GB2502939A

GB2502939A - Anti-torpedo device

Info

Publication number: GB2502939A
Application number: GB8506419A
Authority: GB
Inventors: Claus Buddruss; Christoph Hampe; Manfred Meyersieck
Original assignee: Fried Krupp AG
Current assignee: Fried Krupp AG
Priority date: 1984-04-21
Filing date: 1985-03-12
Publication date: 2013-12-18
Anticipated expiration: 2005-03-12
Also published as: DE3415107B3; GB8506419D0; GB2502939B

Abstract

In an anti-torpedo device having a towed, noise-radiating jammer (16), to improve the efficiency of the device even against "smart" torpedoes, the jammer (16) is coupled with a hydrophone chain (11) forming the reception antenna of an on-board sonar (15) and an electronic switching system (20) is provided which actuates the noise radiation by the jammer (16) and the signal reception through the hydrophone chain (11) only alternately for predeterminable time intervals. In place of the electronic switching system (20) a controlled filter can be provided which screens out the frequency range of the jammer (16) in the on-board sonar (15). The jammer (16) with transmission antenna (18) may be housed (as shown) within a depth-control buoy (12) at the end of the hydrophone chain (11).

Description

S -1 -

ANTI-TORPEDO DEVICE

The invention relates to an anti-torpedo device having a noise-radiating jammer towed by a ship.

Such a jammer generates a noise which covers the noise of the ship, so that acoustically directed torpedos are attracted away from the ship towards the jammer.

Such jammers have the disadvantage that they can be located over a substantially greater range than the ship itself and thus considerably increase the probability of self-betrayal of the ship. Therefore they are only ever used in the case of most extreme need, especially only when the probability of a torpedo attack is very high, or even only when a torpedo attack can reliably be presumed. Since moreover an attacking torpedo is recognised by the location equipment situated ordinarily on board the ship only with great difficulty and mostly only very late, the jainmers are frequently thrown out or switched on too late, so that thus their effectiveness is considerably reduced.

The invention is based upon the problem of improving an anti-torpedo device of the initially stated kind in such a way that its setting in action at.the right time is automatically ensured and also the prerequisites are* provided for increasing its efficiency even against "smart" torpedos.

In accordance with this invention, the problem is solved by the use of an anti-torpedo device having a noise-radiating jamnier towed by a ship, characterised * C -.

in that with the jammer there is mechanically connected a hydrophone chain -so called towed array -as receiption antenna of a passive sonar installation, installed on the ship, for torpedo location.

The combination in accordance with the invention between the hydrophone chain towed by the ship (towed array) and the jammer connected with it offers the advantage first of substantially improving the torpedo detection, especially at an earlier time when the torpedo is stillat a great distance from the ship, and next of being able to switch on the jaminer without loss of time immediately after detection of a torpedo, namely automatically in the case of electric coupling of the jammer with the on-board sonar. After the jammer is switched on then jamming and location are carried out in alternation by the electronic switching system in phases fixed by the on-board system, and/or it is ensured by a filter (band elimination filter) controlled on board that the.freguency range of the noise radiated by the jammer is cut out of the signal processing of the reception signals received by way of the hydrophone chain. Thus the minimum possible influencing of the reception antenna for torpedo location and at the same time maximum interference with the approaching torpedo are achieved. Moreover the effectiveness o the jamming measures of the jammer and the reaction of the torpedo can be observed and measured by the on-board sonar, which is thus constantly effective without interference, so that again it is possible to draw cqnclusions as to further defensive measures to be initiated against the attacking torpedo.

Compared with parallel use of trailed antenna and a jammer towed separately therefrom, the constructive combination of trailed antenna and jammer in accordance * with the invention has the advantage of substantially simpler handling. Since only one towing means in total * is present, the nianoeuvrability of the towing ship is hardly impaired, which is of essential importance especially for submarines. At the same time it is thus ensured that trailed antenna and jammer automatically always run at the same depth, advantageously at the usual running depth of torpedos, and thus no further discrepancies occur between location and jamming.

Trailed antenna and janimer, the latter after switching over of its antenna to reception, can moreover be used as monitoring sensors for the noise radiated by the ship. Both are situated astern of the towing ship, that is in a region from which an attacking acoustically directed torpedo also misses the towing ship. Thus the measurement is possible of the range of betrayal and of the characteristic noise pattern of the towing ship, as presented,to the torpedo. The exploitation of these possibilities, the on-board chances of detection of and tracking the attacking torpedo, which are substantially improved by the hydrophone chain, and the fixed coupling of the jammer with the on-board system provide the prerequisite for making the jammer itself technically more complex, more * expensive and thus wore efficient than conventional jammers, which as disposable articles had to be the best possible value for money, and thus of imparting to * the jammer a certain "intelligence" superior to a * * torpedo. * * * -4-.

The invention is described in greated detail below by reference to an example of embodiment which is represented in the drawing wherein, in each case in diagrammatic representation:--Figure 1 shows a lateral view of a surface ship with anti-torpedo device in use, Figure 2 shows a block circuit diagram of the anti-torpedo device in Figure 1.

The anti-torpedo device comprises a hydrophone chain 11 towed by a surface ship 10, also called a trailed antenna,, on the end of. which there is arranged a depth-control buoy 12, also called otter, for controlling the depth position of the hydrophone chain 11, as necessary especially in shallow-water regions.

The hydrophones aligned in the hydrophone chain 11 are indicated diagrammatically and designated by 13 in Figures 1 and 2. The hydrophone chain 11 with its hydrophones 13 is connected through a signal lead 14 (Figure 2) to a known pass,ive sonar installation 15 installed on board the surface ship 10, and forms its reception antenna.

In the depth-control buoy 12 there is integrated a jaminer 16 which., is indicated diagrammatically in Figure 2 by a symbol of an amplifier and an elebtro-acoustic transducer. In known manner the jammer 16 radiates into the water, a noise which masks the ship's noise.

The noise pattern is generated on board by a noise generator 17 to which a transmitter, with transmission antenna 18,' dontained in the jammer 16 is connected

-I

through a connecting cable 19 extending through the hydrophone chain 11.

* On board there is further provided an electronic switching system 20 which is symbolised in Figure 2 by a change-over switch in the leads; 14, 19 to the hydrophone chain 11 and to the jarnxner 16. This electronic switching system 20 is formed so that it releases the connection to the hydrophone chain 11 and to the jammer 16 only in alternation, so that it is possible to locate by means of the liberated hydrophone chain 11 and to jam by means of the jammer 16 only in alternation. Thus the powerful noise radiated by the jammer is prevented from "blinding" the sonar installation in the location phase of the passive sonar installation 15. The controlling of the time intervals for the switching on of location and jamming is effected by a time control circuit or a timer 21. Both the timer 21 and the noise gencrator 17 can be started automatically by the passive sOnar installation 15, for example if the passive sonar installation 15 detects an attacking torpedo.

The manner of operation of the anti-torpedo device as described above is as follows: In torpedo-endangered areas the surface ship 10 travels with the hydrophone chain or trailed antenna 11 let out, as represented diagrammatically in Figure 1. The hydrophcne chain 11 is initially constantly electrically connected with the passive sonar installation 15, and through the hydrophone chain 11 the entire sea area on both sides of the direction of ) LI -travel of the surface ship 10 is monitored by the passive sonar installation 15. As soon as the passive sonar installation 15 detects an attacking torpedo, the timer 21 and the noise generator 17 are automatically started. In fixed phases now location and jamming are effected in alternation, so that the least possible impairment of the function of the on-board sonar installation with at the same time maximum disturbance of the approaching or attacking torpedos are ensured.

Due to the minimal impairment of the passive sonar installation 15, which continues intermittently to monitor the attacking torpedo, it is possible to observe the effectiveness of noise jamming upon the torpedo and to detect the reaction of the torpedo.

Thus further additional anti-torpedo measures can be selected to directed manner, and additional anti-torpedo means can be optimally used.

The invention is not limited to the example of embodiment as described above. Thus is not necessary for the jammer 16 to be integrated into the depth-control buoy 12. It. can also be accommodated in a separate float which is arrange at the end cr at the beginning of the hydrophone chain 11. If a possibility is provided of switching over the transmission antenna 18 of the janimer 16 to reception, the jammer 16 can be used as a medium to high-frequency self-noise-monitor.

In combination with the hydrophone chain 11 thus the noise radiated from the ship 10 can be measured and thus the range of betrayal and the characteristic noise pattern can be determined.

In place of the intermittent release of jaminer 16 and hydrophone chain 11 by the electronic control system 20 it is also possible to provide a filter, here a band-elimination filter, which is controllable on board, which is controlled so that the frequency band of the januner 16 is suppressed inthe passive sonar installation 15. For this purpose the blocking range of the band-elimination filter is to be set to the frequency band of the noise radiated by the jaxnmer 16.

Due to this measure it is possible to locate and jam at the same time without danger of the powerful noise radiated by the jammer 16 "blinding" the passive sonar installation. In that case the electronic control system 20 is eliminated.

Claims

CLAIMS:- 1. Anti-torpedo device having a noise-radiating jammer towed by a ship, characterised in that with the S jammer (16) there is mechanically connected a hydrophone chain (11) -so called towed array -as reception antenna of a passive sonar installation (15) installed on the ship, for torpedo location.
2. Device according to claim 1, characterised in that the jammer (16) Is arranged on the end of the hydrophone chain (11) and the hydrophone chain (11) at the same time forms the towing cable for the jaminer (16).
3. Device according to claim 1 or 2, characterised in that the hydrophone chain (11) comprises a depth-control buoy (12) and the jammer (16) is integrated into the depth-control buoy (12).
4. Device according to any one of claims 1 to 3j characterlsed by an electronic switching system (20) which releases noise radiation by the jammer (16) and signal reception by way of the hydrophone chain (11) only in alternation for predeterminable time intervals.
5. Device according to any one of claims 1 to 3, characterised in that the hydrophone chain (11) has connected after it at least one controllable band-elimination filter the blocking range of which covers the frequency range of the jammer (16).