RU19161U1 - THE WAY OF DETERMINING AND MONITORING HYDROACOUSTIC INTERFERENCE TO THE WORK OF A HYDROACOUSTIC MEANS - Google Patents

Description

The path for the determination and control of sonar interference to the work of sonar

The utility model relates to the sonar field of technology, and more specifically, to the paths for determining and monitoring sonar interference to the sonar tool. Hydroacoustic interference - an acoustic wave propagating in an aqueous medium and not being a signal for a given hydroacoustic means (GOST 22547-81, Hydroacoustic means). Hydroacoustic interference is the main factor limiting the range of sonar. Hydroacoustic interference is divided into noise of the sea and the noise of ships carrying hydroacoustic means.

A known path for the determination and control of sonar interference on a ship from the book of R.D. Urik. Basics, sonar. - D .: shipbuilding, 1978, - S. 371-372, containing a series-connected sonar antenna, an amplification path and a rms voltage meter (Fig. 1). The level of hydroacoustic interference, measured at the output of the directional hydroacoustic antenna, is manually converted to the equivalent level of isotropic noise, which would have been with undirectional radiation.

The disadvantage of this tract is the practical impossibility of reducing to undirectional under conditions of anisotropic noise of the sea.

The closest analogue adopted for the prototype is the path for the determination and control of sonar interference, described in the book B, M, Bolgov, D, D. Plakhov, V, E, Yakovlev. Acoustic noise and

interference on ships. L .; Shipbuilding, 1984. - p. 157-161. The sonar interference detection and control path includes a servo-sonar antenna consisting of electro-acoustic transducers, a linear multichannel amplifier, a directivity beamforming device, a voltmeter, or a calibrated level recorder (p. 161 second paragraph from above the mentioned book). The magnitude of ship hydroacoustic interference is determined when the sea state is close to calm in the water area with a depth of three to four depths of the ship's hull, at a great distance from the coast and shipping lanes (more than 5-7 km). In measurements, a directivity characteristic formed by the entire aperture of the antenna is used. The measurement result is recalculated to equivalent conditions: non-directional reception, reference frequency, unit band according to the formula: where: 1Ап SQ, 4 К Vi vj 4et is the rms interference voltage at the channel output. IN; gain; electro-acoustic sensitivity of the hydro-acoustic antenna, concentration coefficient of the hydro-acoustic antenna; reference frequency, Hz; geometric mean frequency of the working range of the sonar, Hz;

in (I) the calculated concentration coefficient is usually used, since K measurement on ships is difficult. Therefore, it is more correct to speak not about measuring interference, but about determining them.

The disadvantage of the path of the prototype is its suitability only for the determination and control of the noises of ships carrying hydroacoustic means. Progress in the field of shipbuilding has led to the fact that at present, ship noise is dominated by ships that have pronounced anisotropy, especially in the vertical plane (Fig. 3). Hydroacoustic devices are designed for a specific sea level at which the noise level is set, which can be received by an omnidirectional hydrophone. In the anisotropic noise of the sea, it is impossible to use the concentration coefficient in formula (I), since it is applicable only to an isotropic acoustic field. The hydrophone installed in the fairing of the hydroacoustic antenna loses its directional property and cannot be used. Using the calculated value of the noise immunity coefficient is practically not possible, since the noise immunity coefficient is an integral convolution of millet: the natural spectrum of sea noise (about which information is practically absent on the ship) and the spatial directivity of the hydroacoustic antenna placed in the ship's fairing. The second disadvantage of the prototype path is that it does not provide the definition and control of sonar interference in narrow spectral bands in which modern sonar tools work.

The objective of the utility model is to create a path for the determination and control of hydroacoustic interference to the operation of hydroacoustic means, use) to ensure the determination of hydroacoustic interference in

. the process of testing and operating sonar equipment with prevailing sea noise and for determining sonar noise during spectral analysis (FIG. 4),

To solve this problem, this path is made in the form of sequentially. . - -Jr, -.: Connected sonar antennas from electro-acoustic transducers, a linear multichannel amplifier, a directivity beam former. A serial analyzer is introduced into the path, the input of which is connected to the output of the shaper of the directivity characteristic, a conversion unit to an equivalent level, and an indicator is also introduced

 CHANNEL

a linear amplifier, the input of which is connected to the output of a single electro-acoustic transducer of a hydro-acoustic antenna, and the output is connected to the second input of a spectrum analyzer, while an electro-acoustic transducer with a solution of directivity at a level of 0.7 in pressure is much larger than the solution of the refractive minimum of sea noise and the directivity axis is engraved horizontally, a control unit connected to digital units has also been introduced

In a number of cases, anisotropy of the noise of the sea is observed in the horizontal plane, for example, from the noise of the sea, noise from shipping lanes, during a squall, from accumulations of sea fairings, from hummocking of ice, etc. Therefore, noise is received not by one but several electro-acoustic transducers sonar antenna, with the axes of the directivity characteristics directed in different directions horizontally (at different directional angles)

Due to the fact that the dynamic noise of the sea is mainly due to the sea waves, the sea noise in the upper hemisphere is larger than in the lower hemisphere (Fig. 3). Therefore, noise is additionally used

electro-acoustic transducers of a hydro-acoustic antenna, the axes of the directivity characteristics of which are directed not only at the raster course angles, but also at different elevation angles relative to the horizon.

For this, in some cases, in parallel with the amplifier of Fig. 4, additionally connected 1 amplifiers are introduced, the inputs of which are connected to I-electroacoustic transducers, the axes of the directivity characteristics of which are located at different directional angles and different elevation angles within the solid viewing angles of space, and the outputs are connected to 2, I inputs of a spectrum analyzer (figure 5),

The technical result from the use of the utility model is the ability to determine and control sonar interference as a ship’s sink, and when noise from the anisotropic noise prevails. This is achieved by identifying and controlling interference during operation with the help of unidirectional receiving channels in the proposed path construction.

The essence of the utility model is illustrated in the figures:

In Fig. 1 is a block diagram of an analog device.

Figure 2 shows a block diagram of a prototype device.

Figure 3 shows, for example, one of the characteristics of the anisotropy of ocean noises in a vertical plane at a frequency of 4 °.

Figure 4 shows a block diagram of a utility model with two amplifiers.

In Fig. 5 is a block diagram of a utility model with I- + I amplifiers.

interference to the operation of hydroacoustic means on a ship, according to figure 4, made in the form of series-parallel connected hydroacoustic antennas from electroacoustic transducers I, a linear multichannel amplifier 4, a shaper of directivity 5, a spectrum analyzer 7, a conversion unit to an equivalent level 8, indicator 9, also containing parallel to O HOvCAV AN VlblK

member; a linear amplifier 10, the input of which is connected to the output of a single electro-acoustic transducer of the antenna I, and the output to the second input of the spectrum analyzer 7, also introduced control unit II, connected to the spectrum analyzer 7, the conversion unit to the equivalent level 8 and indicator 9,

For the design scheme of the device, it is also important to select the directivity characteristics of the electro-acoustic transducer of antenna I, As is known (Acoustics of the Ocean / Ed. .. Brekhovskkk. M .: Nauka, 1974), in the deep-sea region okes1a the level of sea noise with non-directional reception:

P 30 - 16.8 8.5 (2)

where: P is the noise level in the band of I Hz at a frequency, dB, relative to 2 10 Pa;

 - frequency, kHz;

 wind speed, .

If the speed of sound at the surface of Cn is greater than the speed of sound Go at the position of the sonar antenna I, then the rays coming out at angles in the range of values

, (3)

will not reach the surface (B, M, Bodgov D.D. Plakhov, V.E. Yakovlev. Acoustic noises and interference on ships. - I .: Shipbuilding, 1984. p.77), for this reason the intensity of the noise coming in the observation point in this range of angles has a maximum.

If the directivity characteristic of the electro-acoustic transducer of the hydro-acoustic antenna I had the form of a hemisphere with an axis in the horizontal direction, then the noise level of the sea could be defined as the doubled intensity of the received noise. When the directionality is close to hemispherical, the concentration coefficient can be taken into account. This is achieved by the fact that in the case when the solution has directivity characteristics in vertical

§ {, the error does not exceed approximately I dB when determining the level P of sea noise using this receiver.

The measurement and control of hydroacoustic interference to the work of a hydroacoustic tool on a ship works as follows. Hydroacoustic interference in the form of shipborne noise and noise of the sea (dynamic, technical, shipping, bionic and other types) affect the electroacoustic transducers of hydroacoustic antenna I. They are amplified in a linear multi-channel amplifier 4 and in additional linear amplifiers 10,11, ... , + I, The signals amplified in block 4 are fed to a directivity characteristic shaper 5, the output of which is connected to a spectrum analyzer 7. In a spectrum analyzer 7, energy spectra are generated ( t (4-); JiW;; rP / for all receiving channels. These energy spectra are reduced to equivalent levels in block 8 according to the algorithm

where: TL (H is the energy spectrum for the Uth receiving channel,. I, va + I; 1 is the frequency response of the sensitivity of the Lth

channel, L I, And +1; , Ш - concentration coefficient of the nth receiving channel,

L 1GNGTT;

 Jf.- resolution spectral analysis.

Prior to the output of the directivity characteristics of the hydroacoustic antenna I, the hydroacoustic interference is measured during the delivery of the vessel and periodically monitored in calm weather at special ranges. During operation, sonar interference is measured and monitored through channels 10, II, ..., iru-1, which are affected by both ship noise and sea noise interference.

In the block of conversion to equivalent level 8, both reduced values are calculated for the output of the directional characteristics of the hydroacoustic antenna I, and for each of the electro-acoustic transducers 10.11, ..., yy + I. In addition, in some cases, the averaged values are grouped closely located electro-acoustic transducers, for example, along the paths of amplifiers 10, II, 12, when they are located in the bow tip, along the group of paths of amplifiers 13, 14, 15 when they are located on the port side and the like.

The construction of blocks and the detection and control of sonar interference is known from the practice of sonar technology.

S G- / 1

Claims (2)

1. The path for the determination and control of hydroacoustic interference to the operation of a hydroacoustic device (HAS), containing a series-connected sonar antenna from electro-acoustic transducers, a linear multi-channel amplifier and a directivity beamformer, characterized in that a series-connected spectrum analyzer is introduced into it, the input of which is connected to the output of the characteristic shaper directionality, a unit for converting to the equivalent level of hydroacoustic interference and an indicator, also a single-channel linear amplifier, the input of which is connected to the output of a single electro-acoustic transducer, and the output is connected to the second input of the spectrum analyzer, a control unit is also introduced, the input and outputs of which are connected to the spectrum analyzer, with a directivity characteristics shaper, a unit for converting to the equivalent level of hydroacoustic interference and an indicator, the electro-acoustic transducer has a solution of directivity much larger than the solution of the refractive minimum of sea noise and the directivity axis is oriented horizontally. 2. The path for the determination and control of hydroacoustic interference to the operation of a hydroacoustic device (HAS) according to claim 1, characterized in that it is additionally introduced in parallel connected n single-channel amplifiers, the inputs of which are connected to n electro-acoustic transducers with solutions of directional characteristics, much larger than the solution of refractive minimum noise of the sea and with the axes of the directivity characteristics oriented at directional and elevation angles, within the solid angle of view of the HAS space, and the outputs of the amplifier connected to

spectrum analyzer inputs.