RU2800186C1 - Method for calibrating log installed on underwater vehicle - Google Patents

Abstract

FIELD: navigation.

SUBSTANCE: secant alignments on the measured line, instead of visually well-distinguished buoys, are equipped with radio-acoustic buoys with directional sonar antennas, which makes it possible to take the direction finding of the UV when it moves under the water and, by equality of the second derivative of the bearing to zero, to detect the moment the underwater vehicle crosses the secant alignment.

EFFECT: ensuring the specified accuracy of calibration of the logs installed on the UVs during movement under water.

1 cl, 2 dwg

Description

The invention relates to the field of navigation, and in particular to methods and devices for measuring the speed of manned and unmanned underwater vehicles (UA).

One of the conditions for safe navigation of the PA is the constant control of its speed. The main means of speed control in a submerged position is the log. Logs are divided into absolute (hydroacoustic), measuring the speed of the UAV relative to the ground, and relative (electromagnetic or hydrodynamic), measuring the speed relative to the water [1-5]. Since navigation requires knowledge of the ship's speed over the ground, it is preferable to use an absolute log. However, the absolute log has a depth limit under the keel, which is determined by the size of the hydroacoustic antenna (and, accordingly, the frequency of the emitted signal), which can be placed on the ship. Since the dimensions of the PA are limited, it is possible to install a hydroacoustic antenna on them with dimensions that ensure the measurement of speed to depths of no more than 400 m. In view of this, when swimming in deep water areas, it is necessary to use a relative log.

In order for the lag readings to have the required (specified) accuracy, absolute and relative lags must be calibrated on the measuring line.

Methods for calibrating logs on a measured line are well known [1-5].

To date, the calibration of logs of both surface ships and vessels, and submarines is carried out on specially equipped measuring lines, the number of which is limited in the country. They are located in close proximity to large shipbuilding enterprises.

The measured line includes (figure 1) the run line 1 and two secant target 2, equipped at the ends with well-defined landmarks, for example, buoys 3. The length of the segment the line of run, located between the secant sections, is called the measured length. The run line is parallel to the flow. The secant lines are perpendicular to the run line. On the line of each secant target on a floating craft or on the shore, there is a human observer 4, ready, when the ship crosses the secant target, to fix the moment of crossing and report it to the control point (CP) located on the shore or on the ship. Observers' stopwatches and PU stopwatches must be synchronized with an accuracy of 1 s.

A ship with a calibrated log moves with a constant course and speed along the run line. The moments of intersection of the first and second secant lines are fixed by observers. Next, the actual speed is determined passing the measured length on the first tack:

(1)

To compensate for the influence of the current, the vessel passes the measured line in the opposite direction with the determination of the actual speed . Arithmetic mean of And is the actual ship speed, which is used to calculate the lag correction.

The advantage of the described method is the ease of calibration of logs installed on surface ships.

At the same time, this method has a significant drawback when calibrating logs installed on submarines and UAVs, for which the main position during navigation is underwater. The fact is that the described method provides for the passage of the measuring line by the vessel in principle on the surface, which is why in the case of submarines and UA it is not possible to correctly calibrate the logs, since when they move in the surface position, additional fatal errors are introduced into the measurement of the actual speed associated with yaw on the wave and the difference in the dynamic resistance of water in the underwater and surface positions of the UA.

A known method of calibrating the logs installed on submarines, when they move in a submerged position [1, 7], characterized in that the secant alignments are replaced by secant underwater cables under electrical voltage. The moment of passage of a submarine in a submerged position over a secant cable is determined by special equipment installed on the submarine. However, due to the complexity and high cost of implementation (due to the need for special equipment for submarines), this method has not found practical application.

There is also a method [8] that allows you to calibrate the logs of submarines and PA when they move in a submerged position. The method consists in equipping secant alignments with bottom transponder beacons (DMOs), which make it possible to determine the distance between the ship and the DMO. This is implemented as follows. The PA periodically sends a hydroacoustic request signal to the DMO. DMO, having received it, sends a hydroacoustic response signal with a known delay. On the PA, having received a response signal, the distance between the PA and the DMA is determined by the difference between the times of receipt of the response signal and the emission of the request signal (minus the known radiation delay on the DMO of the response signal) and the known speed of sound in water. As a result, the moment of crossing the secant alignment corresponds to the minimum distance between the PA and DMO.

However, this method has not found practical application due to the complexity of its implementation, which consists in the difficulty of determining the exact distance between DMS installed at different secant alignments, the need to control the speed of sound at the DMS installation sites, and the need to periodically raise the DMS to the surface to recharge batteries.

As a prototype method, we choose a widely used in practice method for calibrating the lag on a measured line, described in detail in [1, p.195]. The measuring line equipment is described above.

Log calibration according to the prototype method includes the following steps:

A vessel on which a calibrated log (absolute or relative) is installed in the surface position with a given constant speed starts moving along the run line from outside the measured length, approaching the nearest secant alignment.

At the moment of crossing the first secant alignment, a human observer located on it fixes the exact time of crossing and one of the ways reports it to the PU.

At the moment of crossing the second secant alignment, a human observer located on it fixes the exact time of crossing and one of the ways reports it to the PU.

On the PU according to the formula (1) determine the actual speed passing the measured length on the first tack.

To compensate for the speed of the current, the actions according to paragraphs 1-4 are repeated when the ship is moving in the opposite direction, as a result, the actual speed is determined on the PU passing the measured length on the second (back) tack.

Lag correction is determined on PU corresponding to the speed , which is then entered into the computing device of the lag:

(2)

The actions according to claims 1-6 are repeated for a set of speeds from the range of possible vessel speeds.

The advantage of the prototype method is the ease of calibrating the logs installed on surface vessels.

However, as noted above, the prototype method has a significant drawback when calibrating the logs installed on the PA, for which the main position when swimming is underwater.

Also, the disadvantage of the prototype method in the case of calibrating the logs installed on the PA is that the calibration is carried out on specially equipped measuring lines, which are available only at the locations of large shipyards. PA, as a rule, are manufactured at small enterprises and their delivery for lag calibration to equipped measuring lines is associated with significant financial costs.

The technical problem being solved is the improvement of the methods for calibrating the lags installed on the PA.

EFFECT: ensuring the specified accuracy of the calibration of the logs installed on the PA during their movement under water.

The specified technical result is achieved by the fact that the secant sections, instead of visually well distinguishable buoys, are equipped with radio-acoustic buoys (Fig. 2, item 5, one for each section) with directional sonar antennas. The directional sonoacoustic antenna of a radio-sonobuoy (RSL) makes it possible to determine the current bearing of the UV and, by the maximum rate of its change (which corresponds to the shortest distance between the UV and the RSL), to fix the moment when the UV passes the secant target. Most accurately, the moment of passage of the UA of the secant alignment is fixed by the equality to zero of the second derivative of the change in the bearing of the UA in time.

The essence of the invention is as follows:

1) UA in a submerged position with a constant set speed starts moving along the run line from outside the measured length, approaching the nearest secant alignment.

2) In the computing device of each RSL, periodically with a period of a few seconds, time-bound PA bearings . If, due to the low noise level of the UV, its RSL direction finding throughout the entire route is not possible, the UV periodically, with a period of a few seconds, emits signals with a sonar, according to which the RSL carries out UV direction finding.

3) In the computing device of each RSL using an array of measured bearings tied to time , the current value of the second derivative is calculated changes in the UV bearing over time.

4) In the computing device of each th RSL using the dependence of the second derivative of the bearing change, the moment of time is fixed the equality of the second derivative to zero, which corresponds to the moment of crossing the secant alignment of the PA. This moment of time is transmitted to the PU via radio communication or by reading from the memory of the computing device after completion of work.

5) The actual speed is determined on the PU passing the measured length on the first tack:

(3)

Where is the distance between the RSL.

6) To compensate for the influence of the current, the actions according to paragraphs 1-5 are repeated when the UA moves in the opposite direction, as a result, the actual speed is determined on the PU passing the measured length on the second (back) tack.

7) On the PU, according to the formula (2), the lag correction is determined and introduced into the computing device of the lag corresponding to the speed :

8) The actions according to paragraphs 1-7 are repeated for a set of speeds from the range of possible PA speeds.

Distinctive features of the proposed method are:

1) The movement of the PA along the run line in a submerged position. ?

2) Measurement of the moments of time of intersection of the secant alignments by equality to zero of the second derivatives of the change in bearings, measured by the RSL with directional hydroacoustic antennas.

Let us determine the accuracy of measuring the speed of the PA according to the formula (3) by the proposed method.

Since the relative root-mean-square errors (RMS) of estimating the distance between the RSL and time difference are small, then according to [9]

(4)

Where - UPC, respectively, estimates of the speed of the PA, estimates of the distance between the RSL and estimates of the difference in the time of crossing the secant lines.

From (4) it follows

(5)

According to [10], using a differential satellite navigation system, the location of the RSL can be determined with the UPC of 3 cm, therefore the distance between the RSL can be determined with the UPC =5 cm.

The experiment showed that the difference in the times of intersection of the secant alignments along the bearings is determined from the UPC <5s.

As a result, with a typical distance between the RSL =1000 m and PA velocity 2 m/s relative SCP of PA velocity measurement does not exceed 1%, which corresponds to the accuracy required for lags.

Thus, it can be argued that the claimed technical result has been achieved.

Information sources:

1. Vinogradov K.A., Koshkarev V.N., Osyukhin B.A., Khrebtov A.A., Absolute and relative lags // L .: Shipbuilding, 1990.

2. Khrebtov A.A., Vinogradov K.A., Koshkarev V.N. etc. Ship speed meters. // L.: Shipbuilding, 1978.

3. Hydroacoustic navigation aids. Ed. V.V. Bogorodsky // L.: Shipbuilding, 1983. 262 p.

4. Bogorodsky V.V., Hydroacoustic technology for research and development of the ocean // L .: Gidrometizdat, 1984.

5. Vinogradov K.A., Novikov I.A., Hydroacoustic navigation systems and means // Navigation and hydrography, GNINGI MO RF, No. 7, 1999.

6. Kamanin A.V., Lavrentiev A.V., Skubko R.A. Fleet navigator. Handbook of ship navigation. Moscow: Military Publishing House, 1986.

7. RF patent No. 2259572.

8. Vinogradov K.A. Hydroacoustic traverse measuring line // Collection of reports of the 4th Russian scientific and technical conference "Current state, problems of navigation and oceanography". 2001. Volume 2. P.18-20.

9. Ventzel E.S., Ovcharov L.A. Probability theory and its engineering applications. // M.: Nauka, 1988, p.273.

10 en/wikipedia.org

Claims (1)

A method for calibrating a log installed on an underwater vehicle (UA), including the movement of the UA at a given constant speed along the run line of the measuring line, fixing the time of crossing the first secant target, fixing the time of crossing the second secant target, determining the actual speed of the UA movement by dividing the measured length by the difference in the times of crossing the secant targets, repeating the determination of the actual speed when the UA moves at the same speed along the run line in the opposite direction, determining the lag correction by subtracting the given speed from the average value of the actual speed when the UV moves along the runway in both directions, repeating the determination of the lag correction for other given UV speeds from the range of possible UV speeds, characterized in that the UV moves along the runway in a submerged position, the first and second cross sections are implemented using the first and second sonobuoys with directional sonoacoustic antennas, periodically measuring and storing with reference to time the bearings of the UV when the UV moves along the runway, the moments of crossing The values of the first and second secant alignment are determined by the equality to zero of the second derivative of the bearing change in time.