An acoustic array circuit system

Abstract

The present invention discloses an acoustic array circuit system, which includes an FPGA processing unit. The FPGA processing unit is respectively connected to a power supply module, an AD conversion circuit, a sound velocity profiler, and a second DA conversion circuit. The AD conversion circuit is connected to an amplification buffer circuit, the amplification buffer circuit is connected to a band-pass filter, the band-pass filter is connected to a programmable amplifier, the programmable amplifier is connected to an analog front-end amplification circuit, the analog front-end amplification circuit is connected to a limiting circuit, the limiting circuit is respectively connected to a plurality of receiving transducers, the second DA conversion circuit is connected to an attenuation buffer circuit, the attenuation buffer circuit is connected to a low-pass filter, and the low-pass filter is connected to a transmitting transducer. The sound velocity profiler can collect and correct the sound velocity of the water area where it is located in real time, so as to make the positioning distance of the acoustic beacon more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic arrays, and more specifically, to an acoustic array circuit system. Background Art

[0002] The acoustic array is mainly used in the ultra-short baseline underwater acoustic positioning system, which is mainly divided into three parts: the upper computer part of the deck main control cabin, the transmitting and receiving device of the bottom-mounted acoustic array of the ship, and the acoustic beacon part installed on the underwater equipment.

[0003] The ultra-short baseline acoustic array is generally installed at the bottom of the ship or the bottom of the water surface detection equipment according to actual needs. To expand the angle and range of acoustic wave detection, a spherical hydrophone can be selected. The bottom-mounted acoustic array equipment can communicate with the upper computer system on the deck through a network cable, and the upper computer can control the acoustic array in real time and set relevant parameters, such as: controlling the acquisition, transmission of acoustic wave signals, gain adjustment of the signal acquisition amplifier, size of the transmitted signal, setting and compensation of the sound speed, etc. At the same time, the serial communication can be used to print the real-time acquisition and configuration information of the system on the serial port assistant interface.

[0004] The hydrophone uses a spherical pressure hydrophone, and its main structure consists of two piezoelectric ceramic hemispheres, vulcanized sound-transmitting rubber, a fixing structure, etc. It can omnidirectionally receive acoustic wave signals from different directions.

[0005] The existing acoustic arrays generally only locate the distance through underwater acoustic signals. Since the sound speed in different waters is slightly different, if the underwater acoustic signals are not corrected according to the waters, it is very easy to cause inaccurate positioning distance of the acoustic beacon.

[0006] In view of the problems in the related art, no effective solution has been proposed yet. Summary of the Invention

[0007] In view of the above technical problems in the related art, the present invention provides an acoustic array circuit system, which is provided with a sound speed profiler. Through the sound speed profiler, the sound speed of the water area where it is located can be collected and corrected in real time, so as to make the positioning distance of the acoustic beacon more accurate.

[0008] To achieve the above technical objectives, the technical solution of the present invention is realized as follows:

[0009] An acoustic array circuit system includes an FPGA processing unit, which is respectively connected to a power supply module, an AD conversion circuit, a sound velocity profiler, a first DA conversion circuit, and a second DA conversion circuit. The AD conversion circuit is connected to an amplification buffer circuit, which includes a post-stage amplifier and a first buffer. The amplification buffer circuit is connected to a band-pass filter, which is connected to a programmable amplifier. The programmable amplifier is respectively connected to an analog front-end amplification circuit and the first DA conversion circuit. The analog front-end amplification circuit includes a differential amplifier and is connected to a limiting circuit, which is respectively connected to a plurality of receiving transducers. The second DA conversion circuit is connected to an attenuation buffer circuit, which includes an attenuator and a second buffer. The attenuation buffer circuit is connected to a low-pass filter, which is connected to a first-stage audio transformer. The first-stage audio transformer is connected to a digital audio power amplifier, which is respectively connected to a second-stage audio transformer and the FPGA processing unit. The second-stage audio transformer is connected to an impedance matching circuit, which is connected to a transmitting transducer.

[0010] Further, the first DA conversion circuit is connected to the programmable amplifier through an operational amplifier buffer circuit, which includes an inverting operational amplifier and a third buffer.

[0011] Further, the band-pass filter is an eighth-order Butterworth band-pass filter.

[0012] Further, the low-pass filter is a second-order Bessel low-pass filter.

[0013] Further, the FPGA processing unit is also connected to a GPS positioning module.

[0014] Further, the FPGA processing unit is also connected to an azimuth and attitude sensor, which includes a gyroscope.

[0015] Further, the FPGA processing unit is also connected to a communication serial port.

[0016] Further, the digital audio power amplifier is connected to the FPGA processing unit through a circuit provided with a relay.

[0017] Further, the power supply module includes a main power supply inlet and a 5V isolation chip.

[0018] Advantages of the present invention: While collecting and transmitting sound waves, the GPS positioning module can be combined to ensure the certainty of the acoustic array coordinates. The angle and angular velocity changes of the overall spherical surface of the acoustic array can be measured according to the azimuth and attitude sensor when the hull fluctuates. The sound velocity of the water area can be collected and corrected in real time according to the sound velocity profiler, so as to make the positioning distance of the sound beacon more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 is the principle block diagram of the acoustic array circuit system according to the embodiment of the present invention;

[0021] Figure 2 is the circuit of the acoustic array circuit system according to the embodiment of the present invention Figure 1 ;

[0022] Figure 3 is the circuit of the acoustic array circuit system according to the embodiment of the present invention Figure 2 ;

[0023] Figure 4 is the circuit of the acoustic array circuit system according to the embodiment of the present invention Figure 3 ;

[0024] Figure 5 is the circuit of the acoustic array circuit system according to the embodiment of the present invention Figure 4 ;

[0025] Figure 6 is the circuit of the acoustic array circuit system according to the embodiment of the present invention Figure 5 ;

[0026] Figure 7 is the circuit of the acoustic array circuit system according to the embodiment of the present invention Figure 6 . DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0028] AsFigures 1-7 As shown in Figures 1-7 , a sound array circuit system according to an embodiment of the present invention includes an FPGA processing unit, which is respectively connected to a power supply module, an AD conversion circuit, a sound velocity profiler, a first DA conversion circuit, and a second DA conversion circuit. The AD conversion circuit is connected to an amplification buffer circuit, which includes a post-stage amplifier and a first buffer. The amplification buffer circuit is connected to a band-pass filter, which is connected to a programmable amplifier. The programmable amplifier is respectively connected to an analog front-end amplification circuit and the first DA conversion circuit. The analog front-end amplification circuit includes a differential amplifier and is connected to a limiting circuit, which is respectively connected to a plurality of receiving transducers. The second DA conversion circuit is connected to an attenuation buffer circuit, which includes an attenuator and a second buffer. The attenuation buffer circuit is connected to a low-pass filter, which is connected to a first-stage audio transformer. The first-stage audio transformer is connected to a digital audio power amplifier, which is respectively connected to a second-stage audio transformer and the FPGA processing unit. The second-stage audio transformer is connected to an impedance matching circuit, which is connected to a transmitting transducer.

[0029] In a specific embodiment of the present invention, the first DA conversion circuit is connected to the programmable amplifier through an operational amplifier buffer circuit, and the operational amplifier buffer circuit includes an inverting operational amplifier and a third buffer.

[0030] In a specific embodiment of the present invention, the band-pass filter is an eighth-order Butterworth band-pass filter.

[0031] In a specific embodiment of the present invention, the low-pass filter is a second-order Bessel low-pass filter.

[0032] In a specific embodiment of the present invention, the FPGA processing unit is further connected to a GPS positioning module.

[0033] In a specific embodiment of the present invention, the FPGA processing unit is further connected to an azimuth and attitude sensor, and the azimuth and attitude sensor includes a gyroscope.

[0034] In a specific embodiment of the present invention, the FPGA processing unit is further connected to a communication serial port.

[0035] In a specific embodiment of the present invention, the digital audio power amplifier is connected to the FPGA processing unit through a circuit provided with a relay.

[0036] In a specific embodiment of the present invention, the power supply module includes a main power supply inlet and a 5V isolation chip.

[0037] To facilitate the understanding of the above technical solution of the present invention, the above technical solution of the present invention will be described in detail below through specific usage modes.

[0038] The acoustic array circuit system described in the present invention includes a GPS positioning module, a communication serial port, an acoustic wave transmitting circuit, an acoustic wave receiving circuit, a sound velocity profiler, an azimuth attitude sensor, an FPGA processing unit, a power supply module, etc.

[0039] The acoustic wave receiving circuit includes a receiving transducer, a limiting circuit, an analog front-end amplification circuit, a programmable gain amplifier, a band-pass filter, an amplification buffer circuit, an AD conversion circuit, a first DA conversion circuit, and an operational amplifier buffer circuit. The acoustic wave transmitting circuit includes a transmitting transducer, an impedance matching circuit, a secondary audio transformer, a digital audio power amplifier, a primary audio transformer, a low-pass filter, an attenuation buffer circuit, a relay, and a second DA conversion circuit.

[0040] The limiting circuit is used for performing limiting processing on the electrical signal before amplifying the electrical signal after the acoustic wave signal is converted into an electrical signal by the receiving transducer, to avoid the distance between the acoustic array and the acoustic beacon being too close, resulting in a stronger electrical signal after amplification being higher than the acquisition voltage of the ADC chip, and can effectively protect the subsequent circuits.

[0041] The analog front-end amplification circuit includes a hundred-fold differential amplifier. The analog front-end amplification circuit is used for low-noise amplification of the weak positive and negative electrical signals obtained after the limiting processing through a rail-to-rail differential operational amplifier. Thus, the weak electrical signal can be amplified hundreds of times without distortion.

[0042] The programmable gain amplifier is controlled by the FPGA processing unit. The FPGA processing unit controls the programmable gain amplifier by controlling the output voltage of the first DA conversion circuit. The programmable gain amplifier amplifies the electrical signal by a hundred times and then sends it to the band-pass filter.

[0043] The first DA conversion circuit includes a DAC chip. In addition to outputting voltage to the programmable gain amplifier, the DAC chip also has an enable or data latch function. The enable or latch signal can be controlled by the upper computer, so as to control whether to start measurement, or change the analog amplification factor, etc., which is convenient for real-time control. The DAC chip supports 16-bit bipolar output.

[0044] The operational amplifier buffer circuit includes an inverting operational amplifier (or a reverse operational amplifier) and a third buffer.

[0045] The band-pass filter adopts a high-performance eighth-order Butterworth band-pass filter, which can determine the center frequency, start frequency, and cut-off frequency by configuring different resistance values, can expand the frequency bandwidth, enable the system to have strong anti-interference ability, and improve the positioning accuracy of the entire system.

[0046] The amplification buffer circuit includes a post-stage amplifier and a first buffer. The amplification buffer circuit is used to amplify the electrical signal processed by the band-pass filter by 2 times and then perform buffer processing.

[0047] The AD conversion circuit includes a high-precision dual-channel ADC chip. The AD conversion circuit is used to convert the analog signal (i.e., the electrical signal) processed by the amplification buffer circuit into a digital signal and then send it to the FPGA processing unit for processing.

[0048] The FPGA processing unit has the following functions: 1) perform digital processing on the digital signal converted by the AD conversion circuit; 2) send the digital signal to the first DA conversion circuit to control the amplification factor of the programmable amplifier; 3) send the digital signal to the second DA conversion circuit to make the second DA conversion circuit output an electrical signal; 4) complete the calculation of the azimuth attitude sensor, and fuse the calculated data with the digital signal transmitted by the AD conversion circuit and the data corrected by the sound velocity profiler; 5) communicate with the host computer through the communication serial port, and the communication protocol is the TCP network protocol, so that the host computer can control the acoustic array system and view the uploaded information, etc.

[0049] The second DA conversion circuit includes a DAC chip. The DA conversion circuit is used to convert the digital signal sent by the FPGA processing unit into an analog signal and then send it to the low-pass filter. The DAC chip supports 16-bit bipolar output.

[0050] The low-pass filter is a fourth-order Bessel low-pass filter. The low-pass filter is used to filter the analog signal. The Bessel low-pass filter is widely used in audio equipment. In audio equipment, it is necessary to eliminate out-of-band noise without damaging the phase relationship of multiple signals in the frequency band. In addition, the step response of the Bessel low-pass filter is very fast and there is no overshoot or ringing, which makes it an excellent choice as a smoothing filter at the output end of the audio DAC.

[0051] The attenuation buffer circuit includes an attenuator and a second buffer. Here, the operational amplifier is used as the attenuator. The first buffer, the second buffer, and the third buffer are all 1:1 amplifiers. They do not amplify the signal but play the role of impedance matching, which can reduce signal distortion and anti-interference.

[0052] Both the first-stage audio transformer and the second-stage audio transformer are transformers operating in the audio range, also known as low-frequency transformers. The working frequency range is generally from 10 to 20000 Hz. Both the first-stage audio transformer and the second-stage audio transformer are used to transform the impedance of the load.

[0053] The high-power digital audio power amplifier uses a Class D power amplifier (referred to as Class D amplifier) as the core component, plus a power supply module, a housing, signals, power supply wiring, etc. It has the characteristics of small size, wide voltage range, high power, low distortion rate, etc., and the sound effect is comparable to that of an analog audio power amplifier. The core component of the digital audio power amplifier adopts the PWM (pulse width modulation) working mode, with small size, high reliability and complete functions. The digital audio power amplifier is used to amplify the filtered electrical signal.

[0054] The impedance matching circuit is used for impedance matching between the backend and the transmitting transducer.

[0055] The power supply module is used to supply power to this system. Since there are a large number of analog and digital signal processes in this system, and it involves the amplification of tiny signals by hundreds or even thousands of times, the power supply module must have very high performance. The power supply module includes a main power supply inlet and a 5V isolation chip. The main power supply inlet inputs 220VAC. At the same time, the differential amplifier requires ±5V power supply, and the FPGA processing unit needs to provide clean power for it, so the 5V isolation chip is used for power supply. In addition, protection circuits such as slow charging during power-on startup and fast discharging during power-off need to be set up. At the same time, other voltage requirements such as the reference voltages of the ADC chip and the DAC chip are also involved.

[0056] In summary, with the above technical solutions of the present invention, in addition to completing basic tasks such as collecting and transmitting sound waves, the acoustic array will also combine the GPS positioning module of the hull itself to ensure the certainty of the acoustic array coordinates. According to the relative positions of the acoustic array and the underwater acoustic beacon, the absolute coordinates of the equipment carrying the underwater acoustic beacon can be determined. For different complex situations in different waters, azimuth and attitude sensors such as gyroscopes are added, which can measure the angles and angular velocity changes of the overall spherical surface of the acoustic array when it fluctuates with the hull. At the same time, this information can be displayed on the upper computer in real time. A sound velocity profiler is added to collect and correct the sound velocity of the water area in real time. Through the positioning algorithm of the upper computer and by comprehensively considering the different test results of the above sensors, the positioning distance of the underwater acoustic beacon can be made more accurate.

[0057] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A sound array circuit system, including an FPGA processing unit, Characterized in that, The FPGA processing unit is respectively connected with a power supply module, an AD conversion circuit, a sound velocity profiler, a first DA conversion circuit and a second DA conversion circuit. The AD conversion circuit is connected with an amplification buffer circuit. The amplification buffer circuit includes a post-stage amplifier and a first buffer. The amplification buffer circuit is connected with a band-pass filter. The band-pass filter is connected with a programmable amplifier. The programmable amplifier is respectively connected with an analog front-end amplification circuit and the first DA conversion circuit. The analog front-end amplification circuit includes a differential amplifier. The analog front-end amplification circuit is connected with a limiting circuit. The limiting circuit is respectively connected with a plurality of receiving transducers. The second DA conversion circuit is connected with an attenuation buffer circuit. The attenuation buffer circuit includes an attenuator and a second buffer. The attenuation buffer circuit is connected with a low-pass filter. The low-pass filter is connected with a first-stage audio transformer. The first-stage audio transformer is connected with a digital audio power amplifier. The digital audio power amplifier is respectively connected with a second-stage audio transformer and the FPGA processing unit. The second-stage audio transformer is connected with an impedance matching circuit. The impedance matching circuit is connected with a transmitting transducer.

2. The sound array circuit system according to claim 1, Characterized in that, The first DA conversion circuit is connected with the programmable amplifier through an operational amplifier buffer circuit. The operational amplifier buffer circuit includes an inverting operational amplifier and a third buffer.

3. The sound array circuit system according to claim 1, Characterized in that, The band-pass filter is an eighth-order Butterworth band-pass filter.

4. The sound array circuit system according to claim 1, Characterized in that, The low-pass filter is a second-order Bessel low-pass filter.

5. The sound array circuit system according to claim 1, Characterized in that, The FPGA processing unit is further connected with a GPS positioning module.

6. The sound array circuit system according to claim 1, Characterized in that, The FPGA processing unit is further connected with an azimuth attitude sensor. The azimuth attitude sensor includes a gyroscope.

7. The sound array circuit system according to claim 1, Characterized in that, The FPGA processing unit is further connected with a communication serial port.

8. The sound array circuit system according to claim 1, Characterized in that, The digital audio power amplifier is connected with the FPGA processing unit through a circuit provided with a relay.

9. The sound array circuit system according to claim 1, Characterized in that, The power supply module includes a main power supply inlet and a 5V isolation chip.

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