阅读说明：本技术 水池近场的双水听器相位差校准测量系统及其相位差校准测量方法 (Bi-hydrophone phase difference calibration and measurement system and method for near field of pool ) 是由 孙大军 兰华林 吕云飞 梅继丹 师俊杰 滕婷婷 靳建嘉 于 2019-10-22 设计创作，主要内容包括：水池近场的双水听器相位差校准测量系统及其相位差校准测量方法,属于水声测量技术领域,为解决现有低频近场条件下位置误差对双水听器相位差校准影响大的问题。低频发射换能器刚性安装在支架的中部,两个水听器分别刚性安装在支架的两端,信号源发射的信号经过功率放大器提供给低频发射换能器,采用双通道数据采集器对两路数据进行同步采集；采集到的两路数据经过数据处理获得每个频点的相位；经过多次测量后求取平均值,获得两个水听器所在两个通道信号的相位差；将两个水听器的位置互换,获得两个水听器换位置后所在两个通道信号的相位差,求取两个相位差的平均值,获得测量系统所需测量的相位差。本发明用于对低频近场条件下的相位差测量。(A phase difference calibration and measurement system and a phase difference calibration and measurement method for a hydrophone of a pool near field belong to the technical field of underwater sound measurement and aim to solve the problem that position errors have large influence on phase difference calibration of the hydrophone under the existing low-frequency near field condition. The low-frequency transmitting transducer is rigidly arranged in the middle of the bracket, the two hydrophones are rigidly arranged at two ends of the bracket respectively, signals transmitted by the signal source are provided to the low-frequency transmitting transducer through the power amplifier, and two paths of data are synchronously acquired by adopting the two-channel data acquisition unit; the two collected paths of data are subjected to data processing to obtain the phase of each frequency point; after multiple measurements, an average value is obtained to obtain the phase difference of signals of two channels where the two hydrophones are located; and interchanging the positions of the two hydrophones to obtain the phase difference of the signals of the two channels where the two hydrophones are positioned after the positions of the two hydrophones are interchanged, and solving the average value of the two phase differences to obtain the phase difference required to be measured by the measuring system. The method is used for measuring the phase difference under the condition of the low-frequency near field.)

1. The hydrophone phase difference calibration and measurement system for the near field of the pool is characterized by comprising a low-frequency sound source transmitting system (1), a hydrophone receiving system (2) and a support (3);

the low-frequency sound source transmitting system (1) comprises a low-frequency transmitting transducer (11), a power amplifier (12) and a signal source (13);

the double-hydrophone receiving system (2) comprises two hydrophones (21), two signal conditioning circuits (22) and a double-channel data acquisition unit (23);

the low-frequency transmitting transducer (11) is rigidly arranged in the middle of the bracket (3), the two hydrophones (21) are respectively and rigidly arranged at the two ends of the bracket (3),

the signal transmitted by the signal source (13) is supplied to the low-frequency transmitting transducer (11) through the power amplifier (12), the low-frequency transmitting transducer (11) transmits a chirp signal,

the two hydrophones (21) receive the linear frequency modulation signals and convert the linear frequency modulation signals into electric signals, the electric signals are filtered and amplified through a signal conditioning circuit (22), and two paths of data are synchronously collected through a two-channel data collector (23);

the two collected paths of data are subjected to data processing to obtain the phase of each frequency point;

after multiple measurements, the average value is obtained to obtain the phase difference of signals of two channels where the two hydrophones (21) are located;

the positions of the two hydrophones (21) are exchanged to obtain the phase difference of the signals of the two channels where the two hydrophones (21) are positioned after the positions are exchanged,

and calculating the average value of the two phase differences to obtain the phase difference required to be measured by the measuring system.

2. The hydrophone phase difference calibration measurement system of the near field of the water pool of claim 1, wherein the low frequency transmitting transducer (11) and the two hydrophones (21) are equally spaced by 1 meter.

3. The hydrophone phase difference calibration measurement system of the near field of the pool of water of claim 1, wherein the low frequency transmitting transducer (11) and the two hydrophones (21) are at equal depth from the water surface, both being half the depth of water.

4. The hydrophone phase difference calibration measurement system of pool near-field according to claim 1, characterized in that the chirp signal emitted by the low frequency emitting transducer (11) is set to:

the bandwidth of the frequency modulation is set according to the phase difference calibration requirement;

the pulse width is 30 s;

the amplitude is adjusted by the output amplitude of the signal source (13) and the gain of the power amplifier (12) so that the signal-to-noise ratio of the signals received by the two hydrophones (21) is greater than 20 dB.

5. The phase difference calibration and measurement method of the hydrophone phase difference calibration and measurement system based on the pool near field of claim 1, characterized in that the specific process of the measurement method is as follows:

s1, mounting the low-frequency transmitting transducer (11) and the two hydrophones (21) on the support (3);

s2, receiving the chirp signals transmitted by the low-frequency transmitting transducer (11) by the two hydrophones (21) and converting the chirp signals into electric signals;

s3, the signal conditioning circuit (22) filters and amplifies the electric signal obtained in S2, and the two-channel data acquisition unit (23) acquires two paths of data synchronously;

s4, solving a cross-power spectrum of the two collected paths of data by adopting a periodogram method;

s5, obtaining an argument according to the cross-power spectrum, wherein the argument is the phase of the cross-power spectrum corresponding to each frequency point;

s6, obtaining an average value after N times of measurement;

S7、S6, the average value is the phase difference of the signals of two channels where two hydrophones (21) are positioned

Wherein:

s8, interchanging the positions of the two hydrophones (21), and repeatedly executing S2-S6 to obtain the phase difference of the signals of the two channels where the two hydrophones (21) are positioned after being transposed

Wherein:representing the phase of the cross-power spectrum corresponding to each frequency point after the positions of the two hydrophones (21) are changed;

s9, calculating the average value of the two phase differences of S7 and S8, namely the phase difference required to be measured by the measuring system:

6. the phase difference calibration measurement method of the hydrophone phase difference calibration measurement system based on the pool near-field according to claim 5, wherein the specific process of obtaining the cross-power spectrum by the periodogram method in S4 is as follows:

the two collected data are segmented in the same segmentation mode, discrete Fourier transform is carried out on each segment of data, the Fourier transform results of the data segments corresponding to the two data segments are subjected to conjugate multiplication, the cross spectrum result of each data segment is obtained, the cross spectrum results of all the data segments are averaged, and the cross power spectrum of the two data segments is obtained.

7. The phase difference calibration measurement method of the hydrophone phase difference calibration measurement system based on the pool near-field according to claim 5 or 6, wherein the specific method for obtaining the argument from the cross-power spectrum in S5 is as follows:

the cross power spectrum of the two paths of data is complex, and the included angle between the vector corresponding to the complex and the positive direction of the real axis is the argument.

Technical Field

The invention relates to a double hydrophone phase difference calibration and measurement system of a pool near field and a phase difference calibration and measurement method thereof, belonging to the technical field of underwater acoustic measurement.

Background

Phase errors between channels are an important factor affecting the signal processing of the array. The phase error is composed of two parts, namely the phase difference caused by the circuit system between channels and the phase difference caused by the hydrophone. The phase difference caused by the inter-channel circuitry can be measured using electrical signals. While the phase difference between the hydrophones needs to be calibrated by measurement with the acoustic source.

For low-frequency signals, it is difficult to satisfy far-field conditions in a pool of limited size, which mainly shows that the position error of the acoustic center of the hydrophone or the position error of the acoustic source has a large influence on the phase error.

Disclosure of Invention

The invention aims to solve the problem that the phase difference calibration of a hydrophone is greatly influenced by position errors under the condition of a low-frequency near field, and provides a hydrophone phase difference calibration and measurement system of a pool near field and a phase difference calibration and measurement method thereof.

The invention relates to a hydrophone phase difference calibration and measurement system of a near field of a pool, which comprises a low-frequency sound source transmitting system, a hydrophone receiving system and a bracket;

the low-frequency sound source transmitting system comprises a low-frequency transmitting transducer, a power amplifier and a signal source;

the double hydrophone receiving system comprises two hydrophones, two signal conditioning circuits and a two-channel data acquisition unit;

the low-frequency transmitting transducer is rigidly arranged in the middle of the bracket, the two hydrophones are respectively and rigidly arranged at the two ends of the bracket,

the signal transmitted by the signal source is provided to the low-frequency transmitting transducer through the power amplifier, the low-frequency transmitting transducer transmits a chirp signal,

the two hydrophones receive the linear frequency modulation signals and convert the linear frequency modulation signals into electric signals, the electric signals are filtered and amplified through a signal conditioning circuit, and two paths of data are synchronously collected through a two-channel data collector;

the two collected paths of data are subjected to data processing to obtain the phase of each frequency point;

after multiple measurements, an average value is obtained to obtain the phase difference of signals of two channels where the two hydrophones are located;

interchanging the positions of the two hydrophones to obtain the phase difference of the signals of the two channels where the two hydrophones are positioned after the positions of the two hydrophones are interchanged,

and calculating the average value of the two phase differences to obtain the phase difference required to be measured by the measuring system.

Preferably, the chirp signal emitted by the low frequency transmitting transducer is set to:

the bandwidth of the frequency modulation is set according to the phase difference calibration requirement;

the pulse width is 30 s;

the amplitude is adjusted by the output amplitude of the signal source and the gain of the power amplifier, so that the signal-to-noise ratio of the signals received by the two hydrophones is more than 20 dB.

The invention relates to a phase difference calibration and measurement method of a hydrophone phase difference calibration and measurement system based on a pool near field, which comprises the following specific processes:

s1, mounting the low-frequency transmitting transducer and the two hydrophones on a support;

s2, the two hydrophones receive the linear frequency modulation signals transmitted by the low-frequency transmitting transducer and convert the linear frequency modulation signals into electric signals;

s3, the signal conditioning circuit filters and amplifies the electric signal obtained in S2, and the two-channel data acquisition unit acquires two paths of data synchronously;

s4, solving a cross-power spectrum of the two collected paths of data by adopting a periodogram method;

s5, obtaining an argument according to the cross-power spectrum, wherein the argument is the phase of the cross-power spectrum corresponding to each frequency point;

s6, obtaining an average value after N times of measurement;

the average value obtained by S7 and S6 is the phase difference of the signals of two channels where two hydrophones are positioned

Wherein:

the phase of the cross-power spectrum corresponding to each frequency point is represented, i represents the ith frequency point, and i is 1,2, … and N;

s8, interchanging the positions of the two hydrophones, repeatedly executing S2-S6, and obtaining the phase difference of the signals of the two channels where the two hydrophones are positioned after the positions of the two hydrophones are interchanged

Wherein:representing the phase of each frequency point corresponding to the cross-power spectrum after the two hydrophones are transposed;

s9, calculating the average value of the two phase differences of S7 and S8, namely the phase difference required to be measured by the measuring system:

preferably, the specific process of obtaining the cross-power spectrum by using the periodogram method in S4 is as follows:

the two collected data are segmented in the same segmentation mode, discrete Fourier transform is carried out on each segment of data, the Fourier transform results of the data segments corresponding to the two data segments are subjected to conjugate multiplication, the cross spectrum result of each data segment is obtained, the cross spectrum results of all the data segments are averaged, and the cross power spectrum of the two data segments is obtained.

Preferably, the specific method for obtaining the argument according to the cross-power spectrum in S5 is:

the cross power spectrum of the two paths of data is complex, and the included angle between the vector corresponding to the complex and the positive direction of the real axis is the argument.

The invention has the advantages that: the hydrophone phase difference calibration and measurement system and the method for calibrating and measuring the phase difference of the pool near field can eliminate the influence of large phase difference measurement errors caused by position errors and inaccurate acoustic centers under the condition of a low frequency near field, and obtain the phase difference of the hydrophone under the condition of a low frequency.

Drawings

FIG. 1 is a schematic view of the arrangement of a low frequency transmitting transducer and two hydrophones under a pool of water according to the present invention;

FIG. 2 is a schematic block diagram of the hydrophone phase difference calibration measurement system of the near field of the water pool of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.