RU2376612C1 - Method of hydrometeorological monitoring water body of sea test site and device to this end - Google Patents

Abstract

FIELD: physics; acoustics.

SUBSTANCE: method of hydrometeorological monitoring a water body of a sea test site involves placing equipment for measuring hydrometeorological parametres on the test site. Depth distribution of sound speed is determined through laser-hydroacoustic probing while making hydrological cuts to the discontinuity layer in periodic mode. The device for realising the method includes a parametric locator, a medium parametre measuring device and a computation module. The parametric locator consists of two tunable oscillators, two pulse modulators, a pulse generator, two power amplifiers, pumping transducer, reception antenna, reception amplifier and a recording device. The device also includes a solid-state laser, which has an active element inside a resonator. The reception antenna is in form of a cylinder with tangential polarisation. The inner surface of the cylinder is shielded. The cylinder is put into a reflector with angle of inclination of the generatrix to the base equal to 45 degrees.

EFFECT: wider functional capabilities of the device with increase in accuracy of hydrometeorological monitoring of a water body of a sea test site.

2 cl, 6 dwg

Description

The invention relates to methods for determining hydrometeorological parameters, namely, the complex determination of such parameters as wind speed in the water area, sea surface swell and dynamic underwater noise in the water area with preliminary processing of information, transmitting information to the consumer to illuminate the hydrometeorological situation during work in marine areas.

Known methods and devices for hydrometeorological observations of the water area of the marine landfill [1, 2, 3, 4, 5, 6], as a rule, solve a specific problem, which consists in determining one parameter characterizing the current state of the environment, by instrumental registration of signals with their subsequent broadcast to dispatch stations for the subsequent processing of the information received and the transmission of this information to consumers.

In the known device [1], which consists of at least two electrodes connected to a high-resistance voltmeter, the gradient of the potential of electric fields is measured, which determines the height of the waves. In this case, the registration devices are placed in the coastal zone at a depth of more than 100 m in groups and at a distance from the coastline to a distance of 4000 m and connected by communication lines to the coastal dispatch station. This device is mainly used to determine the danger of a tsunami.

The disadvantages of this device is that to ensure reliable observations in the vast water area of the marine landfill, it is necessary to place a significant number of recording devices connected by communication lines to the dispatch station, as well as a limited range of measured parameters.

In the known device [2], which is a device for measuring wave parameters from aircraft, including blocks of radiation, reception, amplification, formation and conversion of radio signals reflected from the sea surface, determining the power of the reflected signals depending on the flight altitude based on functional dependencies, heights of sea waves.

For the practical implementation of this device, in order to obtain reliable information, it is necessary to correctly select and maintain at a given level the ratio of values characterizing the flight altitude of the aircraft and the duration of the probing short pulse, which can only be achieved under favorable weather conditions, which significantly limits the use of this device for long and continuous observations of the water area of the marine landfill.

Known devices [3] are bottom stations installed from carriers to the bottom of the sea and equipped with recording equipment of a geophonic and hydrophone type for recording signals in the frequency range from 3-5 to 200-300 Hz with their transmission to a control station after surfacing after three weeks, for subsequent processing and determination of the functional dependencies of the parameters characterizing the environment at the installation site of the devices.

In this case, the wavelength of the emitted oscillations is automatically maintained constant. The need to take into account the speed of sound significantly increases the complexity of observations, and with frequent and abrupt changes in hydrometeorological conditions in the area of the landfill, it may introduce an additional error in the final results of observations.

All this requires continuous measurement of hydrological parameters and more reliable methods of processing the measured signals, excluding indirect methods for determining hydrometeorological parameters from the processing of recorded signals. An increase in information content is possible by performing hydrological sections to the jump layer, which will also make it possible to obtain such an important characteristic as the characteristic of the distribution of sound velocity over the entire depth from the surface to the bottom, which requires continuous measurement of hydrometeorological characteristics and more advanced methods of processing the measured signals and obtaining redundancy of the measured parameters.

The objective of the proposed technical solution is to expand the functionality of the device while increasing reliability during hydrometeorological observations of the water area of the marine landfill.

The problem is solved due to the fact that in the method of hydrometeorological observations of the water area of the marine landfill, which includes placing on the landfill measuring instruments for hydrometeorological parameters for determining wind speed, sea waves, classification of sea noise by a selected part of the spectrum, measurement of hydroacoustic signals, processing of measured signals, formation of profiles temperature, salinity, acoustic resistance, distribution of the speed of sound in depth and density of a medium with inhomogeneities - pa the depth velocity distribution of sound is determined by laser-hydroacoustic sounding with hydrological sections to the jump layer in periodic mode, and a device for implementing the method, including a parametric locator, a medium parameter meter and a computational module in which the parametric locator consists of two tunable generators, two pulse modulators, a pulse generator, two power amplifiers, a pump converter, a receiving antenna, a receiving amplifier, reg a trimming device into which an additional laser sensing device is introduced in the form of a solid-state laser, including an active element placed in the resonator, the receiving antenna of the parametric locator is made in the form of a cylinder with tangential polarization, the inner surface of the cylinder is shielded, the cylinder is placed in a reflector with an inclined generatrix to the base under angle of 45 degrees, the receiving antenna consists of n separate elements located at an equal distance from each other, while at the same time f elements, voltage is shifted in phase by a constant angle.

The invention is illustrated by drawings (Fig.1-6).

Figure 1. The block diagram of the device includes a parametric locator 1, a medium meter 2, a computing module 3, a laser sensing device 4.

Figure 2. The parametric locator 1 includes two generators 5 and 6, a pulse generator 7, pulse modulators 8 and 9, a recording device 10, power amplifiers 11 and 12, a receiving amplifier 13, a pump converter 14, a receiving antenna 15.

Figure 3. The environmental meter 2 includes sensors for determining air temperature 16, atmospheric pressure and water temperature 17, hydrodynamic pressure 18, electrical conductivity 19, salinity 20, a unit for determining the average speed of sound in water 21, a unit for collecting, processing and mapping the water area of a marine landfill 22, a spectrum analyzer 23, a block for selecting a portion of the spectrum 24, a block for classifying noise of the sea 25, a unit for determining wind speed 26, a unit for determining sea waves 27, a synchronization and control unit 27, a satellite navigation and measuring unit barrel 28.

Figure 4. Computing module 3 consists of micro-ROM ROM 29, address selection ROM 30, microprogram LSI 31, two microprocessors 32 and 33, ROM 34, RAM 35, transfer schemes 36, three buffer registers, five mains — address 37 mains, micro-command mains 38, highway D 37, highway M 38, highway L 39 and two analog-to-digital converters 40 and 41.

Figure 5. The satellite navigation and measuring module 28 consists of a magnetic compass 42, an inertial measuring circuit 43, a receiver 44, an antenna-feeder device 45, a controller 46, including RS232 interfaces - up to 8 channels, EPP / ECP - 1 channel parallel to 8-bit bus - 12 channels, power control line of external devices 5/12 V, up to 0.5 A - up to 8 lines, SPI up to 3 channels, 12S - up to 2 channels, CAN-channel, USB-1 channel, ultrasonic channel-1, fiber-optic modem-1, radio-modem-1, FLASH-memory up to 4 GB, real-time clock, input filters of analog channels.

6. Placement of transducers of a radiating antenna.

Parametric locator 1 operates on the principle of nonlinear interaction of acoustic waves. The formation of the initial electrical signals is carried out according to a two-channel scheme. The signals from the generators 5, 6 are fed to pulse modulators 8, 9, which are controlled by a pulse generator 7. Then, the radio pulses are amplified by power amplifiers 11, 12 and radiated into the water by the pump converter 14. The antenna 15, the receiving amplifier 13, and the recording device 10 form a receiving path. The receiving antenna 15 of the parametric locator 1 is made in the form of a cylinder with tangential polarization, and the inner surface of the cylinder is shielded. The cylinder is placed in a reflector with an inclined generatrix to the base at an angle of 45 degrees.

The area of the antenna 15 is formed of linear elements located at an equal distance from each other. Adjacent antenna elements are powered by a phase-shifted voltage at a constant angle Δφ. The main maximums of the radiation pattern are formed in the direction for which the in-phase addition of oscillations of all antenna elements is ensured. As is known, the angle α between the plane of the antenna and the direction of the main maximum is determined in this case by the expression α = arc cos Δφλ ₀ / 2dπ (1), where Δφ is the phase shift between adjacent elements, λ ₀ is the calculated radiation wavelength, d is the distance between elements.

In the proposed device, the antenna consists of 72 individual elements receiving power with a phase shift of 120 degrees. In this case, expression (1) will have the form cosα = λ ₀ / 3d = C / f _o k (2), where k = 1 / 3d is the antenna array constant. Taking into account (2), the adopted frequency fpr = 2Vk.

This design of the antenna allows you to automatically change the angle of inclination of the beam when changing the radiation wave (Senpaku, 1975, v.48, p.75-79).

The laser sensing device 4 is a solid-state laser including an active element placed in a resonator having a resonant reflector as an output mirror and a cuvette with a phototropic solution (ed. St. USSR No. 791157), which is based on a method for isolating optical inhomogeneities in scattering media (ed. St. USSR No. 1788485), including probing the scattering medium with short pulses of optical radiation, photo-detection of backscattered radiation with a time resolution Δτ, finding the ratios qi of Si signals of this radiation, comparing these ratios with a threshold level of unity, taking into account the measurement error of the signals of backscattered radiation σS, and processing the measurement results to determine the presence of interfaces between media of different composition, in which the qualitative composition of scattering media is additionally determined by comparing correlations qi with a threshold level equal to unity determine the deviation of this ratio from the threshold level, and the presence of interfaces between media of different composition and Nia their qualitative composition judged respectively by excess ratio qi deviation from the threshold level σ - σS and an absolute value of this ratio at the boundaries of inhomogeneities, the ratio qi Si signals is found from the expression

qi = (Si + 2 / Si + 1) ² × Si-Si-1 / Si + 2-Si + 3.

As an atmospheric pressure sensor 17, a RTV-10 sensor (Finland) was used with atmospheric pressure limits of 600 - 1100 hPa and a measurement accuracy of 1 hPa. The sensor is connected to the atmosphere by a thin elastic tube passing through the top cover and extending to the beam, where the buoy antennas are located.

As an air temperature sensor 16, a TSP-002-03 sensor was used with a measuring range from -50 to + 60 ° С, with an error of ± 0.15 ° С.

As the hydrodynamic pressure sensor 18, a sensor developed by FSUE OKB Oceanological Engineering RAS, having a pressure measurement range from 0 to 10 m, with an error of 0.1%, as well as a range of water temperature measurements from -2 to + 32 ° C with an error, was used 0.05 ° C.

The environment meter 2 for the operation of the units for determining the average speed of sound in water 21 and the classification of sea noise 25 also contains hydrophones (positions 1-5 in FIG. 6) equipped with parametric antennas and having the following characteristics: operating frequency range 15-50 kHz The frequency of the pump waves is 125.5-148 kHz and 153-175.5 kHz. The type of emitted signal is a rectangular radio pulse, a linearly frequency-modulated pulse signal, a signal with a tunable frequency from pulse to pulse, the duration of the probe pulse is 1, 2, 4, 8, 16, and 32 ms, the pulse repetition rate is not more than 2 Hz.

In this case, electric pump signals with pump frequencies and a given type of modulation are generated in the signal shaper and fed through power amplifiers to a pump transducer that emits acoustic oscillations with pump frequencies. When pump waves propagate in an aqueous medium, a parametric antenna of difference frequency waves with the necessary characteristics is formed. Shaper operating modes (changing the duration of the probe pulse, changing the sending frequency, changing the difference frequency and the law of its modulation) are controlled by the shaper control circuit. The scattered signals as a result of the interaction of the waves of the difference frequency and the hydrophysical layers are received by the receiving antenna, which is necessary, since the emitting parametric antenna is irreversible, and the pump converter at the frequency of the difference wave has low sensitivity due to operation far from resonance. Electrical signals through a low-pass filter, in which pump waves are suppressed, are fed to a pre-amplifier and then to a matching device, which is designed to match the input and output impedances of the amplifier and the analog-to-digital converter of computing module 3. The gain of the receiving part, the passband, depending the type of signal and the pulse duration are controlled by the receiver control unit.

Salinity, temperature and pressure sensors are located directly at the pump transducer and are designed to measure the parameters of the aqueous medium in the zone of interaction of the pump waves, which are necessary in the future to calculate the change in the signal of the differential frequency wave along the propagation path for the reasons due to the fact that the generation of differential wave signals frequencies occur in space and their levels cannot be obtained by bringing to a normalized level at a certain distance, as is done in t traditional radiating antennas, and also because the levels depend on the values of the parameters of the medium in the zone of interaction of the pump waves. The signals from the measuring sensors are converted into electrical signals and fed to the computing module 3, which performs all the calculations to determine the profiles of temperature, salinity, acoustic resistance, sound velocity, and density of the medium with inhomogeneities.

The determination of the parameters of the layers of hydrophysical inhomogeneities is carried out by their calculations in the following sequence.

The signals from the receiving antenna of the parametric locator 1, the sensors of the medium parameter meter 2, the laser sensing device 4 through the corresponding analog-to-digital converters are sent to the computing module 3, where they are processed in the pre-processing part, in which the amplitudes of the reflected signal and the probing signal in place are calculated installing a receiving antenna, coordinated processing of received signals to accurately determine the position of the scattered signals and determine the various moments of channels, analysis of mutual correlation of signals, calculation of reflection coefficients of layers, formation of initial data of hydrophysical characteristics at the place of installation of the pump transducer, calculation of characteristics of the probe signal along its propagation path, which is necessary to calculate the true value of the amplitude and phase of the wave of the difference frequency incident on the scatterer calibration of the probe signal measured at the installation site of the pump transducer, calculation of the acoustic impedance of the layers, calculation of the depth p the position of the layer, the thickness of the layer, and the speed of sound in it, calculating the density of the layers, forming profiles of temperature, salinity, acoustic resistance, density and speed of sound, calculating the temperature and salinity of the layers.

The use of such processing allows, knowing the hydrophysical parameters of the layer located at the pump transducer, to calculate successively layer by layer the parameters of the remaining layers.

The unit for determining the sea waves 27 is a microprocessor device consisting of an analog-to-digital converter, a controller, random-access memory, programmable memory, a suboptimal filter.

The measurement of the wave profile is based on the integral method based on the indirect determination of the wave profile based only on the data on the vertical velocity of the device on the water surface in accordance with the dependence:

where S is the movement of the device during time T;

V (t) is the speed of movement of the device.

The movement of the device at a particular moment is determined by the formula

where S (t) is the current position of the device;

S ₀ - the position of the device at the previous moment;

and - acceleration.

This method allows you to completely exclude rough height measurements from processing and get information about drifter movement only from high-precision speed data.

To exclude highly noisy code measurements of height by phase velocities of drifter movements, a suboptimal filter is used. The current estimate of Z _i using any linear filter as the sum of the forecast Z _i and the filtered estimate of the current measurement:

- текущее значение измерения;Where

- current measurement value;

α - transmission coefficient determines the filter time constant α = 1τ _s ;

Since the Z estimate is formed in satellite receivers from high-precision phase measurements that reproduce drifter dynamics with millimeter (submillimeter) accuracy, formula (2) determines the most accurate forecast for any linear satellite measurements filter. Substituting (2) into (1), we obtain an α - IIR filter that optimally smooths phase measurements of code measurements:

The result of processing are optimally smoothed code measurements, however, this filter cannot remove the constant low-frequency trend of errors in high-altitude measurements, due to a sufficiently large value of α. To eliminate this trend, it is sufficient to apply the same filter repeatedly to an already smoothed estimate, but with a large coefficient α (deep smoothing). Analysis of low-frequency noise allows us to conclude that the choice of α = 0.15 1 / s will be a compromise. Next, centering is performed (subtracting from the trend estimate). After trend exclusion, the variance of the obtained centered estimate is calculated:

where H _i - the values of the centered trend,

N is the number of values in the sample.

The amplitude of the oscillations is derived through the dispersion

where A is the desired amplitude, σ is the mean square error.

Next, the period of the waves is calculated by counting the number of intersections by the zero line wave profile.

Moreover, by means of a satellite navigation system of the type SN-3800, the velocity vector of the flow of the water surface is determined by the change in the horizontal movement of the drifter.

The wave height h _i is defined as h _i = r ₁ + r ₂ , where r ₁ is the height of the previous half-period, r ₂ is the height of the subsequent half-period. If there are several identical maximum amplitudes for a half-period, any of them is used to calculate the wave height. After determining the values of the wave heights and their number in the implementation, the average value of the wave height is calculated

where m is the number of waves during the measurement of 20 minutes.

To determine the wave height of 3% of coverage, 20 maximum waves are selected from the array of wave heights, which are arranged in decreasing order of 1 to 20, starting with the maximum amplitude. Then the index of 3% security K _3% = 3m / 100 is calculated. The wave height corresponding to this index will be three percent.

The collection and processing of measured information is carried out in a satellite navigation and measuring module 28.

The drift drift velocity V (t), determined by the satellite navigation system, is nothing more than the drift drift velocity Vd of drifter movement, which is defined as Vd = (0,0127 / √ sinφ) W, where φ is the latitude of the place, W is the speed wind (see. Shuleykin VV Short course of sea physics. L., Hydrometeorological publishing house, 1959, p.40). From where the wind speed can be defined as W = Vd / 0,0127√sinφ, which is carried out by means of the unit for determining the wind speed 26.

Hydroacoustic antennas are configured to provide a phase shift by a constant angle, which makes it possible to implement a frequency-independent antenna, which eliminates the influence of changes in the speed of sound in water, and in addition, it becomes possible to measure the speed of the drifter relative to the bottom or relative to the water layers using volumetric reverb signals.

Due to the fact that the received signal is characterized not by one fixed frequency, but by a frequency spectrum of width Δf _d , the position of this spectrum on the frequency axis relative to the radiation frequency is determined by the average Doppler frequency and when the drifter moves, the Doppler frequency shift f _d = 2V _d , where V _d - drifter speed, which can be used to analyze the final research results or to control drifter movements during the period of work.

The device as a whole is made in the form of a single monolithic structure in which the measuring units are located. In the upper part there is a cover used to install measuring units. A satellite navigation antenna is mounted on the lid. The recessed part of the body is equipped with a polyurethane stepped frame made in the form of a truncated pyramid, in the lower part of which there are hydrophones, four of which are oriented in parts of the world, respectively, and another hydrophone is oriented vertically towards the bottom. The stepped frame, expanding to the bottom with hydrophones installed on it, serves as a stabilizing device and serves to dampen the vibrations of the device as a whole.

The technical result, which consists in increasing the reliability during hydrometeorological observations of the water area of the marine landfill and in expanding the functionality of similar devices, is achieved due to the fact that the distribution of sound velocity in depth is determined by laser-hydroacoustic sounding with hydrological sections to the jump layer in periodic mode by a device into which an additional solid-state laser is introduced, including an active element placed in a rez nator, the receiving antenna of the parametric locator is made in the form of a cylinder with tangential polarization, the inner surface of the cylinder is shielded, the cylinder is placed in a reflector with an inclined generatrix to the base at an angle of 45 degrees, and the receiving antenna consists of n separate elements located at equal distance from each other while the neighboring elements are supplied with voltage, shifted in phase by a constant angle.

The industrial implementation of the proposed technical solution of technical complexity does not represent the way that commercially mastered products and approved hardware are used.

Information sources

1. RF patent No. 2066466.

2. RF patent No. 1240169.

3. Modern bottom stations for seismic exploration and seismological monitoring. / Zubko Yu.N., Levchenko D.G., Ledenev V.V., Paramonov A.A. // Scientific Instrumentation, 2003, volume 13, No. 4, p. 70-82.

4. High-precision water-level monitoring / Massatoshi Harigae, Isao Yamaguchi, Tokio Kasai, Hirotaka Igava, Hiroto Nakanishi, Takahiro Murayama, Yasunori Iwanaka, Hirotaka Suko / GPS World, April 2005.

5. US patent No. 6847362 B2, January 25, 2005.

6. Zagorodnikov A.A. Radar survey of the sea surface from aircraft. L., Shipbuilding, 1978, 376p.

7. RF patent No. 2079168 C1.

8. Voronin V.A., Tarasov S.P., Timoshenko V.I. Hydroacoustic parametric systems. Rostov-on-Don. Rostizdat, 2004, p. 288-293.

Claims (2)

1. The method of hydrometeorological observations of the water area of the marine landfill, including the placement on the landfill of measuring instruments for hydrometeorological parameters for determining wind speed, sea waves, classification of sea noise by a selected part of the spectrum, measurement of hydroacoustic signals, processing of the measured signals, the formation of temperature, salinity, and acoustic resistance profiles, distribution of sound velocity over depth and density of a medium with inhomogeneities, characterized in that the distribution of sound velocity in depth is determined by laser-hydroacoustic sounding with the implementation of hydrological sections to the jump layer in periodic mode. 2. A device for hydrometeorological observations of the water area of the marine landfill according to claim 1, including a parametric locator, a medium parameter meter and a computational module, in which the parametric locator consists of two tunable generators, two pulse modulators, a pulse generator, two power amplifiers, a pump converter, a receiving antenna, a receiving amplifier, a recording device, characterized in that an additional solid-state laser is introduced, including an active element placed in a tab, the receiving antenna of the parametric locator is made in the form of a cylinder with tangential polarization, the inner surface of the cylinder is shielded, the cylinder is placed in the reflector with an inclined generatrix to the base at an angle of 45 °, and the receiving antenna consists of n separate elements located at equal distance from each other while the neighboring elements are supplied with voltage, shifted in phase by a constant angle.

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