A scalar and vector hydrophone composite linear array for underwater three-dimensional positioning

Abstract

The present invention belongs to the field of acoustic metrology and testing, and specifically relates to a scalar and vector hydrophone composite line array for underwater three-dimensional positioning, including a composite line array. The composite line array includes a vector hydrophone, a sound beacon 1, a sound beacon 2, and a scalar line array. One end of the scalar line array is provided with a sound beacon 1, the other end of the scalar line array is provided with a vector hydrophone, one end of the vector hydrophone is provided with a sound beacon 2, and a counterweight is connected to one end of the sound beacon 2. The sound beacon 1 and the sound beacon 2 cooperate with an ultra-short baseline installed on an external seagoing ship to correct the attitude of the composite line array. The present invention uses a combination of a scalar line array and vector hydrophone array elements, and utilizes the directivity characteristics of the vector hydrophone in the horizontal direction to fill the deficiency that it is difficult to separate interference in the horizontal directivity of the scalar line array, and also utilizes the stability of the scalar line array in water measurement to make up for the disadvantage of poor stability of the vector hydrophone, improving the accuracy of calibration measurement.

Description

Technical Field

[0001] The present invention belongs to the field of acoustic metrology and testing, and particularly relates to a scalar and vector hydrophone composite linear array for underwater three-dimensional positioning. Background Art

[0002] With the progress of sonar technology, while the detection ability of underwater sonar is improving, its structural composition is becoming increasingly complex. From single transducers to multi-transducers, and from omnidirectional emission to beamforming, the technical composition of the software and hardware of sonar emission systems is also becoming more diverse. While the function is enhanced, the performance of sonar in different environments is more likely to change. First of all, the performance of sonar transducers itself will change over time. Currently, most sonar equipment uses multi-element arrays. When sonar works, it needs the cooperation of each element in the array to meet the performance requirements. In this case, even if the performance change of each element transducer is very small, the superposition of the performance changes of the element transducers may cause an obvious change in sonar performance. Secondly, after the transducer is installed on the acoustic array frame in the sonar fairing of the submarine, due to the difference between the actual working environment of the sonar and the theoretical design and acceptance measurement environment, the design parameters and acceptance measurement parameters will be different from the performance parameters during actual use. In addition, affected by the harsh marine environment and other structures at the installation position on the submarine, the transducer installed in the sonar fairing of the submarine is affected by the scattered reflection of the array frame and the internal structure of the fairing; at the same time, after a period of time, the acoustic performance of the element will decline. When the underwater acoustic components of the sonar equipment are damaged or fail and are replaced with transducer elements with good performance, the performance parameters of the sonar equipment will also change. The above factors affecting sonar performance all occur after the sonar equipment has been installed and used for a period of time, which generates the need for on-line calibration of underwater sonar equipment. Among them, the transmitting source level of sonar is an important technical index to evaluate the performance of active sonar. Accurately calibrating the transmitting source level of sonar is of great significance for China's national defense construction, marine environment development, etc.

[0003] The linear array is the main equipment for measuring the transmitting source level of sonar. The traditional receiving linear array can reduce the influence of background noise and improve the signal-to-noise ratio through multi-element measurement, and separate the interference of sea surface reflection waves through signal processing means. However, due to the structural limitations of the linear array, it can only control the receiving directivity in the vertical plane, and the linear array is omnidirectional in the horizontal plane. This leads to the situation that when processing measurement data, if there is an interference sound source at the same depth as the measurement target, it is impossible to separate the interference sound source from the target sound source. In addition, due to the rapid undercurrents and large waves on the seabed, it will greatly affect the measurement attitude of the linear array on the seabed and also bring a large measurement uncertainty component. In order to improve the accuracy of calibration measurement, it is necessary to improve the receiving linear array used in the calibration test. Summary of the Invention

[0004] The main object of the present invention is to overcome the deficiencies of the prior art and provide a scalar and vector hydrophone composite linear array for underwater three-dimensional positioning.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A scalar and vector hydrophone composite linear array for underwater three-dimensional positioning, including a composite linear array, the composite linear array includes a vector hydrophone, a sound beacon one, a sound beacon two and a scalar linear array, one end of the scalar linear array is provided with a sound beacon one, the other end of the scalar linear array is provided with a vector hydrophone, one end of the vector hydrophone is provided with a sound beacon two, one end of the sound beacon two is connected with a counterweight, and the sound beacon one and the sound beacon two cooperate with an ultra-short baseline installed on an external seagoing ship to correct the attitude of the composite linear array.

[0007] Further, the sound beacon one and the sound beacon two are respectively placed on both sides of the scalar linear array, and the sound beacon one and the sound beacon two are positioned by an ultra-short baseline. Taking the ultra-short baseline as the origin, the x-axis, the y-axis and two mutually perpendicular straight lines in the horizontal direction coincide, and the z-axis coincides with the vertical direction to establish a coordinate system. If the position coordinates of the located sound beacons are (x1, y1, z1) and (x2, y2, z2) respectively, then the angle α between the composite linear array and the vertical direction should be:

[0008]

[0009] During the calibration process, α should not be greater than the main lobe width of the composite linear array. To achieve the calibration target, a counterweight needs to be set, and the calibration time should avoid the peak periods of flood tide and ebb tide to reduce the influence of undercurrents on the attitude of the composite linear array.

[0010] Further, after confirming the attitude of the composite linear array, the vector hydrophone judges whether the sound wave direction of the sound beacon deviates from the target direction, excludes interference signals, and is used to correct the reference system coordinates of the vector hydrophone. The electrical signals generated by the vector hydrophone are a total of 4 types, namely the projections P x 、P y 、P z of the sound wave vector on the x, y, and z axes and the modulus |P| of the sound wave vector. According to the vector calculation formula, the direction of the sound wave is calculated

[0011]

[0012] During the measurement process, it is necessary to first process the sound wave direction measured by the vector hydrophone, and then use formula (Ⅱ) to confirm the segment that is not affected by the interference source, and use this segment as valid experimental data.

[0013] Preferably, the operating frequency of the acoustic beacon exceeds 20 kHz, and the measurement range of the composite line array is below 20 kHz.

[0014] Preferably, the lower limit of the operating frequency of the composite line array is 2 kHz, and the distance between the elements of the composite line array should be greater than 37.5 cm.

[0015] Preferably, the number of elements on the composite line array should be no less than 6, and the total length of the composite line array should not exceed 3 m.

[0016] Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0017] In the present invention, the scalar and vector hydrophone composite line array for underwater three-dimensional positioning uses a combination of a scalar line array and vector hydrophone elements. By utilizing the directivity characteristics of the vector hydrophone in the horizontal direction, it fills the deficiency that it is difficult to separate interference in the horizontal directivity of the scalar line array. It also makes use of the stability of the scalar line array in underwater measurement to make up for the disadvantage of poor stability of the vector hydrophone, thereby improving the accuracy of calibration measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of the composite line array of the present invention;

[0019] Figure 2 is a schematic diagram of the principle for the ultra-short baseline positioning acoustic beacon to judge the attitude of the composite line array of the present invention;

[0020] Figure 3 is a schematic diagram of the signal composition of the vector hydrophone of the present invention.

[0021] The markings in the figure are as follows:

[0022] 1 - Vector hydrophone; 2 - Acoustic beacon one; 3 - Acoustic beacon two; 4 - Scalar line array; 5 - Counterweight; 6 - Ultra-short baseline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will clearly and completely describe the technical solutions in the embodiments with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all. Based on the embodiments, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] As shown in the attached Figure 1As shown in the figure, on the basis of the traditional scalar line array 4, a vector hydrophone 1 and two acoustic beacons are added. The vector hydrophone 1 can separate the sound waves received in different directions, providing known conditions for the positioning and calibration of the composite line array in the horizontal plane. When performing signal processing, it is possible to better exclude the interference of non-target sound sources. The acoustic beacons can cooperate with the ultra-short baseline installed on the ship to correct the attitude of the composite line array. The acoustic beacons refer to acoustic beacon one 2 and acoustic beacon two 3.

[0025] A scalar and vector hydrophone composite line array for underwater three-dimensional positioning, including a composite line array. The composite line array includes a vector hydrophone 1, acoustic beacon one 2, acoustic beacon two 3, and a scalar line array 4. One end of the scalar line array 4 is provided with acoustic beacon one 2, and the other end of the scalar line array 4 is provided with a vector hydrophone 1. One end of the vector hydrophone 1 is provided with acoustic beacon two 3. One end of the acoustic beacon two 3 is connected with a counterweight 5. Acoustic beacon one 2 and acoustic beacon two 3 cooperate with the ultra-short baseline 6 installed on the external ship to correct the attitude of the composite line array.

[0026] During the measurement process, the composite line array will be affected by ocean currents with different depths and speeds, and the attitude of the composite line array will also change. The ways of attitude change are mainly divided into two types. The first is the position offset of the receiving array caused by the relative speed between the ocean current and the test ship. The second is the deformation of the receiving array caused by the change of ocean current speed with depth.

[0027] In order to effectively reduce the measurement uncertainty through attitude correction, the installation positions of the two acoustic beacons need to be determined. First, the positions of the acoustic beacons must be on both sides of the scalar line array 4 and the vector hydrophone 1. Therefore, the positions of all array elements can be confirmed. If the acoustic beacons are installed on the same side of the composite line array, it will cause the deformation amount of the scalar line array 4 not to be introduced during attitude correction. Secondly, the distance between the acoustic beacons should not be too far. If the distance is too far, the deformation situation of the scalar line array 4 between the acoustic beacons will increase, which is also not conducive to the installation and deployment of the composite line array. Therefore, the acoustic beacons should be installed at both ends of the composite line array as much as possible.

[0028] Acoustic beacon one 2 and acoustic beacon two 3 are placed on both sides of the scalar line array 4. The acoustic beacon one 2 and acoustic beacon two 3 are positioned through the ultra-short baseline 6. Taking the ultra-short baseline 6 as the origin, the x-axis, y-axis and two mutually perpendicular lines in the horizontal direction coincide, and the z-axis coincides with the vertical direction to establish a coordinate system. If the position coordinates of the located acoustic beacons are (x1, y1, z1) and (x2, y2, z2) respectively, then the angle α between the composite line array and the vertical direction should be:

[0029]

[0030] During the calibration process, α should not be greater than the main lobe width of the composite line array. To achieve the calibration goal, a counterweight 5 needs to be set, and the calibration time should avoid the peak periods of high and low tides to reduce the impact of undercurrents on the attitude of the composite line array.

[0031] After confirming the attitude of the composite line array, the vector hydrophone 1 determines whether the direction of the acoustic beacon sound wave deviates from the target direction, excludes interference signals, and is used to correct the reference system coordinates of the vector hydrophone 1. The electrical signals generated by the vector hydrophone 1 are of 4 types, namely the projections P x 、P y 、P z of the acoustic wave vector on the x, y, and z axes and the modulus |P| of the acoustic wave vector. According to the vector calculation formula, the direction of the acoustic wave is calculated.

[0032]

[0033] During the measurement process, it is necessary to first process the direction of the acoustic wave measured by the vector hydrophone 1, and then use formula (Ⅱ) to confirm the segment that is not affected by the interference source, and use this segment as valid experimental data. When the vibration frequencies of the interference source and the target sound source are similar, it is difficult to judge whether the composite line array data is interfered by the interference source. If the direction of the acoustic wave measured by the vector hydrophone 1 deviates, it can be confirmed that there is an interference source. Generally, the duration of each signal acquisition in the measurement experiment is about 20S - 20S. Through the vector hydrophone 1, it can be clearly judged whether the signals collected during a certain period are interfered by an interference source, and then a suitable segment is selected for signal processing.

[0034] Specifically, the operating frequency of the acoustic beacon exceeds 20 kHz, and the measurement range of the composite line array is below 20 kHz.

[0035] Specifically, the lower limit of the operating frequency of the composite line array is 2 kHz, and the distance between the elements of the composite line array should be greater than 37.5 cm; in order to reduce the interference of ocean background noise on the measurement results, the number of elements on the composite line array should not be less than 6, and the total length of the composite line array should not exceed 3 m. The vector hydrophone 1 is suspended below the scalar line array 4. In addition to excluding the interference of non-target sound sources, the measurement results of its sound pressure can also be involved in the calculation.

[0036] The specific working principle of the present invention is as follows:

[0037] 1) Place the scalar and vector hydrophone composite line array into the water;

[0038] 2) Before measurement, use the ultra-short baseline 6 to locate the acoustic beacon one 2 and the acoustic beacon two 3, and use formula (Ⅰ) to recognize the attitude of the composite line array;

[0039] 3) During the measurement process, use formula (II) to observe whether the direction of the sound wave measured by the vector hydrophone 1 deviates from the target direction, and collect the signal after excluding interference;

[0040] 4) Before processing the measurement signal, it is necessary to first process the direction of the sound wave measured by the vector hydrophone 1, use formula (II) again to confirm the segment that is not affected by the interference source, and use this segment as the effective experimental data.

[0041] The above are only the preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any modification and replacement based on the technical solutions and inventive concepts provided by the present invention should be covered by the protection scope of the present invention.

Claims

1. A scalar and vector hydrophone composite line array for underwater three-dimensional positioning, comprising a composite line array, characterized in that: The composite line array includes a vector hydrophone (1), a first acoustic beacon (2), a second acoustic beacon (3), and a scalar line array (4). One end of the scalar line array (4) is provided with the first acoustic beacon (2), and the other end of the scalar line array (4) is provided with the vector hydrophone (1). One end of the vector hydrophone (1) is provided with the second acoustic beacon (3). One end of the second acoustic beacon (3) is connected with a counterweight (5). The first acoustic beacon (2) and the second acoustic beacon (3) cooperate with an ultra-short baseline (6) installed on an external seagoing ship to correct the attitude of the composite line array. The first acoustic beacon (2) and the second acoustic beacon (3) are respectively arranged on both sides of the scalar line array (4). The first acoustic beacon (2) and the second acoustic beacon (3) are positioned by the ultra-short baseline (6). Taking the ultra-short baseline (6) as the origin, the x-axis, the y-axis, and two mutually perpendicular lines in the horizontal direction coincide, and the z-axis coincides with the vertical direction to establish a coordinate system. If the position coordinates of the located acoustic beacons are respectively (x1, y1, z1) and (x2, y2, z2), then the angle α between the composite line array and the vertical direction should be: During the calibration process, α should not be greater than the main lobe width of the composite line array. To achieve the calibration target, it is necessary to set the counterweight (5), and the calibration time should avoid the peak periods of flood tide and ebb tide to reduce the influence of groundswell on the attitude of the composite line array. After confirming the attitude of the composite line array, the vector hydrophone (1) determines whether the direction of the acoustic beacon sound wave deviates from the target direction, excludes interference signals, and is used to correct the reference system coordinates of the vector hydrophone (1). There are 4 types of electrical signals generated by the vector hydrophone (1), namely the projections P x 、P y 、P z on the x, y, and z axes of the acoustic wave vector, and the modulus |P| of the acoustic wave vector. According to the vector calculation formula, the direction of the acoustic wave is calculated During the measurement process, it is necessary to first process the direction of the sound wave measured by the vector hydrophone (1), and then use formula (Ⅱ) to confirm the segment that is not affected by the interference source, and use this segment as the effective experimental data.

2. The scalar and vector hydrophone composite line array for underwater three-dimensional positioning according to claim 1, characterized in that: The working frequency of the acoustic beacon exceeds 20 kHz, and the measurement range of the composite line array is lower than 20 kHz.

3. The scalar and vector hydrophone composite line array for underwater three-dimensional positioning according to claim 1, characterized in that: The lower limit of the working frequency of the composite line array is 2 kHz, and the distance between the array elements of the composite line array should be greater than 37.5 cm.

4. The scalar and vector hydrophone composite line array for underwater three-dimensional positioning according to claim 3, characterized in that: The number of array elements on the composite line array should not be less than 6, and the total length of the composite line array does not exceed 3 m.

Images