GB2108246A

GB2108246A - Apparatus for combatting targets

Info

Publication number: GB2108246A
Application number: GB08229029A
Authority: GB
Inventors: Wolf-Dieter Schuck
Original assignee: Messerschmitt Bolkow Blohm AG
Current assignee: Airbus Defence and Space GmbH
Priority date: 1981-10-14
Filing date: 1982-10-11
Publication date: 1983-05-11
Also published as: DE3140728A1; FR2514486B1; DE3140728C2; FR2514486A1; GB2108246B

Abstract

Apparatus for combatting targets, such as tanks or grounded aircraft, comprise a directable launcher which is coupled with a target location device (9) which controls the alignment movements of the launcher and the triggering of the projectile fired. The target location device (9) has a passive acoustic direction sensor (15) as well as an active acoustic range sensor (17). A common directional microphone arrangement (11) is used for both sensors. As soon as a target is located with the passive direction sensor, the active range sensor (17) is switched on and a short sound impulse is sent out from a sound source (27). The sound reflected by the target is picked up by the microphone arrangement (11) and evaluated in a transit time circuit (29) to determine the range of the target. The launcher is aligned at the target by virtue of the direction signals of the passive direction sensor (15) and the range signals of the active range sensor (17). <IMAGE>

Description

SPECIFICATION Apparatus for combatting targets This invention relates to apparatus for combatting targets, such as tanks or the like.

Known apparatus (which is also referred to as "munition" in this specification) for the combatting of ground targets, such as tanks, grounded aircraft or the like is set out near the expected location of the target and, aftertarget location, automaticallydis- charges its ammunition in the direction of the target.

The munition may be, for example, a launcher (or mortar) or a launcher arrangement which is equipped with one or more projectiles (or shells) to be fired from the launcher. Coupled to the munition is a target location device. This target location device may be designed in a variety of ways.

One possible design consists, for example, in equipping the target location device with a passive acoustic direction sensor. This direction sensor has a directional microphone arrangement consisting of, for example, four microphones which are arranged in the corners of a tetrahedron and the microphone outputs of which are coupled with an evaluation circuit. If sound signals fall onto this microphone arrangement, then the microphone output signals can be correlated with one another and the direction of the target to be combatted be determined therefrom. By virtue of this determination, the launcher is aligned to the latter. Upon a specific criterion of the signal of the evaluation circuit, which can for example be coupled to the intensity of the evaluation signal, the projectile or mortar shell is fired.In the case of such a passive acoustic target acquisition, merely the direction of the target is determined. The same holds good for other such passive target location devices which work on an optical, electromagnetic or any other basis.

More particularly in the case of ground targets which are moving fairly rapidly, it would be desirable to make possible, in addition to direction finding, a range determination. By virtue of this range determination, for example, the launcher could be directed with a specific lead towards the target and the projectile then fired. In this way the probability of a direct hit on the target of the shell is increased. Various methods are possible for providing such a range determination. A laser range finder is most suitable for this purpose, since this can be integrated into the munition because it has comparatively little space requirement. In principle, if it is designed as a scanning apparatus, also additionally the direction of the target could be determined with such a laser range finder.

The disadvantage of such active sensors, which continually in operation, is the fact that they can be traced comparatively simply by an enemy and the munition and ammunition can subsequently be made harmless. Moreover, a laser range finder is not always reliable particularly if it operates in unfavourable atmospheric conditions such as speaks against a laser range for example, a mist or a dense dusty atmosphere, as is often present on a battlefield.

Furthermore, the active sensor has to be supplied constantly with energy, which, more particularly in the case of a laser range finder, considerably limits the overall operating time of the munition. As a rule such active sensors are largerthan passive sensors, so that additionally the problem of a good camouflage arises. Moreover, the active systems are, as a rule, very complex, so that the possibility of error is greater as compared to passive sensors.

The problem underlying the invention is to improve the target location device for apparatus of the kind with which the present invention is concerned in such a way that a simple and relatively small system is achieved, with which, without great expenditure, the target direction and the target range can be determined.

This problem is solved in that the present invention provides apparatus for combatting targets, such as tanks or the like, with an ammunition which, by virtue of signals of a target location device, can be aligned at the desired target and be triggered, characterised in that the target location device has, for determining the target direction, a passive acoustic direction-finding sensor with a microphone arrangement which picks up sound signals from the target, and, for determining the target range, an active acoustic range sensor which can be switched on by the direction sensor after target location and which has a sound source as well as a microphone arrangement, and in that a single common microphone arrangement is used for the direction sensor and the range sensor.

Advantageously, the apparatus of the present invention comprises a passive acoustic direction sensor and an active acoustic range sensor, for both of which the same microphone arrangement is used.

Moreover, the active acoustic range sensor may only be activated when a spatially concentrated target has been ascertained by the passive direction sensor.

Several advantages are achieved with such a target location device. Thus, through the common use of the microphone arrangement for the passive direction sensor and the active range sensor, the entire installation can be constructed very compactly with small space requirement. In addition to, for example, an already existing passive direction sensor, only a small impulse sound source, for example a blank cartridge, needs to be provided, which is detonated after target location by the direction sensor. Additionally an electronic circuit for measuring the transit time of the sound impulse from the impulse source to the located target and back may be provided. The radiation of the sound impulse can basically be effected in an undirected manner.

However, this impulse may also be sent out in a course preferential direction with the aid of the passive acoustic direction finding. Also it is possible to send out not only one impulse, but several thereof, in that, for example, at specific intervals of time several blank cartridges are detonated one after the other.

The impulse sent out from the sound source are advantageously detected by the microphone arrangement of the passive direction sensor. Such a microphone arrangement is, for example, a known tetrahedron arrangement, as has been indicated above. The differences in transit time, calculated upon this range determination, of the microphone output signals allow a directional reception of the proportion of the sent-out impulse reflected by the target, for example, a tank or grounded aircraft.

An active acoustic range finder is known 'per se' (see, for example, German Offenlegungsscrift No. 30 38 974). Also, tetrahedron microphone arrangements in acoustic direction-finding sensors are known, for example, from United States Patent No. 3 421138. With the present invention protection is only claimed for the combination indicated in the characterising part of patent claim 1 and the cooperation of a passive and an active acoustic sensor.

The invention will be described further by way of example, with reference to the accompanying drawings, in which Figure 1 is a schematic perspective view of a preferred embodiment of the apparatus in accordance with the invention; and Figure 2 is a schematic circuit diagram of the apparatus shown in Figure 1.

The preferred apparatus 1 for combatting ground targets, such as tanks, grounded aircraft orthe like, comprises a launcher 3 which is mounted on a stand ortriped 5, and is alignable in azimuth and elevation on the triped 5 with the aid of motors (not shown).

The launcher 3 has four short conical launcher tubes 7, in which are mounted and stored small hollow charge projectiles, which after detonation are fired from the launcher tubes at a target (not shown).

Mounted on the launcher 3 is a target location device 9 which locates the target acoustically in direction and range. This target location device controls the directional movements of the launcher 3 and also triggers the detonation of the projectiles.

As is apparent from Figure 2, the target location device 9 has a microphone arrangement 11 consisting of four microphones, which are arranged in the corners of a tetrahedron 13 which is indicated in broken lines here. A current supply for the microphone arrangement 11 as well as the subsequent electronic circuit is not shown. The microphone output signals are processed twice, namely on the one hand in a passive direction sensor 15 and on the other hand in an active range sensor 17. The microphone output signals are supplied in the passive direction sensor 15 to a correlation circuit 19, in which they are correlated in a known manner, as is described, for example, in United States Patent No. 3 421138 indicated above. From this correlation the direction of the located target in azimuth and elevation can be determined.These direction values are fed to a direction transmitter 21. The direction transmitter 21 supplies, in accordance with the azimuth value and the elevation value, signals to the directing motors for the launcher 3, which adjust this to the ascertained azimuth and elevation value. The control circuit with which this is undertaken is designated in Figure 2 generally as 23. The launcher is aligned in this way at a target, for example a tank, the motor noise of which has been picked up by the microphone arrangement 11.

This alignment of the launcher 3 by itself does not ensure that the projectiles fired from the launcher tubes 7 hit the target with high reliability. This is due to the limited range and limited initial velocity of the projectiles. In order to hit the target reliably, additionally a range finding is necessary, by virtue of which the launcher can be aligned with a certain superelevation and with a lead. This is ensured by the active range sensor 17.

As soon as a target and the target direction thereof is determined with the passive direction sensor 15, the active range sensor 17 is activated by a starting circuit 25, which receives a starting impulse from the correlation circuit 19. At the same time two triggering impulses are omitted by the starting circuit 25.

With one triggering impulse an impulse sound source 27 is switched on, which source 27 emits a short sound impulse. With the other triggering impulse a transit time circuit 29 is activated to the inputs of which the output signals of the microphones 11 are fed. The differences in transit time, calculated upon the direction finding in the correlation circuit 19, of the signals of the four microphones allow a directional receptional of the proportion, reflected from the target, of the sound impulse emitted by the sound source 27. The range ascertained from the transit time measurement is fed to a range transmitter 31. By virtue of this range value, the launcher can, as indicated above, be corrected in its alignment ascertained by the passive direction sensor 15.The firing direction of the launcher is by virtue of this range measurement raised correspondingly and adjusted with a certain lead angle relative to the target direction. This adjustment is undertaken by the control circuit 23. Each projectile of the launcher 23 is detonated by this control circuit 23.

This detonation is effected, for example, when the alignment of the launcher 3 with the aid of the range value is concluded. By virtue of the corrected alignment of the launcher 3 with the aid of the active range sensor 17 the probability of a direct hit on the target is very high.

The sound source 27 can, as indicated in Figure 1, be arranged on the side of the launcher 3. The sound source 27 is, for example, a blank cartridge. In order to be able to undertake several range measurements, either in order to determine the range of a target more accurately or in order to combat several targets successively with the launcher 3, several blank cartridges (not shown) may be used as sound sources. The cartridges are arranged on both sides of the launcher in corresponding housings 33. These housings 33 may be so designed that the triggered sound impulse is given a course preferential direction which lies in the target direction, i.e. in the alignment determined by the passive direction sensor 15. By virtue of the correlation of the signals it is, of course, also possible to send out the sound impulse in an undirected manner.

In order to separate the signals for the range measurements as extensively as possible from background noises which are present on a battlefield, sound sources of a frequency range which lies at least partially outside the frequencies prevailing on the battlefield may be used. In this way a high signal-to-noise ratio for the range measurement can be achieved. In a transit time circuit 29 appropriate frequency filters are present, which mask out the frequency range relevant for the transit time measurement. Suitable as sound sources, for example, in the ultra-sonic range, are for instance, piezoelectric oscillators having high output power, in the same way as small bursting charges with ultra-sonic portions in the detonation report.Sufficient for an adequate signal-to-noise ratio against the prevailing battlefield noise is a relatively high sound frequency range of signal source, since battlefield noise lies substantially at low frequencies and drops off to wards higher frequencies. Furthermore, it is possible, by making the housings 33 in which the blank cartridges are mounted funnel shaped to imprint on the emitted sound impulse a characteristic signature, i.e. for example a characteristic frequency or amplitude source. With the aid of matched filters in the transmit time circuit 29, these characteristically imprinted sound impulses can be filtered out of the background noise. The reception of the emitted sound impulse or several sound impulses reflected by the target is effected in directed manner by way of the microphone arrangement 11, in which respect this target direction is derived by the correlation maximum from the direction finding with the passive direction sensor 15.

Claims

1. Apparatus for combatting targets, such as tanks or the like, with an ammunition which, by virtue of signals of a target location device, can be aligned at the desired target and be triggered, characterised in that the target location device has, for determining the target direction, a passive acoustic direction-finding sensor with a microphone arrangement which picks up sound signals from the target, and, for determining the target range, an active acoustic range sensor which can be switched on by the direction sensor after target location and which has a sound source as well as a microphone arrangement, and in that a single common microphone arrangement is used for the direction sensor and the range sensor.

2. Apparatus as claimed in claim 1, characterised in that the microphone arrangement comprises an arrangement consisting of four microphones which are arranged in the corners of a tetrahedron.

3. Apparatus as claimed in claim 1 or 2, characterised in that the sound source is in the form

4. Apparatus as claimed in claim 3 wherein the pyrotechnical means is blank cartridges.

5. Apparatus as claimed in any one of the preceding claims, characterised in that at least a part of the frequency range of the sound source lies outside the frequency range of background noise, and in that filters for filtering out this frequency range are provided in the target location device.

6. Apparatus as claimed in any one of the preceding claims, characterised in that means is provided for imprinting a characteristic signature on the sound impulse sent out from the sound source, and in that adapted or matched filters, for filteringout the signals characterised in such a way, are provided in the target location device.

7. Apparatus for combatting targets substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.