RU2464205C1 - Method of seadrome preparation for boatplane takeoff and surfacing - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to aviation, particularly, to preparation of seadrome for boatplane takeoff and surfacing. Proposed method comprises defining position of runway without the boundaries of seadrome surface with due allowance for wind direction and minimum wind-induced wave. Hovercraft crew arrange marker buoys to allow check up, both visually and by radars and sonars, aircraft path on water surface. Boatplane is moored, cast off and towed after surfacing or prior to taking off. Glide and on-course beacons are installed aboard air-cushion vessel to receive and transmit radio signals to provide for boatplane surfacing in poor visibility. Sea floor semispherical transceiver antennas are installed along runway axes to allow direction- and frequency-quantised echo-ranging of under and surface objects in all-around or sector mode in azimuth and elevation.

EFFECT: higher safety.

5 cl, 11 dwg

Description

The invention relates to the field of amphibious transport and can be used to solve problems associated with improving the safety of the takeoff and landing operations of main amphibious aircraft. The objective of the invention is achieved through the implementation of hydroacoustic monitoring of the water volume of the flying pool of a hydroaerodrome using hemispherical bottom receiving-emitting antenna devices. Hydroacoustic monitoring of the water volume using ultrasonic waves is carried out for operational and remote detection, determination of coordinates and motion characteristics of potentially dangerous submerged objects of neutral buoyancy located in the near-surface layer of the runway; as well as measurements of such dynamically changing characteristics of the flight basin as depths, state of the water surface: - altitude, speed and direction of movement of wind waves, as well as the direction of flow of water masses at various points in the water area, which together will allow the coastal hydroacoustic service to have a sufficient amount of information on time underwater conditions and the state of the water surface, on the basis of which a different decision is made, which is communicated by radio on board to crews as an airborne vessel shke conducting the inspection of the surface waters of the summer pool and a seaplane, preparing for the implementation of take-off and landing operations.

The primary area of use is the system for ensuring the safe operation of the inland and offshore water transport system of Russia - natural and artificial reservoirs: rivers, lakes, reservoirs, and the sea shelf, which make up it, in particular, to ensure the safety of take-off and landing of the seaplane in the water basin of the hydroaerodrome during amphibious transport activities.

As the first analogue, the method is selected (see US patent No. 2692101, CL B64F 1/00, 1954), the purpose of which is to increase the safety of take-off and landing events. So, light seaplanes are equipped with skis, and for takeoff and landing, it is proposed to use flooded floating take-off and landing platforms of the required geometric dimensions, which can unfold on the surface of the water, providing takeoff and landing against the wind. Monitoring the cleanliness of the water surface of the runway from dangerous for splashdown and take-off objects includes only a visual inspection. Floating platforms have significant limitations both in terms of weight and size indicators of seaplanes and the safety of takeoff and landing operations, being, in fact, a floating runway of an airfield, and are fundamentally unsuitable for use on modern main bottom seaplanes, since they exclude contact bottom seaplane with an aqueous medium, which is necessary, for example, to fill fire tanks with water in the direction of travel (for the A-200 Albatros seaplane orosti about 200 km / h). Hydroacoustic monitoring of the water volume of the flight pool, currently existing services to ensure the functioning of the hydroaerodrome, is not carried out, there are no specialized hydroacoustic equipment for these purposes, nor reliable methods for close underwater observation in shallow water bodies.

The reasons that impede the achievement of the claimed technical result is the lack of sonar echo search for drowned and, accordingly, visually undetectable objects within the water volume of the runway, which reduces the safety of taking off and landing of seaplanes.

Signs that coincide with the claimed method: determining the position of the runway in the wind direction, conducting a visual inspection of the water surface.

As the second analogue, a method was selected that includes operations to determine the position of the runway in the wind direction and the installation of marker marks in open sea areas (see. "Aviation Engineering and Aircraft Operation", N.N. Andreev et al., M .: Publishing House of the VVIA named after Zhukovsky N.E., 1970, p.276-280), which, however, does not provide for the use of both sonar echo search for flooded objects within the runway, and special boats for inspection and cleaning finely One of the outdoor swimming pool area. As a result, this method does not provide the proper level of safety during maneuvers of a seaplane both in displacement and planing modes in the water area of the hydroairdrome flight pool.

The reasons that impede the achievement of the claimed technical result is the lack of sonar echo search for drowned and, accordingly, visually undetectable objects within the water volume of the runway, which reduces the safety of taking off and landing of seaplanes.

Signs that coincide with the claimed method: determining the position of the runway in the direction of the wind, installing marker marks in the water area, conducting a visual inspection of the water surface.

As a prototype, the “Method for the preparation of hydroaerodromes for takeoff and landing of seaplanes” was selected (see RF patent No. 2093428, class B64F 1/00, publ. 10/20/1997), which consists in the fact that the position of the takeoff is determined within the flight pool of the hydroaerodrome -A landing strip, taking into account the direction of the wind, and from the condition of minimality of the wind wave present in the water area, the SVP crew installs marker signs, during which, visually, as well as using radar and sonar, it inspects the seaplane moving path and in the water area, it carries out mooring, unmooring and towing of the seaplane after it is splashed or before take-off, and also onboard the SVP places glide-slope and course radio beacons for sending and receiving radio signals that provide splashing of the seaplane in conditions of poor visibility

However, if equipping an amphibious vehicle with radionavigation equipment, in particular, radar, glide path and directional beacons, contributes to the safety of take-off and landing events, then the placement of sonar equipment - sonar cannot provide effective echo search of submerged objects in the water for a number of reasons considered below . To detect submerged objects using a sonar in the aquatic environment on the way the seaplane moves around the water area, the pulse method of distance determination and the amplitude direction finding method are used (see Mitko V.B., Evtyutov A.P., Gushchin S.E. Hydroacoustic communication and observation . - L .: Shipbuilding, 1982, p. 25-38). The sonar installed on the SVP is a one-position system for determining the location of underwater objects, in connection with which stringent requirements are imposed on the severity of the directional action and the level of the side field of the hydroacoustic antennas used. Indeed, the scheme of pulse measurement of the distance to the target, and determining the direction to the target by turning the main lobe of the directivity of the antenna in the direction-finding plane, involves measurements in an unlimited environment, while it is necessary to reliably detect submerged objects “dangerously” located near an extended interface “ water-air ”with geometric dimensions (length ~ 2500 m, width ~ 200 m, depth ~ 3 m to 6 m) of the examined near-surface aerated water layer -posadochnoy bands that determine the appearance of the masking reflections and at the display "false" purposes.

Consider the reasons for the inefficiency of the implementation of sonar echo search of flooded objects in the water volume of the runway directly from the SVP in the prototype method:

1) the sonar interference antenna has an extended near “spotlight” diffraction zone

,

,

where k = 2π / λ = ω / c is the wave number, λ, ω = 2π · f is the wavelength and cyclic frequency of the ultrasonic probe signal, a is the aperture size (half width, radius) of the emitter (see Kobyakov Yu.S., Kudryavtsev N.N., Timoshenko V.I. Construction of hydroacoustic fish-finding equipment. - L .: Sudostroenie, 1986, p. 92-112). Within the vicinity of the “floodlight” diffraction zone, both the axial and angular distributions of the sound pressure amplitudes of the working ultrasonic signal experience significant fluctuations, as a result of which the effectiveness of the horizontal “near” echo search of submerged objects will be extremely low. This is due to significant levels of echo signals from the “water-air”, “water-bottom” interfaces, recorded both in the directions of the main and side lobes of the directivity pattern, which, combined with boundary reverb, makes it impossible to register useful reflections from search objects. The effectiveness of using sonars largely depends on the size of the side lobes of the directivity of the interference antenna: receiving and registering an echo signal from an object located in the direction of the side lobe leads to the registration of a “false” target on the acoustic axis and, accordingly, an error in determining the angular coordinates. The levels of the side lobes of the directivity characteristics depend on the wave size and shape of the antenna, as well as the law of distribution of the amplitudes of the excitation along the radiating surface. So, the calculated levels of the first and second side lobes of the directivity characteristics of a flat piston antenna with a circular aperture are 13% and 6% (by pressure), and the ratios for calculating their directions are of the form

и

and

respectively (see Evtutov A.P., Mitko V.B. Engineering calculations in hydroacoustics. - 2nd ed., revised. and add. - L.: Shipbuilding, 1988. - p.5-66);

2) during the initial processing, it is difficult to distinguish echo signals from objects against the background of surface and volume reverb due to the smallness of their classification differences (frequency, duration, amplitude, correlation characteristics);

3) SVP is a source of both intense acoustic noise and interference, as well as aeration of the near-surface water layer directly at the installation site of the sonar receiving-emitting antenna, which worsens the signal-to-noise ratio, reduces the efficiency of radiation and ultrasound reception due to shielding of veiled air bubbles;

4) due to the small displacement, the SVP is highly prone to pitching, which, in the absence of stabilization in space of the position of the main maximum, the directivity characteristics of the sonar interference antenna will negatively affect the confident registration of echo signals from the search objects, to a certain extent, it will only satisfactorily solve the problem of recording water depths in the echo sounder mode;

5) to view a given part of the water volume of the surface layer of the runway, as well as to determine the azimuth and course angles of the detected object, the sonar interference antenna should be mechanically lowered to a sufficient depth, rotated in vertical and horizontal planes, moreover, any recessed location of the antenna in under the given search conditions is not optimal, since the effective detection of near-surface objects “against the background” of the air-water interface You can with radiation antenna ultrasonic signals in a direction "bottom-up";

6) due to the narrowband resonance electro-acoustic transducers of interference antennas, the echo search of submerged objects with different reflectivity is carried out in the small frequency range of ultrasonic signals, and when performing echo search in a shallow water area using several SVPs with the same type of sonars, the task of detecting objects will be complicated by interference of mutual influence ;

7) hydroacoustic control of the water volume of the flying basin of a hydroaerodrome as one of the operations to ensure take-off and landing operations is carried out sporadically, and not on an ongoing basis, which makes it possible to covertly install various bottom devices with the aim of causing material damage and damage to the seaplane.

As a result, an important operation of the method for preparing a hydroaerodrome — sonar echo search of submerged objects in the water volume of the runway cannot be effectively performed directly from the SVP board, which reduces the safety of takeoff and landing operations.

Let us consider in detail an example of a low-performance echo search from a surface swimming craft in specific conditions of shallow water. Known experience in the use of sonar echotral to detect underwater obstacles, to determine their coordinates in shallow water at distances up to 50 meters, used to trawl from a surface ship in order to check the cleanliness of ship passages and to identify underwater objects that are dangerous for navigation (see Short-range sonars A.N. Yakovlev, G.P. Kablov. L .: Shipbuilding, 1983. S.174-178). The occurrence of underwater objects that are dangerous for navigation is associated with the natural process of changing the channel, and also due to the possibility of the current pollution of waterways by random objects, for example, sunken logs, etc. They distinguish between continuous trawling (carried out within the established navigation time limits within the entire shipping lane) and local trawling (carried out on the most dangerous sections - rapids, rifts, approaches to berths, etc., for the purpose of operative search for submerged objects), moreover, underwater inspection situation in both cases is carried out on board the carrier ship. In the process of testing and operation of the echo trail, various designs of the interference antenna were used: periscopic, horn and the so-called “cosecance”, and the latest design of the receiving-emitting antenna, according to the developers, ensured the formation of radiation directivity characteristics with a low level of the side field in the elevation plane down towards bottom.

The active element of the "cosecant" interference antenna consisted of four electro-acoustic transducers having different spatial radiation characteristics, the acoustic fields of which as a result of a superposition of oscillatory processes in the location medium and created the desired shape of the directivity pattern (Fig. 1). It should be noted that the formation of the directivity characteristics of the interference antenna with a low level of the side field in the elevation plane down towards the bottom led to an unacceptable increase in the level of radiation of the side field in the same plane up towards the water surface. So, when using a working radiation frequency of 525 kHz, the electro-acoustic transducer formed an ultrasonic field with the following characteristics in the elevation plane - the width of the main lobe of the directivity characteristics at the level of 0.9 θ _{0.9 B} ~ 4 °, the first side lobe in the direction (5 °) from horizon with a level (-1.4 dB), the second side lobe in the direction (7 °) from the horizon with a level (-3.7 dB), the third side lobe in the direction (10 °) from the horizon with a level (-9 dB) ; the fourth side lobe in the direction (30 °) from the horizon with a level (-20 dB). The water surface is the interface for which the acoustic impedances of air and water (air - Z _Air = 442 kg / m ² × s; water - Z _WATER = 1.5 × 10 ⁶ kg / m ² × s) are so different that all the energy of an acoustic wave falling from below to the surface returns to water, which caused the appearance of intense masking reverberation noise at all echo-search distances.

With these parameters of the interference antenna, the conclusions made by the developers themselves after the tests are logical: “Under conditions of limited depth in the river channel (~ 4 m) and the emitter deepened (from 0.5 m to 2.4 m), the sound pulse could not pass the distance more than 30 m without experiencing reflections from the surface of the water or the bottom; in some cases, these reflections caused intense interference on the indicator. ... A small part of the sound impulses propagated with reflection from the water surface and from the bottom along the entire length, starting from the emitter itself. ... To eliminate reverberation noise on the indicator, the beginning of the sweep was artificially delayed, although the possibility of detecting underwater obstacles in the radius around the emitter of about 3 m was excluded ... The image on the screen of the small obstacle indicator (echo from the buoy) caused the mark to triple due to the side lobes of the directivity of the antenna ... ”

The reasons hindering the achievement of the claimed technical result is the lack of efficiency of conducting onboard an air cushion of a sonar sonar echo search for submerged and, accordingly, visually undetectable objects within the water volume of the runway, which reduces the safety of taking off and landing of seaplanes.

Signs that coincide with the claimed method: determination of the position of the runway within the flight basin of the hydroaerodrome, taking into account the direction of the wind, and from the condition of the minimality of the wind wave present in the water area, the hovercraft crew installs marker marks, during which visually, as well as using a radar and sonar, inspects the seaplane’s movement in the water area, mooring, unmooring and towing the seaplane after it is splashed or before on take-off, as well as on board the hovercraft, places glide-slope and heading radio beacons for sending and receiving radio signals, providing splashdown of the seaplane in conditions of poor visibility.

The objective of the invention is to increase the safety of takeoff and landing operations. The task is achieved by placing hemispherical bottom receiving-emitting antenna devices along the axes of the runway of the hydroaerodrome of the hydro-aerodrome of the hydro-aerodrome, providing ultrasound-quantized objects in the water volume in circular or sector-wide viewing modes in both azimuthal and elevation planes (see Multi-frequency hydroacoustic receiving-radiating antenna device // Positive decision of January 24, 2011 on the grant of a patent for a utility model by application No. 201049910/28 (072080) author in Voloschenko VY, Voloschenko AP).

The technical result of the invention is to obtain updated information in a wide range of operating frequencies both about the detected targets and the characteristics of their movement (bearing, range, speed), and about the general situation in the water area (depth, direction and speed of the flow of water masses, height, speed and direction of movement of wind waves, ice thickness, etc.), which will improve the safety of take-off and landing operations in shallow waters.

The technical result is achieved by the fact that in the method of preparation of the hydro-airdrome flight pool for take-off and landing of the seaplane, the position of the runway within the hydro-airdrome flight pool is determined both taking into account the direction of the wind and the minimum condition of the wind waves, the crew of the hovercraft installs marker marks, during which visually, as well as using radar and sonar, inspects the path moved I am seaplane in the water area, mooring, unmooring and towing the seaplane after it is brought down or before take-off, and also on the ship on an air cushion it places glide-slope and course radio beacons for sending and receiving radio signals providing splashing of the seaplane in conditions of poor visibility, the following operations are additionally introduced :

placement of a hemispherical bottom receiving-emitting antenna devices along the axis of the runway of the hydroaerodrome along the axes of the bottom, providing quantized both in direction and “frequency coloring” ultrasonic echo search of objects in the water volume in circular or sector-wide viewing modes both in azimuthal and in elevation planes (see. Multifrequency sonar receiving-emitting antenna device // Positive decision of January 24, 2011 on the grant of a patent for a utility model according to application No. 201014991 0/28 (072080) authors Voloshchenko V.Yu., Voloshchenko A.P.);

connecting the receiving-emitting antenna devices with a cable to the equipment of the coastal hydroacoustic service of the hydroaerodrome, providing the generation of sounding excitation signals of the same type of pump transducers of parametric antennas, forming a hemispherical aperture of the receiving-radiating antenna device, processing and displaying information received in a wide frequency, but "individual" for each antenna device, range , which eliminates the interference of the mutual influence of neighboring bottom antenna devices;

the implementation by the coastal hydroacoustic service operators of various types of underwater monitoring: - ultrasonic sounding of the water volume of the runway corresponding to the existing wind direction; - current echo search on the perimeter of the flight basin of the hydroaerodrome; - passive observation of distant underwater conditions in the shelf zone adjacent to the water area of the hydroaerodrome, etc., moreover, the coastal hydroacoustic service can perform the above operations on an ongoing basis, regardless of weather conditions, time of day or year;

the simultaneous use of adjacent hemispherical bottom antenna devices provides an additional opportunity to remotely obtain information about the state of the water volume (depth, direction and speed of the flow of water masses), the air-water interface (height, speed and direction of movement of wind waves), and the interface " water-ice ”(ice thickness) at various points in the water area of the flight pool;

on the basis of the information received about the underwater situation in the water area, the coastal sonar service of the hydroaerodrome makes one or another decision regarding take-off and landing operations, which is communicated via radio channel to the crews of both the hovercraft operating the above actions and the seaplane preparing to take off landing operations.

Figure 1 shows the form of the directivity characteristics of the "cosecant" interference antenna (see short-range sonars. A.N. Yakovlev, G.P. Kablov. L .: Shipbuilding, 1983. P.174-178), in figure 2 - design of a multi-frequency bottom receiving-radiating antenna device; on figa, B presents the experimental directivity characteristics of a square (80 mm × 80 mm) electro-acoustic transducer of a parametric antenna: for a pump wave (A) with a frequency of 230 kHz and the signals of several difference (B) frequencies formed in the aquatic environment - 40, 20 and 2.5 kHz (a, b, c, respectively); figure 4 presents the experimental directional characteristics of two of the same type of parametric antennas with round (diameter 65 mm) electro-acoustic pump transducers for the difference frequency signal formed in the aquatic environment F = 50 kHz; figure 5 presents the directional characteristics of the electro-acoustic pump transducer of a parametric antenna experimentally measured in a hydro-acoustic basin for a pump signal of frequency f = 270 kHz and higher harmonic components formed in a nonlinear aqueous medium 2f = 540 kHz, 3f = 810 kHz; on figa, b - two projections of the layout configuration of the portion of the strip of the largest perimeter of the receiving-emitting antenna device, which is made on the basis of five electro-acoustic pump transducers; 7, 8, 9 - sectorial directional characteristics of the layout in the azimuthal plane: for the pump signal f = 270 kHz, for the second harmonic of the pump signal 2f = 540 kHz, for the third harmonic of the pump signal 3f = 810 kHz; figure 10 - sector directional characteristics of the layout in the azimuthal plane for the signal of the differential frequency F = 50 kHz; figure 11 - layout of the receiving-emitting antenna devices at the bottom of the water basin of the hydroaerodrome in the scale of "1 cell-100 meters".

Development and economically sound operation of an amphibious transport system (see Sokolyansky V.P., Morozov V.P., Dolgopolov A.A., Zakharchenko Yu.A. Amphibious aircraft and transport equipment for hard-to-reach regions of Russia / Collected reports of the VIIth scientific conference on hydroaviation “Gidroaviasalon-2008.” - M .: TsAGI, 2008, part 1, p.10-17) requires stability and security of the functioning of the network of hydroaerodromes based amphibious aircraft and transport equipment. Long-term basing on the territory of the hydroaerodrome makes it possible to conduct hydroacoustic control of the water volume of the summer basin with geometric dimensions: length ~ 2500 m, width ~ 200 m, depth ~ 3 m to 6 m on an ongoing basis: both around the clock and all year round. Efficiency of effective hydroacoustic monitoring of the water layer of the summer basin of significant transverse dimensions, but of such small depths, can be ensured with simultaneous "multifrequency" ultrasonic sounding of its individual parts, display and analysis of the information received, on the basis of which the underwater situation in the entire water area is clarified in real time hydroaerodrome. For this purpose, it is necessary to equip the bottom of the coastal section of the water area of the hydroaerodrome with stationary receiving-emitting antenna devices located in a certain way along the flight basin and each connected via cable to the shore-based equipment of the hydroacoustic service of the hydroaerodrome, which ensures the formation of sounding signals, processing, recording, and display of the received information. Note the advantages of the proposed option:

1) the location of the receiving-emitting antenna devices at the bottom of the water area allows you to connect them in the necessary sequence, which determines the fulfillment of the task, for example, conducting ultrasound sensing of the water volume of the runway corresponding to the available wind direction, conducting current echo search on the perimeter of the hydro-airfield airfield, passive mode observations of the distant underwater situation in the shelf zone adjacent to the water area of the hydroaerodrome based, etc .;

2) a significant reduction in acoustic noise levels: for example, it is known from fishing experience that the use of a towed antenna remote from the ship’s hull reduces the level of recorded noise by an order of magnitude in comparison with the base model of antenna placement (see Kobyakov Yu.S., Kudryavtsev N.N., Timoshenko V.I. Construction of hydroacoustic fish finding equipment.- L .: Shipbuilding, 1986, p.154-181);

3) stabilization of the position in space of the main lobes of the directivity characteristics of the receiving-emitting antenna devices;

4) the ability to remotely obtain information about the state of the water volume (depth, direction and speed of the flow of water masses), the air-water interface (height, speed and direction of movement of wind waves, the water-ice interface (ice thickness) in various points of the water area (waveograph mode);

5) improving the conditions for the replacement, maintenance and repair of receiving-emitting antenna devices;

6) the possibility of continuous hydroacoustic underwater observation in the water area of both the hydroairdrome flight basin and the adjacent reservoir, regardless of weather conditions, time of day or year, not only in active, but also in passive modes of operation of the equipment.

It should be borne in mind that in order to increase productivity during echo-searching within specified parts of the water volume of a shallow summer basin of a hydroaerodrome, each bottom receiving-emitting antenna device should provide unique conditions for underwater observation: in the elevated plane - in a narrow angular sector, and in the azimuthal plane - in a wide (optimal is a circular view), moreover, the position in the elevation plane of the narrow angular sector of observation while maintaining the circular view should vary by steps atoms on the direction of "parallel" to the direction "normal" with respect to the interface "water-to-air." This is possible if the design of the antenna device is a hemisphere, the surface of which is divided by parallels into strips of the same width, and, to simplify the design and manufacturability, the curved surfaces of all circular strips of different lengths can be replaced by different numbers of small flat platforms that approximate them and located normally relative to the radius (figure 2). The described design features make it possible, through the use of various bands, to change the echo search geometry in shallow water: from horizontal (lower circular strip with the largest perimeter) and inclined in the direction from the bottom to the top at a certain angle of slip to the water-air interface (circular stripes with smaller perimeters) to vertical (upper segment of the spherical surface). Following this approach, the design of the receiving-emitting antenna device can be formed by placing bands of small-sized electroacoustic transducers with the same aperture on the given sites - radiating elements whose acoustic axes are spaced apart by a given angle but go from one point - the center of curvature of the approximated hemisphere surface. A receiving-emitting device of this design can provide both a circular (all elements of the selected bands work in the radiation and reception modes), and a sector (part of the elements of the selected bands work in the radiation and reception modes), as well as discrete scanning of the resulting directivity characteristics (set in time and in the direction, a certain order of the modes of emission and reception by each element of the selected band separately) both in the azimuthal and elevation planes.

Unique characteristics of polyharmonic “acoustic illumination” of interfaces and search objects: a low level of lateral radiation with a constant sharpness of directional action in a wide range of operating frequencies, acceptable weight and size indicators, etc. can be provided only when using parametric antennas as radiating elements. A radiating parametric antenna is two spatially aligned interference antennas emitting coaxial intense ultrasonic pump beams, in the axial region of which, when the synchronism conditions are fulfilled, new spectral components are generated. The occurrence of a polyharmonic probe signal in an acoustic field should be considered as a result of a change in the elastic properties of a nonlinear aqueous medium in the region of propagation of a powerful biharmonic (f ₁ , f ₂ ) pump signal, which leads to a redistribution of the energy of intense ultrasonic waves along the frequency axis as “up” - generation of higher harmonic components of the pump waves, the waves of the total frequency (nf ₁ , nf ₂ , f ₊ = f ₁ + f ₂ ), where n = 2, 3, 4, ..., and “down” - the generation of the difference wave F = | f ₁ -f ₂ | frequency (see Hydroacoustic Encyclopedia. - Taganrog, Publishing house TRTU. 1999, p. 389-402). The practical use of only one component of the spectrum — difference-frequency waves — from the entire set of spectral components of the radiation of a parametric antenna that forms in the aquatic environment to obtain information that reflects the presence, certain properties, and characteristics of underwater objects is “energetically wasteful”, while receiving and processing echoes sum frequency and higher harmonic signals pump - f ₊ = f ₁ + f _2, nf _{1, 2} (n = 2, 3, ...) will increase the operational capabilities of bottom priemoizluchayu their devices used in the proposed method for the preparation of a hydroairdrome flight pool, as it enhances one of the most important qualities of parametric sonar systems: the ability to quickly reconfigure the parameters of sounding signals, which allows it to be adapted to a specific echo search situation (see V.Yu. Voloshchenko, V. I. Timoshenko Parametric sonar aids for near underwater observation (Part 1) - Taganrog: Publishing House of TTI SFU, 2009).

The generation of a difference frequency wave by a parametric antenna has been studied theoretically and experimentally, several practical applications have been proposed, in particular, using the formation of directional radiation of low-frequency signals in a wide frequency range for small weight and size characteristics of electro-acoustic pump transducers. Figures 3A, B show typical experimental directivity characteristics of a square (80 mm × 80 mm) electro-acoustic transducer of a parametric antenna: for a pump wave (A) with a frequency of 230 kHz and signals of several difference (B) frequencies formed in an aqueous medium - 40, 20 and 2.5 kHz (a, b, c, respectively) (see V. A. Voronin, S. P. Tarasov, V. I. Timoshenko. Hydroacoustic parametric systems. Rostov n / A: Rostizdat, 2004, p. 67 -69). Using the scale grid plotted in Fig. 3, we will compare the angular distributions of the amplitudes of the sound pressures of these signals: for example, it can be seen from the records for the difference frequency signals formed in the aqueous medium that the width of the directivity at the levels of (-3 dB), (-6 dB ) and (-10 dB) in the frequency range (2.5-40) kHz is almost constant and equal to 4 °, 6 ° and 8 °, respectively, with almost complete absence of a side field, while the directivity characteristic for the pump signal has a classical interference type: width and directivity characteristics at a level of (-3 dB) about 5 °, a side field is recorded - the first additional maximum with a level (-18 dB) in directions (± 6 °) relative to the acoustic axis, the second - (-28 dB) in directions - ( ± 12 °), etc. Based on the analysis of the spatial characteristics of the formed acoustic fields described above for the difference frequency signal formed in a nonlinear aqueous medium, it can be concluded that it is advisable to use precisely parametric radiating antennas as radiating elements in the design of bottom receiving-radiating antenna devices located in the water area of the swimming pool in accordance with the proposed method long-term hydroaerodrome. In this case, the resulting acoustic field of a separate band assembled from electroacoustic transducers of parametric antennas, while maintaining a high severity of directional action on the difference frequency signal in the elevation plane, is omnidirectional in the azimuthal plane, since it is formed as a result of a structurally specified partial overlap of the main maximums of the directivity characteristics for the wave differential frequency at a certain level (0.8; 0.7 or 0.5 in pressure).

Figure 4 shows the experimental directivity characteristics of two of the same type of parametric antennas with round (diameter 65 mm) electro-acoustic pump transducers for the difference frequency signal formed in the aquatic environment F = 50 kHz, which implies that for each of them the main lobe width is at level 0, 7 for a low-frequency sounding signal is 6 ° at the level of lateral radiation (-30 dB). It should be noted that the reduction in the overall dimensions of the antennas of parametric systems of active location occurs only in the radiation path of low-frequency signals of difference frequency, and in order to provide a sufficient resolving angle, the receiving interference antenna must have significant transverse dimensions determined by the laws of "linear acoustics": for example, in receiving echoes of a difference frequency of 50 kHz to the same round (diameter 65 mm) electro-acoustic transducer ystviya level of 0.7 will account for 28 °, and permitting adjustment capabilities in emission and in reception requires the use of a receiver electroacoustic transducer piston diameter of 300 mm. In turn, the resolution of parametric systems of active location can be increased by receiving and processing echo signals of the total frequency, higher harmonics of the pump signals - f ₊ = f ₁ + f ₂ , nf _{1, 2} (n = 2, 3, ...), which will allow expand the operational capabilities of bottom receiving-emitting devices.

Figure 5 shows the directional characteristics of the electro-acoustic pump transducer of a parametric antenna experimentally measured in a hydroacoustic basin for a pump signal of frequency f = 270 kHz and higher harmonic components formed in a nonlinear aqueous medium 2f = 540 kHz, 3f = 810 kHz (see Voloshchenko V. Yu., Timoshenko V.I., Volkov S.V., Panchenko P.V., Volkov A.S. Short-range acoustic location system for amphibious aircraft / Collection of reports of the 7th hydroaviation show 2008 scientific conference on hydroaviation, Part 2 - M .: TsAGI, 2008 .-- S.96-101). Using the scale grid plotted in FIG. 5, we compare the angular distributions of the amplitudes of the sound pressures of these signals. So, from the records for the signals formed in the aquatic environment, it follows that the electro-acoustic pump transducer has: at a frequency f = 270 kHz, the radiation pattern width at the level of 0.7 θ _{0.7 (f)} = 5.2 °, the first side lobe at an angle (± 8.3 °) to the acoustic axis with a level (-11 dB), the second side lobe at an angle (± 14 °) to the acoustic axis with a level (-30 dB); at a frequency of 2f = 540 kHz, the radiation pattern width at the level of 0.7 θ _{0.7 (2f)} = 3.8 °, the first side lobe at an angle (± 5.2 °) to the acoustic axis with a level of (-20 dB); at a frequency of 3f = 810 kHz, the radiation pattern width at the level of 0.7 θ _{0.7 (3f)} = 2.6 ° with a side field with a level of (-43 dB). It can be seen from the presented data that the acoustic fields of the high-frequency spectral components formed in the aquatic environment correspond to the conditions of underwater observation in the shallow water of the hydro-aerodrome flight pool, while echo search on the signal of the fundamental frequency will be significantly complicated. The generation in the propagation medium of the higher harmonic components of the emitted acoustic signal of finite amplitude is due to a change in the elastic properties of the nonlinear aqueous medium. On the acoustic axis, the amplitude-dependent change in the properties of the medium under the action of a powerful pump wave with a frequency f occurs to the greatest extent, while for off-axis directions, due to a decrease in the amplitudes of sound pressures, the properties of the propagation medium differ little from their unperturbed values. This leads to the appearance of an interesting effect: the main radiation maximum of the emerging acoustic fields for each subsequent harmonic is narrower, and the level of the side field is less than that of the previous one. As follows from the presented data, in spite of the fact that the efficiency of converting the energy of the pump wave upward in the frequency spectrum decreases for each subsequent harmonic, the acoustic fields of these signals have “useful” spatial characteristics from the point of view of developing location-based systems for short-range underwater observation, since increasing the radiated acoustic power makes it possible to simultaneously perform horizontal echo search in shallow water with an adjustable resolution obnostyu the angle, the choice of values which is defined as information of a particular portion of the physical properties of the aqueous medium and the plurality of external environmental factors: the presence of suspended particles, air bubbles, and the direction of water flow velocity, depth, wind waves, etc. (see Voloshchenko V.Yu., Voloshchenko A.P., Volkov A.S., Kupovy V.G. Non-linear hydroacoustic location system for monitoring the water volume of the runway of a hydroaerodrome // Materials of the Fourth All-Russian Scientific and Practical Conference “Perspective management systems and tasks. ”- Taganrog: Publishing House of TTI SFU, 2009. V.1. - S.274-276).

These parameters of the ultrasonic fields of the components F = | f ₁ -f ₂ |, f ₊ = f ₁ + f ₂ , nf _{1, 2} (n = 2, 3, ...) of the radiation spectrum of the parametric antenna satisfy the conditions of the near location at shallow water, which allowed using several similar round (diameter 65 mm) electro-acoustic pump transducers to test the layout of the proposed design. Experimental tests of the developed layout of the portion of the strip of the largest perimeter of the receiving-radiating antenna device (two projections of the layout are presented in Figs. 6a, 6b), which are made on the basis of five electro-acoustic pump transducers (the surface diameter of each electro-acoustic pump transducer (1-5) is 65 mm, the acoustic separation angle is the axes of adjacent transducers α = 6 °, the radius of curvature of 0.55 m, the frequencies of the central source and difference waves f ₀ = (f ₁ + f ₂ ) / 2 = 275 kHz and F = | f ₁ -f ₂ | = 50 kHz, respectively ) under hydro conditions The Bush basin showed the following:

1) the design of the developed layout allows, by switching the electro-acoustic pump converters, to produce on the working signals F = | f ₁ -f ₂ |, f ₁ , 2f ₁ , 3f _{1, a} discrete scan of the corresponding directivity characteristics of the parametric antennas with a step of 6 ° in the 30 ° sector;

2) the simultaneous excitation of several layout pump converters allows the formation of sector directivity characteristics in the horizontal plane. So, for three adjacent parametric antennas, the values of the width at the level of 0.7 of the resulting main maximum of the sector directivity in the horizontal and vertical planes are: for the pump signal f = 270 kHz 18 ° and 5.2 ° (Fig. 7), for the second harmonic pump signal 2f = 540 kHz 16 ° and 3.8 ° (Fig. 8), for the third harmonic of the pump signal 3f = 810 kHz 16.6 ° and 2.6 ° (Fig. 9). As follows from Figs. 7, 8, 9, fluctuations in the levels of amplitudes of sound pressure in the region of the resulting principal maxima for signals f, 2f, 3f were no more than 3 dB, 7 dB, and 9 dB, respectively, which was caused by the choice of a too large value of the separation angle ( 6 °) acoustic axes of adjacent pump converters; and the levels of lateral radiation in mutually perpendicular planes are (-11 dB), (-20 dB) and (-43 dB), respectively. For two adjacent parametric antennas, the values of the width at the level of 0.7 of the resulting main maximum of the sector directivity in the horizontal and vertical planes are: for the difference frequency signal F = 50 kHz 12 ° and 6 ° (Fig. 10) when the sound pressure amplitude fluctuates in the area of the resulting main maximum of not more than 2 dB and the level of side radiation (-24 dB);

3) the design of the layout allows you to save the benefits of parametric antennas, and the rotation of the resulting main maximum of the sector directivity is made in the most simple way - by switching the electro-acoustic pump converters, which compares favorably with electronic and mechanical discrete scanning;

4) the passband of the electro-acoustic pump transducer is about 55 kHz, which allows the formation of a parametric antenna in an aqueous medium, the pump wave frequencies of which vary in the ranges f ₁ = (248.5-272.5) kHz and f ₂ = (277.5- 302.5) kHz and efficiently generates additional components of the emission spectrum in the frequency ranges: difference F = (5-55) kHz, second harmonics of the pump waves 2f ₁ = (497-545) kHz and 2f ₂ = (555-605) kHz.

Expanding the range of working frequencies of echo search due to the redistribution of the parametric antenna of the energy of the pump waves both “down” and “up” over the spectrum, within the framework of the proposed method, it is possible to propose a solution to the problem of the mutual interfering effect of sonar devices used in the water area for echo search at small distances from each other friend. Modern microprocessor means allow for each electro-acoustic transducer included in the set of bottom receiving-emitting antenna device to program an “individual” set of radiation and reception parameters: the moment of radiation in the desired direction of the echo search, the duration of the probe pulse, the values of the biharmonic pump frequencies f _2i , f _1i included in the passband of the electro-acoustic transducer, as well as the recorded spectral component from the set of frequencies F _i = | f _2i -f _1i |, f _1i , f _2i , f _{+ i} = f _2i + f _1i , 2f _1i , 2f _2i , ... received polyharmonic echo (see Voronin V.A., Tarasov S.P., Timoshenko V.I. Hydroacoustic parametric systems. - Rostov n / A: Rostizdat, 2004, p. .243-247). This makes it possible to carry out an important operation during echo search in shallow water, eliminating the cause of the occurrence of ultrasonic interference of mutual influence along the hydroacoustic channel during the “oncoming” or “sliding” mutual irradiation of each other with the neighboring bottom receiving-emitting modules - a unique “frequency coloring” of each spatial angular sector in the upper hemisphere underwater observation due to appropriate filtering of polyharmonic echo signals received by electro-acoustic transducers of bottom radiation emitting antenna devices.

The general arrangement of receiving-emitting antenna devices in the water area in accordance with the proposed method for preparing a hydroairdrome flight pool for take-off and landing of a seaplane is shown in Fig. 11 on a scale of “1 cell-100 meters”. The position of the necessary runway 1 in the flight pool 2 for splashing the seaplane against the wind (arrow 3) is marked by hatching between two solid parallel lines, as can be seen from Fig. 11, there are several more possible directions of the runways (parallel lines, between which the dash-dot line is located) . As follows from the drawing, the underwater volume of the runway 1, which is planned to splash the seaplane, is pre-probed using three bottom receiving-emitting antenna devices 4 operating in one of the above modes.

The circles in Fig. 11 mark the boundaries of the proposed underwater observation zones for the corresponding signals: - - • • - difference frequency wave, - pump wave, - - - second pump harmonic, - • - third pump harmonic. The elimination of interference of mutual influence during the implementation of the regime of ultrasonic round-the-clock monitoring of the water volume of the hydroaerodrome can be achieved in a similar way when using receiving-emitting antenna units 4 located along the perimeter of the flight pool 2.

In accordance with the proposed method, it becomes possible to implement an even simpler variant of eliminating interference of mutual influence during the simultaneous operation of several receiving-emitting antenna devices 4 located within the surveyed runway (see 11, weak hatching section), which is based on a unique the ability of parametric radiating paths to form broadband radiation of low-frequency and high-frequency spectral components in an aqueous medium. Indeed, using the same type of electroacoustic transducers with a central resonant frequency f ₀ = 250 kHz, which are excited at different pump frequencies within the passband, it is possible to form a set of operating signals for each transceiving antenna module: for example, the first transceiving antenna device for 245 kHz pump signals and 255 kHz will have signals of difference and total frequencies - 10 kHz and 500 kHz, second harmonic pump - 490 kHz and 510 kHz; the second - for 240 kHz and 260 kHz pump signals - differential and total frequency signals - 20 kHz and 500 kHz, second pump harmonics - 480 kHz and 520 kHz, etc., moreover, the frequency of the spectral component determines the echo search geometry in shallow water: horizontal - differential frequency signals, inclined in the direction from the bottom up, at a certain angle of slip to the water-air interface - total frequency signals, second harmonics of the pump waves, vertical signal of the third pump harmonic.

The first parametric devices for active location and measuring purposes were created in the 80s of the last century at the Taganrog Radio Engineering Institute at the Department of Electro-Hydroacoustics and Ultrasound Engineering (now the Department of Electro-Hydroacoustic and Medical Technology at the Taganrog Technological Institute of the Southern Federal University) (see Novikov B.K. , Rudenko O.V., Timoshenko V.I. Nonlinear hydroacoustics. - L .: Shipbuilding, 1981. - 264 p.). Among them, the leading position is occupied by research parametric sonars, the design process of which made it possible to develop principles for constructing and using parametric sonar equipment for serial production (see Novikov B.K., Timoshenko V.I. Parametric antennas in sonar. - L .: Sudostroenie, 1989 - 256 p., Voronin V.A., Tarasov S.P., Timoshenko V.I. Hydroacoustic parametric systems .-- Rostov n / A: Rostizdat, 2004. - 400 p., V.Yu. Voloshchenko, V. I. Timoshenko Parametric hydroacoustic means bl lower pole underwater observation (part 1) - Taganrog Univ. of TTI SFU, 2009. - 294 c).. For the hardware implementation of the proposed method, a parametric emitting sonar path with a scanning directional characteristic for detecting silted objects and pipelines, which includes a pump signal shaper in the form of forty-eight frequency-modulated components, as well as forty-eight-channel power amplifiers and two-resonance ones, can be taken as a basis for the hardware implementation of the proposed method electro-acoustic pump transducer (see Voronin V.A., Tarasov S.L., Timoshenko V.I. Hydroacoustic parametric systems topic - Rostov n / D:. Rostizdat 2004, s.247-252). As an alternative implementation of the pump signal generator of the radiating path, which implements the proposed method, which combines the capabilities of digital and computer technology, the hardware-software complex of the pump signal synthesizer based on an IBM-type personal computer can be used, which provides task, input, correction of the generated signal parameters in the interactive mode and the generation of pump signals with given parameter values (see Voronin V.A., Tarasov S.P., Timoshenko V.I. Gidroakustiche Parametric systems. - Rostov n / A: Rostizdat, 2004, p. 243-247). The issues of developing parametric sonars for underwater unmanned vehicles towed by a ship, as well as deep-sea probes immersed from a fixed vessel, the common feature of which is the hardware division into two parts: airborne (surface) and submersible (underwater) blocks connected with a multi-strand cable up to 2000 m (see Voronin V.A., Tarasov S.P., Timoshenko V.I. Hydroacoustic parametric systems. - Rostov n / A: Rostizdat, 2004, p. 252-268, 293-302). In accordance with the proposed method, each transceiving antenna device 4 must be equipped with an electro-acoustic pump transducer, the acoustic axis of which is directed towards the water-air interface and oriented strictly vertically to ensure the measuring mode of the hydro-acoustic waveograph. The principle of operation of hydroacoustic devices for measuring the parameters of sea waves - waveographs, the features of constructing structural diagrams, parameters of the signals used are described in detail in the literature (see Prostakov A.L. Electronic key to the ocean: Hydroacoustic technology today. - L .: Sudostroenie, 1978, p. .126-128, Bogorodsky A.V., Yakovlev G.V., Korepin E.A., Dolzhikov A.K. Hydroacoustic technology for research and development of the ocean. - L .: Gidrometeoizdat, 1984, p.90-93). The specifics of the operation of a hydroacoustic waveograph is determined by a continuous change in the shape of the reflecting surface and the distance to it, the strong influence of volume reverberation arising in the near-surface layer and masking the useful signal, and therefore, the total frequency signal can be used as a measuring one. The probing pulses of the signal of the total frequency are reflected from the interface, the distance to which is continuously changing according to the law characterizing the sea waves, which allows you to get the wave profile, determine the shape, height of the waves and the direction of their movement at different points in the water area of the hydroaerodrome. In the winter period of operation of the water area of the hydroaerodrome summer basin, the use of vertical sounding in the echo-meter mode using an electro-acoustic transducer for pumping a parametric antenna, whose acoustic axis is turned vertically upwards towards the water-ice-air interface, will allow us to evaluate the dynamics of thickening of the ice cover and its strength (see V.Yu. Voloshchenko, V.I. Timoshenko. Parametric sonar aids for near-water underwater observation (Part 1). - Taganrog: Publishing House of TTI SFU, 2009, p. 250-266). When sonar, three methods of viewing the space are used: 1) stepwise with a narrow directivity characteristic of the antenna both in radiation and in reception, which mechanically rotates in the viewing plane, 2) circular with omnidirectional radiation in the viewing plane and scanning with a narrow receive directivity antennas, 3) circular in the viewing plane with a narrow directivity characteristic of the emitting antenna scanning during pulsed sounding and statically formed petals of the directivity characteristics of the receiving antenna, evenly covering the entire horizon or the desired viewing sector (see Prostakov AL Electronic key to the ocean: Hydroacoustic technology today. - L .: Sudostroenie, 1978, p.10-21). The last circular viewing method can be used in the proposed method and has advantages: the viewing area is quantized in the direction due to the proposed form of the receiving-emitting antenna device — each lobe (i.e., the main maximums of the directivity characteristics of the electro-acoustic pump transducers in the receiving mode) of the statically formed directivity module and the individual channel for processing the echo signal connected to it provides information about the goals that are in a particular Mr. Sector Review. Overview of the entire horizon is carried out by sequentially polling the outputs of all channels and connecting them to the all-round indicator.

The implementation of hydroacoustic monitoring of the underwater volume of the water basin in accordance with the proposed method will significantly increase its effectiveness by eliminating the ultrasonic interference of mutual influence through a shallow hydroacoustic channel due to quantization of the viewing sectors both in direction and frequency of the recorded echo signal (“frequency staining), which will increase safety of takeoff and landing operations in the water basin of the hydroaerodrome.

Claims (5)

1. A method of preparing a hydro-airdrome flight pool for take-off and landing of a seaplane, which consists in determining the position of the runway within the hydro-airdrome flight pool, taking into account the direction of the wind and the minimality of the existing wind wave in the water area, the crew the air cushion installs marker signs, during which visually, as well as using a radar and sonar, inspects the seaplane's movement in the water area, implements mooring, unmooring and towing of the seaplane after its landing or before take-off, as well as on board the hovercraft, places glide-slope and course radio beacons for sending and receiving radio signals providing splashing of the seaplane in conditions of poor visibility, characterized in that they are placed within the limits of the flight basin of the hydro-aerodrome along the axes of the runways, hemispherical bottom receiving-radiating antenna devices providing quantized both in direction and frequency frequency e "Ultrasound ehopoisk objects in the body of water in a circular or sector modes viewing both azimuthal and elevation planes. 2. The method according to claim 1, characterized in that the receiving-emitting antenna devices are connected by cable to the equipment of the coastal hydroacoustic service of a hydroaerodrome, providing the generation of probing excitation signals of the same type of pump transducers of parametric antennas forming a hemispherical aperture of the receiving-radiating antenna device, processing and displaying information obtained in a wide frequency, but "individual" for each antenna device, range. 3. The method according to claim 1, characterized in that the operators of the coastal hydroacoustic service carry out various types of underwater monitoring: ultrasonic sounding of the water volume of the runway corresponding to the available wind direction; current echo search on the perimeter of the flight basin of the hydroaerodrome; passive observation of distant underwater conditions in the shelf zone adjacent to the water area of the hydroaerodrome, and the coastal hydroacoustic service can perform the above operations on an ongoing basis, regardless of weather conditions, time of day or year. 4. The method according to claim 1, characterized in that the simultaneous use of adjacent hemispherical bottom antenna devices makes it possible to remotely obtain information about the state of the water volume (depth, direction and speed of the flow of water masses), the air-water interface (height , the speed and direction of movement of the wind waves), the water-ice interface (ice thickness) at various points in the water basin. 5. The method according to claim 1, characterized in that on the basis of the received information about the underwater situation in the water area, the coastal hydroacoustic service of the hydroaerodrome makes one or another decision regarding take-off and landing operations, which is communicated via radio channel to the crew as an air cushion carrying out the described above the action, and the seaplane preparing to perform takeoff and landing operations.

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