Quadrant and I logical quadrant constitute the right half of the virtual split beam;

The array element receives the acoustic wave signal through the phase difference between the upper half of the virtual split beam and the lower half of the virtual split beam to determine the vertical offset angle φ of the target to be measured, and then passes the left half of the virtual split beam and the virtual split beam. The phase difference of the right half beam determines the horizontal offset angle θ of the target to be measured, and then determines the position of the target to be measured in the virtual split beam.

By rotating and measuring the logical quadrants I, II, III, and IV along the circumference, a 360° all-round virtual beam splitting beam is formed to realize the all-round measurement of the target.

As one of the improvements to the above technical solution, the cylindrical array transducer array includes P circular arrays; the circular array includes: Q array elements; the P circular arrays are along the cylinder axis direction of the cylindrical array Evenly distributed on the array surface of the cylindrical surface array, the entire cylindrical surface array has a total of P×Q array elements, which are connected with P×Q taps.

As one of the improvements of the above technical solution, the array element receives the signal through the phase difference between the upper half beam of the virtual split beam and the lower half beam of the virtual split beam to determine the vertical offset angle of the target to be measured; specifically includes:

Determine the phase of the received signal of the array element through the upper half of the virtual split beam:

Among them, K _u is the phase of the upper half beam of the received signal of the array element through the virtual split beam; m ₁ is the index of the last row array element of the upper half beam of the virtual split beam;

Determine the phase of the received signal of the array element through the lower half of the virtual split beam:

Among them, K ₁ is the phase of the lower half beam of the virtual split beam through which the received signal of the array element passes; m ₂ is the first row array element index of the right half beam of the virtual split beam;

Among them, M and N respectively represent the number of array elements in the columns and rows of the logic area; b _nm is the weighted output of the array elements:

表示波束形成或相控的加权值；p_nm表示阵元采集的原始输出信号；in,

Represents the weighted value of beamforming or phase control; p _nm represents the original output signal collected by the array element;

Calculate the cross-correlation function R(τ) of the upper half beam K _u and the lower half beam K _l , and detect the correlation peak R(τ ₀ ), so as to obtain the upper half beam and the lower half beam of the virtual split beam when the received signal of the array element passes through the virtual split beam The phase difference of the half-beam, and use this phase difference as the azimuth angle of the target to be measured, that is, the vertical offset angle

As one of the improvements of the above technical solution, the horizontal offset angle of the target to be measured is determined through the phase difference between the left half beam of the virtual split beam and the right half beam of the virtual split beam; specifically includes:

Determine the phase of the element's received signal through the left half of the virtual split beam:

Among them, K _L is the phase of the left half beam of the array element receiving signal through the virtual split beam; n ₁ is the last row array element index of the left half beam of the virtual split beam;

Determine the phase of the received signal of the array element through the right half beam of the virtual split beam:

Among them, K _R is the phase of the right half beam of the received signal of the array element through the virtual split beam; n ₂ is the array element index of the first row of the right half beam of the virtual split beam;

Among them, M and N respectively represent the number of array elements in the columns and rows of the logic area; b _nm is the weighted output of the array elements:

表示波束形成或相控的加权值；p_nm表示阵元采集的原始输出信号；in,

Represents the weighted value of beamforming or phase control; p _nm represents the original output signal collected by the array element;

Calculate the cross-correlation function R1(τ) of the left half-beam K _L and the right half-beam K _R , and detect the correlation peak R1(τ ₀₁ ), so as to obtain the phases of the left half beam passing through the virtual split beam and the right half beam of the virtual split beam difference, and take this phase difference as the azimuth angle of the target to be measured, that is, the horizontal offset angle θ.

As one of the improvements of the above technical solution, the determination of the position of the target to be measured in the virtual split beam specifically includes:

Determine the distance r of the target to be measured:

Among them, c is the speed of sound; t is the time when the echo of the target to be measured is detected;

Establish a spherical coordinate system with the center of the virtual split beam as the coordinate origin, then the position of the target to be measured in the virtual split beam is the coordinate

进行坐标转换，获得待测目标在直角坐标系中的位置为坐标(x，y，z)；and put the coordinates

Perform coordinate conversion to obtain the position of the target to be measured in the Cartesian coordinate system as coordinates (x, y, z);

in,

And the position of the target to be measured in the Cartesian coordinate system is used as the position of the target to be measured in the virtual split beam.

The beneficial effect of the present invention compared with prior art is:

1. The omni-directional split beam array of the present invention utilizes the signal processing of a cylindrical surface array transducer array to form multiple virtual split beams, which can realize single detection, target measurement and target Tracking, rapid assessment of biological resources;

2. The omni-directional split beam array of the present invention can realize the efficient evaluation of biological resources while the fixed monitoring of marine organisms and the tracking of biological targets, and is especially suitable for fixed installation in oceans, rivers, lakes and other water areas to realize all-round real-time monitoring of water bodies Application, so that the acoustic high-efficiency monitoring of fishery resources and resource assessment are integrated and rapid.

Description of drawings

Fig. 1 (a) is the I logical quadrant, the II logical quadrant, the III logical quadrant and Schematic diagram of the logical division of IV logical quadrants;

Fig. 1(b) is a schematic diagram of virtual split beam target positioning and monomer detection in Fig. 1(a);

Fig. 2 (a) is a schematic diagram of the left half beam and the companion beam of the virtual split beam;

Figure 2 (b) is a schematic diagram of the upper half beam and the lower half beam of a virtual split beam;

Fig. 3 is a schematic diagram of the directivity and rotation process of the virtual split beam;

Fig. 4 is a schematic diagram of converting a circular arc physical array into a virtual straight line array;

FIG. 5 is a schematic diagram that each array element in the active area is connected to a tap, and each axis head is connected to a transceiver circuit.

Detailed ways

The present invention will be further described now in conjunction with accompanying drawing.

The present invention provides a method for measuring omni-directional split beams of a cylindrical array transducer array. In the method of the present invention, the four logical quadrants of the cylindrical array are sequentially rotated a circle to obtain a full range of virtual split beams. Furthermore, the omnidirectional split beam measurement can be realized, and the omnidirectional measurement of the intensity of the biological target within 360° of the water body can be completed, and then the position of the biological target can be obtained.

The method comprises: a cylindrical surface array transducer array composed of P×Q array elements;

Divide a certain part of the P×Q array elements in the cylindrical surface array transducer array (such as the array elements on half a cylindrical surface) into 4 continuous areas connected end to end to form I logical quadrant and II logical quadrant , III logical quadrant and IV logical quadrant, perform circular rotation on the above four logical quadrants in sequence, and use the beamforming method to obtain independent beams for all array elements in each logical quadrant, and then form four independent equivalent beams , get the virtual split beam;

Logical quadrant I and quadrant II form the upper half beam of the virtual split beam, logical quadrant II and logical quadrant III form the left half beam of the virtual split beam, logical quadrant III and logical quadrant IV form the lower half beam of the virtual split beam, 1V logic Quadrant and I logical quadrant constitute the right half of the virtual split beam;

The received signal passes through the phase difference between the upper half of the virtual split beam and the lower half of the virtual split beam to determine the vertical offset angle (φ) of the target to be measured, and then passes through the left half of the virtual split beam and the right of the virtual split beam The phase difference of the half beam determines the horizontal offset angle (θ) of the target to be measured, and then determines the position of the target to be measured in the virtual split beam.

By rotating and measuring the logical quadrants I, II, III, and IV along the circumference, a 360° all-round virtual beam splitting beam is formed to realize the all-round measurement of the target.

Specifically, determine the phase of the received signal of the array element passing through the upper half beam of the virtual split beam:

Among them, K _u is the phase of the upper half beam of the received signal of the array element through the virtual split beam, that is, the beamforming (integration of echo energy) output of the received signal of all array elements in the I logical quadrant and II logical quadrant of the cylindrical array; m ₁ index of the last row array element of the upper half beam of the virtual split beam;

Determine the phase of the received signal of the array element through the lower half of the virtual split beam:

Among them, K ₁ is the phase of the received signal of the array element passing through the lower half beam of the virtual split beam, that is, the beamforming (integration of echo energy) output of the received signal of all array elements in the third and fourth quadrants of the cylindrical array; m ₂ is the virtual The array element index of the first row of the right half beam of the split beam;

Among them, M and N respectively represent the number of array elements in the columns and rows of the logic area; b _nm is the weighted output of the array elements, which is the weighted (phase-controlled) data of the transducer array elements:

表示波束形成或相控的加权值；p_nm表示阵元采集的原始输出信号；in,

Represents the weighted value of beamforming or phase control; p _nm represents the original output signal collected by the array element;

Calculate the cross-correlation function R(τ) of the upper half beam K _u and the lower half beam K _l , and detect the correlation peak R(τ ₀ ), so as to obtain the upper half beam and the lower half beam of the virtual split beam when the received signal of the array element passes through the virtual split beam The phase difference of the half-beam, and use this phase difference as the azimuth angle of the target to be measured, that is, the vertical offset angle

Determine the phase of the element's received signal through the left half of the virtual split beam:

Among them, K _L is the phase of the left half beam of the received signal of the array element through the virtual split beam, that is, the beamforming (integration of echo energy) output of the received signal of all array elements in the second and third quadrants on the left side of the cylinder; n ₁ is The index of the last row element of the left half of the virtual split beam;

Determine the phase of the received signal of the array element through the right half beam of the virtual split beam:

Among them, K _R is the phase of the right half beam of the received signal of the array element passing through the virtual split beam, that is, the beamformed (integration of echo energy) output of the received signal of all array elements in the I and IV quadrants on the right side of the cylinder; n ₂ is the virtual split The array element index of the first row of the right half of the beam;

Among them, M and N respectively represent the number of array elements in the columns and rows of the logic area; b _nm is the weighted output of the array elements, which is the weighted (phase-controlled) data of the transducer array elements:

表示波束形成或相控的加权值；p_nm表示阵元采集的原始输出信号；in,

Represents the weighted value of beamforming or phase control; p _nm represents the original output signal collected by the array element;

Calculate the cross-correlation function R1(τ) of the left half-beam K _L and the right half-beam K _R , and detect the correlation peak R1(τ ₀₁ ), so as to obtain the phases of the left half beam passing through the virtual split beam and the right half beam of the virtual split beam difference, and take this phase difference as the azimuth angle of the target to be measured, that is, the horizontal offset angle θ.

Determine the distance r of the target to be measured:

Among them, c is the speed of sound; t is the time when the echo of the target to be measured is detected;

Establish a spherical coordinate system with the center of the virtual split beam as the coordinate origin, then the position of the target to be measured in the virtual split beam is the coordinate

进行坐标转换，获得待测目标在直角坐标系中的位置为坐标(x，y，z)；and put the coordinates

Perform coordinate conversion to obtain the position of the target to be measured in the Cartesian coordinate system as coordinates (x, y, z);

in,

And the position of the target to be measured in the Cartesian coordinate system is used as the position of the target to be measured in the virtual split beam.

Wherein, the cylindrical array transducer array includes P circular arrays; the circular array includes: Q array elements; the P circular arrays are evenly distributed in the cylinder axis direction of the cylindrical array On the array, the entire cylindrical array has a total of P×Q array elements, which are connected to P×Q taps; where each array element is connected to a tap;

Among them, a cylindrical array transducer array composed of P×Q array elements is used, the purpose of which is to obtain a full range of virtual split beam measurements, and the array elements on the array of the cylindrical array are formed by virtual split beams. The method obtains the virtual split beam, which is mainly used for the horizontal direction detection of the water body, and the two form a full range of virtual split beams, which can realize the measurement of the whole water body.

Wherein, the array elements are used for transmitting and receiving acoustic signals.

For all array elements in each logical quadrant, the beamforming method is used to obtain independent beams, that is, the left half beam, right half beam, upper half beam, and lower half beam of the virtual split beam, and then four independent equivalent beams are formed. Then the virtual split beam is obtained, and the four logical quadrants of the cylindrical array rotate along the circumference in order to form an all-round virtual split beam, and then realize the omni-directional split beam measurement.

The four independent beams of the all-round virtual split array beam are realized by the array elements arranged on the cylindrical array using the beamforming method, and the multiple array elements in the four logical quadrants form four independent receiving signals, and the target The vertical offset angle (φ) and horizontal offset angle (θ) are then determined by the measured phase difference between quadrant pairs consisting of any two of the four logical quadrants, ie the two halves of the array. By comparing the left/right half (lateral angle) and the upper/lower half (vertical angle) to determine the position of the target to be measured and obtain the orientation of the target to be measured, as shown in Figure 2(a) and 2(b).

Using the virtual split beam formed by the cylindrical array, the L (L<Q) array elements of the ring array are activated for signal transmission and reception, and can form narrow beams (K _L and K _R ) in the horizontal direction. In the vertical direction, P array elements are activated and divided into upper and lower halves for signal transmission and reception to form narrow beams (K _u and K _l ). In the circumferential direction, complete 360° omni-directional scanning and measurement as the active array element rotates along the circumference.

Example 1.

Combining Figure 1 (a), 1 (b) and Figure 2 (a), 2 (b) schematic diagram of the circular array.

The cylindrical array is composed of a multi-layer circular array. The array elements are piezoelectric ceramic substrates with a central frequency of f = 120kHz and a bandwidth of B = 40kHz. They are uniformly arranged along the circumferential direction. Uniform and symmetrical array in the circumferential direction. The cylindrical surface array is composed of P ₌ 8 ring arrays in the axial direction, and the number of array elements of each ring array is Q=64. ...64 (i=1...8 are ring labels), and the array elements with the same number between the rings are arranged in a linear array. The device adopts the combination of transceivers, each array element is connected to one tap, and each array element tap is connected to one receiving and transmitting channel of the receiving module and the transmitting module (the connection relationship is shown in Figure 4).

Divide the local 200 (25×8) array elements (the number of array elements on the circular array) on the circular ring on the cylindrical surface array into four areas of I, II, III, and IV as logical quadrants. When the array element m= Array elements 5 to m=29 are activated, and the steering angle is θ=0, which divides the 0° direction into four logical quadrants; when array elements m=13 to m=37 are activated, the steering angle θ=π/ 4. Divide the π/4 direction into four logical quadrants, and so on. With the counterclockwise rotation of the steering angle θ, beams under different steering angles θ are obtained, and then all-round split beam measurement is realized. As shown in Figure 3.

As shown in Figure 5, each array element in the active area is connected to a tap (namely, it is labeled 1, 2, 3, 4...61, 62, 63, 64 in Figure 5), and each tap is connected to the signal transmission It is connected with the receiving conditioning circuit (that is, the transceiver circuit in Figure 5), adopts a large-scale high-speed programmable array gate circuit (FPGA) and a high-performance control chip, and controls the transmitting signal through programming logic to realize flexible control of the transmitting beam, and Realize processing such as split beamforming and segmented beamforming of received signals. For all array elements in each area, beamforming technology is used to obtain independent beams, and then four independent equivalent beams are formed to obtain virtual split beams. The logical area of the cylindrical array rotates along the circumference one by one to form a full range of split beams. Array, and then realize omni-directional split beam measurement.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than limit them. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent replacements to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all of them should be included in the scope of the present invention. within the scope of the claims.

Claims (5)

1. a kind of omni-directional split beam measurement method of cylindrical surface array transducer array, it is characterized in that, the method comprises: Divide a certain part of the P×Q array elements in the cylindrical surface array transducer array into 4 continuous areas connected end to end to form I logical quadrant, II logical quadrant, III logical quadrant and IV logical quadrant. The four logical quadrants are sequentially rotated in order, and for all array elements in each logical quadrant, the beamforming method is used to obtain independent beams, and then four independent equivalent beams are formed to obtain virtual split beams; Logical quadrant I and quadrant II form the upper half beam of the virtual split beam, logical quadrant II and logical quadrant III form the left half beam of the virtual split beam, logical quadrant III and logical quadrant IV form the lower half beam of the virtual split beam, 1V logic Quadrant and I logical quadrant constitute the right half of the virtual split beam; The array element receives the acoustic wave signal through the phase difference between the upper half of the virtual split beam and the lower half of the virtual split beam to determine the vertical offset angle φ of the target to be measured, and then passes the left half of the virtual split beam and the virtual split beam. The phase difference of the right half beam determines the horizontal offset angle θ of the target to be measured, and then determines the position of the target to be measured in the virtual split beam. 2. the omnidirectional split-beam measuring method of cylindrical surface array transducer array according to claim 1, is characterized in that, described cylindrical surface array transducer array comprises P circular ring arrays; This circular ring array comprises: Q array elements; P ring arrays are evenly distributed on the surface of the cylindrical array along the cylindrical axis of the cylindrical array, and the entire cylindrical array has P×Q array elements, which are connected with P×Q taps . 3. the omni-directional split beam measurement method of cylindrical array transducer array according to claim 1, is characterized in that, described array element receives signal through the upper half beam of virtual split beam and the lower half beam of virtual split beam The phase difference determines the vertical offset angle of the target to be measured; specifically includes: Determine the phase of the received signal of the array element through the upper half of the virtual split beam:

Among them, K _u is the phase of the upper half beam of the received signal of the array element through the virtual split beam; m ₁ is the index of the last row array element of the upper half beam of the virtual split beam; Determine the phase of the received signal of the array element through the lower half of the virtual split beam:

Among them, K ₁ is the phase of the lower half beam of the virtual split beam through which the received signal of the array element passes; m ₂ is the first row array element index of the right half beam of the virtual split beam; Among them, M and N respectively represent the number of array elements in the columns and rows of the logic area; b _nm is the weighted output of the array elements:

in,

Represents the weighted value of beamforming or phase control; p _nm represents the original output signal collected by the array element; Calculate the cross-correlation function R(τ) of the upper half beam K _u and the lower half beam K _l , and detect the correlation peak R(τ ₀ ), so as to obtain the upper half beam and the lower half beam of the virtual split beam when the received signal of the array element passes through the virtual split beam half-beam phase difference, and use this phase difference as the vertical offset angle of the target to be measured

4. the omni-directional split-beam measurement method of cylindrical array transducer array according to claim 1, is characterized in that, described by the phase difference of the left half-beam of virtual split-beam and the right-half beam of virtual split-beam, Determine the horizontal offset angle of the target to be measured; specifically include: Determine the phase of the element's received signal through the left half of the virtual split beam:

Among them, K _L is the phase of the left half beam of the array element receiving signal through the virtual split beam; n ₁ is the last row array element index of the left half beam of the virtual split beam; Determine the phase of the received signal of the array element through the right half beam of the virtual split beam:

Among them, K _R is the phase of the right half beam of the received signal of the array element through the virtual split beam; n ₂ is the array element index of the first row of the right half beam of the virtual split beam; Among them, M and N respectively represent the number of array elements in the columns and rows of the logic area; b _nm is the weighted output of the array elements:

in,

Represents the weighted value of beamforming or phase control; p _nm represents the original output signal collected by the array element; Calculate the cross-correlation function R1(τ) of the left half-beam K _L and the right half-beam K _R , and detect the correlation peak R1(τ ₀₁ ), so as to obtain the phases of the left half beam passing through the virtual split beam and the right half beam of the virtual split beam difference, and take this phase difference as the horizontal offset angle θ of the target to be measured. 5. The omnidirectional split-beam measurement method of the cylindrical array transducer array according to claim 3 or 4, wherein the determination of the position of the target to be measured in the virtual split beam specifically includes: Determine the distance r of the target to be measured:

Among them, c is the speed of sound; t is the time when the echo of the target to be measured is detected; Establish a spherical coordinate system with the center of the virtual split beam as the coordinate origin, then the position of the target to be measured in the virtual split beam is the coordinate

and put the coordinates

Perform coordinate conversion to obtain the position of the target to be measured in the Cartesian coordinate system as coordinates (x, y, z); in,

And the position of the target to be measured in the Cartesian coordinate system is used as the position of the target to be measured in the virtual split beam.

Images