RU2259572C2 - Method for determination of true speed of ship at calibration of logs in hydroacoustic traverse trial line - Google Patents

Abstract

FIELD: hydroacoustics, applicable at calibration of absolute and relative logs.

SUBSTANCE: the method includes radiation and reception in equal intervals of time of acoustic signals and measurement of the time of propagation of signals from the ship to each of the hydroacoustic bottom transponder-beacons, additionally measured is the propagation velocity on standard horizons from the water surface from the bottom, measured is the depth of submersion of the ship transceiving antenna, the depth of installation of the bottom transponder beacons, determined is the distance in the horizontal plane from the ship transceiving antenna to each bottom transponder beacon (d₁,d₂), and the longitudinal, traverse and complete true speeds of the ship are calculated.

EFFECT: provided measurement of the true longitudinal and transverse components of the ship speed, both in the submerged and surface positions, enhanced accuracy of speed measurement at variations of flow parameters.

1 dwg

Description

The invention relates to the field of hydroacoustics and is intended to determine the true speed of the vessel during calibration of lags.

Calibration of the lag, in the General case, consists in determining the true V _chi and measured lag (lag) V _chl longitudinal components of the speed of the vessel, the true V _yi and lag V _ul transverse components of speed, in calculating the coefficient of lag

and antenna angle

,

,

introducing the values of these coefficients (corrections) into the lag equipment to eliminate systematic errors inherent in this lag.

There are various methods for determining the true speed of the vessel [1, 2]. The essence of all methods is to measure the distance traveled by the vessel, and the time it takes to travel, using known methods. Most methods are implemented only in the water position.

The main disadvantage of the methods for calibrating the lags in the above-water position is the dependence of the possibility of its implementation on weather conditions, sea waves and the design features of the vessel, because lag calibration can be carried out when the ship is pitching no more than 1-2 ° and yaw no more than 0.3-0.4 ° [1, p. 194, 195].

Submarines can calibrate the logs in the underwater position, where the stability of the motion parameters is easier, but measuring the distance traveled is more difficult. One of these methods is realized when the vessel crosses two cables laid at the bottom, however, laying them at the bottom is a very time-consuming and expensive operation and is only possible in limited cases for stationary landfills.

The most universal is the underwater calibration method using bottom transponder beacons (DMO), the installation of which in any training ground can be performed promptly. In this case, multiple use of the same DMO in different ranges is possible.

The disadvantage of most known methods for determining the true speed is the impossibility of using them in the calibration of absolute lags, when it is necessary to evaluate not only the longitudinal but also the transverse component of the path (speed).

The closest analogue of the invention, selected as a prototype, is the method described in [3].

This method of calibrating relative lags is characterized by the following operations:

- set on the bottom two DMEs at a distance S from one another so that the direction of the base П _s approximately coincides with the direction of the current in this region;

- lead a vessel with a lag and ship equipment installed on it, designed to work with DME, heading parallel to the direction of the base П _s , at a given speed;

- at the time of approach to the traverse, the DME turn it on using ship equipment by sending a request signal, measure the propagation time of the signals (HRV) Δ _τ from the vessel to the DMO and vice versa [4] according to the DMO response signals emitted with a period of about 10 s, and register the ship time t corresponding to the moments of reception of signals from the DME;

- after passing the traverse, the DME is turned off with the help of ship equipment and continues to follow a constant course to the second DMO, at the approach to which all of the above actions are repeated;

- determine the ship time t ₁ and t ₂ corresponding to the moments of the traverse with the minimum values of the HRV for the first and second DMO, respectively;

- based on the known base and the time difference t ₂ -t ₁ = T calculate the true speed of the vessel.

When implementing this method, two DMEs and ship equipment (SC) are used.

The DMO includes: a receiving-emitting antenna, a transceiver switch, a receiving path, a supply voltage switch, a response signal conditioner, and a power source.

The spacecraft includes: a transceiving antenna, a transceiver switch, a pulse shaper, a signal shaper, a receive path, a signal propagation time (delay) meter.

The device operates as follows: they give a signal to turn on DMO No. 1, at the same time, the Δ _τ meter starts _. A DMO antenna receives a request signal, which, after passing through the switch and the receiving path, turns on the switch, through which the voltage from the power source is supplied to the response signal shaper, a response signal from which is transmitted to the water through the switch and antenna. A DMO response signal is received by the SC antenna, amplified by the receiving path, and stops the Δ _τ meter, on which the HRV is indicated. HRV measurement can be performed between the moments of the emission of the request signal and reception of the response signal or between the leading edges of the clock pulses generated in the spacecraft synchronously with the formation of a series of response signals in the DME and the received response signals [4].

The disadvantage of the considered method is the impossibility of using it when calibrating lags that measure, in addition to the longitudinal, the transverse component of speed, as well as the influence on its accuracy of measuring the direction and speed of the current in the area of work. This is due to the fact that the distance S passed between the DME is taken for the path traveled by the vessel, which is possible with the exact coincidence of the direction of the current with the direction of the base П _s and with the path of the vessel. Otherwise, due to the deviation of the track line from the true course by the drift angle β, the path traveled by the vessel increases and the transverse component of the track and speed appears.

The objective of the invention is to increase the accuracy of calibration by eliminating the inherent disadvantages of the prototype and making it possible to use the method for calibrating absolute lags.

To solve the problem with the method of determining the true speed of the vessel when calibrating lags on a hydroacoustic traverse measuring line, including the movement of the vessel at a constant speed, a constant course parallel to the direction of the base, consisting of the first and second sonar DMS, the distance S between which and the direction of the base are known, emission and reception of acoustic signals at regular intervals, measurement of HRV from the vessel to each of the DME and vice versa, registration of ship time and signal reception times of the answer, determining the time interval T between the moments when the vessel traverses the first and second DME, which correspond to the minimum HRV values, additionally measure the signal propagation speed at standard horizons from the water surface to the bottom, measure the immersion depth of the ship’s transceiving antenna, the depth of the DMO installation, determine the distance in the horizontal plane from the ship’s receiving-emitting antenna to each DMO (d ₁ , d ₂ ) and calculate the longitudinal, transverse and full true speed of the vessel according to the formulas am

The essence of the method is illustrated in the drawing, in which in a projection on a horizontal plane are shown:

DMO-1, DMO-2 - bottom transponder beacons;

S is the distance between the DMO;

P - bearing from DMO-1 to DMO-2;

N — direction to the north;

d ₁ and d ₂ - the distance to the DMO when the DMO on the beam of the vessel;

PU - track angle;

IR - true course;

β is the drift angle that occurs when a vessel is exposed to current or wind.

The distance from the vessel to the DMO d is measured indirectly by the measurement results:

- the propagation time of the signals Δ _τ from the vessel to DMO-1 and DMO-2 and vice versa;

- deepening of the vessel’s antenna from surface h;

- depths of the installation DMO-1 and DMO-2 H _i ;

- sound velocities at standard horizons [5].

Taking into account that the greatest accuracy of fixing the moments of passage of the traverse of the DMA is provided at the shortest distances to the DMA, of the order of 100-500 m, at which the refractive distortions of the trajectories of acoustic rays are not large, the distances are calculated by the formula

Where

where n is the number of water layers in which the gradient of the speed of sound (equal to the ratio of the change in the speed of sound to a unit of distance [3]) is constant;

C _i is the speed of sound at the boundaries of a water layer of thickness ΔН _i [6];

C _i and C _{i + 1} are the sound velocities at the upper and lower boundaries of the ith water layer of thickness ΔН _i , in which the gradient of sound velocities is constant, respectively.

A vessel following a constant course, under the influence of drift or drift, moves along the line of the path, maintaining parallelness of the diametrical plane to the true course, and acquires longitudinal displacements

, а также поперечные смещения d_поп=d₁-d₂ и скорость

.and speed

as well as transverse displacements d _pop = d ₁ -d ₂ and speed

.

.In this case, the true net speed of the vessel

.

Thus, the true values of the components of the vessel’s speed are found, the use of which together with the measured lag makes it possible to determine the lag coefficient and antenna rotation angle [1], which are necessary for calibrating absolute or relative lags.

With the possibility of measuring both the longitudinal and transverse components of the speed, the transverse displacements of the vessel do not impair the accuracy of the measurements, and the procedure for determining the speed of the vessel may not be necessary provided that the directions of the current and the base are parallel, as well as in the above-water position.

Sources of information

1. K.A. Vinogradov et al. “Absolute and relative lags”, Reference, L., Shipbuilding, 1990, pp. 189-203, 209-210.

2. V.I.Kamanin and others. "Navigator's guide", Military. published USSR Ministry of Defense, Moscow, 1968, pp. 58-66.

3. K.A. Vinogradov et al. “Hydroacoustic traverse measuring line” in the collection of reports of the Fourth Russian Scientific and Technical Conference “Current State, Problems of Navigation and Oceanography” (“HO-2001”), vol. 2, June 6–9, 2001 GNINGI, Ministry of Defense of the Russian Federation, St. Petersburg, 2001, pp. 18-20.

4. A.P. Prostakov "Electronic key to the ocean", Shipbuilding, L., 1978, pp. 82-87.

5. A.P. Belobrov "Hydrography of the sea", Transport, Moscow, 1964, p. 224.

6. "Terminological dictionary-reference book for hydroacoustics", L., Shipbuilding, 1989, p. 72.

7. Nikolaenko Yu.A. "The accuracy of determining the location of ships with hydro-acoustic navigation systems with responder beacons" in the journal "Sudostroenie" No. 2-3, 1996, pp. 32-34.

Claims (1)

A method for determining the true speed of a ship when calibrating lags on a hydroacoustic traverse measuring line, including the movement of the ship at a constant speed, at a constant heading parallel to the direction of the base, consisting of the first and second sonar transponder beacons (DMO), the distance S between which and the direction of the base are known the radiation and reception at regular intervals acoustic signal, measuring the signal propagation time (HRV) Δτ ₁ and Δτ ₂ from the vessel to each of DMO and back registration battleship- about the time and moments of receiving response signals, determining the time interval T between the moment of passage of the traverse of the first and second DMEs to the vessel, which correspond to the minimum HRV values, characterized in that they additionally measure the signal propagation speed at standard horizons from the water surface to the bottom, measure the immersion depth h the transceiver antenna of the vessel, the installation depth of the DMO H ₁ and H ₂ , determine the horizontal distance from the ship's transceiver-emitting antenna to each DMO (d ₁ , d ₂ ), as well as linear, transverse and full true vessel speeds according to the formulas

where H _i - the depth of the installation of DMO; C _i and C _{i + 1} - sound speeds at neighboring (i and i + 1) standard horizons; ΔН _i is the distance between adjacent (i and i + 1) standard horizons.