GB2185556A

GB2185556A - Actuation arrangement for aiming mines

Info

Publication number: GB2185556A
Application number: GB08630194A
Authority: GB
Inventors: Gunther Sepp; Gunthard Born; Willi Platz; Wolf-D Schuck
Original assignee: Messerschmitt Bolkow Blohm AG
Current assignee: Airbus Defence and Space GmbH
Priority date: 1986-01-16
Filing date: 1986-12-17
Publication date: 1987-07-22
Also published as: DE3601053A1; FR2592948B1; GB8630194D0; FR2592948A1; GB2185556B; DE3601053C2

Abstract

The fuze comprises a laser range finder LEM acting as a trigger for the mine, two IR detectors IR1 and IR2 serving as arming switches and a microprocessor (not shown) for calculating the target's range R, its speed or angular velocity v and its length L. Should these parameters indicate that the target cannot be hit by reason of too great a range, too high a speed or too small a length, the microprocessor blocks the trigger signal from the range finder. For short targets moving quickly at great range, the hit probability can be increased by the provision of a lead sensor. For targets moving at slow speeds at short ranges, hit probability is increased by delaying the trigger signal. <IMAGE>

Description

SPECIFICATION Actuation arrangementfor aiming mines This invention relates to an actuation arrangement for a fixed position aiming mine having a laser range finder in the weapon direction as release sensor.

Various actuation arrangements for weapons directed towards moving targets are known. For example, in German Patent Specification DE-AS 2262 366 the applicants have disclosed an actuation device which responds to magnetic field changes.

Furthermore, the applicants have also proposed a so-called CW-lasersensorwith which an additional guard switching sensor in the form of a microphone having level measurement is associated. All these sensors have in principle proved their worth, but in combat situations they are still too restricted or else, for example, require complex and expensive instrumentation for combatting targets where a lead time is required. In the latter case twice as many sensors having double sensor apertures are necessary, and in many cases this is simply not feasible solely from the point of view of space restrictions, without even considering the cost.

The problem underlying the invention is to provide an actuation arrangement of the kind mentioned at the beginning hereofwhich obviates the aforesaid disadvantages and includes a release sensor which, despite simpler and reduced components, is absolutely reliable and can be used for situations which require a lead calculation or a firing delay, for example on account of too high or respectively too lowtarget speed, without an additional second laser rangefinderbeing needed.

This problem is solved by an actuation arrangementfor a fixed position aiming mine having a laser range finder as release sensor, characterised in that connected to the laser range finder are two infra-red (IR) detectors which serve as arming or guard switches and with which a microprocessor for measuring the velocity or angularvelocity of a target and the length of same is associated, which microprocessor blocks the fi ring signal ofthe laser range finder in those cases where a hit is achievable only with a lead.

The invention will be described further, by way of example,with reference to the accompanying drawings in which: Figure lisa diagrammatic sketch illustrating an arrangementfortarget combatting in accordance with the invention, with range finding in the weapon direction; Figure2 is a similardiagrammaticsketch illustrat ingan arrangementforcombatting alltargetswithin a specific firing range radius rwhere the direction of movementoftargets is known; Figure 3 is a schematic diagram of one embodiment of release sensor which may be used in the arrangement ofthe invention; Figure 4 is a schematic diagram of another embodiment of release sensor which may be used in the arrangement of the invention; and Figure5is a block wiring diagram of a release sensor, such asthatin Figure 3.

The release sensor concept described hereinunder is based onthe understanding thatthe rangeRtothe target, the target speed v and the target length L are calculated by the microprocessor from the measured values of the laser range finder (LEM) 11 and of the two IR detectors 12, 13, which are additionally used as arming or guard switches. If these parameters indicate that the target cannot be hit, for example by reason of too great a target range with simultaneous high speed and/or small length L of the target, then the LEM release signal is blocked. In cases where very low values of rangeand/ortransversespeed are present, the release signal is delayed.Furthermore, with the release sensor 20 described hereinafter it is possible, when the direction of movement of the target is previously known, to actuate the mine in ac cordancewith an appropriate lead.

In many combat situations the sequence of events is as follows: Upon the approach of a tank, the acoustic sensor 17 switches on the two IR detectors 12, 13 which are directed laterally to the weapon direction. Ifthe tank travels into the field of vision of one of the two laser detectors/lR detectors, the LEM 11 is armed i.e. switched to operative condition. Subsequently, if thetanktravels through the weapon direction, the LEM, which points in the same direction, re sponds when the laser beam impinges on the front edge of the vehicle and actuates firing of the shot. In the case of a tanktravelling at average range and transverse speed, the effective part of the mine, flying at about 100 mis, strikes the central part ofthe tank.In the case of two marginal situations, however, the previously described sequence leads to an unsatisfactory hit orto no hit at all. Firstly, with great target range, if the transverse speed of the vehicle is high and/orthe vehicle length is too small, and the shot is still fired or released when the front edge of the vehicle crosses into the laser beam of the LEM, as a result of the necessary flight time of the effective part, at best a hit only in the rearmost part ofthetank is achieved, or at worst no hit at all is achieved. Conversely, with very low target speed and/or slight target range, the effective part will strike only the front edge of the vehicle, which likewise is not evaluated as optimum.

In accordance with the previous state of the artto attack all these targets within a mine range radius r of, for example, 50 m,two LEM pointing in the lead direction to right and left of the weapon direction would be necessary, and, to measure the targetan- gular speed "w", two additional further outwardly looking LEM's or two IR detectors or pairs of detectors would be required. Then, by means of a microprocessor, the travelling speed can be calculated from range and angular speed, and the vehicle length can be calculated from the temporal course of the signal of the relevant IR detector. Thus a lead cal culation forthe so-called "early firing" or, re- spectively, " late firing" is made possible, in orderto deal with the aforementioned border-line situations.

Now it can easily be established that the proportion oftargets which travel at great range and atthe sametime at high speed and/or have a very short length is very low, so that provision for combatting them can be dispensed with. Therefore, an actuation arrangement is proposed which comprises only a single-beam laser range finder (LEM) 11 for range finding in the weapon direction, and, to measure the targetangularspeed "w", has two IR detectors 12, 13, which possess a common optical receiving system l4andinputtheirsignalstoa micro- processor 16 for lead calculation.However, in the case oftargets having great range and high transverse speed and/or small target length (Figure 1 the latter serves only for blocking the LEM actuation impulse. The previously necessary guard switching sensor, usually a microphone with level measurement, is in itself no longer necessary, since the IR sensorformedfromthetwo IR detectors 12, takes overthis guard switching (arming) function.However, to increase reliability and the useful life ofthe battery, it is sensible to use an acoustic guard switch 17 in conjunction with the aforedescribed actuation sensor arrangement, as indicated in Figure 3, in order to avoid possible non-firing oftheweapon or the aiming mine 10 in the case of target speeds close to zero.

In an exemplified embodiment in which considerably reduced space is required, it is proposed that a common optical receiving system 15 be associated both with the LEM 11 and with the IR detectors 12,13, as indicated in Figure 4. Of course, in such a case the assembly and adjustment complexity is greater. In all cases, or all exemplifiedembodiments,thelRdet- ectors are wired to a microprocessor 16, which both performs the lead calculation and controls the mine arming mechanism and the LEM.

Also, it should be noted that the LEM 11 is swingable out of a symmetrical position with respect to the two IR detectors 12, 13 whenever necessary.

Thus, as regards both apparatus and procedure, lesser demands are made on the proposed actuation sensor arrangement 20, which nevertheless ensures absolutely reliable operation. Furthermore, since in the case of low speed targets a hit is always achieved,thetwo IR detectors only have to measure high speeds more accurately, so that the previous compromise between high sensitivity at higher frequencies and least-possible lower limiting frequ ency of the IR detectors is dispensed with.

The sensor concept proposed here thus allows a widening of the combat situations, which results from the functional procedures. Afew examples will be given in this respect. The response duration ofthe IR detectors 12,13 (or of the IR sensorformedfrom them) indicates the length L of the target. If, a short target (jeep instead oftank) having high speed or range is ascertained, the LEM actuation impulse is automatically blocked. Or, in the case of very low ranges and speeds oftarget, an appropriate latefir ing is actuated so the quality of hits is considerably improved. Furthermore, if the direction of move mentofthetarget is known atthetimethemine is installed, the complete sensor 20 is swung into the lead direction and a lead sensor acting on one side is provided. This allows the combatting of all targets, even targets having great range, great transverse speed and short length within the afforded mine range radius, usually 50 metres.

Claims

1. An actuation arrangement for a fixed position aiming mine having a laser range finder as release sensor, characterised in that connected to the laser range finder are two infra-red (IR) detectors which serve as arming or guard switches and with which a microprocessor for measu ring the velocity or angularvelocity of a target and the length of same is associated, which microprocessor blocks the firing signal of the laser range finder in those cases where a hit is achievable only with a lead.

2. An actuation arrangement as claimed in claim 1, characterised in that the microprocessor app- ropriately delays the firing signal of the LEM laser range finder in those cases where a central target hit position is thereby achieved.

3. An actuation arrangement as claimed in claims 1 or 2, characterised in that the laser range finder is mounted so as to be swingable out of a symmetrical position with respectto the two IR detector dir- ections.

4. An actuation arrangement as claimed in claims 1 to 3, characterised in that the two IR detectors are additionallyused as arming orguardcircuitforthe laser range finder.

5. An actuation arrangement as claimed in any preceding claim, characterised in that a common optical receiving system is associated with the two IR individual detectors.

6. An actuation arrangement as claimed in any preceding claim, characterised in that a common optical receiving system is associated with the laser range finder and with the two IR individual detectors.

7. An actuation arrangement as claimed in any preceding claim, characterised in that the release sensor consisting of the laser range finder and the two IR individual detectors is additionally provided with an acoustic sensor.

8. An actuation arrangementforafixed position aiming mine substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.