RU2737166C1 - Method of high-speed underwater vehicle coordinates determination using doppler effect - Google Patents

Abstract

FIELD: physics; vessels and other floating facilities.

SUBSTANCE: disclosed method relates to underwater navigation and can be used in solving the problem of determining the location of high-speed autonomous unmanned underwater vehicles (AUUV) based on information on Doppler shift of frequency of hydroacoustic signal from one output buoy. Increased self-sufficiency is ensured by the design of the apparatus allowing to accommodate an output buoy, which is separated by the control system command. Buoy is equipped with a buoyancy device, due to which it floats to the surface after separation. Satellite signal receiver and the hydroacoustic communication modem located on the output buoy enable to obtain the geographic coordinates of the output buoy and transmit them to the AUUV. Equipment for receiving hydroacoustic signals from an output buoy, which is mounted on the AUUV, enables to obtain not only its geographic coordinates, but also to measure Doppler signal frequency shift, which enables to calculate radial (Doppler) velocity. Having at least two measurements of Doppler frequency shift, it is possible to calculate inclined distances to outlet buoy according to information on Doppler speed and speed of flight and determine bearing on output buoy with due allowance for data on course and depth of subsidence of AUUV, which will enable to obtain in the end the geographical coordinates of AUUV.

EFFECT: technical result is increasing autonomy of AUUV in part of navigation in the absence of requirements for time synchronization of output buoy and AUUV, as well as to presence of acoustic transmitting equipment on AUUV with radiating antenna.

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Description

The technical field to which the invention relates

The proposed method relates to the field of underwater navigation and can be used to solve the problem of determining the location of high-speed autonomous unmanned underwater vehicles (AUV) based on information on the Doppler shift of the sonar signal frequency from one outlet buoy. State of the art

A known method of navigation AUV [1], in which the coordinates of underwater objects are determined relative to various types (bottom and floating) hydroacoustic beacons (GM) in a mode with an ultrashort base containing a navigation base of hydroacoustic transponders with different response frequencies and located on the navigation object of the hydroacoustic transceiver , by means of which the time intervals of signal propagation are measured with their subsequent transformation into the distance between the underwater object and the hydroacoustic transponders.

The disadvantage of this method [1] is the need to perform work on the installation and subsequent coordination of bottom beacons, the ability to determine the coordinates of the AUV in the immediate vicinity of the area of their installation, as well as the need to equip the AUV with a transceiver antenna.

A known method for determining the location using information about the Doppler frequency shift of the received signals from two sources, stationary or towed behind the AUV [2]. The peculiarity of this method is that the AUV must be equipped only with a receiving antenna, which simplifies the design of the AUV. The disadvantages of this approach are the need to have two signal sources and the requirement for mandatory time synchronization of emitting sources.

The known method of single-beacon mobile navigation AUV [3], which consists in the use of an autonomous uninhabited water vehicle (ANVA), carrying GM. To determine the current location of the GM with the required accuracy, the ANVA transporting it is equipped with a combined satellite navigation system (SNS) receiver. This approach is based on the use of modem hydroacoustic communication, which allows AUV and ANVA to exchange data packets, as well as to determine the distance between the vehicles based on measuring the propagation time of the acoustic signal. The AUV position is corrected based on information about the range to the GM using an algorithm based on the use of an extended Kalman filter or a particle filter.

The disadvantages [3] include the mandatory use of ANVA towing the GM, as well as the need to maneuver to improve the accuracy of determining the coordinates of the AUV.

The prototype of the proposed method is a method for determining the location of the AUV, based on the use of information about the ranges to one or more drifting or detachable buoys, the coordinates of which are known from information from the SNS [4]. The peculiarity of this approach is that the location of the AUV is determined in the computer of one of the buoys using information from the navigation system installed on the AUV. This leads to the need to install transceiver equipment and specialized modems on the AUV and the buoy to ensure the time synchronization of the AUV and the buoys, which complicates the equipment used.

The disadvantages of the prototype pose the problem of increasing the autonomy of the AUV in terms of navigation in the absence of requirements for time synchronization and the presence of transmission equipment for underwater communication with a radiating antenna.

Disclosure of invention

The technical result is an increase in the autonomy of the underwater object in terms of navigation in the absence of requirements for the time synchronization of the buoy and the AUV, as well as for the presence on the AUV of transmitting equipment for underwater communication with a radiating antenna. The increase in autonomy is achieved due to the design of the AUV, which makes it possible to place an exhaust buoy (VB) on it, which is separated by a command from the control system. The WB is equipped with a buoyancy device, due to which it floats to the surface after separation. The SNS receiver, the hydroacoustic (GA) communication modem and the radiating antenna located on the WB allow receiving the geographic coordinates of the WB and transmitting them to the AUV. The GA communication modem and the receiving antenna installed on the AUV make it possible to obtain from the WB not only its coordinates, but also to measure the Doppler shift frequency, which makes it possible to calculate the radial (Doppler) velocity.

The information processing procedure is as follows. The signal arriving through the underwater communication from the WB consists of a signal transmitted at a fixed high frequency with a duration of τ <1 s, the reception and processing of which on the AUV makes it possible to determine the value of the Doppler frequency shift, and messages with the geographic coordinates of the WB location of latitude and longitude - ϕ _b , λ _b , respectively, obtained from the SNA data. This information is transmitted to the input of the coordinate determination algorithm together with data from the AUV navigation sensor unit (BND) (measured values of AUV V speed, heading and diving depth of AUV N _g ). In addition, the algorithm uses information about the accuracy characteristics of the sensors and the accuracy of knowing the location of the WB surfacing. The algorithm provides for taking into account the difference in the immersion depths of the GA equipment of the VB and AUV. As a result, at the output of the algorithm, estimates of AUV coordinates in a relative coordinate system, as well as a covariance matrix, characterizing the current accuracy of coordinate estimation, are generated.

The idea of determining a position using only measurements of the Doppler shift of the signal transmitted from the UU to the AUV is as follows. It is assumed that the problem is solved in a relative Cartesian coordinate system Oξης (see Fig.), Where point O is the origin of this coordinate system, which coincides with the coordinates of the signal emitter, which contains the SNS data on the WB coordinates. The antenna for receiving HA signals of the AUV is located at the depth of its immersion Н _Г from the location of the HA equipment VB. The Oη axis is directed to the north (in Fig. This direction is denoted as η (N)), the Oξ axis is to the east (in Fig. This direction is denoted as ξ (E)), the Oς axis is vertically downward (see Fig. ). FIG. Also depicted is a similar relative Cartesian coordinate system O ₁ ξ ₁ η ₁ ς ₁ , located at the AUV immersion depth H _g , equal to the segment OO ₁ . This coordinate system is shown in FIG. to understand the relative position of the AUV (located at point M) and WB (located at point O) relative to each other.

относительно точки О известным соотношениемLet the AUV be at point M and move at a speed V along the AUV track line ML (AUV heading), and at point O there is a WB with a radiating HA antenna. The Doppler frequency shift ƒ _d associated with the radial velocity of the AUV is measured

with respect to point O by the well-known relation

where c _s is the speed of sound propagation in water, ƒ ₀ is the frequency of the emitted signal.

Consider two successive times t _i and t _{i + 1 of} the measurements. Let us introduce the time interval between them Δt = t _{i + 1} -t _i and denote by γ _{i the} value of the angle ∠OML, where L is the point located on the continuation of the AUV track. Let us write down the relations connecting the slant range D _i (in Fig. The segment OM) and the angles γ _i for two consecutive moments of time with the value p = OL, which determines the slant distance from the WB to the track (in Fig. The angle γ _{i + 1} and the slant range D _{i + 1 are} not shown in order to simplify the image - these are analogs of the angle γ _i and the slant range D _i over a time interval Δt when the AUV moves along the track at a speed V; the value of p ₁ shown in Fig. Is the horizontal distance from the WB to the line path and is shown for a better understanding of the relative position of the described objects):

From relations (2) one can find

It should be noted that

и скорости V движения АНПА и с учетом данных о курсе (направление линии пути ML) и относительной глубине Н_г АНПА определить пеленг на ВБ, что позволит получить относительные координаты АНПА ξ и η в относительной декартовой системе координат Oξης.Hence, it is quite simple, having at least two measurements of the Doppler shift ƒ _d , it is possible to calculate the slant ranges D _i and D _{i + 1} from the information about

and the speed V of the AUV and, taking into account the data on the heading (direction of the track ML) and the relative depth H _{g of the} AUV, determine the bearing to the WB, which will allow obtaining the relative coordinates of the AUV ξ and η in the relative Cartesian coordinate system Oξης.

The recalculation of the relative coordinates of the AUV into the geographic ones ϕ _a , λ _a can be performed using the following formulas:

where ϕ _b , λ _b - geographic coordinates of the WB,

ξ (t), η (t) - the current coordinates of the AUV in the relative Cartesian coordinate system Oξης;

R _ϕ , R _λ - current radii of curvature of the meridian and parallel.

Thus, the proposed method, in comparison with the prototype and other technical solutions, does not require the installation and coordination of the GM, it uses only one WB, does not require the presence of ANVA with the GM and the installation of a radiating antenna on the AUV, does not impose requirements on the time synchronization of the WB and AUV and increases the autonomy AUV in terms of navigation due to the presence of a GM in the form of a WB on board the AUV.

Literature:

1. Patent 2456634 Russian Federation, IPC G01S 15/06. Method of navigation of an underwater object by means of a hydroacoustic navigation system / Zhukov Yu.N., Rumyantsev Yu.V., Kursin S.B., Brodsky P.G., Pavlyuchenko E.E., Anosov V.S., Sukonkin S.Ya. , Rudenko E.I., Chernyavets V.V .; patent holders are authors. - No. 2011109995/28, app. 03/16/2011; publ. 07/20/2012; Bul. No. 20. - 20 p.

2. Carof A.N. Acoustic differential delay and Doppler tracking system for long range AUV positioning and guidance / OCEANS'94.'Oceans Engineering for Today's Technology and Tomorrow's Preservation / Proceedings. - IEEE, 1994. - T. 3. - C. III / 389-III / 394 vol. 3.

3. Dubrovin F.S., Shcherbatyuk A.F. Investigation of some algorithms for single-beacon mobile navigation of AUV: Results of modeling and sea tests // Gyroscopy and navigation. - 2015. - No. 4 (91) - p. 160-172.

4. Patent 5579285 (A) United States, IPC G01S 5/00. Method and device for the monitoring and remote control of unmanned, mobile underwater vehicles / Thomas Hubert; patent holders are authors. No. 5,579,285, app. 03.12.1993; publ. 11/26/1996; - 13 p.

Claims (9)

A method for determining the geographic coordinates of a high-speed autonomous unmanned underwater vehicle (AUV) using the Doppler effect, which consists in using information from the launch buoy (WB) with known coordinates, obtained wireless (hydroacoustic), together with heading, speed and depth data diving of the AUV relative to the WB, characterized in that separate WB; make a maneuver in order to move the AUV in the direction that allows to receive from the WB not only its coordinates, but also to measure the frequency of the Doppler shift, which makes it possible to calculate the radial Doppler velocity; using a satellite navigation system receiver, the coordinates of the WB are determined; via the hydroacoustic communication channel, the WB coordinates and a high-frequency signal are transmitted to the AUV, the processing of which on the AUV makes it possible to determine the value of the Doppler frequency shift; by measuring the Doppler frequency shift of this signal, the radial Doppler velocity is determined: the speed of convergence of the AUV and the WB; find the slant range to the WB and determine the bearing to the WB; calculate the relative coordinates of the AUV: displacement relative to the WB; recalculate relative coordinates into geographic coordinates of the AUV.

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