Method of surveying bottom topography of water area and apparatus therefor

FIELD: physics.

SUBSTANCE: unlike the existing method, the present method includes, while emitting hydroacoustic signals towards the bottom, performing magnetic survey using a gradient metre which is towed 5 m from the bottom, seismoacoustic profiling using a profile recorder with operating frequency of 3.5 kHz, measuring the sea level, when processing depth measurements, further performing linear interpolation of the obtained bottom surface through triangulation, when mapping the obtained information with determination of geodesic coordinates of the depth measurements, evaluating the degree of spatial homogeneity of coverage of the survey region by measurement points by determining outer boundaries (contour) of the survey region using the apparatus for surveying the bottom topography of the water area, which consists of a transceiving antenna, a transmitting unit, a receiving-measuring unit, a control unit, a unit for determining the average speed of sound in water, a unit for collecting and processing information and mapping the bottom topography, a multibeam echo sounder, a unit for imaging the region of the bottom topography, a hydroacoustic Doppler log, a satellite navigation system receiver, a heading system, a roll measuring device, characterised by that the apparatus for surveying the bottom topography further includes a towed gradient metre, a profile recorder and a sea level metre, connected by their outputs to the inputs of the unit for collecting and processing information and mapping the bottom topography.

EFFECT: broader functional capabilities while increasing reliability and information value when mapping the bottom topography of a water area based on depth measurements using a multibeam echo sounder.

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The invention relates to hydrography, in particular to methods and technical means of barometric relief survey of the seabed by determining the depths at a given water area determining their geodetic coordinates.

There is a method of shooting of the bottom relief of water sounder (kolomiychuk N Hydrography. L., GUNiO MO USSR, 1988, s-277 [1]), including the ship with the installed sonar set shallower waters, the radiation of the acoustic signals toward the bottom, receiving reflected from the bottom of signals, measurement of the distances from pievescola antenna sonar to the reflecting surface (bottom points), the determination of geographical coordinates of the vessel, the determination of geodetic coordinates pievescola antenna sonar measurements onboard, roll and heave, true course and speed of the vessel, determining the true depth values and their geodetic coordinates and their subsequent registration and indication.

It is also known a device for implementing this method, representing the sounder ('hare R. Depth and position error budgets for multibeam echosounding // International Hydrographic Review. 1995, v.LXXII, No. 2, p.37-69 [2]), containing priemyslu antenna, the transmitting unit, priamosmaritime unit, control unit, registration unit, the processing mapping of bottom topography, in which the output of pievescola antenna under the offline to the entrance premoistening block, the output of the emitting unit is connected to pievescola antenna outputs priekaistaudami unit is connected to the input of the reception, processing and mapping of bottom topography, the inputs of which are connected to the outputs of the ship's gauges components pitching, of course, the velocity and position, and the control unit is connected with the transmitting unit, priemyselna block and the block of information gathering, processing and mapping of bottom topography.

Significant disadvantages of the known method and device are relatively low precision shooting of bottom waters, which does not meet the requirements for hydrographic surveying, as well as the substantial complexity of the process, because of the need to perform calculations related to determining corrections for the deviation of the actual average speed of sound in water used in the calculations, the calculated values of the average speed of sound in water for a particular sonar is determined indirectly from the measured values of temperature, salinity and density of sea water on accepted practice standard horizon depth or by direct measurement of sound velocity uniformly distributed points throughout the area.

Due to the fact that the required accuracy of determining the average speed of sound, you is anaemia by calculation, is provided only in a small local spatial region in which the measured temperature, salinity and density of sea water or directly the speed of propagation of sound in water for a particular sonar, the precision shooting of bottom topography in the end, weighted by the error due to the influence of small-scale and large-scale variability over time of wind movement and turbulence, internal waves, underwater currents. This error can reach 3% of the measured depth (see, for example: D.E. Dinn, B.D. Loncarevic et al. The effect of so und velocity errors on multibeam sonar depth accuracy // Proceedings of American Hydrograhic Symposium. 1995, p.1001-1009). In accordance with the requirements of the standards of the International hydrographic organization (see, for example: Notes on hydrography. SPb., GUNiO MO of the Russian Federation, No. 248,1999, p.27-32) in waters with depths of over 200 m, on which the picture is taken in the interests of safety of navigation, the mean square error (RMS) to determine the depth should not exceed 0.3%.

When using the known method for surveying terrain and device for its implementation CSP to determine the depth is for depths up to 100 m from 0.7 to 3.5 m, and for depths up to 200 m from 2.3 to 11.0 m, respectively, which does not meet the requirements.

The mapping of bottom topography UPC build bottom relief must not exceed 0.5 the m-scale tablet, that combined with the error in the determination of the depth of the known method and device for its implementation in most cases does not allow for this requirement.

In addition, in the production of imagery bottom relief with subsequent mapping of bottom topography, especially in the coastal area and in narrow places, you must have map information on both land and in the adjacent offshore area. The use for these purposes typographical topographic and navigation map is rather difficult. One of the reasons for this are the different map projections. Topographic maps are built in the projection of the Gauss-krüger and navigation in Mercator projection. This reason is the main obstacle to the use of raster images of the printed maps in electronic geoinformation systems, such as display devices mapped information when you are shooting a bottom relief.

There is also known a method of shooting of bottom waters and device for its implementation (patent RU No. 2340916 [3]), in which the technical result consists in increasing the accuracy will be solved due to the fact that the way to capture the topography of the area the sounder installed on the vessel, including radiation hydroacoustic signals in the direction of the bottom receiving reflected from the surface on the and signals, measuring distances from pievescola antenna to the bottom, the coordinates of the ship on external sources of information, the measurement side, roll and heave, true course and speed of the vessel, the binding of the measurement time determining the true depth values to determine the correction for the deviation of the actual speed of sound in water from the calculation, mapping the received information identifying the geodetic coordinates of the measured depths, where when determining the true depths of the correction for the deviation of the actual speed of sound in water is determined from the calculated taking into account the Doppler frequency shift between the emitted and the reflected sonar signals hydroacoustic log from the sea floor, when mapping the terrain bottom perform pairing topographic raster maps and navigation.

This method is due to the fact that when determining the true depths of the correction for the deviation of the actual speed of sound in water is determined from the calculated taking into account the average speed of sound propagation in water through the values of the Doppler frequency shift between the emitted and the reflected sonar signals hydroacoustic log from the sea floor, allows to achieve the technical result consists in increasing the accuracy of survey of the topography of aquat the series. However, due to the fact that the survey carried out by the measuring equipment installed on the surface vessel, influenced by external conditions, while shooting, there are so-called bad data that is in final processing measured information are wrong. Bad data increases the time of the shooting, and therefore the complexity of processing.

Provided in the analogues of the adjustments are made depending on the current values of yaw, pitch and roll media measuring equipment is also fully addresses the measurement of depths of water area both because of the large inertia sensors, and due to non-uniform energy loss on the way from the vibrator to the bottom and at the bottom (due to incomplete reflection), but also on the way back.

More complex conditions occur when the radiation reflected signals from any obstacles that are in the aquatic environment. Here we have to reckon with the influence of solid angles, inside of which is covered by the flow energy of the acoustic waves: solid angle within which the vibrator sends signals, and the solid angle under which the size of the obstacle is visible from the center of the probe waves (see, for example: Shuleykin CC Short course of physics of the sea. Leningrad, Gidrometeoizdat, 1959, s.400-401). And if shooting in a known manner about who has the necessary requirements for navigation, then when you are shooting in the interests of a search under a layer of silt facilities and pipelines or define limits of the continental shelf of the requirements for precision shooting is not provided. Sonar search in such conditions is accompanied by a large number of false alarms.

When you are shooting in the waters of the continental shelf to meet the requirements of precision, it is necessary to eliminate or reduce the influence of the errors that are systematic or slowly changing nature, which include errors due to spatial-temporal variability of the velocity of sound in the area of the shooting; error caused by the deviation of the instantaneous level of observable level post; error associated with determining the position and orientation of the instrument coordinate system in the ship coordinate system. When searching for subsea facilities and pipelines at a small thickness of silt silty pipeline must use only vysokonapolnennyh systems to obtain high resolution. The system should be low for good penetration of the signal into the thickness of sediments. The problem of control of pipelines and define the limits of the continental shelf/occurs usually in shallow water that requires limited GABA is itov antennas. Given the comparatively small size silty objects it is necessary to use a scanning narrow parametric beam.

The known method of shooting of the bottom relief (patent RU №2434246 [4], improving the accuracy of the shooting of the bottom topography in comparison with the known method [3] is due to the fact that additionally perform sonar sensing the bottom of the parametric sonar scan directional characteristic, mounted on excellent levels of depth from the ship's sonar funds can be moved both in the vertical and horizontal planes of the sectorial overview scanning directivity in the radiation mode parametric antenna with the reception of reflected signals from an antenna of the same dimensions as the antenna pumping parametric antenna, the width of the directivity in receive mode exceeds the value of the sector review and the scanning plane antenna declined relative vertical locations on the angle of 15 degrees in the direction of movement of the vessel.

However, when solving applied problems, for example, associated with the construction of underwater pipelines at great depths, it is very important that all forms of relief or artificial underwater objects were identified during the bath the metric instrumental shooting on the measured depths of the sound signals, formed, in particular, high frequency by multi-beam echo sounders to get a detailed picture of the bottom relief.

When shooting topography by multi-beam echo sounders depth in the horizontal plane are measured (formed) with a certain resolution, which is associated with the angle beam method for beam forming, frequency multibeam sonar resolution beam forming. Moreover, this resolution is in General a function of depth L=f(H).

For example, for high-frequency multibeam echo sounder type EAT 100 used to carry out bathymetric instrumental shooting for project works for laying underwater pipelines for transportation of hydrocarbons, the horizontal resolution of the distribution of depths at equal distance in the shallow mode is equal to L=6.3%Of N, where N is the depth. When the distribution of depths at equal angles is the distance on the lateral rays is increased in comparison with the Central rays. This leads to the fact that with increasing depth of capture possible threat to pipeline landforms. From the point of view of the design parameters of the pipeline crossing pipeline such dangerous forms leads to an increase of the free span of the pipe and increase the load at the point of contact of the pipe with dangerous terrain forms the. When designing a pipeline based on the bathymetric profile, and the lack of fixation on the profile of a dangerous depth in real conditions can result in exceeding the allowable loads on the pipe and thus to its damage, so the problem of determining the probability of missing dangerous forms of relief when conducting bathymetric surveying is very important. There are also known methods of topographic relief of the bottom (patent RU №S, 10.12.2006 [5], patent RU NO. S, 20.01.2007 [6], patent RU NO. S, 10.06.2006 [7], the patent EP NO. A, 09.06.2004 [8]) this problem is also not solved. The unique geographical position of the Arctic ocean basin, inadequate hydrographic and geological-geophysical investigation, the ambiguity in the interpretation of the deep structure of his bowels, the absence of a clear concept of the formation of this young ocean causes considerable difficulty in defining the outer limits of the continental shelf to the Arctic States in the legal framework of the UN Convention on the law of the sea 1982. Ways to determine the position of the outer limits of the continental shelf associated, primarily, with the need to calculate the foot of the continental slope in the bathymetric data. In accordance with the provisions of the Scientific and technical guidelines of the UN Commission on the boundary of the continental shelf "foot of the continental slope is defined as the point of maximum change of gradient at its base". Existing algorithms to determine the points of local maxima, the change of slope of the bottom on the continental edge. These points can be a large number in connection with complication of the relief of the continental margin forms the lower orders. According to the Convention the maximum change of slope of the bottom (second derivative of elevation), corresponding to the foot of the continental slope (PKS), should be at the base of the continental slope (ACS). Hence, an important task is the determination of the position of the ACS, which objectively can be based on bathymetric, geomorphological and geological and geophysical information (the international Convention on the law of the sea 1982): Military publishing house of the USSR Ministry of defense, 1985, - 224; Scientific and technical guidelines of the Commission on the limits of the continental shelf. New York: Commission on the limits of the continental shelf. 1999, - 92). The objective of the proposed technical solution is the extension of functionality while enhancing the reliability and informative for mapping of bottom waters on the measured depths through hydroacoustic measurement tools.

The problem is solved due to the fact that the way to capture the topography of the area([4] -a prototype), including radiation hydroacoustic signals in the direction of the bottom receiving otrajennyh bottom surface of the signals, measuring distances from pievescola antenna to the bottom, the coordinates of the ship on external sources of information, the measurement side, roll and heave, true course and speed of the vessel, the binding of the measurement time determining the true depth values to determine the correction for the deviation of the actual speed of sound in water from the calculation, mapping the received information identifying the geodetic coordinates of the measured depths, in which the mapping of bottom topography perform pairing topographic raster maps and navigation, in addition execute sonar probing the bottom with sonar and/or survey echo sounder installed on different horizons depth from the ship's sonar tools with the ability move them both in vertical and in horizontal planes of the sectorial overview scanning directivity in the radiation mode parametric antenna with the reception of reflected signals from an antenna of the same dimensions as the antenna pumping parametric antenna, the width of the directivity in the receive mode exceeds the value of the sector review and the scanning plane antenna declined relative vertical locations on the angle of 15° in the direction of movement of the vessel, in the cat the rum unlike the prototype simultaneously with the radiation of hydroacoustic signals in the direction of the bottom perform magnetic sensing through gradienter, towed at a distance of 5 m from the bottom acoustic profiling by profilometer with an operating frequency of 3.5 kHz, measure the sea level, when processing values measured depths additionally perform a linear interpolation of the resulting surface of the bottom through triangulation, the mapping of the received information identifying the geodetic coordinates of the measured depths assess the degree of spatial uniformity of the coating dots measurement area measurement by determining the outer boundary (contour) of the field survey, and in the device to capture the topography of the area, consisting of pievescola antenna, the transmitting unit, premoistening block, control block, the block determining the average speed of propagation of sound in water, block collection, information processing and mapping of bottom topography, multibeam echo sounder, the visualization module the field of relief, acoustic Doppler log, receiver satellite navigation system, foreign exchange system, measures of pitching, added towed gradienter, the profilograph and the meter sea level, connected by their outputs to the inputs of the block collection, information processing and mapping of bottom topography.

The invention is illustrated by drawings (Fig.1-7).

Figure 1. Structural block diagram of the device. Device is isto to capture the topography of the bottom of the water area consists of pievescola antenna 1, the transmitting unit 2, premoistening unit 3, a control unit 4, unit determining the average speed of propagation of sound in water 5, block collection, information processing and mapping of bottom topography 6, multibeam sonar 7, the visualization module field elevation 8, sonar Doppler log 9, the receiver 10 satellite navigation system, the exchange system 11, meters pitching 12, towed gradienter 13, profilograph 14 gauge sea level 15.

In the drawings (figure 2-4) illustrations of the application of the algorithm for computing the contour shooting multibeam echo sounder to specific measurements, obtained by multibeam sonar.

Figure 2. Coordinate points of measurement by multi - beam echo-sounder stereographic projection. Measurement points 16, omissions measurements 17.

Figure 3. A graph of the distribution function of the radii of the circles circumscribed around the triangle.

Figure 4. The contours of the external borders and gaps calculated by the algorithm to capture (stereographic projection, figure 2). Figa - the overall picture shooting. Figb - increased the selection. The contours of the external borders of 18 shooting, omissions measurements 17, the selection of 19 shooting, the coordinates of the 20 measured depths.

Figure 5. An example of executing a linear interpolation through triangulation.

6. An example of building a surface of the second derivative is in the direction of the gradient, corresponding to the maximum change of slope base at this point, by means of the algorithm for constructing the surface of the norm of the matrix of the second derivative of the depth. Figa - surface interpolation for depth measurement. Fig. 6b - surface of the second derivative in the direction of the gradient.

7. Example find the line DCC (approximation line in pixels).

The output of transceiver antenna 1 (Fig 1) is connected to the input premoistening unit 3, the output of the emitting unit 2 is connected with pievescola antenna 1, and outputs premoistening unit 3 is connected to the input of the block collection, information processing and mapping of bottom topography water area 6, the inputs of which are connected to the outputs of the ship's gauges components pitching, of course, the velocity and position, and the control unit 4 is connected with the transmitting unit 2, priemyselna unit 3 and unit information gathering, processing and mapping of bottom topography 6. The input unit determining the average speed of propagation of sound in water 5 in the direction of radiation of the acoustic signal through the control unit 4 is connected to the output of shipboard acoustic Doppler log 9 and the output of the satellite navigation system receiver, and the output connected to the input of the block collection, information processing and mapping of bottom topography 6 waters, multibeam sonar 7 is connected by its input-output the AMI with the control unit 4 and the input of the block collection, information processing and mapping of bottom topography water area 6, the visualization module field elevation 8, is connected by its input to an output unit of data collection, processing and mapping of bottom topography waters 6. Towed gradientunits 13, the profilograph 14 and the meter sea level 15 is connected by its outputs to the inputs of the block collection, information processing and mapping of bottom topography 6. The device and the principle of blocks 1-9 similar devices and the principle of blocks 1-6 prototype [4]. In this case, as in the prototype, pievescola antenna 1 are collected from the piezoelectric acoustic transducers placed in the same housing, which can be used for both emission and reception of reflected from the bottom of signals. In the cycle of radiation these converters are connected in parallel, and during reception of the echo signals they operate independently from each other.

The transmitting unit 2 consists of a crystal oscillator is stable in frequency, shaper of the repetition period of the emitted pulses, the device forming the duration of the emitted pulse synchronizer device of quantization, power amplifier, inverter, switch.

The generator produces a continuous oscillation frequency of 4.8 MHz, through which the synchronizer is reduced to 600 kHz, and generates a pulse. The amplifier increased the t of the pulse to a value required for excitation of electro-acoustic transducers pievescola antenna 1. Through the switch converters pievescola antenna 1 during radiation are connected to the transmitting unit 2, and during the reception to priemyselna block 3.

Priamosmaritime unit 3 consists of a bandpass amplifiers, antenna amplifier, the main amplifier unit shapers control codes, block filters, amplitude detector, a lowpass filter switch, the output of the amplifier and is designed to receive, amplify, and frequency selection of the signals received.

The control unit 4 is composed of a ROM of the microinstructions, the ROM control address selection, BIS firmware control, two microprocessors, ROM, RAM, pattern transfers, three buffer registers and five highways: highway address line of the microinstructions, line D, line M, line L, and is designed to generate and transmit commands and information files received from external sources, as well as information contained in ROM.

The block determining the average speed of propagation of sound in water 5 consists of a decoder of the microinstructions, buffer stages, register addresses, arithmetical and logical devices, multiplexers, decoder, line A, line D, recharge the A.

Block collection, information processing and mapping of bottom topography 6 consists of receiving registers, block highway system, amplifier, memory Manager, operating unit, the flow control unit commands, block microprogram control unit interrupts the output registers.

Multibeam sonar 7 is a multibeam sonar with complex linearly frequency-modulated signal and is designed to measure depths from 20 to 6000 m Scan power of received signals is carried out in range and angle. The changing nature of power in the beam with distance depends on the shape of the bottom topography. Of the 32 receiver channels form a 256-rays, which allows to obtain quasi elevation profile. Receiving antenna multibeam sonar 3 frequency range 30 kHz consists of 32 elements.

Towed gradientunits 13 is designed for magnetic survey and represents a proton gradientunits type "Sea SPY" or "Marine Magnetic Explorer". Trailed gandola of gradiententry 13 in deep water is towed at a distance of 5 m from the bottom. For a stable hold of the towed body at a given distance from the bottom is used winch type "DT VARINE 2005EHLWR" with remote control. In the shallow parts trailed gandola of gradiententry 13 is towed on the surface, its location is determined by the length of the cable and the distance to the antenna of the GPS satellite navigation system.

To determine the location of the vessel and sensor information with the required accuracy using equipment users of satellite navigation systems GPS in differential mode (DGPS), working on two independent control and correction stations, as well as geodetic control and correction stations for RTK or to accept amendments Starfix HP on the satellite channel.

This coordinate system provides the place with an average RMS error of no more than 0.3 m at any point in the district at the clock work.

For navigation support is also used basic geodetic station type "MS 750 Base", marine receiver type Trimble 5700 RTK and Trimble DSM 2121", the navigation computer software. Electronic navigation and information system (ECDIS), ECS -1000 software "dKart Navigator", ultramarathoning system underwater navigation type "Simrad HPR 4 YR" for high-precision positioning of the nacelle gradienter 13 with two beacons-defendants.

The profilograph 14 is a bottom type profilograph "SPB Klein 2275" (working frequency 3,5 kHz, a resolution of 75 cm, the maximum depth of the tow 600 m).

Gauges rolling 12 are sensors of the course and the dynamic movements of the ship type "Octans" compensat is her dynamic displacements of 0.01 deg at the rate the vertical movement of the side and keel rolling with the frequency data 40 Hz.

As a meter of sea level used meter sea level 15 type "(MCM-2".

The block determining the average speed of propagation of sound in water 5 is a measuring speed of sound "SVP 15" or type "OLD 1".

Block collection, information processing and mapping of bottom topography 6 based on math software "Trimble Geomatics Office, geographic information system type "Mapinfo v.7". The operation of the device is as follows.

Command pulses generated by the control unit, the transmitting unit 2 by the formation of the acoustic pulse and the radiation pievescola antenna 1 toward the bottom, as well as the reception and conversion into an electrical signal reflected by the bottom of acoustic signals, transmission of these signals to the input premoistening block 3, which produces electrical signals proportional to the time delay of arrival of reflected from the bottom surface of the signals, which are determined by the distance from pievescola antenna 1 to the points of reflection signals from the seabed. At the same time on the command pulses from the control unit 4 electrical signals proportional to the Doppler shift frequency of the reference acoustic signal from the court of the first acoustic Doppler velocity meter (lag) (which is similar lag described in the book: Absolute and relative logs / Vinogradov K.A., the way V.I., Aswhin B.A., Ridges A.A. // Sudostroenie, Leningrad, 1990, p.30), and electrical signals proportional to geodetic coordinates x, y from marine receiver 10 satellite system, is fed to the input of block determine the average speed of propagation of sound in water 5, which is determined by the average velocity of propagation of sound in water by the algorithms given in [4].

Next on the command pulses from the control unit 4 units 3, 4 and 5 is supplied to the block collection, information processing and mapping of bottom topography 6, which also receives information from the ship's gauges components 12 and pitching of the course 11.

In block 6 is defined by an amendment to the depths, measured by multi-beam sonar 7. Information from multibeam sonar 7 is fed to the visualization module area relief 8.

The mapping information is carried out by applying the geodesic coordinates of the reflection of hydroacoustic signals from the seabed on the tablet, which is constructed by pairing topographic raster maps and navigation in the following sequence:

- raster navigation map in Mercator projection is subjected to vectorization shoreline navigation maps;

- sampled plot, the corresponding Aqua marine is Oria, where is the shot of the bottom topography given vectorization shoreline navigation maps;

- an entry is made in the final raster navigational charts;

- raster topographic maps in the projection of the Gauss-krüger is to scale the navigation map;

- convert the coordinates of the projection of universal transverse Mercator geographic coordinate;

- converts geographic coordinates Mercator projection;

- selection is part of the raster corresponding to the land (coastal) region;

- writes in the final raster topographic maps;

- according to the results of the records in the resulting raster navigational and topographical maps based final raster map combined navigation and topographic information in Mercator projection;

- in the final raster map to be displayed on the display device also displays the path of the vessel.

When rendering a registered area of the bottom topography data to VRML interpreter are formed in the computer memory of the computing device is further loaded into the interpreter. Why in the boot VRML file included site JavaScript functions which control the area of the visible space. Software tools for mapping visualizacoeslas data structures in SVG format, which supports vector and raster data.

Rendering data in SVG format is a declarative language interpreter SVG. The data in the SVG structure are formed similarly to the formation of data in VRML format. Based on the data in the XML structure (geospatial information)obtained from the database on request, carried out the conversion in browser memory in the structure of the SVG using XSLT T. For simultaneous presentation of geospatial data in two-dimensional and three-dimensional representation is to support the synchronization of navigation and the other scene. To map the scene is the rectangle corresponding to the current region of space, the data which is loaded into the memory of the VRML interpreter. The synchronization SVG is based on JavaScript functions embedded in SVG and HTML. Since synchronization from VRML to make more difficult, the boot file VRML enabled site with JavaScript navigation function, which does not allow three-dimensional image beyond the window of view and constantly monitoring window coordinates of view. These coordinates the necessary information for synchronization with the map stage, which is possible using the timer HTML.

The navigation system is built using an alternative to Izv the STN technology GA organizing principle point of observation of three-dimensional scenes which uses the standard principle is the observation point is located outside the stage and when navigating the scene is stationary, and change the coordinates of the observation point and the angle. Thus, the center of rotation is not explicitly specified, which is one of the reasons for the loss of image when navigating. In the proposed technology, the observation point is always in the center of the window of observation and visualized small trihedron axes, and the beginning of the trihedron is always the center of rotation of the image and when navigating the stage moves relative to this center. The block 6 is fed to the visualization module field elevation 8, whereby perform the interpolation points of the heights (depths) methods of two-dimensional spline functions, specifically in the form of two-dimensional irregular rational fundamental splines (NURBS) (see, for example: N. Golovanov. Geometric modeling. M, Fitalic, 2002. - 472 p), mathematical expressions which are not presented due to lack of sufficient space. The advantage of the proposed method is to perform interpolation of the elevation points in the form of two-dimensional rational two-dimensional spline NURBS functions, allowing you to build up a smooth surface for any form of relief, even for breakages with a negative angle. Secondly, the surface elevation is specified analytical the dependence i.e. a finite set of parameters fixed set of functions (polynomial splines). The analytical form of the task of relief, i.e. in the form of superposition of analytic functions of two variables, allows you to use the entire apparatus of differential geometry to describe the morphometric properties of the terrain, for example, compute the value function (height, depth) or differential (slope) at any point (or points) the area of assignment functions. Thirdly, NURBS provide local edit the shape of the surface. In addition, for the same area of land the size of the array DEM data using NUBRS will be at least an order of magnitude less than traditional point of view. Consequently, the use of NURBS increases the efficiency of the automated geospatial systems by reducing processing time and required memory. The use of NURBS in computing is already a fait accompli - in graphics packages all operating systems embedded processing algorithms and visualization NURBS, such as graphics packages low: DirectX and OpenGL for Windows. However, when DEM obstacles associated with the effect of the occurrence in some situations, violations of monotonicity in the change of the surface - local appearance of spurious oscillations. In the inventive fashion this obstacle is eliminated either by adding new points in the array for interpolation, or by using methods isogeometric approximation by splines. In the first case, the resolution of problems associated with the increasing importance of expert work in an iterative procedure for constructing NURBS, the second - with a significant complication of mathematical algorithms technology.

In the proposed method is implemented the construction of a DEM-based NURBS in the form of iterative expert automated procedure. As a programming language used the language MatLab. In this system, the build quality of a DEM is determined by expert comparison of the position of the contour calculated by NURBS, with the position of the corresponding isohypse (isobaths) on the original map. In a particular implementation of the proposed method, source of information about the terrain serve as a raster map.

In General, when the approximation of the elevation profile of one-dimensional splines should be set to the values of the two first derivatives at the end points of the section. However, this information is unknown, and get it in practice impossible. Therefore, as the base spline to approximate the elevation profile along the section used a simple cubic spline with zero boundary derivatives. Due to the fact that there is no explicit two-dimensional splines, because you cannot construct the infinite system of algebraic equations from which losowania first two derivatives in all directions at adjacent edges of two pieces of spline surfaces, building a two-dimensional spline function is performed using tensor products of univariate splines. Approval of the first two differentials center for adjacent rectangular areas of the map is provided by the overlap of job related NURBS.

Thus, the technology of construction of the DEM in analytical form based on NURBS eliminates the phase triangulation and thus to eliminate the drawbacks of the existing technologies. The proposed implementation of the technology can be adapted to other types of source information, and may include more complex types of basic splines.

When using the proposed method and device for its implementation, intended to capture the topography of the area, the requirement for precision depth when taking relief of the bottom waters specified applicable regulations, due to the possibility of measuring the Doppler shift frequency of the reference acoustic signal acoustic Doppler log, the absolute velocity of the ship with sonar on external sources of information (for example, satellite navigation systems like GPS), which determine the average vertical velocity of propagation of sound in the aquatic environment. When taking relief of the bottom echo the mean square for RESNET determine the vertical speed of sound should not exceed ±7.5 m/s This requirement can be achieved if the speed of the vessel will be determined from the mean square error not exceeding ±0.037 m/s, which may be implemented with the determination of geodetic coordinates from the mean square error not exceeding ±7,8 m

Installed on hydrographic ships navigation system, in particular a combined receiver-indicators-satellite and radionavigation systems, shore-based, allow to determine the geodetic coordinates with an accuracy of ±6.0 m, and during their operation in differential mode ±3,0 m

When pairing topographic raster maps and navigation for mapping of bottom topography errors obtained raster maps are no more than two pixels. For example, for scale maps 1:250000 with a resolution of 400 dpi, this amounts to 30 m on the earth's surface that does not exceed the error of a raster map.

In the process of shooting from a set of measured depths are selected informative depth, which are amended for the speed of sound calculated and linked to veroyatnym coordinates for drawing on a working tablet and operational assessment of the quality of the shooting.

Next, assess the degree of spatial uniformity of the coating measurement points in the area of measurement, namely precise the of esneh border (outline) the field survey, torn, local gaps (holes) and their boundaries in accordance with the algorithm for computing the contour shooting multibeam echo sounder 7.

The imaging results of the multibeam echo sounder are large arrays (files) data, including latitude, longitude and depth when passing techniques gals. Upon results of the survey, the problem of assessing the degree of spatial uniformity of the coating measurement points in the area of the survey, namely: the exact external borders (path) field survey, torn, local gaps (holes) and their boundaries. In turn, the definition of these boundaries survey multibeam echo sounder 7 will allow you to precisely set the square made of the shooting.

Given the large amount of measurements obtained using multibeam sonar 7, the problem of determining the location of boundaries of the survey should be sought with the help of automation of calculations on the computer. To build an automated algorithm to calculate the boundaries of the survey it is necessary to formalize the idea of the badge between the points of measurement depth. Build an automated algorithm based on theory of computational topology (see, for example: A. Zomorodian Topology for Computing. - ser. Cambr. Mon. Appl. TCS. Math. Cambr. Univ. Press, 2005, 259 p.).

The core of the algorithm consists in the following. For simplicity, we assume that co is rdinate of measurement points set in the Euclidean plane with the natural metric (distance between points). Essentially the set of coordinates of points {x_i, y_i} (i=[1, N]) measure the depth multibeam echo sounder 7 is a disordered "cloud" of points. To organize sets of coordinates of points you must specify ordering some formal structure. Select the patterns triangulation network. Then this network specifies an array of sets of three points {i₁, i₂, i₃}that form a triangle in the triangulation. Strictly speaking, an array {i₁, i₂, i₃} and specifies the ordering structure on {x_i, y_i}.

The measurement technology multibeam echo sounder 7 involves obtaining measurements, "evenly" distributed in space, i.e. almost equal distances between neighboring points. We denote this distance by the symbol R. From this point of view, the structure defined by the set {i₁, i₂, i₃}, redundant. Indeed, by construction, the set {i₁, i₂, i₃} includes triangles, the lengths of the sides are arbitrary, that is, they are defined only by the process of triangulation. Therefore, the set {i₁, i₂, i₃} includes both triangles with small lengths of the sides formed close to the inner points and triangles with large lengths of the sides, educated boundary and triangles sides of which form the convex hull {x_i, y_i}. (The convex hull of {x_i, y_i} is the smallest convex set of points of the plane containing {x_i, y_i}).

Eliminate from the set {i₁, i₂, i₃} triangles, for which the length of any side is greater than the value of R. the result will be the set {i₁, i₂, i₃}_≤Rtriangles have all sides of less than or equal to R. Then the Union of the set of triangles {i₁, i₂, i₃}_≤Rto determine the exact area covered by the survey multibeam echo sounder.

To build a triangulation in the set {i₁, i₂, i₃} each edge {i₁, i₂} triangulation is part of the parties, or two triangles, either one. It is obvious that the boundary of this region is only the sides of the triangles of the set {i₁, i₂, i₃}_≤Rpresented in {i₁, i₂, i₃}_≤Rin a single instance. These sides of the triangle is a boundary edge. At the same time, if a certain side of the triangle represented in {i₁, i₂, i₃}_≤Rmore than one instance, it lies within the region (with the possible exception of the end (end point). We will denote the set of boundary with the Oron triangles symbol {i ₁i₂,}_≤R;G.

The entire algorithm for computing the contour shooting multibeam echo sounder 7 is a simple linear sequence of calculations.

Input: an array of latitudes and longitudes of the points of measurement by multi - beam echo-sounder {φ_i, λ_i}.

Step 1. For {φ_i, λ_i} calculate the arithmetic mean of the longitude and latitude - [φ₀, λ₀].

Step 2. Convert geographic coordinates {φ_i, λ_i} in stereographic coordinates {x_i, y_i}. Pole stereographic projection set value [φ₀, λ₀].

Step 3. Triangulorum {x_i, y_i} method Delaunay. The result is {i₁, i₂, i₃}.

Step 4. Calculate the lengths of sides of triangles {i₁, i₂, i₃}. The result is the set {l(i₁i₂)}.

Step 5. Calculate the value of R to find the distribution function of {l(i₁i₂)}, the value of R is equal to the length value, which gives the saturation distribution functions {l(i₁i₂)} (see figure 3).

Step 6. Find the set {i₁, i₂, i₃}_≤R.

Step 7. Find the set {i₁i₂}_≤R;G.

Step 8. Using {i₁, i₂, i₃}_≤Rand {i₁i₂}_≤R;Gdefine a coherent sequence of boundary sides, the set {P_j} (j=[1, K]. All K mnogougolnik the RC. Each connected sequence forms a simple polygon. Each polygon defines the outer boundary or internal (the border of the hole).

Step 9. Using {x₁, y₁} and {P_j}define the set of coordinates of corner points of the boundaries of the polygons - {XY_j}.

Step 10. Using {XY_j}define the set {XY_n}_OL(n=[1, N], N≤K) - sets of corner points of the polygon forming the outer boundary. Criterion: polygons from a set of pairwise disjoint [XY_n}OL (except maybe touch one point of the polygon boundaries of another).

Step 11. Excluding the set {XY_n}_OLfrom {XY_j}, get {XY_m}_H(m=[1, M], M=N-K) be the set of sets of corner points of the polygon constituting the inner border (the border of the holes). If {XY_m}_His not empty, then for each polygon {XY_n}_OLto find the indices Inch those polygons from {XY_m}_Hthat completely lie in it.

Step 12. Convert stereographic coordinates {XY_m}_OLand {XY_m}_Hin geographical coordinates {φλ_n}_OLand {φλ_m}_Hconsidering that, in accordance with step 2 pole stereographic projection was [φ₀, λ₀].

Output: the Geographical coordinates of the corner outer {φλ_n} _OLand inner {φλ_m}_Hpolygon, the set of indices of nesting inner polygons in the outer polygons.

Convert geographic coordinates in stereographic caused by the necessity of the transition from the spherical to the Euclidean metric.

Use of the method of Delaunay is determined by the extremal properties of the triangulation obtained by this method (see, for example: D Azevedo .F., Simpson R.. On optimal interpolation triangle incidences. // SIAM J. Sci. Statist. Comput., 1989. 10 (6). P. 1063-1075). In particular, for the Delaunay triangulation characteristic property is that inside the circle circumscribed around each triangle, are the only points that form the triangle. The triangles of the Delaunay triangulation is "stable" in the sense that they are most similar on the right and their sizes tend to be the same.

As R can be used not only trivial Euclidean metric is the edge length of the triangle, but other isomorphic her metrics, for example, the radius of the circumscribed around the triangle circle. The latter is due to the fact that the Delaunay triangulation minimizes the maximum radius of the circumcircle among all triangles of the triangulation.

The output of the algorithm allows to calculate the total area covered by hydrographic survey multibeam echo sounder 7. However, if the ex cases, when the coordinates of the borders are not important, and only need to estimate the area of the shooting, then the algorithm can be completed step 6. Then, using {φ_i, λ_i}, calculate the area of each spherical triangle of {i₁, i₂, i₃}_≤Rand fold, having received the required total area of the shooting.

In figures 2-4) provides illustrations of application of the algorithm to the specific measurements obtained by multibeam sonar 7.

The definition of these boundaries survey multibeam echo sounder 7 will allow you to precisely set the square made of the shooting.

To determine the foot of the continental slope (DCC) developed algorithms based on the three-dimensional determination of foot of the continental slope, i.e. determining the PCB is performed over the entire area of distribution of the measured depths, while in the known methods, the algorithms developed on the basis of two-dimensional determination of the PCB, i.e. the definition of the PCB is the profile depths. The algorithms developed in the software package Math Lab.

The input of the algorithm is the base of bathymetric data, based on the tablets of soundings. The tablet is an array of two-dimensional coordinates and depths at these points. The accuracy of depth measurements is 1% of absolute value. The set of points of measure is rhenium, distributed unevenly, forming a polygon with convex boundary and vertices in the "boundary" points.

Due to the insertion randomization at the output of the algorithms it turns out the band, asked two limiting extreme polylines. A broken line is set as a sequence of segments on the tablet. The most extreme of these lines form a band, within which lies the real line to the PCB. The width of this band in different parts of the tablet is changing, reflecting the stability of the data in a particular region of the map. Based on this, you can specify specific regions in which depth information requires more refinement.

In order to avoid errors arising from the interpolation of the surface due to the uneven distribution of measurements, the tablet was limited to a convex polygon to search line to the PCB inside it. The algorithm is based on the construction of the convex hull of the points ({x_i}, {y_i}) by the method of Graham (Graham scan). The algorithm uses a LIFO structure (Last In - First Out), "Last in - first-out) stack S contains the point ({x_i}, {y_i}) candidates on the "boundary points" of the convex hull (at the end of the algorithm in the stack will be the points forming the convex hull in the traversal order). Also uses two auxiliary procedures - Top(S) and Next_To_Top(S), returns with the responsibly the top and the next (second from top) at the highest point in the stack. Push(x_i, y_i), S and Pop(S) - standard operations add to the point in the stack (stack up) and removing (deleting) the highest point.

The pseudocode of the algorithm Graham is as follows.

Let (x₀, y₀- the point from multiple dimensions with the minimum y coordinate or the left of these points if there are matches.

Let [(x_i, yi,...,x_n, y_n)] - other points of this set, sorted in ascending order of the polar angle measured counterclockwise relative to the point (x₀, y₀if the polar angles several points coincide, then one of the many deleted all of these points except one, the farthest from the point (x₀, y₀)):

Push(x₀, y₀),

S Push(x₁, y₁),

S Push(x₂, y₂), S

For i ← 3 to N do while (angle formed by the points of the Top(S) and Next_To_Top(S) and (x_i, y_i), forms a left turn) do

Pop(S)

Push(x_i, y_i), S

Return S.

Further, to reduce the empty space on the border of the tablet is a refinement of the obtained polygon replacement long edges shorter. The result is a non-convex polygon, bounding the region of measurement.

Processing of experimental data was selected linear interpolation through triangulation, as it provided nailuchshie the resistance in the measurement line of the PCB under the action of the trial perturbation (figure 5).

On the basis of the obtained algorithm interpolation surface built surface of the second derivative in gradient direction corresponding to the maximum change of slope base at this point (6) by means of the algorithm for constructing the surface of the norm of the matrix of the second derivative from the depths.

Based on the model of the surface of the second derivative is calculated line to the PCB. Each tablet calculates the amount of barrier gradient-based dispersion gradient across the plate. The algorithm starts from a point lying within the boundaries of the tablet at some distance from it. After determining the highest point on the field of the second derivative for the current profile, the algorithm proceeds to the next profile and fits it into the highest point shifted in the neighborhood of the previous one. The selected point, the height of which was greater than the specified barrier, form the sequence of the ends of the segments of the polyline that defines the approximation line of the PCB (Fig.7).

Distinctive features:

- use as source data of a two-dimensional array of point coordinates and depths at these points;

- possibility to define trust within which with 95% probability, lies the foot of the continental shelf.

The obtained results fully correspond to the requirements of the UN Commission and Scientific-t is khnichenkova guidelines on limits of the continental shelf, to get additional information for the expert evaluation of the PCB, therefore, be used to define and justify outer limits of the continental shelf of the Russian Federation in SLO.

For confident detection of potentially dangerous objects corridor width is 60 m along the centerline of the track being tested with the distance between profiles 10 meters Next to the width of the corridor 400 and 2000 m (land expansion) step between profiles 50 m This allows us to track linearly elongated objects - pipes, cables etc. For control perform measurements on longitudinal lines through 1 km

Shooting of the bottom topography is carried out by multi-beam echo sounders with no gaps, overlap adjacent strips. For the shooting of the bottom topography used multibeam echo sounders (Sea Beam 1180, Simrad EM 3002). Sonar sensing is performed using sonar with a frequency of 500 kHz. The complex areal imagery includes measuring the speed of sound and the heave-pitch and roll-pitch, which provide correction data area bathymetric and sonar imagery.

The measured depth in postprocessing corrected depths of the sea level data obtained from the meter sea level 15. The results of the survey are compiled tablets depths scale 1:2000.

The practical implementation of the proposed method technical clonos is and is not due to the fact, for its implementation uses standard measuring tools installed on hydrographic vessels intended to capture bottom relief.

Sources of information

1. Kolomiychuk N Hydrography. L., GUNiO MO USSR, 1988, s-277.

2. Hare R. Depth and position error budgets for multibeam echosounding // International Hydrographic Review. 1995, v.LXXII, No. 2, p.37-69.

3. Patent RU No. 2340916.

4. Patent RU No. 2434246.

5. Patent RU NO. 2272303C1, 10.12.2006.

6. Patent RU NO. 2292062C2, 20.01.2007.

7. Patent RU NO. 2326408C1, 10.06.2006.

8. Patent EP NO. 1426787A1, 09.06.2004.

1. The way to capture the topography of the area, including radiation hydroacoustic signals in the direction of the bottom receiving reflected from the bottom surface of the signals, the measurement of distances from pievescola antenna to the bottom, the coordinates of the ship on external sources of information, the measurement side, roll and heave, true course and speed of the vessel, the binding of the measurement time determining the true depth values to determine the correction for the deviation of the actual speed of sound in water from the calculation, mapping the received information identifying the geodetic coordinates of the measured depths, the mapping of bottom topography perform pairing topographic raster maps and navigation, in addition execute sonar sensing bottom sonar and/or surveying the sounder is m, established on different levels of depth from the ship's sonar funds can be moved both in the vertical and horizontal planes of the sectorial overview scanning directivity in the radiation mode parametric antenna with the reception of reflected signals from an antenna of the same dimensions as the antenna pumping parametric antenna, the width of the directivity in the receive mode exceeds the value of the sector review and the scanning plane antenna declined relative vertical locations on the angle of 15° in the direction of movement of the vessel, characterized in that simultaneously with the radiation of hydroacoustic signals in the direction of the bottom perform magnetic sensing through gradienter, towed on a distance of 5 m from the bottom acoustic profiling by profilometer with an operating frequency of 3.5 kHz, measure the sea level, when processing values measured depths additionally perform a linear interpolation of the resulting surface of the bottom through triangulation, the mapping of the received information identifying the geodetic coordinates of the measured depths assess the degree of spatial uniformity of the coating dots measurement area measurement by determining the external borders (loop) region p. the Omer.

2. The device for the capture of bottom waters, consisting of pievescola antenna, the transmitting unit, premoistening block, control block, the block determining the average speed of propagation of sound in water, block, collection, information processing and mapping of bottom topography, multibeam echo sounder, the visualization module the field of relief, acoustic Doppler log, receiver satellite navigation system, foreign exchange system, meter pitching, characterized in that the device for imaging the topography additionally introduced towed gradienter, the profilograph and the meter sea level, connected by their outputs to the inputs of the block collection, information processing and mapping of bottom topography.