GB2252398A - Apparatus for aiming at a moving target - Google Patents

Abstract

Apparatus for aiming at a moving target includes means for marking a first point (73) of the target (2) with the energy of a laser beam (8), means (31) which are sensitive to the infrared radiation emitted by the first point as it is heated by laser beam (8) for tracking the target, and means for then designating a second, more vulnerable, point of the target and causing this second point to be tracked. The complete system includes a turret 4 which is initially moved to acquire the target in the field of view of a t.v. camera 23. A first tracking system responsive to the t.v. image of the target is then switched in to centre the target on the turret axis in a first, coarse, aiming stage. The 10.6 mu m laser 7 is then pulsed to heat a spot 73 on the target, and on receipt (31) of radiation in the 3 to 5 mu m range from this spot a second tracking system responsive to this radiation is automatically switched in to track the spot and thus aim the axis more accurately. Finally, by moving crosswires over the now-stabilised t.v. image of the target the operator can shift the aim to a selected, more-vulnerable spot. The apparatus finds application to the destruction of a target by laser energy. <IMAGE>

Description

APPARATUS FOR AIMING AT A MOVING TARGET The present invention relates to apparatus for aiming at a moving target.

A known device for aiming at a moving target includes a base on which a support can rotate about two rectangular axes by means of two drive motors. A distance-measuring receiver such as a television camera is mounted on the support. The output of the distance-measuring receiver is connected firstly to a television receiver and secondly to a regulator system which controls the rotation of the two support drive motors. Such a device also generally includes manual control means for the drive motors so as to make the target appear on the television receiver screen.

As soon as the image appears, the distance-measuring regulator system takes over the manual control and therefore the target can be tracked automatically. Such a device can further include a laser illuminator fixed on the support and able to form a bright spot on the target, which spot can serve as an aiming point for means such as a self-guided missile for attacking the target.

The above-mentioned device has a drawback. Indeed, it allows only a bright spot on the target to be aimed at and hit, the bright spot not necessarily being situated in a vulnerable area of the target aimed at.

According to the present invention there is provided apparatus for aiming at a moving target, comprising a support structure universally adjustably mounted with respect to a base; means on the support structure arranged to emit laser radiation along an axis; means operative to adjust the position of the support structure relative to the base so as to vary the directivity of the said axis; a first distance-measuring detector, including a light detector, on the support structure arranged to receive light propagating along said axis towards the support structure; a display device responsive to the output of the light detector to form, on a screen, an image of a target when the said axis is directed at the target; controllable means operable to cause the position adjusting means to vary the directivity of the said axis until an image of the target appears on the screen, whereupon the first distance-measuring detector is arranged to deliver a first signal which represents the distance of the image with respect to a fixed reference disposed on the screen, the reference representing said axis; a switch having first and second operative positions; a first servo system responsive, in the first position of the switch, to said first signal so as to control the position adjusting means in such manner so as to reduce said distance, means to enable a pulse of laser radiation to be triggered after the image df the target has become visible on the screen so as to heat a first point on the target under the effect of the energy of the pulse; a second distance-measuring detector, including an infrared radiation detector, on the support to receive, on the radiation receiving surface of the infrared radiation detector, infrared radiation emitted from said first point, the detector being arranged to deliver a second signal which represents the place of reception on said radiation receiving surface of the infrared radiation with respect to a fixed reference on that surface, the fixed reference representating the third axis, the first servo system being responsive, in the second position of the switch, to said second signal so as to control the position adjusting means in such manner as to bring the place of reception, on said radiation receiving surface, of the infrared radiation close to the fixed reference so as to track the first point on the target; means responsive to the output of the infrared radiation detector and arranged to control the switch such that the switch assumes the first position in the absence of infrared radiation being received but changes to the second position when receipt of infrared radiation occurs; a cross-wire which is movable across the screen; manually controllable means for moving the cross-wire across the screen so as to designate, on the image of the target on the screen after the second signal has been delivered, any selected second point on the target; means sensitive to the movement of the movable cross-wire so as to deliver a third signal which represents the position of the movable cross-wire with respect to the fixed reference; and a summing device arranged to add said third signal to said second signal to produce a fourth signal such that, in the second position of the switch, the first servo system responds to the fourth signal to control the position adjusting means so as to track the second point on the target.

For the avoidance of doubt the ambit of the term "light detector" as used herein includes detectors of radiation in the infrared.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which: Figure 1 illustrates an aiming turret which forms a part of a preferred embodiment of the device in accordance with the invention; and - figure 2 is a block diagram of the electric circuits of the device which includes the turret illustrated in figure 1.

In figure 1, an aiming turret 1 pointed towards a helicopter 2 is mainly constituted by a base 3 and a support 4 rotatably mounted on the base 3 by means of a universal joint which allows the support to rotate about a vertical axis 5 and a horizontal axis 6 by means of two electric motors situated in the base 3 and not seen in figure 1.

A laser emitter device which includes a carbon dioxide laser generator 7 is disposed on the support 4 and is capable of emitting a beam 8 at a wavelength of 10.6 microns. There is also disposed on the support 4 a reflector capable of reflecting the beam 8 towards another reflector 10 which returns the beam which it receives successively on a convex mirror 11 and a concave mirror 12 to form an output light beam 13 whose axis 14. is related to the support 4. Renown means 28 connected to the laser generator 7 are provided for triggering a laser pulse.

The reflector 9 is a reflecting mirror preferably rotatably mounted with respect to the support 4 about two rectangular axes, rotation being controlled respectively by two electric motors such as the motor 15. The reflector 10 is a mirror of the type whose reflecting surface is deformable. In accordance with a known disposition of these mirrors, the reflector 10 comprises n elementary mirrors which are respectively integral with n electrochemical transducers such as piezoelectric cells mounted on a stand fixed on the support 4.

The mirrors 11 and 12 form a telescope assembly of the Cassegrain type. The mirror 12 whose axis is 14 has an axial opening 16 to pass the laser beam returned by the mirror 10 towards the mirror 11 which is also centred on the axis 14.

The mirro 11 is fixed on a support 17 which can be moved in relation to the mirror 12 along the axis 14 by means which are not shown.

There is also fixed on the support 17 a receiving mirror 18 whose reflecting surface points towards the outside of the support 17 so as to reflect at right-angles light which propagates along the axis l4..The The-light.reflected by the mirror 18 is returned at right-angles by a reflecting mirror 19 towards a separating mirror 20 preferably rotatable with respect to the support 4 about two rectangular axes, rotation being controlled respectively by two electric motors which are not shown on the figure. Part of the light which corresponds to the visible spectrum received by the separating mirror 20 is returned via an afocal system constituted by two lenses 21 and 22 onto the receiving surface of a light receiver 23 which can be constituted by a television camera.Another part of the light received by the mirror 20 and having a wavelength of 10.6 microns passes through the mirror 20 to be received on the receiving surface of an infrared light sensor 24 via a concentrating system constituted by two lenses 25 and 26 and a diaphragm 27. The sensor 24, which is sensitive to infrared radiation with a wavelength of 10.6 microns can be constituted by a suitably cooled mercury-cadmium telluride cell. The output of the sensor 24 is electrically connected to the input of an electronic processing system 29 and the output of the system 29 is connected to the electrodes of the piezoelectric cells of the mirror 10 whose reflecting surface is deformable.

A separating mirror 30 which reflects at 900 the infrared light whose wavelength lies between three and five microns in the example chosen is disposed between the mirror 19 and the mirror 20. The separating mirror 30 fixed on the support 4 allows light whose wavelength is outside the 3 to 5 micron range to pass without deviation. The light reflected by the mirror 30 is received by an infrared distance-measuring receiver 31 via a light concentrating system formed by two lenses 32 and 33. The distance-measuring receiver 31 can be formed by four cooled mercury-cadmium telluride cells.

Figure 2 shows very schematically the electric circuits of the device which includes the turret 1 illustrated in figure 1, the components which are identical in both figures being designated by the same reference numbers.

A display device 34 such as a television receiver tube is connected to the output of the light receiver 23. The device 34 includes a screen 35 on which is disposed a fixed central reference 36 which represents the axis of reception 14 (figure 1).

A movable cross-wire 37 can be moved over the surface of the screen 35 by known manually controllable means 38.

The position of the movable cross-wire 37 with respect to the fixed reference 36 is recorded by a movement sensor 39.

The output of the receiver 23 is also connected to a distance-measuring circuit 40 whose output is connected to a terminal 41 of a two-position rotary switch 42. Another terminal 43 of the switch 42 is connected to a device 44.

The switch 42 includes a third terminal 45 which can be connected to the terminal 41 in one operating position of the switch or to the terminal t3 in the other operating position of the switch.

The output of the infrared light receiver 31 is connected via an amplifier 46 to an infrared distance-measuring circuit 47 whose output is connected to an input 48 of a summing circuit 49. The second input 50 of the summing circuit 49 is connected to the output of the movement sensor 39. The output 51 of the summing circuit 49 is connected to a terminal 52 of a two-position rotar switch 53. A second terminal 54 of the switch 53 is connected to the terminal 45 of the switch 55 42. The switch 53 includes a third terminal/which can be connected to the terminal 52 in one operating position of the switch or to the terminal 54 in the other operating position of the switch.

The switch 53 is operated by a control unit 71 whose input is connected to the common link between the amplifier 46 and the circuit 47.

The terminal 55 of the switch 53 is connected via a servo-control circuit 56 to the to motors such as 57 which control the rotation of the support 4 about the axes 5 and 6.

The terminal 55 is also connected via a switch 58, in series with a servo-control circuit.59, to the to motors such as 15 which control the rotation of the reflector 9 about two perpendicular axes.

Likewise, the terminal 55 is connected via a switch 60 in series with a servo-control circuit 61 to two motors such as 62 which control the rotation of the reflector 20.

Lastly, the terminal 35 is connected via a switch 63 in series with a servo-control circuit 64 to motors such as 65 which are capable of moving the diaphragm 27 on the receiving surface of the light sensor 24.

The switches 58 and 60 are operated by a unit 70 controlled by the switch 42. The switch 63 is operated by a control unit 72 whose input is connected to the common link between the amplifier 46 and the circuit 47.

The output of the sensor 24 is connected via an amplifier 5 to the processing circuit 29 whose output is connected to the electrodes of electro-mechanical transducers such as piezoelectric cells 67 and 68 which control the deformation of the reflecting surface 69 of the mirror 10.

The operation of the device hereinabove and illustrated in figures 1 and 2 can be divided into four successive steps.

At the beginning of the first step, the terminals 43 and 45 of the switch 42 are connected together. Since no signal is delivered by the receiver 31, the switch 53 is in its rest position which is that represented in figure 2, the terminals 54 and 55 being connected together. Further, the switches 58, 60 and 63 are also in their rest position represented in figure 2, i.e. they are open, the control unit 70 not operating.

The device 44 allows the operator to control manually or by means of an automatic accuisition device the motors for rotating the support 4 with respect to the base 3 so that the receiving axis 14 related to the support scans the surrounding space vertically and horizontallv. The light which comes from the portion of space situated at each instant in the field of reception whose axis is 14 is received on the receiver 23 and the image of the portion of space appears on the screen 35 of the display device 34.

When the image of a target such as the helicopter 2 appears on the screen, the operator turns the switch 42 so that the terminals 41 and 45 are connected together. The rotation of the switch 42 causes, via the unit 70, the closing of the switches 58 and 60.

The distance measuring circuit 40 connected to the output of the television camera 23 delivers on its output a signal which represents the distance of the image of the target with respect to the fixed reference 36 of the screen. Distance measuring circuits of this type which operate by correlation of zones or by difference in contrast of the image are well known and will therefore not be described here. The signal delivered by the circuit 40 is received at the input of the servo-system 56 which controls the rotation of the motors such as 57 of the turret so as to reduce the distance between the image of the target and the reference 36 of the screen 35.The target is thereby automatically followed fairly accurately (by way of indication, to within about 1 milliradian) taking into account the mechanical play and the inertia of the drive system for rotating the support 4 with respect to the base 3. But since the switch 58 is closed, the output signal of the circuit 40 is also received -at the input of the servo system 59 which controls the rotation of the motors such as 15 of the mirror 9 so as to reduce the distance between the image of the target and the reference 36. Since the mirror 9 is very light compared with the support the target is ollowed more accurately and the accuracy can be brought, for example, to 150 microradians.

When the switch 60 is closed, the output signal of the circuit 40 is also received at the input of the servo system 61 which controls the motors such as 62 so as to rotate the mirror 20 to reduce the distance between the image of the target and the reference; this allows the instabilitv of the age of the target which appears on the screen to be reduced a little.

In the second step of operation, by means of te device 28, the operator triggers a pulse of radiation emitted by the laser generatpr y wdy of-tnd t-4n=~the~nulse e may last a few milliseconds. After reflection on the mirrors 9 and 10, the pulse is concentrated on the target by the Cassegrain system formed by the mirrors 11 and 12. To concentrate the pulse automatically, the device further includes a regulator system, not shown, which receives data concerning the range of the target. This data is given by a rangefinder mounted on the support 4. The regulator system controls the movement of the support 17 along the axis 14 so as to adjust the position of the mirror 11 with respect to the mirror 10 as a function of the range of the target.Due to the overall inaccuracy of the aiming system which has been used up till now, the energy of the laser pulse falls on a point 73 situated inside a fairly large area of the target; this point is generally not the most vulnerable. The aiming system is incapable of providing very great stability of the laser impact in time. However, the concentration of the laser energy is sufficient to heat this point greatly; this point then emits an infrared radiation 74.

In a third step of the operation7 the infrared radiation 74 is received after reflection on the mirrors 18, 19 and 30, at a point of the receiving surface of the infrared distance measuring receiver 31 which is sensitive to a part of the radiation emitted by the heated area 73, for example, in the example described here, to the part of the radiation whose wavelength lies between three and five microns. In response to the lighting of this point of its receiving surface, the receiver 31 delivers an electric signal which, after passing the control through the amplifier 46, is transmitted to 2/unit 71 which rotates the switch 53, the terminals 52 and 55 then being connected together.Likewise, the electric signal delivered by the receiver 31 is received on a control unit 72 which controls the closing of the switch 63.

The electric signal delivered by the distance-measuring receiver 31 is also transmitted via the amplifier 46 to the distance-measuring processing circuit 47 which delivers a signal which represents the distance between firstly the point of reception of the infrared radiation on the receiver 31 and secondly a fixed reference of the receiving surface of the receiver 31, the fixed reference representing the axis of reception 14. The signal passes through the summing circuit 49 without being modified. Indeed, the movable cross-wire 37 is made to coincide with the fixed reference 36 and no electric signal is delivered on the second input 50 of the summing circuit 49.The electric signal delivered by the circuit 47 is therefore transmitted via the terminals 52 and 55 to the servo systems 56, 59 and 61 which control respectively the rotation of the support 4, of the mirror 9 and of the mirror 20 so as to reduce the distance between the infrared radiation receiving point and the fixed reference of the receiver 31.

It is therefore seen that the tracking of the target which was controlled in the first step of the operation bv the television receiver 23 is controlled in the third step by the receiver 31 which is sensitive to infrared radiation emitted by the point 73 of the target struck by the energy o the laser pulse. Taking into account the fact that the tracking is now attached to a fixed point of the target, accuracy is very much greater than that of the first step. By way of indication, the tracking accuracy can be about 10 to 20 microradians in the third step.

The third operation step can last as long as the radiation whose wavelength lies between three and five microns is knitted by the marked area of the target i.e. in practice, for several seconds.

During the third phase, the sensor 24 receives, via a diaphragm 27, a part of the radiation whose wavelength is 10.6 microns emitted by the laser generator and returned by the target towards the support 4. In response the sensor 24 delivers electric signals which represent the mutual phase shift of the laser waves which come from the n elementary mirrors of the deformable surface 69 of the mirror 10. These signals pass through the amplifier 56 and the processing circuit 29 which biases the electrodes of the ii piezoelectric cells so as to correct the mutual phase shift.

The m-rrwsv placed optically in series on the path of the radiation emitted by the laser generator improves the coherence of the laser radiation and con emePLlL increases the density of the laser energy received by the target.

When the switch 63 is closed, the diaphragm 27 is moved along the receiving surface of the sensor 24 by motors such as 65 whose rotation is controlled by the servo system 64 in the direction which tends to bring the fixed receiving point, on the receiver 31, which point receives the infrared radiation whose wavelength lies betunn three and five microns, closer to the fixed reference. The diaphragm 27 makes it possible to filter spatially the radiation received by the sensor 24, and thus fixing its position on the receiving surf ace of the sensor increases its efficiency and consequently the effect of concentration of laser energy on the target due to the presence of the mirror 10 with a deformable reflecting surface.

It should be observed that the putting into operation of the mirror 10 during the third step aims only to prepare the laser emission system to emit high-energy pulses in the fourth step of operation.

During the third step of operation, the stability of the image of the target on the screen 35 is improved as a function of the increase in tracking accuracy. In the fourth step of operation, on the stabilized image of the target, the operator can designate a new point which is more vulnerable than the first point.

The new point is designated by moving the movable crosswire 37 on the surface of the screen 34 by means of the control unit 38, so as to make the cross-wire 37 coincide with the new point chosen. The output of the movement sensor 39 then delivers a signal which represents the position of the movable cross-wire 37 with respect to the fixed reference 36. The signal delivered by the receiver 39 is received by the summing circuit 49 on its second input 50 and is therefore added to the signal delivered by the receiver 47. The signal delivered at the output 51 of the circuit 50 towards the servo systems 56, 59, 61 and 64 therefore corresponds to the sum of the signals delivered by the uni 39 and the circuit 47. Therefore the target tracking which in the third step took place in relation to the first point marked by the energy of the laser pulse is directed, in the fourth step, towards the second, more vulne- rabble point designated by the operator b morment of the crosswire 37.

Of course, in the very exceptional case where the first point marked on the target is a vulnerable point, the second point designated by the operator would be the same as the first point.

In the example described above, the device for aiming at a moving target is applied to attacking a target with a laser pulse. In that case, after having designated the second point of the target, the operator triggers the emission of a highenergy pulse delivered by the laser generator 7 so as to destroy the vulnerable point of the target by thermal effect. It is clear that the aiming device in accordance with the invention can also be applied to the destruction of a moving target by weapons of all types,e.g. by missiles.

Ilaht svstem which is in the rorm or a In the above-describea device, the/television system omich take the form of

controls target tracing in the first step caP4

detection system such as the one usually designated by the expression "Forward Looking Infrared" or FLIR. In that case, the receiver 23 is formed by a plurality of mercury-cadmium telluride infrared detectors cooled by Joule-Thomson effect.

Lastly, it should be noted that the proper operation of the various servo systems which form a part of the aiming device shown in figures 1 and 2 requires the use of a computer which receives the data concerning the relative movement of the various servo controlled units, the data being delivered by sensors which are integral with these units. The computer can then determine for each unit the direction in which said unit must be moved to reduce the distance-measurement signal. The direction of movement must also depend preferentially on the anticipated path of the target, such as determined by means of the computer at each instant of tracking. For simplicity's sake, the computer has not been described or illustrated.

Claims (7)

CLAIMS:

1. Apparatus for aiming at a moving target, comprising a support structure universally adjustably mounted with respect to a base; means on the support structure arranged to emit laser radiation along an axis means operative to adjust the position of the support structure relative to the base so as to vary the directivity of the said axis; a first distance-measuring detector, including a light detector, on the support structure arranged to receive light propagating along said axis towards the support structure; a display device responsive to the output of the light detector to form, on a screen, an image of a target when the said axis is directed at the target; controllable means operable to cause the position adjusting means to vary the directivity of the said axis until an image of the target appears on the screen, whereupon the first distance-measuring detector is arranged to deliver a first signal which represents the distance of the image with respect to a fixed reference disposed on the screen, the reference representing said axis; a switch having first and second operative positions; a first servo system responsive, in the first position of the switch,to said first signal so as to control the position adjusting means in such manner so as to reduce said distance, means to enable a pulse of laser radiation to be triggered after the image of the target has become visible on the screen so as to heat a first point on the target under the effect of the energy of the pulse; a second distance-measuring detector, including an infrared radiation detector, on the support to receiver on the radiation receiving sur face of the infrared radiation detector, infrared radiation emitted from said first point, the detector being arranged to deliver a second signal which represents the place of reception on said radiation receiving surface of the infrared radiation with respect to a fixed reference on that surface, the fixed reference representing the third axis, the first servo system being responsive, in the second position of the switch, to said second signal so as to control the position adjusting means in such manner as to bring the place of reception, on said radiation receiving surface, of the infrared radiation close to the fixed reference so as to track the first point on the target; means responsive to the output of the infrared radiation detector and arranged to control the switch such that the switch assumes the first position in the absence of infrared radiation being received but changes to the second position when receipt of infrared radiation occurs; a cross-wire which is movable across the screen; manually controllable means for moving the cross-wire across the screen so as to designate, on the image of the target on the screen after the second signal has been delivered, any selected second point on the target; means sensitive to the movement of the movable cross-wire so as to deliver a third signal which represents the position of the movable cross-wire with respect to the fixed reference; and a summing device arranged to add said third signal to said second signal to produce a fourth signal such that, in the second position of the switch, the first servo system responds to the fourth signal to control the position adjusting means so as to track the second point on the target.

2. Apparatus according to claim 1, wherein the means arranged to emit laser radiation includes a laser generator and a reflector disposed at the output of the laser generator and mounted rotatably with respect to the support about second and third axes which are mutually perpendicular, the said apparatus further comprising first and second motors operable to effect angular rotations of the reflector about said second and third axes respectively, and a second servo system arranged to control the motors, in the second position of said switch, so as to enhance the tracking of the first and second points on the target.

3. Apparatus according to claim 1 or 2, and additionally comprising a further reflector which is mounted rotatably with respect to the support structure about fourth and fifth axes which are mutually perpendicular, so that light, after propagating along the first-mentioned axis towards the support structure, is reflected by the second-mentioned reflector along an optical path towards the first distance-measuring receiver, third and fourth motors operable to effect angular rotations of the second-mentioned reflector about said fourth and fifth axes respectively, and a third servo system arranged to control the third and fourth motors, in the second position of said switch, so as to enhance the tracking of the first and second points on the target.

4. Apparatus according to any preceding claim and further comprising an optical system on the support structure, associated with the laser radiation emitting means, the optical system being operable to concentrate the energy of the laser radiation on the target and being provided with means to maintain the concentration of the laser radiation energy on the target irrespective of changes in the distance of the target from the said apparatus.

5. Apparatus according to claim 2 or claim 3 or 4 as appended to claim 2, wherein the laser radiation emitting means further comprises a reflector fixed on the support structure and disposed optically in series at the output of the laser generator, this third-mentioned reflector having a deformable reflect ing surface and being provided with n electromechanical transducers fixed respectively to n parts of the reflecting surface of the third-mentioned reflector, the said apparatus further comprising a light sensor fixed on the support structure to receive laser light after being reflected by the target towards the support structure along the first-mentioned axis, the sensor being arranged, whenever infrared radiation is received by the infrared radiation detector, to deliver signals representing the mutual phase shift of the laser waves coming from the n parts of the reflecting surface of the thirdmentioned reflector, and a processing circuit arranged to receive the signals representing the mutual phase shift of the laser waves and, accordingly, to control the n electromechanical transducers to correct the mutual phase shift.

6. Apparatus according to claim 5 and additionally comprising a movable diaphragm on the receiving surface of the light sensor, means arranged to move the diaphragm along the receiving surface of the light sensor, and a fourth servo system arranged to control the diaphragm moving means, whenever radiation is received by the infrared radiation detector, so as to enhance the tracking of the first and second points on the target.

7. Apparatus for aiming at a moving target, substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

7. Apparatus for aiming at a moving target, substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

8. A device for aiming at a moving target, said device including - a base - a support rotatably mounted with respect to the base about a first rectangular axis and a second rectangular axis - a first motor and a second motor which are capable of rotatig the support respectively about the first axis and the second axis - a first distance-measuring detector disposed on the support to receive the light which propagates along a third axis related to the support - a display device connected to the output of the first distance-measuring receiver to form, on a screen, the image of the target when it is in the direction of the third axis - controllable means to make the first motor and the second motor rotate so that their rotation will make the image of the target appear on the screen, the first distance-measuring detector then being able to deliver a first electric signal which represents the distance of the image with respect to a fixed reference disposed on the screen, the reference representing the third axis - a first servo system whose input can be connected to the output of the first distance-measuring detector so as to receive the first signal and whose output is connected to the input of the first motor and of the second motor to control their rotation so as to reduce said distance ; and - a laser emitter disposed on the support to emit a laser radiation along the third axis towards the target characterized in that it further includes - means for triggering a pulse of the laser radiation when the target is visible on the screen so as to heat a first point of the target under the effect of the energy o the pulse, the first heated point emitting an infrared radiation - a second distance-measuring detector fixed on the support to receive the infrared radiation on its receiving sur ace, the detector then being able to deliver a second electric signal which represents the place of reception of the infrared radiation with respect to a fixed reference of the reception surface, the fixed reference representing the third axis;; - a switch which includes a first terminal connected to the input of the first servo system, the first terminal being connected to a second terminal in a first position of the switch1 the second terminal being connected to the output of the first distance-measuring detector, the first terminal being connected to a third terminal in a second position of the switch, the third terminal being connected to the output of the second distance-measuring detector so as to transmit the second signal to the first regulator system which then controls the rotation of the first motor and second motor so as to bring said place of reception of the infrared radiation close to the fixed reference so as to track the first point of the target;; - means for controlling the switch, said means being connected to the output of the second distance-measuring detector, these means keeping the switch in the first position as long as the second signal is not delivered and keeping the switch in the second position as soon as the second signal is delivered; - a cross-wire which is movable across the screen; - manually controllable means for moving the movable cross-wire across the screen so as to designate, on the image of the target on the screen after the second signal has been delivered, a second point of the target; - a unit which is sensitive to the movement of the movable cross-wire and whose output is able to deliver a third signal which represents the position of the movable cross-wire with respect to the fixed reference; and - a summing circuit inserted in series between the second distance-measuring detector and the third terminal of the switch, the summing circuit including a first input connected to the output of the second distance-measuring detector and a second input connected to the output of said unit, the output of the summing circuit being connected to the third terminal of the switch, the summing circuit being able to deliver a fourth signal which results from the sum of the second signal and of the third signal towards the first regulator system after movement of the movable cross-wire, the first regulator system then controlling the rotation of the first motor and of the second motor so as to follow the second point of the target.

9. A device according to claim 8, characterised in that: - the laser emitter includes a laser generator and a first reflector disposed at the output of the laser generator and mounted rotatably with respect to the support about a fourth rectangular axis and a fifth rectangular axis; and that it sufther includes: - a third motor and a fourth motor which can rotate the first reflector respectively about a fourth axis and a fifth axis; - and a second servo system whose input is connected to the first terminal of the switch and whose output is connected to the third and fourth motors.

10. A device according to claim 9, characterized in that it further includes: - a second reflector mounted rotatably with respect to the support about a sixth rectangular axis and a seventh rectangular axis, the second reflector reflecting the light which propagates along the third axis towards the first distance-measuring receiver; - a fifth motor and a sixth motor which are able to rotate the second reflector respectively about the sixth axis and the seventh axis; and - a third servo system whose input is connected to the first terminal of the switch and whose output is connected to the fifth and sixth motors.

11/ A device according to claim10 characterized in that it further includes - an optical system integral with the support and able to concentrate the energy of the laser radiation on the target, the system including means for keeping the laser radiation energy concentrated on the target when the distance from the target to the base varies.

12/ A device according to claim 11, characterized in that - the laser emitter further includes a third reflector with a deformable reflecting surface, the third ref lec- tor being fixed on the support and disposed optically in series at the output of the laser generator, the third reflector including n electromechanical transducers on which are fixed respectively n parts of the reflecting surface of the mirror; and - in that it further includes - a light sensor fixed on the support to receive an echo of the laser light reflected by the target towards the support along the third axis, the sensor being suitable for delivering in return electric signals which represent the mutual phase shift of the laser waves coming from the n parts of the reflecting surface of the third reflector; and - a processing circuit which receives the electric signals which represent the mutual phase shift of the laser waves and which can control the n electromechanical transducers to correct the mutual phase shift.

13. A device according to claim 5, characterized in that it further includes - a movable diaphragm on the receiving surface of the light sensor; - means for moving the diaphragm along the surface of the light sensor; and - a fourth servo system whose input is connected to the first terminal of the switch and whose output is connected to said means for moving the diaphragm.

Amendments to the claims have been filed as follows 1. Apparatus for aiming at a moving target, comprising a support structure universally adjustably mounted with respect to a base;means on the support structure arranged to emit. laser radiation along an axis; means operative to adjust the position of the support structure relative to the base so as to vary the directivity of the said axis; a first distance-measuring detector, including a light detector, on the support structure arranged to receive light propagating along said axis towards the support structure; a display device responsive to the output of the light detector to form, on a screen, an image of a target when the said axis is directed at the target; controllable means operable to cause the position adjusting means to vary the directivity of the said axis until an image of the target appears on the screen, whereupon the first distance-measuring detector is arranged to deliver a first signal which represents the distance of the image with res

pect to affixed reference disposed on the screen, the reference representing said axis; a switch having first and second operative positions; a first servo system responsive, in the first position of the switch, to said first signal so as to control the position adjusting means in such manner so as to reduce said distance, means to enable a pulse of laser radiation to be triggered after the image of the target has become visible pn the screen so as to heat a first point on the target under the effect of the energy of the pulse; a second distance-measuring detector, including an infrared radiation detector, on the support to receive, on the radiation receiving sur face of the infrared radiation detector, infrared radiation emitted from said first point, the detector being arranged to deliver a second signal which represents the place of reception on said radiation receiving surface of the infrared radia

tion with respect to a/fixed reference on that sur face, the fixed reference representing the - sasl axis, the first servo system being responsive, in the second position of the switch, to said second signal so as to control the position adjusting means in such manner as to bring the place of reception, on said radiation receivipg surface, of the infrared

radiation close to theZfixed reference so as to track the first point on the target; means responsive to the output of the infrared radiation detector and arranged to control the switch such that the switch assumes the first position in the absence of infrared radiation being received but changes to the second position when receipt of infrared radiation occurs; a cross-wire which is movable across the screen; manually controllable means for moving the cross-wire across the screen so as to designate, on the image of the target on the screen after the second signal has been delivered, any selected second point on the target; means sensitive to the movement of the movable cross-wire so as to deliver a third signal which represents the position of the movable

cross-wire witn respect to tnerlxee reference, ana a summing device arranged to add said third signal to said second signal to produce a fourth signal such that, in the second position of the switch, the first servo system responds to the fourth signal to control the position adjusting means so as to track the second point on the target.

2. Apparatus according to claim 1, wherein the means arranged to emit laser radiation includes a laser generator and a reflector disposed at the output of the laser generator and mounted rotatably with respect to the support about second and third axes which are mutually perpendicular, the said apparatus further comprising first and second motors operable to effect angular rotations of the reflector about said second and third axes respectively, and a second servo system arranged to control the motors, in the second position of said switch, so as to enhance the tracking of the first and second points on the target.

3. Apparatus according to claim

2, and additionally comprising a further reflector which is mounted rotatably with respect to the support structure about'fourth and fifth axes which are mutually perpendicular, so that light, after propagating along the first-mentioned axis towards the support structure, is reflected by the second-mentioned reflector along an optical path towards the first distance-measuring receiver, third and fourth motors operable to effect angular rotations of the second-mentioned reflector about said fourth and fifth axes respectively, and a third servo system arranged to control the third and fourth motors, in the second position of said switch, so as to enhance the tracking of the first and second points on the target.

4. Apparatus according to any preceding claim and further comprising an optical system on the support structure, associated with the laser radiation emitting means, the optical system being operable to concentrate the energy of the laser radiation on the target and being provided with means to maintain the concentration of the laser radiation energy on the target irrespective of changes in the distance of the target from the said apparatus.

5. Apparatus according to claim 2 or claim 3 or 4 as appended to claim 2, wherein the laser radiation emitting means further comprises a reflector fixed on the support structure and disposed optically in series at the output of the laser generator, this third-mentioned reflector having a deformable reflect ing surface and being provided with n electromechanical transducers fixed respectively to n parts of the reflecting surface of the third-mentioned reflector, the said apparatus further comprising a light sensor fixed on the support structure to receive laser light after being reflected by the target towards the support structure along the first-mentioned axis, the sensor being arranged, whenever infrared radiation is received by the infrared radiation detector to deliver'signals representing the mutual phase shift of the laser waves coming from the n parts of the reflecting surface of the thirdmentioned reflector, and a processing circuit arranged to receive the signals representing the mutual phase shift of the laser waves and, accordingly, to control the n electromechanical transducers to correct the mutual phase shift.

6. Apparatus according to claim 5 and additionally comprising a movable diaphragm on the receiving surface of the light sensor, means arranged to move the diaphragm along the receiving surface of the light sensor, and a fourth servo system arranged to control the diaphragm moving means, whenever radiation is received by the infrared radiation detector, so as to enhance the tracking of the first and second points on the target.