RU2303275C2 - Method for determination of co-ordinates of submerged objects - Google Patents

Abstract

FIELD: underwater navigation, applicable at determination of geographic co-ordinates of deep sea-towed complexes in the process of sea geologo-geophysical explorations.

SUBSTANCE: a co-ordinates system with of base length of 2-3 km towed by a ship is produced, each GPS buoy with a built-in hydroacoustic system, composing the base of the co-ordinates system, is linked with the ship with the aid of its cable, which makes it possible, while correcting the cable length to keep the ratio of the lengths of the co-ordinates system in the process of towing, i.e. to keep the deep-sea towered complex in the most favorable zone for high-precision measurements. The buoys can transmit information to the ship with the aid of radio communication or cable.

EFFECT: enhanced accuracy and reliability of determination of a submerged object co-ordinates.

5 cl, 2 dwg

Description

The invention relates to the field of geophysical exploration, high-precision navigation, geology. In particular, the present invention relates to the field of underwater navigation and can be applied in determining the geographical coordinates of deep-sea towed complexes during marine geological and geophysical surveys.

For example, the invention relates to the field of sonar navigation systems, allowing to determine the spatial geographical coordinates of a moving object when it moves below the surface of the water. The proposed invention allows more accurate and reliable determination of the output navigation parameters of a moving object. In particular, the proposed system includes navigation measuring devices using measurement methods in the base and geological coordinate systems of the object. As a basic coordinate system, a remote measuring base is selected to determine the coordinates of an object moving behind the vessel.

Several types of systems are known for determining the coordinates of underwater objects using hydroacoustics, differing in the dimensions of the baselines (measuring bases), which are the distances between the hydroacoustic antennas that form the measuring grid. These are systems with a short base (Short Baize Line), systems with an ultrashort base (Ultra Short Baize Line), systems with a long base (Lounge Baize Line).

Systems with an ultrashort base refer to goniometer systems in which the direction to the object is determined by measuring the phase difference between the antenna elements formed by at least two sonar transducers installed in one housing at distances from each other less than the wavelength of the carrier wave, which is centimeters. However, these systems are affected by the noise of the vessel, which reduces the accuracy of determining the coordinates.

Systems with a short base belong to the so-called difference-ranging systems in which the coordinates of the underwater object are calculated by the difference in the arrival times of the leading edges of the pulses emitted by the hydroacoustic transducer from the underwater object to three hydroacoustic transducers located underwater and forming two intersecting bases. The accuracy of determining the coordinates depends on the length of the base, which for systems with a short base is limited by the size of the vessel and is about 20 meters. These systems are also affected by the noise of the vessel, and in addition, equipping the vessel with launching devices with hydroacoustic antennas to form a short base requires a large amount of expensive work when docking the vessel. In this case, the baseline must be accurately aligned relative to the diametrical plane of the vessel. The accuracy of determining the coordinates is also reduced due to inaccuracies in the orientation of the baselines, as well as because of the need to take into account random errors arising from the heel and trim of the vessel. The practical range of short base systems is limited to a distance of 1-2 km.

The closest to the claimed technical solution are systems with a long base, they relate to rangefinder systems in which the location of the underwater object is calculated by measuring the distances between the underwater object and at least three transponder beacons installed at different points of the seabed at distances of several kilometers apart from each other. The coordinates of the defendant beacons are determined during the passage of the vessel in the area of their setting by measuring the distances to the beacons and simultaneously measuring the ship’s own coordinates using GPS data. The towed complex sends and receives response data from the respondent beacons and transmits them via a cable to the ship.

The invention is known "Method of expanding the use of GPS under water", US patent No. 5119341, published on 02/06/1992, IPC Н04В 001/59, according to which freely drifting buoys forming a long-base system are installed at various points of a given area of work on the sea surface . Each buoy incorporates a GPS navigation receiver and a sonar system with a transducer buried beneath the surface of the sea. The own coordinates measured by each buoy are transmitted to the underwater vehicle. The hydroacoustic system on the underwater vehicle, having received data on the distances to each buoy and their coordinates, enters this information into a computing device that determines the coordinates of the underwater vehicle directly on its board. However, the underwater vehicle knows its own coordinates, but it is impossible to track its location from the ship. The disadvantage is the transfer of a large amount of data via the sonar channel from each of the buoys.

Closest to the proposed invention is the invention "Method and device for monitoring and remote control of an unmanned mobile underwater device", US patent No. 5579285, published 08.21.1995, international publication No. W0 94/14081 from 06.23.1994, IPC G01S 005/00; G01S 005/14; G01S 011/14, according to which drifting buoys are formed at different points on the surface of the sea, forming a long base. Each buoy in its composition has a GPS navigation receiver, a clock synchronized with the GPS clock, a sonar receiving system with a recessed converter and a radio modem. Such buoys are called GIB buoys, and their application technology is called GIB technology (GIB - global intelligent buoy). Each buoy measures its own coordinates and lag times at predefined times it transmits along with coordinates in the NMEA standard over the air via a radio modem to the ship. According to the accepted delay times of the pinger signals, taking into account the speed of sound in water on board the vessel, the distances from the underwater object to each of the buoys are calculated, and the coordinates of the underwater object and the coordinates of all buoys are calculated and displayed using the well-known algorithm. However, to determine the coordinates of deep-sea towed complexes in this case, a large number of buoys is required, since the towing trajectory, as a rule, has a considerable length. In addition, drifting buoys can be taken down from the area of operations at distances exceeding the range of the sonar system and radio modems.

The technical task of the proposed invention is the provision of deep-sea research using a towed object by accurately linking its location to geographical coordinates throughout the towing. In this case, the distance between the vessel and the towed measuring complex can reach several kilometers, and the trajectory of the vessel does not coincide with the trajectory of the towed complex. In this case, using the coordinate determination system, it is required to accurately, throughout all studies, determine the coordinates of a moving underwater object, for example, deep-sea towed complexes involved in geological exploration.

Existing measuring systems with long or short base require the installation of stationary buoys and / or tripping devices with hydroacoustic antennas on ships, which leads to expensive work. Thus, the determination of the coordinates of the staging points of the defendant beacons takes up to 8 hours of ship time for one beacon and is very expensive. Significant costs of ship time are spent on the setting, surfacing and boarding of defendant beacons. The installation of hoisting devices with hydroacoustic antennas requires expensive work with the docking of the vessel.

Using the proposed invention can be reduced errors in the determination of coordinates due to the exclusion of the vessel from the sonar tract, i.e. eliminating the effect of vessel noise, which positively affects the stable reception of signals. The accuracy of determining coordinates can also be improved by reducing random measurement errors, increasing the measurement base (within the limits that provide the measurement conditions). The proposed technical solution eliminates the limiting conditions for determining coordinates due to the unfavorable geometric (spatial) location of the towed underwater object, for example, if the object is near the bottom. That is, in all cases, beacons are always in sight. The main technical result is the provision of a constant spatial location inside the measuring base of the system for any extended trajectories of the object, while the beacons do not need to be rearranged, and therefore, the number of buoys installed is reduced regardless of the length of the trajectory of the object.

Thus, the technical result is to increase the accuracy of measurements while increasing the reliability and cost of the system by reducing the number of buoys, regardless of the length of the trajectory of the object.

The claimed technical result is ensured by a system for determining the coordinates of underwater objects. The problem is solved as follows. The coordinate determination system contains a system of towed object 1 and buoys 2 located on the sea surface, in which the buoys are made as part of the system in an amount of at least three, equipped with a GPS (Global Positioning System) 3 radio receiver, highly stable clock 4, pre-synchronized by the clock GPS (Global Positioning System), a hydroacoustic receiving system 5, emitting and receiving a pinger signal 6, by a controller - measuring time intervals 7. The system is characterized in that it is equipped with a towing object 8, includes a dockable underwater object 1 and buoys 2, made as a single system with a towed object, which is moved by a towing object 8 throughout the route, while maintaining the size ratio of the measuring base L of the system, while the buoys and the towed object are fixed, for example, by cables 9 of a given length to the towing the object, forming a system with a calculated measuring base, the buoys are equipped with fixed rudders, pre-installed at a given angle α, and a transducer 10 located below the sea surface, the towed object is equipped with n pinger 6, emitting a hydroacoustic signal at predetermined times, while the towed object 1 is placed so that its projection is inside the coordinate grid formed by buoys 2 on the sea surface. GIB buoys (Global Intelligent Buoy) can be used as buoys. A vessel or other moving object may be used as a towing object. As a towed object, the deep-sea geophysical complex ROV (Remote Operate Vestige) can be used. A long measuring base (LBL) can be taken as a measuring base, while the towed object is equipped with a highly stable clock previously synchronized by the GPS (Global Positioning System) clock with the highly stable clock of each buoy. Or, a short measuring base (SBL) can be taken as the measuring base, while the towed object is equipped with a device for determining the immersion depth of the towed object. The system, for example, includes a computer, which, for example, is located on the ship 1 or on any fixed base. The computer calculates the coordinates of the towed object either on the basis of a long measuring base, or on the basis of a short measuring base, or simultaneously on the basis of a short and long measuring base. The towed object can be equipped with a radio modem or connected to the ship with a cable cable. Buoys can be equipped with radio modems or connected to a towing object with cable cables.

The invention is shown in the drawings, illustrating a system for determining the coordinates of underwater objects.

Figure 1 shows a General diagram of a system for determining coordinates in a perspective view.

Figure 2 shows the projection of the coordinate determination system on the sea surface.

The invention is illustrated in Figure 1, where 8 is a towing vessel, 2 is a GIB buoy on the sea surface, 1 is a towed deep-sea complex, 6 are pingers, 9 is a towing cable or towing cables GIB buoys, R1, R2, R3 - horizontal distances between buoys on the sea surface, forming the measuring base of the sonar navigation system, L1, L2, L3 - slant ranges from, for example, a deep-sea towed complex (1) to sonar transducer (10) of each of the GTB buoys, L1 *, L2 * , L3 * - projections of inclined ranges onto the surface m Oria, A is the projection point of the deep-sea towed complex onto the surface, 11 is the constellation of GPS navigation satellites.

The hydro-acoustic transducer - pinger 6 on a deep-sea towed complex 1, emits a pulse at a preset time moment by a clock signal synchronized with the clock GIB of buoys 2. This pulse, received by each sonar transducer GIB of buoys 10, is delayed relative to a predetermined moment of radiation stored in the buoy hours by an amount proportional to the inclined ranges from the deep-sea towed complex to each of the buoys. The measured delay time is proportional to the inclined ranges, together with its own coordinates obtained by GPS data, each buoy transmits to the vessel through a radio modem or cable. The on-board radio modem or on-board equipment receives the coordinates of each buoy, the delay times of the pinger signals 6 and enters this information into a personal computer, where the coordinates of a deep-sea towed complex are calculated using the well-known algorithm.

Figure 2 shows in plan the relative position of the vessel 8, towed GSB buoys 2 and deep-sea complex 1, 9 - towing cable-cable of the deep-sea complex or towing cables GIB buoys, 12 - rudders of GIB buoys, which have rudders installed at an angle α.

The system operates as follows.

Simultaneously with towing a deep-sea complex 1, a system of three GIB buoys 2, forming a system with a measuring base, is towed on the sea surface. To form a long or short measuring base of the system, each buoy is equipped with a rudder, with the help of which each buoy in the process of towing occupies the required position on the sea surface depending on the length of the towing cable 9, towing speed and a fixed, predetermined position of the rudder. In this case, the inevitable changes in the position of the buoys in the towed coordinate determination system under the influence of external conditions and towing parameters are insignificant, since the current coordinates of each buoy are transmitted by the buoy radio modems with a given time period, measured in units of seconds. The use of such a system allows you to maintain the position of the projection of a deep-sea towed complex inside the coordinate grid formed by buoys on the sea surface. This position supports the most favorable acoustic conditions to ensure high accuracy in determining coordinates throughout the towing. Towing the coordinate system, or sonar navigation system, allows you to practically avoid the influence of the ship's own noise on the range and accuracy of the coordinates. Only three buoys are required, regardless of the length of the towing route, and there is no cost of ship time to determine the location coordinates of the buoys that form the measuring base. At the same time, any leased vessel can be used as a towing vehicle, and there is no need to equip it with a hydro-acoustic navigation system. Buoys are easily mounted on the sea surface and are easily selected on board. It should be noted that the transmission of information from buoys to a ship can be carried out not only by radio using radio modems, but also by cable, which can be used to tow each buoy. In this case, the radio modems on the buoys and on the ship may be absent, and the clocks of the buoys and pinger are synchronized via cable cables through the ship's onboard equipment.

The calculation of coordinates is measured both on the basis of a long measuring base and on the basis of a short measuring base, while the spatial measurement principle is implemented, based on the determination of distances determined by the hydroacoustic method with the definition of the universal characteristic for long and short bases - the delay time of the hydroacoustic signal relative to the sync pulse of radiation .

In the case of calculating the coordinates on the basis of a long measuring base (R1, R2, R3), the calculation is carried out according to the delay time, when the distance of the hydroacoustic signal from the towed object to the lighthouse is measured. In this case, the towed object is equipped with a highly stable clock, previously synchronized by the GPS (Global Positioning System) clock with the highly stable clock of each buoy.

In the case of calculating the coordinates on the basis of a short measuring base (R1, R2, R3), the calculation is carried out according to the delay time, when the difference in the transmission distances of the sonar signal of the pinger passing towards the buoy is measured. In this case, the towed object is equipped with a device for determining the immersion depth of the towed object.

Thus, a more universal way of determining coordinates is proposed, since it is possible to carry out measurements based on a long base, and on the basis of a short base. Moreover, with a short base, signal synchronization is not required. Moreover, the short measuring base has dimensions not less than an order of magnitude larger than the short measuring base, traditionally formed on the ship.

In other words, for a short base, use the differential-far measuring system (Short Baize Line), and for a long base - a range-measuring system (Lounge Baize Line).

In both cases, the principle of calculation is to determine the coordinates by the distance from the object to the buoy through the coordinates of the buoy, calculated in the geographical coordinate system GPS.

As a result, the claimed technical result is achieved.

In addition, a lengthy and costly calibration of transponder beacons is not required. By reducing the amount of data that must be transmitted through the sonar channel, an increase in the accuracy of monitoring is also achieved.

Due to the fact that the information update is increased by 2 times, i.e. by increasing the frequency of updating the information on the coordinates of the respondent beacons, it is possible to achieve a more accurate measurement and monitoring time.

The quality of the received signal is also improved by eliminating the noise of the vessel, the measurement characteristic is improved - the signal-to-noise ratio.

The whole system is significantly cheaper by eliminating expensive equipment and complex preparatory work on the ship.

In addition, restrictive conditions for determining coordinates due to the unfavorable geometric (spatial) location of the object are excluded, for example, if the object is near the bottom. In all cases, buoys are always in sight.

The proposed technical solution provides a constant spatial location inside the measuring base of the system for any extended trajectories of movement of the object, while the buoys and beacons do not need to be rearranged. This leads to a decrease in the number of buoys installed regardless of the length of the trajectory of the underwater object.

Claims (5)

1. A system for determining the coordinates of underwater objects, containing an object towing a system of a towed underwater object and buoys located on the sea surface, in which the buoys are made as part of the system in an amount of at least three, and are equipped with a Global Positioning System radio navigation receiver, highly stable clocks, previously synchronized by the Global Positioning System clock, a hydro-acoustic receiving system that emits and receives a pinger signal emitting a hydro-acoustic signal at preset time points and a cat A towed underwater object is equipped with one, and a time meter controller, characterized in that the buoys and the towed underwater object are connected each to the towing object by a cable cable, forming a system with a long base, with a constant spatial location of the towed object inside the measuring base of the system, while maintaining aspect ratio of the measuring base for any extended trajectories of movement of the underwater object, while the buoys are equipped with fixed rudders, pre-installed at a given angle and a transducer located below the sea surface. 2. The system according to claim 1, characterized in that Global Intelligent Buoy is used as buoys. 3. The system according to claim 1, characterized in that the vessel is used as a towing object. 4. The system according to claim 1, characterized in that as a towed object using a deep-sea geophysical complex Remote Operate Vestige. 5. The system according to claim 1, characterized in that the towed object is equipped with a radio modem.

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