Device for determining direction towards a source of sound

FIELD: tool-making industry.

SUBSTANCE: in device for determining direction to a source of sound, consisting of two photo-electric shadow devices and information processing systems, laser beams are directed at an angle of 90° to each other. In each photo-electric shadow device after focusing objective laser beam is split onto two laser beams, and these two laser beams go to two knives with mutually perpendicular edges. Edge of one of aforementioned knives in each photo-electric shadow device is parallel to plane, parallel to laser beams. Information, received from two photo-receivers, standing behind these knives, is utilized for maintaining similar sensitivity of both photo-electric shadow devices. Output signals from one of these photo-receivers and two other photo-receivers of photo-electric shadow devices are squared, amplified and added. Signal at output of adder is maintained constant due to loop of negative check connection from output of adder to inputs of amplifiers. On basis of signals at outputs of amplifiers with consideration of mutual phases of signal at outputs of photo-detectors by means of phase detectors and electronic computing machine, direction towards sound source is determined.

EFFECT: expanded functional capabilities of device.

7 dwg, 2 tbl

The invention relates to the field of instrumentation, namely, devices for determining the direction to the sound source.

The known device for determining the direction to the sound source (CCLA, Medwin, Acoustical Oceanography, M., Mir, 1980, s) by means of a ruler of the n electroacoustic transducers located at the same distance from each other. Electric signals from the outputs of the converters are served on the n delay lines (smfg). Changing Δt (the difference in the delay of the signal between adjacent delay lines), change the delay of the signal τ=(n-1) Δt on the outputs of the delay lines.

The direction of the sound source is determined by the maximum total signal from the outputs of the delay lines when changing Δt or the maximum mutually correlation function. The angle of the direction to the source of the sound

where Δt_max- Δt, corresponding to the maximum signal;

Δl is the distance between the transducers;

C is the speed zvuchat device has the disadvantage that when the movement of the antenna in the environment occurs incremental noise (relative to the noise of the device and environment)caused by the flow medium of the protective shield of the antenna.

Promising for the detection of sound waves is the use of shadow devices (ETC), recording the presence in the environment of the gradient show the La refractive index (density), as the beam of light does not change in the environment. The deflection angle of a light beam

where z is the direction perpendicular to the light beam;

n is the refractive index of the medium;

L - length of the light beam in the environment.

where- the gradient of the refractive index of the pressure.

Typically, the angle θ measured by the shadow device that uses a parallel light beam in the volume measurement, the change of power of the light signal for the knife, which is placed at the focus of the lens focusing the light beam, using the photodetector, the output of which varies an electrical signal (Masramon, Eigerstrasse, Bphauman, Marine refractometry, L., Gidrometeoizdat, 1986, .183).

In General, when the divergent light beam in the measuring volume of the knife come after the focusing lens in the focus of the converging light beam, that is, in the image plane Svetozara diaphragm, or the laser beam in the plane of the minimum waist of the laser beam.

Known shadow photovoltaic device for registration of the change of pressure (Loucile, Shadow methods, M., Nauka, 1969, p.60). Using this device without making changes in the environment that can determine the presence of an acoustic wave, is not to determine the direction of the sound source.

As a prototype of the selected shadow photovoltaic device with dual filtered light field (Masramon and other Marine refractometry, s).

Shadow device with dual filtered light field, a block diagram is shown in figure 2, includes: a light source (in this case, an incandescent lamp) 1, a condenser 2, a light aperture 3, a lens 4, a protective glass 5, 6, the focusing lens 7, the knife in the form of a half-plane 8, the matching lens 9, the aperture 10, is placed in a plane optically conjugate with the plane located in the middle of the volume measurement (volume located between the protective glass), the photodetector 11.

The above-mentioned shadow a device for recording pressure changes (Masramon and other Marine refractometry, 1986, .183) differs from the shadow of the instrument with a dual filtration because it instead of the diaphragm 10 is installed aperture in front of the protective glass, which leads to an increase of the diffraction blur the image of the light aperture in the plane of the knife.

Note that additional filtering leads to the expansion of the bandwidth of spatial frequencies. The described device with a dual filtration is a type of devices operating according to the method of knife and slit. The use of laser as a light source increases the sensitivity shadow photoelectrics is on device (Masramon and others, Marine refractometry, s).

When using a laser as a light source, the condenser 2 and the lens 4 (see figure 2) are replaced by a telescopic system (collimator), serving to increase the diameter of the collimated laser beam, which leads to the reduction of noise at the output of the photomultiplier is caused by scattering of the laser beam by particles in the measuring volume.

Famous experiments, in which the shadow of the instrument were recorded pressure variations created in the sea of artificial sources (report on research Echo, NII FOOLIOS, St. Petersburg, 2001, inv. No. 4, p.60), however, using the described device it is impossible to determine the direction to the sound source. Indeed, for a parallel beam of light, the amount of movement of the image of the light aperture in the plane of focus of the focusing lens (plane x` y` figure 2) in a direction parallel to the projection of the pressure gradient and the projection vector of the sound waveon a plane perpendicular to the axis of the light beam oz in the environment depends on the magnitude of the gradient of pressure and sound power. The magnitude of this deviation:

where ϕ - the angle between the gradientand oz axis

F is the focal length of the lens.

If the volume is serenia beam, divergent:

where F_pdistance from the main plane of the focusing lens to the focus of the converging beam of light.

The magnitude of the signal U at the output of the photodetector is proportional to the magnitude of the projection of ρ on the ox axis`, perpendicular to the edge of a knife.

The result is:

where θ - the angle between the axis ox` and the direction of movement of the focal spot (the angle between the axis of the Oh` and a projectionon the plane x` y`).

It is obvious that the magnitude of the output signal U is impossible to determine the direction vector of the sound wave.

The aim of the invention is:

- empowering shadow device for determining the direction to the sound source in a given half-space, in which the values of one of the coordinates is always positive;

- determination of the guides of the cosines and the corresponding angles determining this direction;

- noise reduction acoustic antenna due to the use as a sensitive element of the laser beam, do not make changes in density in the environment.

This goal is achieved by the fact that the device (figure 3), consisting of two photovoltaic shadow devices, laser beams are directed into the medium at an angle of 90° each d is uh-huh, each of the two photoelectric shadow of devices contains consistently established laser, collimator, safety glass, safety glass, the focusing lens, a beam splitter for splitting the laser beam into two laser beam, two knives in the form of a half-plane with perpendicular edges, installed in each of the photoelectric shadow of the devices after the beam splitter, one in two planes of the minimum waist of the laser beams on the optical axes of the laser beams from the beam splitter, two matching lens installed one after each of these two knives, two of the photodetector in each of the photoelectric shadow devices, Postanovlenie one after each of the matching lenses in a plane optically conjugate with the middle of the measuring volume located between the protective glass, the outputs of the photodetectors are connected to the corresponding Quad outputs Quad connected to the respective pre-amplifiers, the edge of one of the knives in each photoelectric shadow instrument perpendicular to the plane parallel laser beams in the environment, two of the pre-amplifier (one in each photoelectric shadow instrument), their inputs connected across the Quad to the outputs of photodetectors mounted the donkey matching lenses and knives with edges, parallel planes, parallel laser beams in the environment, their outputs connected to a subtractive device, the output of subtractive device connected to the second inputs of the pre-amplifiers of one of the photovoltaic shadow devices, the pre-amp output of this photoelectric shadow device is not connected to the subtractive input device, and outputs pre-amplifier of another photovoltaic shadow instrument is connected to terminal amplifiers, the outputs of the final amplifiers connected to the adder and multi-channel analog-to-digital Converter; the output of the adder is connected to the second input terminal of the amplifier; the output of one of the two photodetectors installed after matching lenses and knives with edges parallel to the plane parallel to laser beams in the environment that are connected to the inputs of two phase detectors, to the second inputs of which are connected the outputs of the other two photodetectors corresponding to the knives, the edges of which are perpendicular to a plane parallel laser beams in the environment, the outputs of the phase detectors connected to the trigger, the outputs are connected to a multichannel analog-to-digital Converter, and the output multi-channel analog-to-digital Converter connected to the input of the electronic computer.

Nafig shows optical and structural scheme of the proposed optoelectronic device for determining the direction to the sound source, which contains: lasers 1, 22, collimators 2, 23, a protective glass 3, 4, 24, 25, the focusing lens 5, 26, splitters 6, 27, knives, 7, 10, 28, 34 in the form of half-planes, matching lenses 8, 11, 29, 35, photodetectors 9, 12, 30, 36, Quad 13, 19, 31, 37, pre-amplifiers 14, 20, 32, 38, terminal amplifiers 15, 21, 33, the adder 16, multichannel analog-to-digital Converter 17, subtractive device 18, the phase detector 39, 40, triggers, 41, 42, electronic computing machine 43.

Between protective glasses are volume measurements.

The laser beams of the lasers 1, 22 of the two photoelectric shadow of devices (nodes 1, 2, 3, 4, 5, 6, 7, 8, 9, 19, 20, 10, 11, 12, 13, 14 - the first photovoltaic shadow device) and (nodes 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 34, 35, 36, 37, 38 - the second photoelectric shadow unit) fall in the collimators 2, 23, which extend to reduce interference from light-scattering particles from the measuring volume. After the protective glass 3, 24, volume measurement and a protective glass 4, 25, laser beams directed into the medium at an angle of 90° to each other, the focusing lens 5, 26, and each of the laser beams is divided into two converging laser beam splitters 6, 27, after which the laser beams fall on two knife 7, 10 one photovoltaic shadow device, and accordingly, two knives 28, 34 other photovoltaic shadow instrument, to ascertain the data so to their edges in each photoelectric shadow device are mutually perpendicular, and the edge of one of the knives in each photoelectric shadow instrument is perpendicular to the plane parallel laser beams in the environment, after the knives 7, 10 laser beams penetrate through the corresponding matching lenses 8, 11 corresponding to each matching the lens to the photodetector 9, 12 in one photoelectric shadow instrument and, accordingly, after the knives 28, 34 through the corresponding matching lenses 29, 35 corresponding to each matching lens photodetectors 30, 36 in the other photovoltaic shadow instrument.

In the coordinate system in which the ox axis coincides with the direction in the environment of the laser beam from the laser 22, the oy axis coincides with the direction in the environment of the laser beam from the laser 1, and the axis oz is perpendicular to the laser beams, the sensor 9 senses the change of light is proportional to the projection of the movement of the waist of the laser beam on the ox axis, the sensor 12 senses a change in light, is proportional to the projection of the movement of the waist of the laser beam on the axis oz, the sensor 30 senses a change in light, is proportional to the projection of the movement of the waist of the laser beam on the axis oy, the sensor 36 senses a change in light, is proportional to the projection of the movement of the waist of the laser beam on OS is oz (see figure 4). The signals at the outputs of the photodetectors 12, 36 always correlated, as the laser beams through the corresponding matching lenses 11, 35 fall on the photodetectors 12, 36 after the knives 10, 34 with the edges perpendicular to the axis oz and parallel to the plane parallel laser beams in the environment.

Instantaneous values of the electrical signals at the outputs of the photodetector devices contain complete information about the directions of the deviations of the constrictions of the laser beams in the planes of the blades and the direction of the wave vector, oppositely directed to the direction of the sound source.

After Quad lose the information on the phase of the electrical signals, and the three modules of the values of the projections on the axes of coordinates of the vector that defines the direction of the sound source, there are four vector located in the four sectors of the half-space (smpeg):

sector I is limited to the plane xoz, the plane yoz and the first quadrant of the plane xoy;

sector II is limited to the plane xoz, the plane yoz and the second quadrant of the plane xoy;

sector III is limited to the plane xoz, the plane yoz and third quadrant of the plane xoy;

sector IV is limited to the plane xoz, the plane yoz and the fourth quadrant of the plane xoy.

Line parallel to the projection of the vector of the sound wave in the plane xoz and passing through the origin, is the particular quadrant of the plane xoz, depending on, are in-phase or anti-phase signals at the outputs of the photodetectors 9 and 12.

In the plane xoz first quadrant between the axes ox and oz, the second between the axes of(x) and oz.

In the plane yoz the first quadrant between the axes oy and oz, the second between the axes on the(-y) oz.

Indeed, knife with axis of symmetry parallel to the z-axis, overlaps (dims) the third and fourth quadrants of the plane xoz and the knife with axis of symmetry parallel to the x axis, overlaps (dims) the second and third quadrants of the plane xoz (6, 7).

If the line is parallel to the projection of the vector of the sound wave in the plane xoz and passing through the origin is in the first quadrant of the plane xoz (6) (angle ζ positive), then the change in time of the sound pressure and the gradient of the refractive index) of the waist of the laser beam in two mutually perpendicular knives simultaneously emerge from the shadows and at the same time obscured.

If the line is parallel to the projection of the vector of the sound wave in the plane xoz, is in the second quadrant (7) (angle ζ negative), when the shifting of the laser beam on the knife with axis of symmetry parallel to the z-axis, out of the shadow, the shifting of the laser beam on the knife with axis of symmetry parallel to the axis x, is darkened.

Thus, the electrical signals at the outputs of the photodetectors in the first case, the change in f is ze, and the second out of phase, which indicates the quadrant in which is a line passing through the origin and parallel to the projection vector of the sound wave in the plane xoz.

Similarly, the line parallel to the projection of the wave vector in the plane yoz and passing through the origin, is in a particular quadrant of the plane yoz, depending on whether the in-phase or anti-phase signals at the outputs of the photodetectors 30 and 36.

The nature of the signals for the first and the second case is illustrated by table 1.

Thus, the amplitude and the mutual phase of the electrical signals at the outputs of the photodetectors contain information about the directions of projection, etc) the RA sound waves in the plane xoz and yoz and thus, the direction of the sound source.

The electric circuit structure is included in figure 3, processes this information and determines the direction vector of the sound wave in a given half-space, irrespective of the magnitude of a sound signal, the power fluctuations of the laser and changes the transparency of the optical parts (mainly protective glasses). The signals from the outputs of the photodetectors 9, 12, 30, 36 quadricauda respectively Quad 19, 13, 31, 37, from which the signals are sent respectively to the inputs of the pre-amplifier 20, 14, 32, 38 and amplified.

The signals from the outputs of pre-amplifiers 14, 38, correlated among themselves, as they correspond to the photodetectors 12, 36, standing, respectively, after matching lenses 11, 35 and knives 10, 34 with edges parallel to the plane parallel laser beams in the environment, proceed to the inputs of subtractive device 18, the output of subtractive device enters the second input pre-amplifier 32, 38 of one of the photovoltaic shadow of the devices on the optical and structural scheme of the device (figure 3), consisting of nodes: 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 34, 35, 36, 37, 38; the result of this action, the above (second) PV shadow device becomes equivalent with respect to the optical wedge in its measuring about what yeme first photovoltaic shadow device, consisting of nodes of the optical and structural schemes: 1, 2, 3, 4, 5, 6, 7, 8, 9, 19, 20, 10, 11, 12, 13, 14; IFF provides a proportional electrical signals at the output of pre-amplifier 20, 32, 14 squares of the projections of the wave vector on the axis x, y, z without changing power lasers and contamination of the protective glass (as well as collimators and focusing lenses); the signals from the outputs of pre-amplifiers 14, 20, 32 are received respectively to the inputs of the final amplifiers 15, 21, 33, and after amplification are summed in the adder 16, the negative feedback signal from the output of the adder is fed to the second input terminal of the amplifier 15, 21, 33; this feedback provides a constant signal at the output of the adder 16, allowing the signal at the output terminal of the amplifier 15, 21, 33 will be normalized by the pre-set value of output voltage of the adder and is proportional to the values of the squares of the guides of the cosines cos²αcos²βcos²γwhere α - the angle between the direction of the wave vector and the axis on(-x), β - the angle between the direction of the wave vector and the axis on(-y), γ - the angle between the direction of the wave vector and the axis on (-z); angles α, β, γ determine the direction of the sound source; a signal output terminal of the amplifier 15, 21, 33 are received at the inputs of a lot of the anal analog-to-digital Converter 17; the signals from the outputs of the photodetectors 9, 12 are received at the inputs of phase detector 39, the signals from the outputs of the photodetectors 12, 30 are received at the inputs of phase detector 40; the signals from the outputs of the phase detectors 39, 40 are received respectively to the inputs of the triggers 42, 41, triggered by excess input signal zero level, and outputs the signals to the inputs of multi-channel analog-to-digital Converter 17, the output of multi-channel analog-to-digital Converter signals in digital form are received in electronic computing machine, in which the values of cos²αcos²βcos²γ numbers quadrants, which are the projection of the vector of the sound wave in the plane xoz and yoz (non quadrants are determined by the signals at the outputs of the triggers 41 and 42) are determined by the magnitude of the guides of the cosines cos α, cos β, cos γ (and guide corners α, β, γ).

The rules for determining angles α, β, γ sector numbers, which are the vectors defining the direction of the sound source, and the potentials at the outputs of the triggers listed in table 2.

α₀=arccos√cos²α; β₀=arccos√cos²β; γ₀=arccos√cos²γ.

The proposed device allows to determine the direction of the sound source in the half-space by the values of the guides of the cosines cos α, cos βco γ . Compared with the antenna made from a matrix of electro-acoustic converters, the proposed device, the direction of the sound source may be determined using one dual optoelectrical Converter. And most importantly, the proposed device can be achieved a significant decrease in the influence of the driving noise in comparison with the antenna, made in the form of a matrix of electro-acoustic converters.

List of figures.

Figure 1. Device for determining the direction to a sound source using a range of electroacoustic transducers.

Figure 2. The structural scheme of the shadow device with dual filtered light field.

Figure 3. Optical and structural scheme of the proposed optoelectronic device for determining the direction to the sound source.

Figure 4. The projection of the movement of the waist of the laser beam on the z axis.

Figure 5. Four sectors of the half-space.

6. The signals at the output of the photodetectors in the phase.

7. The signals at the output of the photodetectors in antiphase.

Device for determining the direction to a sound source, comprising two photovoltaic shadow devices, laser beams are directed into the medium at an angle of 90° to each other, each of the two photoelectric shadow of devices contains consistently established LAZ is R, collimator, two protective glass, between which are located a number of measurements, a focusing lens, a beam splitter for splitting the laser beam into two laser beam, two knife edges arranged mutually perpendicular to each other, and installed after one beam splitter on the optical axes of the split laser beams in two dimensions the minimum diameter of the waist of the laser beam, two matching lens installed one after each of these two knives, two of the photodetector in each of the photoelectric shadow of instruments installed one after each of the matching lens in a plane optically conjugate with the middle of the measuring volume located between the protective glasses, the outputs of the photodetectors are connected to the corresponding Quad outputs Quad connected to the respective pre-amplifiers, characterized in that the edge of one of the knives in each photoelectric shadow instrument perpendicular to the plane parallel laser beams in the environment, two of the pre-amplifier (one in each photoelectric shadow instrument), their inputs connected across the Quad to the outputs of the photodetectors installed after matching lenses and knives with edges parallel to the plane parallel to the laser pooch who am in the environment, their outputs connected to a subtractive device, the output of subtractive device connected to the second inputs of the pre-amplifiers of one of the photovoltaic shadow devices, the pre-amp output of this photoelectric shadow device is not connected to the subtractive input device, and outputs pre-amplifier of another photovoltaic shadow instrument is connected to terminal amplifiers, the outputs of the final amplifiers connected to the adder and multi-channel analog-to-digital Converter, the output of the adder is connected to the second input terminal of the amplifier, the output of one of the two photodetectors installed after matching lenses and knives with edges parallel to the plane parallel laser beams in the environment that are connected to the inputs of two the phase detector and to the second inputs of which are connected the outputs of the other two photodetectors corresponding to the knives, the edges of which are perpendicular to a plane parallel laser beams in the environment, the outputs of the phase detectors connected to the trigger, the outputs are connected to a multichannel analog-to-digital Converter, and the output multi-channel analog-to-digital Converter connected to the input of the electronic computer.