A split-beam based sonar system

Abstract

The application provides a split-beam based sonar system, comprising: a host computer, a signal preprocessing unit, a transducer array, a sonar transmitting unit and a sonar receiving unit. The host computer is used to send sonar working parameters and transmitting instructions to the signal preprocessing unit; the signal preprocessing unit generates a transmitting signal source; the transmitting signal is converted into an acoustic signal by a plurality of sub-arrays of the transducer array and transmitted to underwater. The transducer array receives the acoustic signal and converts it into a receiving signal, the sonar receiving unit converts the receiving signal into an amplified signal, and the signal preprocessing unit inputs the time delay information and envelope information into the host computer after preprocessing the amplified signal, and then calculates the position information of the underwater target. The position information of the underwater target can be calculated according to the time delay information of the sonar reflected by the underwater target back to each sub-array. The error can be effectively reduced, so as to realize real-time fixed monitoring of underwater organisms and long-term monitoring and evaluation.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of high-frequency sonar hardware design, in particular to a split-beam-based sonar system. BACKGROUND

[0002] Marine resources play an important role in realizing human sustainable development, and fishery resources also occupy an important position in marine resources. From early judgment relying on experience, to now applying various fish-finding sonars and other auxiliary equipment to locate fish schools and estimate the number. Blind fishing is not conducive to the development and sustainable use of fishery resources, so it is necessary to effectively apply scientific and technological means to the development and utilization of fishery resources. Using scientific fish-finding sonar to assess and detect fishery resources is an important means to carry out scientific management of fishery resources, effectively conserve them, ensure the sustainable development of marine resources, protect the marine ecological environment, and achieve comprehensive management of the sea.

[0003] Currently, scientific fish-finding sonars for evaluating marine fishery resources are mostly installed on survey ships and use the underway method to survey and evaluate marine, lake, and other fishery resources or other organisms. However, with the needs of marine ecological environment monitoring, restoration, and protection, the existing method has errors in identifying underwater targets, leading to ineffective monitoring and evaluation of underway survey data and inability to conduct long-term, real-time fixed monitoring. SUMMARY

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a split-beam-based sonar system.

[0005] The present application provides a split-beam-based sonar system, comprising:

[0006] A host computer, configured to issue sonar working parameters and transmission instructions;

[0007] A signal preprocessing unit, connected with the host computer, configured to receive the sonar working parameters and the transmission instructions, and adjust the sonar working parameters according to the transmission instructions, thereby generating a transmission signal source;

[0008] A sonar transmission unit, with an input end connected with an output end of the signal preprocessing unit, configured to receive the transmission signal source and perform step-by-step power amplification on the transmission signal source to obtain a transmission signal;

[0009] a transducer array, an input end of the transducer array being connected with an output end of the sonar transmitting unit; the transducer array having a plurality of sub-arrays arranged in an array; the transducer array being a transceiving transducer for converting the transmitting signal into a sound signal to be transmitted into water, or converting sound signals received by each sub-array into receiving signals respectively;

[0010] a sonar receiving unit, the sonar receiving unit being connected with an output end of the transducer array, for receiving a plurality of the receiving signals, amplifying the plurality of the receiving signals respectively to obtain a plurality of amplified signals, and inputting the plurality of the amplified signals into the signal preprocessing unit;

[0011] the signal preprocessing unit is further configured to preprocess the plurality of the amplified signals to obtain a plurality of time delay information and envelope information;

[0012] the upper computer is further configured to calculate depth information and a phase angle according to the time delay information and the envelope information, calculate the position information of the underwater target object according to the depth information and the phase angle, and display the calculation result.

[0013] According to the technical scheme provided by the embodiment of the application, the sonar transmitting unit comprises a driving circuit, a power amplification circuit, a transformer amplification circuit and a matching circuit.

[0014] The driving circuit, the power amplification circuit and the transformer amplification circuit are used for power amplifying the transmitting signal source respectively.

[0015] The matching circuit is used for line matching the circuit between the sonar transmitting unit and the transducer array, so that the resistance and capacitance of the transducer array are consistent with the resistance and capacitance of the sonar transmitting unit when transmitting sound signals of varying frequencies.

[0016] According to the technical scheme provided by the embodiment of the application, the transducer array is connected with a transceiving conversion circuit, and the transceiving conversion circuit is further connected with the sonar transmitting unit and the sonar receiving unit; the transceiving conversion circuit is used for controlling the sonar receiving unit to be grounded when transmitting sound signals.

[0017] According to the technical scheme provided by the embodiment of the application, the sonar receiving unit comprises a fixed gain amplification circuit, a controllable gain amplification circuit and a band-pass filter circuit.

[0018] The band-pass filter circuit is used for filtering the receiving signals to retain corresponding frequency bands.

[0019] The fixed gain amplification circuit is used for amplifying the receiving signals after wave filtering with a fixed gain.

[0020] The controllable gain amplification circuit is used for TVG gain control, further amplification according to the amplified received signal with fixed gain, and keeping the same gain after twice amplification of the received signal with different gain.

[0021] According to the technical scheme provided in the embodiment of the application, the signal preprocessing unit is specifically configured to:

[0022] Obtain a plurality of amplified signals;

[0023] Perform pulse compression on the plurality of amplified signals to obtain a plurality of compressed signals, perform peak value separation on the plurality of compressed signals respectively, and obtain a plurality of peak value positions;

[0024] Perform phase calculation according to the phases of the plurality of peak value positions to obtain phase angle information and time delay information of the underwater target object;

[0025] The upper computer is specifically configured to:

[0026] Calculate the depth information of the underwater target object according to the time delay information;

[0027] Calculate the position information of the underwater target object according to the depth information and the phase angle information.

[0028] According to the technical scheme provided in the embodiment of the application, the signal preprocessing unit, the sonar transmitting unit, the transducer array and the sonar receiving unit are separately provided with a plurality of; each of the plurality of signal preprocessing units is connected with the same upper computer; the upper computer sends different frequency band sonar working parameters to the plurality of sonar devices respectively;

[0029] Each of the signal preprocessing units is further configured to:

[0030] Perform multi-signal synthesis on the amplified signal of the corresponding frequency band to obtain a single-beam signal of the corresponding frequency band;

[0031] Perform secondary preprocessing on the single-beam signal to obtain envelope information and time delay information under the corresponding frequency;

[0032] The plurality of signal preprocessing units respectively transmit the envelope information to the upper computer;

[0033] The upper computer is further configured to:

[0034] Fit the plurality of envelope information into a full-band sound reflection characteristic curve;

[0035] Judge the type of the underwater target object according to the full-band sound reflection characteristic curve.

[0036] According to the technical scheme provided in the embodiment of the present application, the step of fitting the single-beam signals of multiple different frequency bands into a full-band sound reflection characteristic curve comprises:

[0037] Obtaining multiple single-beam signals;

[0038] Performing time-varying gain adjustment and envelope detection calculation on the single-beam signals to obtain envelope information and time delay information under corresponding frequencies;

[0039] According to the envelope information of multiple different frequencies, a full-band sound reflection characteristic curve containing underwater target intensity of different frequencies is synthesized.

[0040] According to the technical scheme provided in the embodiment of the present application, the method for judging the type of underwater target comprises:

[0041] According to the comparison and fitting of the full-band sound reflection characteristic curve and the sound reflection characteristic curve of the underwater target of known type, the type of the underwater target is determined according to the fitting degree.

[0042] The present application has the following beneficial effects:

[0043] Since the host computer is arranged, the host computer is used to send the sonar working parameters and the transmission instruction to the signal preprocessing unit; the signal preprocessing unit adjusts the sonar working parameters according to the transmission instruction, and then generates a transmission signal source; and the transmission signal is converted into a sound signal by multiple sub-arrays of the transducer array, and then the sound signal is transmitted to the underwater. The transducer array receives the sound signal and converts it into a received signal, the sonar receiving unit receives the received signal and converts it into an amplified signal, and the signal preprocessing unit inputs the time delay information and the envelope information into the host computer after preprocessing the amplified signal; the host computer calculates the phase angle and the depth information according to the time delay information and the envelope information, and then calculates the position information of the underwater target. The position information of the underwater target can be calculated according to the time delay information of the sonar reflected by the underwater target back to each sub-array. The error can be effectively reduced, so that real-time fixed monitoring of the underwater organisms can be realized, and long-term monitoring and evaluation can be performed. BRIEF DESCRIPTION OF DRAWINGS

[0044] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the accompanying drawings:

[0045] Figure 1 A structural schematic diagram of a sonar system based on split beams provided by the present application is provided;

[0046] Figure 2 Another structural schematic diagram of a sonar system based on split beams provided by the present application is provided;

[0047] Figure 3 Flow chart for sonar transmitting unit;

[0048] Figure 4 Flow chart for sonar receiving unit;

[0049] Figure 5 Structure diagram for signal preprocessing unit;

[0050] Figure 6 Structure diagram for power module;

[0051] Figure 7 Structure diagram for transducer array;

[0052] Figure 8 Circuit schematic diagram for sonar transmitting unit;

[0053] Figure 9 Circuit schematic diagram for sonar receiving unit;

[0054] Wherein, 1, first subarray; 2, second subarray; 3, third subarray; 4, fourth subarray; 5, host computer; 6, sonar transmitting unit; 7, transducer array; 8, sonar receiving unit; 9, signal preprocessing unit; 10, first receiver channel; 11, second receiver channel; 12, third receiver channel; 13, fourth receiver channel; 14, driving circuit; 15, power amplification circuit; 16, band-pass filter circuit; 17, transformer amplification circuit; 18, matching circuit; 19, transceiver conversion circuit; 20, first fixed gain circuit; 21, first filter circuit; 22, first controllable gain circuit; 23, second filter circuit; 24, second controllable gain circuit; 25, third filter circuit; 26, second fixed gain circuit; 27, A / D sampling module; 28, D / A conversion module; 29, FPGA; 30, temperature acquisition module; 31, serial communication circuit; 32, network communication circuit; 33, serial port logic control; 34, network port logic control; 35, signal source logic control; 36, D / A logic control; 37, D / A logic control; 38, direct current power supply; 39, switching power conversion module; 40, LDO voltage stabilizing module; 41, analog receiving circuit power supply; 42, vertical circuit power supply; 43, transmitting circuit power supply. DETAILED DESCRIPTION

[0055] The application will be further described below in conjunction with the drawings and examples. It can be understood that the specific examples described herein are only used to explain the related application, and not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings.

[0056] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other in the case of no conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0057] Reference should be made to Figure 1 A split-beam based sonar system schematic diagram is provided for the present embodiment, which comprises:

[0058] The host computer 5 is configured to send sonar working parameters and transmission instructions.

[0059] The signal preprocessing unit 9 is connected with the host computer 5, configured to receive the sonar working parameters and the transmission instructions, and adjust the sonar working parameters according to the transmission instructions, and then generate a transmission signal source.

[0060] The sonar transmission unit 6 is connected with the output end of the signal preprocessing unit 9, configured to receive the transmission signal source, and perform step-by-step power amplification on the transmission signal source to obtain a transmission signal.

[0061] The transducer array 7 is connected with the output end of the sonar transmission unit 6. The transducer array 7 has a plurality of array arranged sub-arrays. The transducer array 7 is a transceiver combined transducer, configured to convert the transmission signal into a sound signal and transmit it into water, or convert the sound signal received by each sub-array into a received signal.

[0062] The sonar receiving unit 8 is connected with the output end of the transducer array 7, configured to receive a plurality of received signals, and amplify the plurality of received signals to obtain a plurality of amplified signals, and then input the plurality of amplified signals to the signal preprocessing unit 9.

[0063] The signal preprocessing unit 9 is further configured to preprocess the plurality of amplified signals to obtain a plurality of time delay information.

[0064] The host computer 5 is further configured to calculate depth information and phase angle according to the time delay information, calculate the position information of the underwater target object according to the depth information and phase angle, and display the calculation result.

[0065] In some embodiments, the sonar working parameters sent by the host computer include frequency, bandwidth, pulse width, duty cycle, Ping rate, TVG curve rate, sampling point number, and sound velocity information.

[0066] Specifically, the host computer sends sonar working parameters to the signal preprocessing unit to obtain a transmission signal source, and then the sonar transmission unit generates a transmission signal; further, the transmission signal is transmitted to the transducer array to be converted into an acoustic signal, and multiple sub-arrays of the transducer array simultaneously emit the same acoustic signal, the acoustic signal is reflected by the underwater target and returned to the transducer array, the transducer array converts the acoustic signal into a received signal and transmits it to the sonar receiving unit; the sonar receiving unit amplifies the received signal to obtain an amplified signal and inputs it to the signal preprocessing unit, and then pre-processes the amplified signal to obtain time delay information and envelope information.

[0067] After transmitting the time delay information and envelope information to the host computer, the host computer calculates the depth information and phase angle according to multiple time delay information, and calculates the position information of the underwater target according to the depth information and phase angle.

[0068] The position information of the underwater target can be calculated according to the time delay information of the acoustic signal reflected by the underwater target and returned to each sub-array. The error can be effectively reduced, so that real-time fixed monitoring of underwater organisms can be realized, and long-term monitoring and evaluation can be performed.

[0069] In some embodiments, with reference to Figure 2 , the transducer array has four sub-arrays, including: a first sub-array 1, a second sub-array 2, a third sub-array 3, and a fourth sub-array 4. The first sub-array 1, the second sub-array 2, the third sub-array 3, and the fourth sub-array 4 are respectively connected to a first receiver channel 10, a second receiver channel 11, a third receiver channel 12, and a fourth receiver channel 13.

[0070] The fixed gain amplification circuit includes a first fixed gain circuit 20 and a second fixed gain circuit 26. The controllable gain amplification circuit includes a first controllable gain circuit 22 and a second controllable gain circuit 24.

[0071] The sonar receiving unit 8 includes a first receiver channel 10, a second receiver channel 11, a third receiver channel 12, and a fourth receiver channel 13.

[0072] The first receiver channel 10, the second receiver channel 11, the third receiver channel 12, and the fourth receiver channel 13 each include a transceiver conversion circuit 19, a first fixed gain circuit 20, a first filter circuit 21, a first controllable gain circuit 22, a second filter circuit 23, a second controllable gain circuit 24, a third filter circuit 25, a second fixed gain circuit 26, and an A / D acquisition module 27.

[0073] The sonar transmitting unit 6 comprises a driving circuit 14, a power amplification circuit 15, a band-pass filter circuit 16, a transformer amplification circuit 17 and a matching circuit 18.

[0074] Further, referring to Figure 3 , the sonar transmitting unit 6 comprises a driving circuit 14, a power amplification circuit 15, a transformer amplification circuit 17 and a matching circuit 18;

[0075] The driving circuit 14, the power amplification circuit 15 and the transformer amplification circuit 17 are used for power amplification of the transmitting signal source respectively;

[0076] The matching circuit 18 is used for line matching of the circuit between the sonar transmitting unit 6 and the transducer array 7: making the resistance and capacitance of the transducer array 7 consistent with the resistance and capacitance of the sonar transmitting unit 6 when transmitting sound signals of varying frequencies.

[0077] In some embodiments, referring to Figure 8 , a schematic diagram of the circuit connection relationship of the sonar transmitting unit is shown. The output end of the signal preprocessing unit is connected with a driving circuit, a power amplification circuit, a band-pass filter circuit, a transformer amplification circuit and a matching circuit in sequence, and finally connected with the transceiver conversion circuit.

[0078] Specifically, the capacitance and resistance of the sonar transmitting unit are fixed values; since the transducer array receives the transmitting signal containing the set frequency band generated by the signal preprocessing unit according to the sonar working parameters and converts it, it transmits sound signals of different frequencies within the same frequency band; when the transmitting frequency changes, the capacitance and resistance of the transducer array also change. The matching circuit is used to adjust the capacitance and resistance of the sonar transmitting unit to match the capacitance and resistance of the transducer array, so that the resistance and capacitance of the transducer array are consistent with the resistance and capacitance of the sonar transmitting unit when transmitting sound signals of varying frequencies. It can improve the transmission efficiency of the signal, and can keep the transmission efficiency consistent before and after the transmission frequency changes. Reduce energy loss and improve transmission power.

[0079] In some embodiments, the driving circuit adopts ADuM3224 driving chip, which can increase the load capacity of the FPGA 29 (Field-Programmable Gate Array) output signal. The power amplifier circuit adopts a class-D power amplifier circuit and adopts a full-bridge circuit structure, and uses IRFH5015PbF as the power tube of the power amplifier circuit. The transformer adopts manganese-zinc ferrite as the magnetic material, adopts a G (can type) magnetic core structure, adopts a 5:35 turns ratio, and is wound with a 0.4mm*4P diameter primary and a 0.3mm*3P diameter secondary enameled wire transformer. The matching circuit adopts a broadband series-parallel matching network matching mode.

[0080] Since the resistance and capacitance of the transducer array change with the change of the transmission frequency, the matching circuit is needed to match the resistance and capacitance of the transducer array and the signal preprocessing unit, thereby improving the transmission efficiency and ensuring the consistency of the efficiency before and after the transmission.

[0081] Further, the transducer array 7 is connected with a transceiver conversion circuit 19, and the transceiver conversion circuit 19 is further connected with the sonar transmitting unit 6 and the sonar receiving unit 8; the transceiver conversion circuit 19 is used to control the sonar receiving unit 8 to be grounded when transmitting the sound signal.

[0082] In some embodiments, the transceiver conversion circuit is arranged to isolate the output interface of the sonar transmitting unit circuit from the input interface of the sonar receiving unit circuit, so that the sonar receiving unit circuit is not affected during signal transmission. The chip of the receiving circuit can be prevented from being burned out by the high-voltage signal output by the transmitting circuit.

[0083] Further, referring to Figure 4 , the sonar receiving unit 8 comprises a fixed gain amplification circuit, a controllable gain amplification circuit and a band-pass filter circuit 16;

[0084] The band-pass filter circuit 16 is used to filter the received signal and retain the corresponding frequency band;

[0085] The fixed gain amplification circuit is used to amplify the received signal after the rate wave with a fixed gain;

[0086] The controllable gain amplification circuit is used to perform TVG gain control and further amplify the received signal after the fixed gain amplification, so that the received signals with different gains maintain the same gain after two amplifications.

[0087] In some embodiments, referring to Figure 9A schematic diagram of a circuit connection relationship of the sonar receiving unit is shown. Output ends of the transducer array are connected in sequence with a transceiving conversion circuit, a fixed amplification circuit, a second filter circuit, a first controllable gain circuit, a third filter circuit, a second controllable gain circuit, a fourth filter circuit, a second fixed gain circuit, a firing circuit, and finally with an input end of the signal preprocessing unit.

[0088] In some embodiments, with reference to Figure 5 , the signal preprocessing unit comprises an FPGA 29, an A / D acquisition module 27, and a D / A conversion module 28. During emission of the sonar, the FPGA 29 generates an initial signal having sonar operating parameters according to the sonar operating parameters. The FPGA 29 controls the D / A conversion module 28 to perform digital-to-analog conversion on the initial signal, converting the digital signal into an analog signal. The emission signal source is obtained, and the emission signal source is input to the sonar emission unit. During reception of the sonar, the FPGA 29 controls the A / D acquisition module 27 to perform analog-to-digital conversion on the amplified signal, converting the analog signal into a digital signal, obtaining an acquisition signal. The FPGA 29 pre-processes the acquisition signal, obtaining the time delay information, and inputs the time delay information to the host computer.

[0089] In some embodiments, the signal preprocessing unit further comprises a temperature acquisition module 30, a serial port communication 31, and a network port communication circuit 32.

[0090] The communication circuit 32 is W5300 Ethernet communication; the FPGA 29 selects the 5CGXFC9D6F27C7N type FPGA 29 of the Cyclone V series of Altera Company, which can provide powerful processing capacity and rich on-chip resources. The A / D acquisition circuit selects the bandpass sampling mode, effectively reduces the sampling rate, and makes the selection range of the ADC chip more wide, which plays a key role in the miniaturization and low power consumption of multi-channel analog signal acquisition. The AD7657 chip with 6 channels of synchronous conversion, maximum support of 250Kbps and 14bit is selected as the analog-to-digital conversion chip. The D / A conversion circuit first selects MAX5442 for digital-to-analog conversion and configures it as a bipolar output, then performs a low-pass filtering, then uses ADA4932 differential operational amplifier for single-ended differential, then performs a low-pass filtering, and then controls AD8336 through the serial communication circuit. One of the serial communication circuits 31 adopts the TTL interface standard, which is used to receive the system synchronization signal, and the other adopts the RS422 interface standard, which is used to receive the serial port instructions issued by the real-time display and control software of the host computer and the auxiliary information issued by the auxiliary equipment; the Ethernet communication circuit adopts the W5300 network port chip for circuit design, selects the TCP protocol for data transmission, and selects the UDP protocol for transmission of working status for debugging, uses the FPGA 29 to drive the W5300 for Ethernet communication, and realizes it through the establishment of Qsys project and the use of Nios II processor; the temperature acquisition module 30 adopts the DS18B20 temperature sensor for real-time monitoring of the temperature in the electronic bin.

[0091] In some embodiments, the logic control of the FPGA 29 includes: serial port logic control 33, network port logic control 34, signal source logic control 35, D / A conversion module 36 and A / D logic control 37.

[0092] In some embodiments, referring to Figure 6 , the signal preprocessing unit further includes: a switching power supply module. The switching power supply module includes: a direct current power supply 38, a switching power supply conversion module 39, an LOD voltage stabilizing module 40, an analog receiving circuit power supply 41, a digital circuit power supply 42, and a transmitting circuit power supply 43. For the switching power supply module, two switching power supply modules of CCG30-48-05S and CCG30-48-12D of TDK-Lambda Company are selected for voltage conversion. For the LDO voltage stabilizing module, the positive LDO is TPS7A8500ARGRT of TI Company, and the negative LDO is LT3091EFE#PBF of ADI Company. The power supply is stabilized to ensure the stable operation of the circuit.

[0093] In some embodiments, the subarray has 4 and is located in four quadrants respectively, the amplified signal corresponding to the subarray in the first quadrant is the first signal; the amplified signal corresponding to the subarray in the second quadrant is the second signal; the amplified signal corresponding to the subarray in the third quadrant is the third signal; the amplified signal corresponding to the subarray in the fourth quadrant is the fourth signal.

[0094] The first signal and the second signal are synthesized, the second signal and the third signal are synthesized, the third signal and the fourth signal are synthesized, and the fourth signal and the first signal are synthesized. Four synthesis signals are generated.

[0095] In some embodiments, the sonar receiving unit includes: a pre-fixed gain amplification circuit, a two-stage controllable gain amplification circuit, a three-stage band-pass filter circuit, and a post-stage amplification circuit. The pre-fixed gain amplification circuit uses an AD8429 instrument amplifier, and the circuit gain is set to 23.8dB; the controllable gain amplification circuit uses AD8336, and the gain code generated by FPGA29 is converted by D / A to perform TVG (gain change with time) gain control, which can provide a gain adjustment range of 120dB. The band-pass filter circuit uses a multi-path negative feedback circuit structure; the post-stage amplification circuit uses an ADA4807-1 operational amplifier, and the circuit gain is set to 14dB.

[0096] Further, the signal preprocessing unit 9 is specifically configured to:

[0097] Obtain a plurality of amplified signals;

[0098] Pulse compression is performed on a plurality of amplified signals to obtain a plurality of compressed signals; peak separation is performed on a plurality of compressed signals respectively; and a plurality of peak positions are obtained.

[0099] Phase calculation is performed according to the phases of a plurality of peak positions to obtain phase angle information and time delay information of an underwater target object;

[0100] The upper computer 5 is specifically configured to:

[0101] According to the time delay information, the depth information of the underwater target object is calculated;

[0102] According to the depth information and the phase angle information, the position information of the underwater target object is calculated.

[0103] In some embodiments, with reference to Figure 7 , the first subarray 1, the second subarray 2, the third subarray 3, and the fourth subarray 4 are respectively connected with the first receiver channel 10, the second receiver channel 11, the third receiver channel 12, and the fourth receiver channel 13.

[0104] The sub-arrays are respectively located in four quadrants of the transducer array, and each sub-array receives an acoustic signal to generate a received signal, and four received signals are generated in total. The received signal generated by each sub-array is converted into a plurality of amplified signals after being filtered, amplified and gain-controlled by the sonar receiving unit, and then is converted into a plurality of collection signals through analog-to-digital conversion. The collection signals corresponding to each two adjacent sub-arrays are subjected to multi-signal synthesis to obtain four synthesized signals. The four synthesized signals are subjected to pulse compression and peak separation in sequence to obtain four peak positions, and then time delay information is calculated. The host computer calculates the position information of the underwater target according to the time delay information of the sonar reflected by the underwater target and returned to each sub-array. The error can be effectively reduced, so that real-time fixed monitoring of underwater organisms can be realized, and long-term monitoring and evaluation can be performed.

[0105] In some embodiments, the adjacent signal synthesis represents that two amplified signals corresponding to each two adjacent sub-arrays are synthesized to obtain four synthesized signals.

[0106] Further, the signal preprocessing unit 9, the sonar transmitting unit 6, the transducer array 7 and the sonar receiving unit 8 are separately provided with a plurality of units; each of the plurality of signal preprocessing units 9 is connected to the same host computer 5; and the host computer 5 sends different frequency band sonar working parameters to a plurality of sonar devices respectively.

[0107] Each signal preprocessing unit 9 is further configured to:

[0108] perform multi-signal synthesis on the amplified signals of the corresponding frequency band to obtain a single-beam signal of the corresponding frequency band;

[0109] perform secondary preprocessing on the single-beam signal to obtain envelope information and time delay information under the corresponding frequency;

[0110] The plurality of signal preprocessing units 9 respectively transmit the envelope information to the host computer 5;

[0111] The host computer 5 is further configured to:

[0112] fit the plurality of envelope information into a full-band acoustic reflection characteristic curve;

[0113] determine the type of underwater target according to the full-band acoustic reflection characteristic curve.

[0114] Specifically, the host computer transmits the sonar working parameters containing different frequency band information to each signal preprocessing unit; each signal preprocessing unit generates a transmission signal of a corresponding frequency band according to the sonar working parameters containing the corresponding frequency band information; each transducer array converts the transmission signal of the corresponding frequency band into a sonar of the corresponding frequency band and transmits it to the underwater; each transducer array converts the sonar of the corresponding frequency band reflected by the underwater target back to the transducer array into a plurality of the receiving signals of the corresponding frequency band; and each signal receiving device pre-processes the receiving signals of the corresponding frequency band to obtain the time delay information and transmits the time delay information to the host computer.

[0115] The host computer synthesizes a plurality of the single-beam signals to obtain a full-band acoustic reflection characteristic curve, compares and fits the full-band acoustic reflection characteristic curve with acoustic reflection characteristic curves of known types of underwater targets, and determines the type of the underwater target according to a fitting degree.

[0116] Further, the step of fitting a plurality of the single-beam signals of different frequency bands into a full-band acoustic reflection characteristic curve comprises:

[0117] obtaining a plurality of the single-beam signals;

[0118] performing time-varying gain adjustment and envelope detection calculation on the single-beam signals to obtain envelope information and time delay information at a corresponding frequency;

[0119] synthesizing a full-band acoustic reflection characteristic curve containing underwater target intensity of different frequencies according to the envelope information of a plurality of different frequencies.

[0120] In some embodiments, the secondary preprocessing comprises time-varying gain adjustment and envelope detection calculation.

[0121] Specifically, a plurality of the acquisition signals are synthesized, time-varying gain adjustment and envelope detection calculation are performed, envelope information and time delay information at a corresponding frequency are obtained, a full-band acoustic reflection characteristic curve containing underwater target intensity of different frequencies is synthesized, comparison and fitting are performed between the full-band acoustic reflection characteristic curve and acoustic reflection characteristic curves of known types of underwater targets, and the type of the underwater target is determined according to a fitting degree.

[0122] Further, the method for determining the type of the underwater target comprises:

[0123] comparison and fitting are performed between the full-band acoustic reflection characteristic curve and acoustic reflection characteristic curves of known types of underwater targets, and the type of the underwater target is determined according to a fitting degree.

[0124] Specifically, the full-band acoustic reflection characteristic curve includes a characteristic curve of acoustic signal reflection of the underwater target object to full frequency, and by fitting with acoustic reflection characteristic curves of known underwater target object species, the highest fitting degree is selected as the species of the underwater target object to be detected.

[0125] The above description is merely preferred embodiments of the present application and a description of the technical principles of the application. It should be understood by those skilled in the art that the scope of the application disclosed in the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by any combinations of the above technical features or equivalent features without departing from the inventive concept. For example, the above features are replaced with each other to form technical solutions with similar functions disclosed in the present application (but not limited to).

Claims

1. A split-beam based sonar system, characterized by, The application relates to a sonar system, which comprises: a host computer (5) for sending sonar working parameters and transmission instructions; a signal preprocessing unit (9) connected with the host computer (5) for receiving the sonar working parameters and the transmission instructions, adjusting the sonar working parameters according to the transmission instructions, and generating a transmission signal source; a sonar transmission unit (6) with an input end connected with an output end of the signal preprocessing unit (9) for receiving the transmission signal source, performing step-by-step power amplification on the transmission signal source, and obtaining a transmission signal; a transducer array (7) with an input end connected with an output end of the sonar transmission unit (6); the transducer array (7) has a plurality of sub-arrays arranged in an array; the transducer array (7) is a transceiving transducer for converting the transmission signal into a sound signal and transmitting the sound signal into water or converting sound signals received by each sub-array into receiving signals respectively; a sonar receiving unit (8) connected with an output end of the transducer array (7) for receiving a plurality of the receiving signals, amplifying the receiving signals respectively, and obtaining a plurality of amplified signals; and then inputting the amplified signals into the signal preprocessing unit (9); the signal preprocessing unit (9) is further configured to preprocess the amplified signals to obtain a plurality of time delay information; the host computer (5) is further configured to calculate depth information and a phase angle according to the time delay information, calculate position information of an underwater target according to the depth information and the phase angle, and display the calculation result; the signal preprocessing unit (9) is specifically configured to: obtain the amplified signals; perform pulse compression on the amplified signals to obtain a plurality of compressed signals, perform peak value separation on the compressed signals respectively, and obtain a plurality of peak value positions; perform phase calculation according to phases of the peak value positions to obtain phase angle information and time delay information of the underwater target; the host computer (5) is specifically configured to: calculate depth information of the underwater target according to the time delay information; calculate the position information of the underwater target according to the depth information and the phase angle information; the sub-arrays are respectively located in four quadrants of the transducer array; each sub-array generates a receiving signal by receiving a sound signal, and a total of four receiving signals are generated; the receiving signal generated by each sub-array is converted into a plurality of amplified signals after being filtered, amplified and gain-controlled by the sonar receiving unit, and a plurality of acquisition signals are obtained after being analog-to-digital converted; a plurality of signals corresponding to each two adjacent sub-arrays are synthesized to obtain four synthesized signals; the four synthesized signals are sequentially subjected to pulse compression and peak value separation to obtain four peak value positions, and time delay information is calculated; the host computer calculates position information of the underwater target according to the time delay information of the sonar reflected by the underwater target and returned to each sub-array. The signal preprocessing units (9), the sonar transmitting units (6), the transducer arrays (7) and the sonar receiving units (8) are provided in plurality; each of the plurality of signal preprocessing units (9) is connected with the same host computer (5); the host computer (5) respectively sends different frequency band sonar working parameters to the plurality of sonar devices; Each of the signal preprocessing units (9) is further configured to: perform multi-signal synthesis on the amplified signals of the corresponding frequency band to obtain a single-beam signal of the corresponding frequency band; perform secondary preprocessing on the single-beam signal to obtain envelope information and time delay information under the corresponding frequency; The plurality of signal preprocessing units (9) respectively transmit the envelope information to the host computer (5); The host computer (5) is further configured to: fit the plurality of envelope information into a full-band acoustic reflection characteristic curve; determine the type of underwater target object according to the full-band acoustic reflection characteristic curve; The step of fitting the single-beam signals of multiple different frequency bands into a full-band acoustic reflection characteristic curve comprises: obtaining a plurality of single-beam signals; performing time-varying gain adjustment and envelope detection calculation on the single-beam signals to obtain envelope information and time delay information under the corresponding frequency; According to the envelope information of multiple different frequencies, a full-band acoustic reflection characteristic curve containing the intensity of underwater target objects of different frequencies is synthesized.

2. The split-beam based sonar system of claim 1, wherein, The sonar transmitting unit (6) comprises a driving circuit (14), a power amplification circuit (15), a transformer amplification circuit (17) and a matching circuit (18); The driving circuit (14), the power amplification circuit (15) and the transformer amplification circuit (17) are used for power amplification of the transmitting signal source respectively; The matching circuit (18) is used for line matching of the circuit between the sonar transmitting unit (6) and the transducer array (7): the resistance and capacitance of the transducer array (7) are consistent with the resistance and capacitance of the sonar transmitting unit (6) when transmitting acoustic signals of varying frequencies.

3. The split-beam based sonar system of claim 2, wherein, The transducer array (7) is connected with a transceiving conversion circuit (19), and the transceiving conversion circuit (19) is further connected with the sonar transmitting unit (6) and the sonar receiving unit (8); the transceiving conversion circuit (19) is used for controlling the sonar receiving unit (8) to be grounded when transmitting acoustic signals.

4. The split-beam based sonar system of claim 3, wherein, The sonar receiving unit (8) comprises a fixed gain amplification circuit, a controllable gain amplification circuit and a band-pass filter circuit (16); The band-pass filter circuit (16) is used for filtering the received signals to retain the corresponding frequency band; The fixed gain amplification circuit is used for amplifying the received signals after the rate wave with fixed gain; The controllable gain amplification circuit is used for TVG gain control and further amplification of the received signals after fixed gain amplification, so that the received signals with different gains maintain the same gain after two amplifications.

5. The split-beam based sonar system according to any one of claims 1-4, characterized in that, The method for determining the type of underwater target object comprises: According to the full-band sound reflection characteristic curve and the sound reflection characteristic curve of the known kind of underwater target object, comparison fitting is carried out, and the kind of the underwater target object is determined according to the fitting degree.

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