RU2717578C1 - Method of determining geographic coordinates of an underwater object - Google Patents

Abstract

FIELD: underwater navigation.

SUBSTANCE: essence of the invention consists in the fact that in the method of determining the geographical coordinates of the underwater object when using a sonar located on a surface ship, based, as well as a prototype, at reception of signals of satellite navigation systems GPS / GLONASS for determination of own geographical coordinates of vessel for selected moment of time, transmission via hydroacoustic channel of information on own geographical coordinates of ship to underwater object, on which, based on its current geographical coordinates determined by the onboard navigation system, determining the true geographical coordinates (ϕ_tr, λ_tr) of the underwater object, in contrast to prototype of surface ship sonar at selected moment of time three spatial coordinates of underwater object – bearing (B), range (R) and elevation angle (EA) are determined, which values are transmitted to onboard computer of surface ship for calculation of true geographic coordinates of underwater object with subsequent transmission of obtained values, reduced to selected moment in time, via information cable into navigation system of underwater object.

EFFECT: invention provides positioning (geo-referencing) of underwater objects with determination of their observed (accurately calculated) geographical coordinates using a sonar and a global navigation communication system (GPS or GLONASS).

1 cl, 5 dwg

Description

The invention relates to the field of underwater navigation and provides positioning (geographical reference) of underwater objects with the determination of their observable (accurately calculated) geographical coordinates using a sonar and a global navigation communication system (GLONASS or GPS).

Known methods for positioning underwater objects using sonar. Among them: the method according to patent RU No. 2032187, IPC G01S 15/08, publ. 03/27/1995, which consists in the fact that at the bottom of the reservoir there are a number of sonar transponder beacons with different response frequencies that create a navigation base, and their calibration in relative and geographical coordinates using a support vessel. For this, the support vessel is equipped with airborne satellite and sonar navigation systems. A hydro-acoustic transmitter located at the navigation object emits hydro-acoustic signals, followed by measuring the time intervals of their propagation from the navigation object to the bottom transponder beacons and vice versa, and converts these intervals in the distance between the navigation object and the bottom navigation transponders located at the bottom. As a result of processing the obtained values of the distance from the navigation object (underwater object) to the bottom defendant beacons, reliable navigation results are obtained that ensure its positioning.

The disadvantages of the analogue are:

- significant costs of ship time, which affects the low efficiency of the method;

- a large number of bottom defendant beacons (12 ... 16 pcs.) with a long battery life and the need for their maintenance;

- the need for calibration work, not only when setting up and removing bottom transponder beacons, but also during their operation when changing external conditions, among which can be hydrological and seismic factors;

- the need to replace bottom defendant beacons after developing their energy resource with the obligatory subsequent calibration of newly installed bottom equipment;

- the complexity of the on-board equipment of the navigation object, which affects its cost.

A known method for determining the geographical coordinates of an underwater object according to US patent No. 5579285. IPC G01S 5/00, G01S 5/14, G01S 11/14, publ. 08/21/1995. The method is implemented on the basis of a device, which includes drifting GIB buoys (Gtobal Intelligent Buoy), forming a long base of kilometers, and an underwater vehicle with a beacon - a hydroacoustic transmitter emitting signals of a certain frequency at predetermined times. Each buoy is equipped with a hydroacoustic receiver (hydrophone), a receiver of the global GPS positioning system, a clock synchronized with a GPS clock, a radio modem. Buoys measure their own geographical coordinates using GPS. At fixed times, the lighthouse emits a sonar signal, which after a certain delay time, determined by the distance, is recorded by each buoy. At the same time, in strict time synchronization, the current geographical coordinates of the buoys at the time the signal began to be emitted by the beacon of the underwater vehicle are assigned to the obtained delay times. All received data via a radio channel is transmitted through a radio modem to a tracking post located either on the escort ship or ashore. At this post, taking into account the received data, the geographic coordinates of the underwater vehicle are calculated using special software.

The disadvantages of the analogue are:

- the possibility of demolition of buoys due to drift from the control area at distances exceeding the range of sonar communication;

- due to the multipath propagation of sonar packages, the possibility of repeated arrival on any of the buoys of the same signal emitted by the beacon of the underwater vehicle, which is clearly manifested at long distances between the underwater vehicle and the buoys or in shallow water;

- since the difference in the time of arrival of the hydroacoustic signal to any of the buoys is determined by the leading edge of the signal coming from the hydroacoustic transmitter, with a small signal-to-noise ratio, taking into account the significant distance between the buoy and the underwater vehicle, there is an ambiguity in determining the delay time due to possible signal damage a hindrance.

Closest to the claimed technical solution is the method according to patent RU No. 2365939, IPC G01S 15/08, publ. 08/27/2009. To implement this method, a station drifting on the water surface is used, equipped with equipment for the continuous reception of signals from satellite navigation systems (GPS or GLONASS). The reception and processing of these signals ensures the determination of the eigenvalues of the drifting station with high accuracy at any time. Upon a request signal from an underwater object or according to a specific program of work of a drifting station, information about its geographical coordinates is transmitted to the underwater object through a sonar channel in the form of a noise-like encoded signal of a certain shape.

The disadvantages of the prototype method is the lack of accuracy in determining the geographical coordinates of the underwater object, caused by:

- the error in determining the coordinates associated with the variability of the signal speed in sea water. This error increases significantly in shallow water, when time delays between individual rays are reduced, while the rays themselves cannot be identified and identified separately;

- the possibility of distortion of the signal transmitted from the drifting station to the underwater object, due to its defeat or weakening in the presence of factors such as hydrology (negative refraction, the layer of the jump in the speed of sound) and reverberation.

The claimed invention solves the problem of increasing the accuracy of determining the geographical coordinates of the underwater object, which ultimately allows more accurately positioning the object in marine waters at working depths.

To solve this problem, the following set of essential features is used: in the method for determining the geographical coordinates of an underwater object when using a sonar located on a surface ship, also based as a prototype, on receiving signals from GPS / GLONASS satellite navigation systems to determine the ship’s own geographical coordinates at a selected time transmitting via sonar channel information about the ship’s own geographical coordinates to an underwater object, on which suschestvlyaetsya definition of true geographic coordinates (cp _ist, lambda _ist..) underwater object in view of its current geographic coordinates defined by the onboard navigation system, unlike the prototype sonar surface vessel to the selected point in time determined by the three spatial coordinates of the underwater object: a bearing (P) , range (D) and elevation angle (UM), the values of which are fed to the on-board computer of the surface vessel to calculate the true geographical coordinates of the underwater object, followed by the transfer of the floor learned values reduced to the selected point in time via an information cable to the navigation system of the underwater object.

The essence of the invention lies in the preliminary calculation of the observable geographical coordinates (ϕ ₀ , λ ₀ ) of an underwater object on board a surface vessel at a selected point in time and their transfer, reduced to this time, to the navigation system of the underwater object, which is achieved using: a sonar located on a surface vessel and determining three spatial coordinates of an underwater object: bearing (P), distance (D), elevation (UM); GPS / GLONASS navigation - a receiver located on a surface vessel and receiving data from an artificial Earth satellite about its true geographical coordinates (ϕ _source , λ _source ); a communication cable providing an information channel for transmitting data to an underwater object from a surface vessel and vice versa. The indicated data are the sought observable (accurately calculated) geographic coordinates of the underwater object (ϕ ₀ , λ ₀ ), which are calculated on the surface ship using certain algorithms taking into account the spatial coordinates of the underwater object (P, D, UM) and the true geographic coordinates of the surface ship (ϕ _source , λ _source ).

The proposed method is implemented as follows.

With the help of a sonar located in the keel of the surface vessel, three spatial coordinates of the underwater object are determined: bearing (P); distance (D); elevation angle (UM). This is carried out as a result of processing the sounding sonar signal reflected from the underwater object, which consists of pulses of a certain amplitude, duration, duty cycle and filling frequency, which are emitted by the surface vessel’s sonar towards the underwater object and, after reflection from it, are received and recorded by two radiation-scanned radiation patterns formed by the sonar antenna of the specified sonar in reception mode. The true geographical coordinates of the surface vessel (ϕ _source , λ _source ) are determined by the signals received from the artificial Earth satellite of the GPS / GLONASS navigation system, which are received by its navigation receiver. Given these coordinates and the obtained spatial coordinates (P, D, UM) of the underwater object, the coordinates of the underwater object on the surface vessel are accurately calculated using certain algorithms, after which the calculated geographical coordinates (ϕ ₀ , λ ₀ ) of the underwater object are transmitted to its navigation system via an information cable from a surface ship.

A comparison of the proposed method and the prototype showed that the task is to increase the accuracy of determining the geographic coordinates of the underwater object, is solved as a result of a new set of features, which proves the conformity of the proposed invention with the criterion of "novelty".

In turn, the information search in the field of underwater navigation did not reveal solutions containing individual distinctive features of the claimed invention, which allows us to conclude that the method meets the criterion of "inventive step".

The essence of the method is illustrated by graphic materials, where in FIG. 1 is a diagram for determining observable geographical coordinates (ϕ ₀ , λ ₀ ) of an underwater object;

in FIG. 2 - a diagram of determining the spatial coordinates (P, D, UM) of an underwater object with a sonar is presented;

in FIG. 3 is a structural diagram of an electronic device of a surface ship that implements the method;

in FIG. 4 - presents an algorithm for calculating the horizontal range D _mountains. between a surface vessel and an underwater object when they are conditionally on the same horizon;

in FIG. 5 - presents the conditional location on one horizon of the support vessel and the underwater object after calculating the horizontal range (D _mountains. ).

In the figures (Fig. 1-5) are indicated: 1 surface vessel; 2 underwater object; 3 information cable; connecting a support surface vessel to an underwater object; 4 artificial Earth satellite implementing the global navigation communication system (GPS / GLONASS); 5 sonar antenna, providing sonar operation; 6 horizontal antenna array; 7 vertical antenna array; 8 a radiation pattern formed by a horizontal antenna array (GAR) 6 sonar antenna 5 sonar and scanning in the horizontal plane; 9 a radiation pattern formed by a vertical antenna array (VAR) 7 sonar antenna 5 sonar and scanning in a vertical plane; 10 narrowly directed (“needle”) radiation pattern, which is the result of the correlation of radiation patterns formed by the GAR and the VAR; 11 strapdown inertial navigation system (SINS), 12 sonar (GL), 13 on-board computer of a surface ship (BC) of a surface ship; 14 is the conditional intersection point of two corresponding virtual lines, namely: horizontal, drawn from the real location of the underwater object and vertical, drawn from the location of the surface ship; 15 D _mountains (horizontal range) the distance between the surface support vessel and the underwater object when they are on the same horizon.

The true geographical coordinates (ϕ _source , λ _source ) of the support surface vessel 1 are determined by the signals received from the artificial Earth satellite 4, which are received by its navigation GPS / GLONASS receiver. Sonar 12 determines the three spatial coordinates of the underwater object 2: bearing (P); distance (D); elevation angle (UM).

The bearing (P) shows the spatial direction from the surface vessel 1 to the underwater object 2, and taking into account the values obtained by the sonar of the distance (D) and elevation angle (UM) to the underwater object 2, the horizontal distance D of the _{mountains is} calculated according to certain algorithms _. between a surface vessel 1 and an underwater object 2 when they are on the same horizon. This calculation is carried out by the on-board computer 13. Observed geographic coordinates (ϕ ₀ , λ ₀ ) of the underwater object are determined when the calculated value of D _{mountains is} deposited on the bearing line (P) _. carried out on the navigation chart from the surface vessel 1 towards the underwater object 2. When transmitting the values of the observed geographical coordinates (ϕ ₀ , λ ₀ ) via the information cable 3 to the navigation system of the underwater object 2, its geographical coordinates are determined at any working depth.

In FIG. 2, to explain the method, the general principle of determining the spatial coordinates of an underwater object 2 is realized by a sonar antenna 5 of a sonar 12. The sonar antenna 5 of a sonar 12 of a surface ship 1, consisting of horizontal 6 and vertical 7 antenna arrays, forms two radiation patterns scanning in the aquatic environment, namely: a radiation pattern 8 formed by a horizontal antenna array 6 that scans in the horizontal plane, and a radiation pattern 9 formed in vertical antenna array 7, scanning in a vertical plane. The formed narrowly directed radiation pattern 10 (“needle”) of the sonar 12 of the surface vessel 1 is capable of scanning in space by the heading angle (KU) and elevation angle (UM), which is the result of the correlation of the radiation patterns 8 and 9.

In FIG. 3 presents a structural diagram of an electronic device of a surface vessel 1 that implements the proposed method. On one of the device’s devices - strapdown inertial navigation system 11, the true coordinates of the surface ship 1 (ϕ _source , λ _source ) are transmitted from the artificial Earth satellite 4 of global positioning, from where they arrive to its on-board computer 13. Space coordinates (P, D , UM) of the underwater object 2, which can be a telecontrolled uninhabited underwater vehicle (TNLA), determined by sonar 12, are also transmitted to the on-board computer 13, where, according to certain algorithms, calculations are performed e horizontal distance D _mountains. between a surface vessel 1 and an underwater object 2 when they are on the same horizon. Given the obtained value of D _mountains. in the on-board computer 13 of the surface vessel 1, the exact coordinates of the underwater object 2 are adjusted according to the corresponding program, the values of which (ϕ ₀ , λ ₀ ) are transmitted to its navigation system via the information cable 3.

In FIG. 4 shows an algorithm for calculating the horizontal range between a surface vessel 1 and an underwater object 2 when they are conditionally located on the same horizon. Taking into account the definition by the sonar 12 of the inclined range (D) between the surface vessel 1 and the underwater object 2, as well as the elevation angle (UM) of the underwater object 2 relative to the surface vessel 1, the horizontal range D _{mountains is} calculated in the on-board computer 13 (Fig. 3) _. between them according to the formula:

D _mountains. = D × Sin (UM)

In FIG. 5 shows the conditional location on one horizon of the support vessel and the underwater object after calculating the horizontal range D of the _mountains. , explaining the procedure for correcting the exact coordinates (ϕ ₀ , λ ₀ ) of the underwater object 2. Correction carried out on-board computer 13, provides a dynamic update of the exact coordinates in real time.

The inventive method allows to increase the accuracy of determining the geographical coordinates of the underwater object, which ultimately provides accurate positioning of the underwater object in the sea at working depths with the determination of their observable geographical coordinates (ϕ ₀ , λ ₀ ). The obtained coordinates (ϕ ₀ , λ ₀ ) from the surface vessel 1 are fed into the navigation system of the underwater object 2 via the information cable 3, which allows real-time determination of the true geographical coordinates of underwater technical structures (pipelines, hydraulic structures, etc.) discovered or inspected by underwater search engines.

The present invention was created as part of scientific research carried out at the Department of Radio Communication in the Navy, Federal State Budgetary Educational Establishment of Higher Education, Admiral S.O. State University of the Sea and River Fleet Makarova. " Calculations were made that showed the possibility of using the proposed method in hard-to-reach areas, for example, during geological exploration in the Arctic shelf, monitoring of underwater technical structures at great depths, conducting search and rescue operations at working depths, etc., which Considering the above, it can be concluded that it can be used industrially.

Claims (1)

A method for determining the geographical coordinates of an underwater object when using a sonar located on a surface vessel, based on receiving signals from GPS / GLONASS satellite navigation systems to determine the vessel’s own geographical coordinates at a selected point in time, transmitting information on the vessel’s own geographical coordinates to the underwater object via a sonar channel, on which, taking into account its current geographical coordinates determined by the on-board navigation system, Leniye true geographic coordinates (φ _ist, λ _ist..) of the underwater object, characterized in that the sonar surface vessel at a selected time determined by the three spatial coordinates of the underwater object: a bearing (P), the distance (D) and elevation angle (PA) the values of which are supplied to the on-board computer of the surface vessel to calculate the true geographical coordinates of the underwater object, followed by the transmission of the obtained values, reduced to the selected time, via an information cable to the navigation system one object.

Images