EP0151480B1 - Laser device for guiding a missile on a target - Google Patents

Laser device for guiding a missile on a target Download PDF

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Publication number
EP0151480B1
EP0151480B1 EP85101158A EP85101158A EP0151480B1 EP 0151480 B1 EP0151480 B1 EP 0151480B1 EP 85101158 A EP85101158 A EP 85101158A EP 85101158 A EP85101158 A EP 85101158A EP 0151480 B1 EP0151480 B1 EP 0151480B1
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EP
European Patent Office
Prior art keywords
missile
frequency
laser
circuit
target
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP85101158A
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German (de)
French (fr)
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EP0151480A3 (en
EP0151480A2 (en
Inventor
Patrice Jano
Michèle Tron
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Compagnie Industriel des Lasers CILAS SA
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Compagnie Industriel des Lasers CILAS SA
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Publication of EP0151480A2 publication Critical patent/EP0151480A2/en
Publication of EP0151480A3 publication Critical patent/EP0151480A3/en
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Publication of EP0151480B1 publication Critical patent/EP0151480B1/en
Expired legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41G—WEAPON SIGHTS; AIMING
    • F41G7/00—Direction control systems for self-propelled missiles
    • F41G7/20—Direction control systems for self-propelled missiles based on continuous observation of target position
    • F41G7/30—Command link guidance systems

Definitions

  • the present invention relates to a laser device for guiding a missile at a target.
  • FIG. 1 shows a carbon dioxide laser emitter 1 emitting a continuous beam 2 of infrared radiation with a wavelength of 10.6 microns.
  • the beam 2 enters a modulator 30 connected to a control circuit 29.
  • Two beams 51 and 52 exit from the modulator 30.
  • the beam 51 is received on a mirror 3 mounted in rotation, in elevation and in bearing, around a ball joint 4 fixed on a support 23, the rotation of the mirror 3 being driven by electric motors such as 5.
  • the mirror 3 is an adaptive mirror, the reflecting surface 16 of which is deformable under the action of a plurality of piezoelectric transducers such as 17.
  • Each transducer 17 comprises two electrodes which are connected to an electrical bias circuit 18 by connections such as 19.
  • a control circuit 20 is connected to the motors 5.
  • a telemetry circuit 21 is connected to circuit 29 and to an electrical output 37 of the receiver 15.
  • An adjustable telescopic sight 22 is mounted on a base 24 around a ball joint 25.
  • the beam 52 leaving the modulator 30 is returned along a beam 53, by a mirror 54 fixed on the telescope 22, to a target 55 such as a tank.
  • a telemetric reception system 56 fixed to the telescope 22 receives along a reception axis 57 part of the laser energy of the beam 53 returned by the target 55.
  • the reception axis 57 is parallel to the optical axis 34 of the bezel 22.
  • An angular measurement system 27 determines the orientation of the mirror 3 relative to that of the telescope 22.
  • a computer 28 has five inputs 39, 60, 38, 41, 40 respectively connected to circuit 21, to output 37 of receiver 15, to another output 36 of receiver 15, to system 27 and to circuit 56.
  • the computer 28 has three outputs 61, 62 and 63 connected respectively to circuit 18, circuit 20 and circuit 29.
  • the missile 7 is equipped with a reception circuit comprising a photoelectric detector 31 disposed at the rear of the missile, the electrical output of the detector 31 being connected to the input of a processing circuit 32.
  • the output of the circuit 32 is connected to a piloting member 33 capable of causing a change in the direction of the missile.
  • the missile 7 furthermore comprises an explosive charge 58 near which there is a system 59 capable of triggering the explosion of the charge 58 at the time of the impact of the missile on the target.
  • the elements referenced from 1 to 5, from 10 to 30 from 38 to 41, 56 and from 60 to 63 are gathered in a guide station 35 which can be located on the ground or on a military vehicle.
  • the beam 9 returned by the retroreflectors 8 fixed on the missile is, after reflection on the movable mirror 3 and the fixed mirror 11, concentrated by the lens 14 on the receiver 15 with four quadrants.
  • On the electrical output 37 of the receiver 15 is delivered a signal representative of the intensity of the laser radiation returned by the missile.
  • On the deviation output 36 of the receiver 15 is delivered a signal representative of the angular deviation between the position of the missile and the axis of the laser beam.
  • the deviation signal is sent to the computer 28 which can thus calculate the direction of the missile taking into account the orientation of the mirror 3 and deliver the information corresponding to the circuit 20.
  • the electrical output 37 is connected to the input 60 of the computer 28 which develops orders for polarizing the electrodes of the transducers 17 of the adaptive mirror 3. This results in a deformation of the reflecting surface 16 of the mirror 3, this deformation tending increasing the concentration of the laser beam 6 on the missile 7. The amplitude of the electrical signal delivered on the output 37 of the receiver 15 is thus increased.
  • FIG. 2 An embodiment 30A of the modulator 30 is shown in FIG. 2. It comprises a crystal 64 with BRAGG effect arranged on the path of the beam 2 emitted by the laser emitter 1. Against the crystal 64 are applied the mechanical outputs of two transducers electromechanical piezoelectric 65 and 66. Two rocker circuits 67 and 68 are connected to the control circuit 29 of the modulator and respectively to the electrical inputs of transducers 65 and 66. The rocker circuits 67 and 68 each have an input, and these inputs are connected at the output of a current generator 69 of acoustic frequency f 2 .
  • the modulator 30A shown in Figure 2 operates as follows.
  • Toggle circuits 67 and 68 identical to each other, each have two positions of stable equilibrium. In a first equilibrium position of the circuit 67 (or 68), the electrical input of the transducer 65 (or 66) is not connected to the output of the generator 69; in the second equilibrium position of the circuit 67 (or 68), the electrical input of the transducer 65 (or 66) is connected to the output of the generator 69.
  • the control circuit 29 of the modulator 30A makes it possible to switch the two rocker circuits sequentially to their equilibrium positions.
  • the transducers 65 and 66 are not supplied by the generator 69 and the laser beam 2 emitted by the emitter 1 is refracted normally in the crystal and leaves it -this according to the beam 51.
  • the beam 51 leaves parallel to the beam 2.
  • the frequency of the radiation of the beam 51 is equal to the frequency F, of the radiation of the beam 2.
  • the transducers 65 and 66 are both powered by the generator 69. These transducers are arranged on the surface of the crystal so that the acoustic waves which they emit in the crystal cause the formation of an output beam 52 parallel to the beam 51 but different from the latter.
  • the frequency F 2 of the radiation of the beam 52 is offset with respect to the frequency F, of the beam 51 of the value f 2 of the acoustic frequency emitted by the generator 69.
  • the modulation of the continuous beam 2 emitted by the laser transmitter 1 is effected by causing, by the control circuit 29, a sequential switching of the two flip-flop circuits 67 and 68 to their positions of stable equilibrium.
  • the control circuit 29 causes alternating switching of the circuit 68 to its first and second equilibrium positions, at a rate which makes it possible to cutting short pulses from the continuous laser beam, so that the beam 51 is formed of a series of pulses.
  • these pulses are sent to the missile 7, after reflection on the mirror 3 along the beam 6.
  • the pulses are returned by the missile and received by the receiver 15 which delivers a return signal on its output 37 connected to circuit 21.
  • the latter has a clock for measuring the time interval which elapses between the emission of a laser pulse towards the missile and its reception on the receiver 15.
  • the telemetry circuit 21 delivers therefore when it leaves the missile distance information.
  • the sequential switching of the flip-flop circuits 67 and 68 may also include, the circuit 68 for example remaining in its second equilibrium position, an alternating switching of the circuit 67 to its first and its second equilibrium position.
  • This alternative switching makes it possible to cut out pulses of short duration from the continuous laser beam, so that the beam 52 is also formed of a series of pulses (see FIG. 2).
  • the beam 52 is reflected by the mirror 54 in a beam 53.
  • the operator directs the telescopic sight 22 towards the target and, at the same time, directs the beam 53, parallel to the axis 34 of the telescopic sight, also towards the target.
  • the target 55 sends back to the reception circuit 56, similar to the circuit 21, part of the energy of the pulses of the beam 53 and the circuit 56 delivers, at the desired times and at regular time intervals, the information of the distance from target.
  • the measurement system 27 delivers at its output two pieces of information defining the angular position of the missile relative to a reference trihedron linked to the orientable telescope 22.
  • the computer 28 receives on its inputs 39 and 40 the information of the respective distances from the station 35 to the missile and to the target, and on its input 41, the two information defining the angular position of the missile.
  • the computer 28 is capable of determining from these two pieces of information the angle which the direction of the missile makes with that of the target.
  • the computer 28 is also capable to develop piloting signals capable of controlling the adjustment of the organs 33 of the missile 7, so as to guide the missile on the determined trajectory.
  • FIGS. 3A, 3B, 3C and 3D are diagrams established for a given sequential switching of the flip-flop circuits 67 and 68.
  • FIG. 3A shows, as a function of time, the amplitude A 51 of the energy of the beam 51, when, the circuit 67 remaining in its first equilibrium position, an alternating switching of the circuit 68 is caused to its two positions. This switching is carried out so as to obtain a series of short duration pulses, these pulses being modulated in position, that is to say shifted in time according to the control signals produced by the computer.
  • FIG. 3B shows as a function of time the amplitude A 52 of the energy of the beam 52 when, the circuit 68 remaining in its second equilibrium position, the circuit 67 is switched alternately to its two positions. This switching is carried out so as to obtain a series of short duration pulses arranged between the successive pulses of the beam 51.
  • FIGS. 3C and 3D show as a function of time the acoustic frequency of the supply current of the transducers 66 and 65. It can be seen in these last two diagrams that the frequency f 2 of the current delivered by the generator 69 varies as a function of time, when this current is applied to the input of the transducer 65. This variation takes place along an upward ramp followed by a downward ramp; these ramps are linear and of the same duration, and their slopes are equal and of opposite sign.
  • the variation of the frequency f 2 makes it possible to incorporate in the reception circuit 56 means for measuring the speed of the target by Doppler effect. Thanks to the symmetrical ramp shape of this frequency variation, it is possible to compress the duration of the pulses at reception using a known technique, which improves the performance of telemetry and speed measurement of the target.
  • the beam 51 is sent to the missile by reflection on the mirror 3, along the beam 6.
  • the receiver 31 of the missile picks up the series of pulses modulated in position carried by the beam 6, and the processing circuit 32 delivers at its output the piloting signals which are transmitted to the piloting member 33, so as to progressively guide the missile towards the target.
  • the device described above with reference to Figures 1 and 2 is therefore capable of guiding a missile at a target.
  • This device uses a single laser 1 from which, thanks to a modulator 30, two separate beams (51 and 52) are formed.
  • the beam 51 makes it possible to perform the functions of deviation measurement, telemetry and transmission of orders to the missile.
  • the beam 52 makes it possible to measure the distance from the target and possibly its speed.
  • the type 30A of modulator represented in FIG. 2, which comprises two transducers, has the advantage of forming two beams (51 and 52) parallel to each other and of direction independent of the frequency of the generator, which facilitates the optical exploitation of the beams from the modulator.
  • the rocker circuit 75 comprises three positions of stable equilibrium, a first position in which the electrical input of the transducer 74 is not connected to any of the current generators, a second position in which the electrical input of the transducer 74 does not is connected only to the generator 76 of frequency f t , and a third position in which the electrical input of the transducer 74 is only connected to the generator 77 of frequency f 2 .
  • the laser radiation 2 leaves the crystal in a beam 51 of frequency F I equal to the frequency of the radiation emitted by the laser transmitter 1.
  • the laser beam 78 which leaves the crystal is deflected angularly relative to the beam 51.
  • This beam 78 is not used in the operation of the device; it is closed by an absorbent material 79.
  • the deflection angle depends on the frequency of the transducer supply current and since f is different from f 2 , the three beams 51, 78 and 52 are distinct from each other.
  • circuit 29 switches alternately the flip-flop circuit 75 between its first and its second equilibrium positions, pulses are formed in the beam 51.
  • the successive pulses thus formed are shifted in time so as to effect a modulation in position according to the control signals produced by the calculator.
  • FIG. 5A represents the variations as a function of time of the amplitude A 51 of the radiation of the beam 51.
  • pulses are formed in beam 52. These pulses are illustrated by FIG. 5B which represents the variations as a function of time of the amplitude A 52 of the beam radiation 52.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Description

La présente invention concerne un dispositif laser pour guider un missile sur une cible.The present invention relates to a laser device for guiding a missile at a target.

Par le document FR-A-2 525 339, on connaît un dispositif laser pour guider un missile sur une cible, le missile étant lancé vers la cible et comportant des moyens de pilotage pour modifier la direction de son déplacement. Ce dispositif est d'un type comprenant

  • - un poste de guidage comportant
  • . un système de pointage automatique du missile, comprenant
  • + un générateur d'un faisceau laser, comprenant un émetteur de rayonnement laser de fréquence F1' ce générateur étant muni de moyens d'orientation du faisceau vers le missile, celui-ci renvoyant en sens inverse une partie de l'énergie du faisceau,
  • + un système écartométrique muni d'un récepteur électro-optique disposé pour recevoir ladite partie d'énergie renvoyée, le récepteur étant apte à délivrer en réponse un signal d'écartométrie représentatif de l'écart angulaire entre la position du missile et l'axe du faisceau + et un circuit d'asservissement apte à commander les moyens d'orientation du faisceau de façon à réduire l'écart angulaire, des moyens pour mesurer la distance du missile, ces moyens comprenant
  • + un modulateur faisant partie dudit générateur, ce modulateur étant apte à recevoir le rayonnement laser délivré par l'émetteur et à délivrer en réponse des impulsions laser de fréquence Fi
  • + et un circuit de télémétrie du missile, relié au modulateur et à la sortie du récepteur électro-optique, pour mesurer l'intervalle de temps compris entre l'émission d'une impulsion laser de fréquence F, et son retour sur le récepteur après renvoi par le missile, cet intervalle de temps étant représentatif de la distance du missile,
  • . des moyens pour mesurer la distance de la cible,
  • . une lunette de visée orientable vers la cible,
  • . des moyens de mesure angulaire pour délivrer des informations de la position angulaire du missile, cette position étant déterminée par lesdits moyens d'orientation, les informations de la position angulaire étant rapportées à l'orientation de la lunette,
  • . un calculateur relié au circuit de télémétrie du missile, auxdits moyens pour mesurer la distance de la cible et auxdits moyens de mesure angulaire, ce calculateur étant capable d'une part de determiner une trajectoire du missile vers la cible à partir des informations de la distance du missile, de la distance de la cible et de la position angulaire du missile, et capable d'autre part d'élaborer des signaux de pilotage aptes à commander lesdits moyens de pilotage de façon à guider le missile sur ladite trajectoire
  • . et un circuit de commande du modulateur relié au calculateur pour moduler lesdites impulsions laser de fréquence F, suivant lesdits signaux de pilotage
  • - et un circuit de réception du faisceau laser, disposé à bord du missile et relié auxdits moyens de pilotage, ce circuit étant capable de capter lesdites impulsions laser modulées de fréquence F, et de délivrer en réponse lesdits signaux de pilotage.
  • Dans ce dispositif laser, les moyens pour mesurer la distance de la cible comportent un télémètre solidaire de la lunette de visée. Ce télémètre peut être par exemple un télémètre à laser. Dans ce cas, le dispositif comporte donc deux émetteurs laser:
  • - un premier émetteur assurant, au moyen d'un récepteur et d'un circuit de télémètrie, la télémètrie et le pointage automatique du missile, ce premier émetteur permettant aussi de transmettre au missile les signaux de pilotage
  • - et un deuxième émetteur laser assurant la télémètrie de la cible.
  • La présente invention a pour but d'apporter un perfectionnement au dispositif décrit dans le document FR-A-2 525 339, pour lui permettre d'assurer toutes les fonctions mentionnées ci-dessus à l'aide d'un seul émetteur laser.
  • La présente invention a pour objet un dispositif pour guider un missile sur une cible, du type mentionné ci-dessus, caractérisé en ce que, ledit faisceau étant un premier faisceau,
  • - ledit modulateur est agencé, en outre, à délivrer un deuxième faisceau laser formé d'impulsions laser de fréquence F2 différente de F,
  • - et les moyens pour mesurer la distance de la cible comportent
  • . un reflecteur fixé sur la lunette de visée pour diriger le deuxième faisceau vers la cible
  • . et un système de réception des impulsions du deuxième faisceau renvoyées par la cible, ce système étant fixé sur la lunette de visée et relié au calculateur, ce système étant capable de mesurer l'intervalle de temps entre l'émission d'une impulsion laser de fréquence F2 et son retour sur le poste de guidage après renvoi par la cible, cet intervalle de temps étant représentatif de la distance de la cible.
  • Plusieurs formes particulières d'exécution de l'objet de la présente invention sont décrites ci-dessous, à titre d'exemple, en référence aux dessins annexés, dans lesquels
  • - la figure 1 représente schématiquement un mode de réalisation du dispositif selon l'invention,
  • - la figure 2 est une vue partielle du dispositif, montrant un exemple préféré de réalisation du modulateur faisant partie du dispositif illustré sur la figure 1,
  • - les figures 3A, 3B, 3C et 3D sont des diagrammes de signaux illustrant le fonctionnement d'un dispositif réalisé selon les figures 1 et 2,
  • - la figure 4 est une vue partielle du dispositif, montrant une variante de réalisation du modulateur faisant partie du dispositif illustré par la figure 1
  • - et les figures 5A, 5B et 5C sont des diagrammes de signaux illustrant le fonctionnement d'un dispositif réalisé selon les figures 1 et 4.
Document FR-A-2 525 339 discloses a laser device for guiding a missile at a target, the missile being launched towards the target and comprising piloting means for modifying the direction of its movement. This device is of a type comprising
  • - a guidance station including
  • . an automatic missile pointing system, comprising
  • + a generator of a laser beam, comprising a laser radiation emitter of frequency F 1 ′ this generator being provided with means for orienting the beam towards the missile, the latter returning part of the energy of the beam in the opposite direction ,
  • + a variometric system provided with an electro-optical receiver arranged to receive said part of returned energy, the receiver being able to deliver in response a deviation measurement signal representative of the angular difference between the position of the missile and the axis beam + and a servo circuit capable of controlling the beam orientation means so as to reduce the angular deviation, means for measuring the distance of the missile, these means comprising
  • + a modulator forming part of said generator, this modulator being able to receive the laser radiation delivered by the transmitter and to deliver in response laser pulses of frequency F i
  • + and a missile telemetry circuit, connected to the modulator and to the electro-optical receiver output, to measure the time interval between the emission of a laser pulse of frequency F, and its return to the receiver after return by the missile, this time interval being representative of the distance of the missile,
  • . means for measuring the distance from the target,
  • . a telescopic sight aimed at the target,
  • . angular measurement means for delivering information on the angular position of the missile, this position being determined by said orientation means, the information on the angular position being related to the orientation of the telescope,
  • . a computer connected to the telemetry circuit of the missile, to said means for measuring the distance from the target and to said angular measurement means, this computer being capable on the one hand of determining a trajectory of the missile towards the target from information on the distance of the missile, the distance from the target and the angular position of the missile, and capable, on the other hand, of developing piloting signals capable of controlling said piloting means so as to guide the missile on said trajectory
  • . and a modulator control circuit connected to the computer for modulating said laser pulses of frequency F, according to said control signals
  • - And a laser beam reception circuit, placed on board the missile and connected to said control means, this circuit being capable of picking up said modulated laser pulses of frequency F, and of delivering said control signals in response.
  • In this laser device, the means for measuring the distance from the target include a rangefinder secured to the telescopic sight. This rangefinder may for example be a laser rangefinder. In this case, the device therefore comprises two laser transmitters:
  • a first transmitter ensuring, by means of a receiver and a telemetry circuit, the telemetry and the automatic pointing of the missile, this first transmitter also making it possible to transmit the piloting signals to the missile
  • - and a second laser transmitter ensuring the telemetry of the target.
  • The present invention aims to provide an improvement to the device described in document FR-A-2 525 339, to enable it to perform all the functions mentioned above using a single laser transmitter.
  • The subject of the present invention is a device for guiding a missile at a target, of the type mentioned above, characterized in that, said beam being a first beam,
  • said modulator is further arranged to deliver a second laser beam formed by laser pulses of frequency F 2 different from F,
  • - and the means for measuring the distance from the target include
  • . a reflector fixed on the telescopic sight to direct the second beam towards the target
  • . and a system for receiving the pulses of the second beam returned by the target, this system being fixed on the telescopic sight and connected to the computer, this system being capable of measuring the time interval between the emission of a laser pulse of frequency F 2 and its return to the guidance station after return by the target, this time interval being representative of the distance from the target.
  • Several particular embodiments of the object of the present invention are described below, by way of example, with reference to the accompanying drawings, in which
  • FIG. 1 schematically represents an embodiment of the device according to the invention,
  • FIG. 2 is a partial view of the device, showing a preferred embodiment of the modulator forming part of the device illustrated in FIG. 1,
  • FIGS. 3A, 3B, 3C and 3D are signal diagrams illustrating the operation of a device produced according to FIGS. 1 and 2,
  • - Figure 4 is a partial view of the device, showing an alternative embodiment of the modulator forming part of the device illustrated in Figure 1
  • - and FIGS. 5A, 5B and 5C are diagrams of signals illustrating the operation of a device produced according to FIGS. 1 and 4.

Bien entendu, les éléments semblables des dispositifs illustrés par les figures 1, 2 et 4 ont été désignés par les mêmes références.Of course, similar elements of the devices illustrated in Figures 1, 2 and 4 have been designated by the same references.

Sur la figure 1, est représenté un émetteur laser 1 à gaz carbonique émettant un faisceau 2 continu de rayonnement infrarouge de longueur d'onde 10,6 microns. Le faisceau 2 entre dans un modulateur 30 relié à un circuit de commande 29. Deux faisceaux 51 et 52 sortent du modulateur 30. Le faisceau 51 est reçu sur un miroir 3 monté en rotation, en site et en gisement, autour d'une rotule 4 fixée sur un support 23, la rotation du miroir 3 étant entraînée par des moteurs électriques tels que 5.FIG. 1 shows a carbon dioxide laser emitter 1 emitting a continuous beam 2 of infrared radiation with a wavelength of 10.6 microns. The beam 2 enters a modulator 30 connected to a control circuit 29. Two beams 51 and 52 exit from the modulator 30. The beam 51 is received on a mirror 3 mounted in rotation, in elevation and in bearing, around a ball joint 4 fixed on a support 23, the rotation of the mirror 3 being driven by electric motors such as 5.

Le miroir 3 réfléchit le faisceau 51 suivant un faisceau 6 illuminant un missile 7. Ce dernier, de préférence équipé à l'arrière de rétroréflecteurs tels que 8, renvoie en sens inverse un faisceau 9 de rayonnement laser vers le miroir 3. Le faisceau 9 est réfléchi par le miroir 3 suivant un faisceau 10, réfléchi lui-même par un miroir de renvoi 11 suivant un faisceau 12 vers un système de réception écartométrique 13. Le système 13 comporte une lentille 14 pour concentrer le faisceau 12 sur la surface sensible d'un récepteur photoélectrique à quatre quadrants 15.The mirror 3 reflects the beam 51 along a beam 6 illuminating a missile 7. The latter, preferably equipped at the rear with retroreflectors such as 8, returns in a reverse direction a beam 9 of laser radiation towards the mirror 3. The beam 9 is reflected by the mirror 3 in a beam 10, itself reflected by a deflecting mirror 11 in a beam 12 towards a variometric reception system 13. The system 13 comprises a lens 14 for concentrating the beam 12 on the sensitive surface d a four-quadrant photoelectric receiver 15.

Le miroir 3 est un miroir adaptatif dont la surface réfléchissante 16 est déformable sous l'action d'une pluralité de transducteurs piézoélectriques tels que 17. Chaque transducteur 17 comporte deux électrodes qui sont reliées à un circuit électrique de polarisation 18 par des connexions telles que 19.The mirror 3 is an adaptive mirror, the reflecting surface 16 of which is deformable under the action of a plurality of piezoelectric transducers such as 17. Each transducer 17 comprises two electrodes which are connected to an electrical bias circuit 18 by connections such as 19.

Un circuit d'asservissement 20 est relié aux moteurs 5.A control circuit 20 is connected to the motors 5.

Un circuit de télémétrie 21 est relié au circuit 29 et à une sortie électrique 37 du récepteur 15.A telemetry circuit 21 is connected to circuit 29 and to an electrical output 37 of the receiver 15.

Une lunette de visée 22 orientable est montée sur un socle 24 autour d'une rotule 25.An adjustable telescopic sight 22 is mounted on a base 24 around a ball joint 25.

Le faisceau 52 sortant du modulateur 30 est renvoyé suivant un faisceau 53, par un miroir 54 fixé sur la lunette 22, vers une cible 55 telle qu'un char. Un système de réception télémétrique 56 fixé sur la lunette 22 reçoit suivant un axe de réception 57 une partie de l'énergie laser du faisceau 53 renvoyée par la cible 55. L'axe de réception 57 est parallèle à l'axe optique 34 de la lunette 22.The beam 52 leaving the modulator 30 is returned along a beam 53, by a mirror 54 fixed on the telescope 22, to a target 55 such as a tank. A telemetric reception system 56 fixed to the telescope 22 receives along a reception axis 57 part of the laser energy of the beam 53 returned by the target 55. The reception axis 57 is parallel to the optical axis 34 of the bezel 22.

Un système de mesure angulaire 27 détermine l'orientation du miroir 3 par rapport à celle de la lunette 22.An angular measurement system 27 determines the orientation of the mirror 3 relative to that of the telescope 22.

Un calculateur 28 comporte cinq entrées 39, 60, 38, 41, 40 reliées respectivement au circuit 21, à la sortie 37 du récepteur 15, à une autre sortie 36 du récepteur 15, au système 27 et au circuit 56.A computer 28 has five inputs 39, 60, 38, 41, 40 respectively connected to circuit 21, to output 37 of receiver 15, to another output 36 of receiver 15, to system 27 and to circuit 56.

Le calculateur 28 comporte trois sorties 61, 62 et 63 reliées respectivement au circuit 18, au circuit 20 et au circuit 29.The computer 28 has three outputs 61, 62 and 63 connected respectively to circuit 18, circuit 20 and circuit 29.

Le missile 7 est équipé d'un circuit de réception comprenant un détecteur photoélectrique 31 disposé à l'arrière du missile, la sortie électrique du détecteur 31 étant connectée à l'entrée d'un circuit de traitement 32. La sortie du circuit 32 est reliée à un organe de pilotagé 33 capable de provoquer une modification de la direction du missile. Le missile 7 comporte en outre une charge explosive 58 à proximité de laquelle est dispose un système 59 capable de déclencher l'explosion de la charge 58 au moment de l'impact du missile sur la cible.The missile 7 is equipped with a reception circuit comprising a photoelectric detector 31 disposed at the rear of the missile, the electrical output of the detector 31 being connected to the input of a processing circuit 32. The output of the circuit 32 is connected to a piloting member 33 capable of causing a change in the direction of the missile. The missile 7 furthermore comprises an explosive charge 58 near which there is a system 59 capable of triggering the explosion of the charge 58 at the time of the impact of the missile on the target.

Comme indiqué sur la figure 1, les éléments référencés de 1 à 5, de 10 à 30 de 38 à 41, 56 et de 60 à 63 sont rassemblés dans un poste de guidage 35 qui peut être situé à terre ou sur un véhicule militaire.As indicated in FIG. 1, the elements referenced from 1 to 5, from 10 to 30 from 38 to 41, 56 and from 60 to 63 are gathered in a guide station 35 which can be located on the ground or on a military vehicle.

Le missile 7 est lancé vers une cible mobile à détruire illustrée sur la figure 1 par le char adverse 55.The missile 7 is launched towards a mobile target to be destroyed illustrated in FIG. 1 by the opposing tank 55.

Le faisceau laser d'émission 6 est orienté vers le missile 7 à l'aide d'un dispositif d'acquisition non représenté.The emission laser beam 6 is oriented towards the missile 7 using an acquisition device not shown.

Le faisceau 9 renvoyé par les rétroréflecteurs 8 fixés sur le missile est, après réflexion sur le miroir mobile 3 et le miroir fixe 11, concentré par la lentille 14 sur le récepteur 15 à quatre quadrants. Sur la sortie électrique 37 du récepteur 15 est délivré un signal représentatif de l'intensité du rayonnement laser renvoyé par le missile. Sur la sortie écartométrique 36 du récepteur 15 est délivré un signal représentatif de l'écart angulaire entre la position du missile et l'axe du faisceau laser.The beam 9 returned by the retroreflectors 8 fixed on the missile is, after reflection on the movable mirror 3 and the fixed mirror 11, concentrated by the lens 14 on the receiver 15 with four quadrants. On the electrical output 37 of the receiver 15 is delivered a signal representative of the intensity of the laser radiation returned by the missile. On the deviation output 36 of the receiver 15 is delivered a signal representative of the angular deviation between the position of the missile and the axis of the laser beam.

Le signal écartométrique est envoyé au calculateur 28 qui peut ainsi calculer la direction du missile compte tenu de l'orientation du miroir 3 et délivrer l'information correspondante au circuit 20.The deviation signal is sent to the computer 28 which can thus calculate the direction of the missile taking into account the orientation of the mirror 3 and deliver the information corresponding to the circuit 20.

Celui-ci commande, par l'intermédiaire des moteurs 5, la rotation du miroir 3 autour de la rotule 4 de façon à diminuer l'écart angulaire. On réalise ainsi un pointage automatique du missile 7.This controls, by means of the motors 5, the rotation of the mirror 3 around the ball joint 4 so as to reduce the angular difference. An automatic pointing of the missile 7 is thus carried out.

Par ailleurs, la sortie électrique 37 est reliée à l'entrée 60 du calculateur 28 qui élabore des ordres pour polariser les électrodes des transducteurs 17 du miroir adaptatif 3. II en resulte une déformation de la surface réfléchissante 16 du miroir 3, cette déformation tendant à augmenter la concentration du faisceau laser 6 sur le missile 7. On augmente ainsi l'amplitude du signal électrique délivré sur la sortie 37 du récepteur 15.Furthermore, the electrical output 37 is connected to the input 60 of the computer 28 which develops orders for polarizing the electrodes of the transducers 17 of the adaptive mirror 3. This results in a deformation of the reflecting surface 16 of the mirror 3, this deformation tending increasing the concentration of the laser beam 6 on the missile 7. The amplitude of the electrical signal delivered on the output 37 of the receiver 15 is thus increased.

Un mode de réalisation 30A du modulateur 30 est représenté sur la figure 2. II comporte un cristal 64 à effet BRAGG disposé sur le trajet du faisceau 2 émis par l'émetteur laser 1. Contre le cristal 64 sont appliquées les sorties mécaniques de deux transducteurs électromécaniques piézoélectriques 65 et 66. Deux circuits à bascule 67 et 68 sont reliés au circuit de commande 29 du modulateur et respectivement aux entrées électriques des transducteurs 65 et 66. Les circuits à bascule 67 et 68 comportent chacun une entrée, et ces entrées sont reliées à la sortie d'un générateur de courant 69 de fréquence acoustique f2.An embodiment 30A of the modulator 30 is shown in FIG. 2. It comprises a crystal 64 with BRAGG effect arranged on the path of the beam 2 emitted by the laser emitter 1. Against the crystal 64 are applied the mechanical outputs of two transducers electromechanical piezoelectric 65 and 66. Two rocker circuits 67 and 68 are connected to the control circuit 29 of the modulator and respectively to the electrical inputs of transducers 65 and 66. The rocker circuits 67 and 68 each have an input, and these inputs are connected at the output of a current generator 69 of acoustic frequency f 2 .

Le modulateur 30A représenté sur la figure 2 fonctionne de la manière suivante.The modulator 30A shown in Figure 2 operates as follows.

Les circuits à bascule 67 et 68, identiques entre eux, ont chacun deux positions d'équilibre stable. Dans une première position d'équilibre du circuit 67 (ou 68), l'entrée électrique du transducteur 65 (ou 66) n'est pas reliée à la sortie du générateur 69 ; dans la deuxième position d'équilibre du circuit 67 (ou 68), l'entrée électrique du transducteur 65 (ou 66) est reliée à la sortie du générateur 69.Toggle circuits 67 and 68, identical to each other, each have two positions of stable equilibrium. In a first equilibrium position of the circuit 67 (or 68), the electrical input of the transducer 65 (or 66) is not connected to the output of the generator 69; in the second equilibrium position of the circuit 67 (or 68), the electrical input of the transducer 65 (or 66) is connected to the output of the generator 69.

Le circuit de commande 29 du modulateur 30A permet de commuter séquentiellement les deux circuits à bascule sur leurs positions d'équilibre.The control circuit 29 of the modulator 30A makes it possible to switch the two rocker circuits sequentially to their equilibrium positions.

Lorsque les deux circuits à bascule sont sur leur première position d'équilibre stable, les transducteurs 65 et 66 ne sont pas alimentés par le générateur 69 et le faisceau laser 2 émis par l'émetteur 1 est réfracté normalement dans le cristal et sort de celui-ci suivant le faisceau 51. Dans le cas montré sur la figure 2 où les faces d'entrée et de sortie du cristal sont parallèles entre elles, le faisceau 51 sort parallèlement au faisceau 2. Bien entendu la fréquence du rayonnement du faisceau 51 est égale à la fréquence F, du rayonnement du faisceau 2.When the two rocker circuits are in their first stable equilibrium position, the transducers 65 and 66 are not supplied by the generator 69 and the laser beam 2 emitted by the emitter 1 is refracted normally in the crystal and leaves it -this according to the beam 51. In the case shown in FIG. 2 where the entry and exit faces of the crystal are parallel to each other, the beam 51 leaves parallel to the beam 2. Of course the frequency of the radiation of the beam 51 is equal to the frequency F, of the radiation of the beam 2.

Lorsque seulement un des deux circuits à bascule est sur sa première position d'équilibre et que l'autre est sur sa deuxième position d'équilibre, un des transducteurs est alimenté par le générateur 69 à la fréquence acoustique f2. Il en résulte la formation d'ondes acoustiques dans le cristal 64, ce qui provoque une déviation, avec changement de fréquence, du faisceau réfracté. Celui-ci sort du cristal suivant un faisceau 70 (ou 71), lorsque les transducteurs 65 (ou 66) sont alimentés. Ces faisceaux 70 et 71 sont déviés par rapport au faisceau 51 d'un angle qui dépend de la fréquence acoustique f2. En pratique ces faisceaux 70 et 71 ne sont pas utilisés pour le fonctionnement du dispositif et on dispose par exemple sur leur trajet un matériau absorbant 72.When only one of the two rocking circuits is in its first equilibrium position and the other is in its second equilibrium position, one of the transducers is supplied by the generator 69 at the acoustic frequency f 2 . This results in the formation of acoustic waves in the crystal 64, which causes a deflection, with frequency change, of the refracted beam. This leaves the crystal in a beam 70 (or 71), when the transducers 65 (or 66) are supplied. These beams 70 and 71 are deflected with respect to the beam 51 by an angle which depends on the acoustic frequency f 2 . In practice, these bundles 70 and 71 are not used for the operation of the device and, for example, an absorbent material 72 is placed on their path.

Lorsque les deux circuits à bascule sont sur leur deuxième position d'équilibre stable, les transducteurs 65 et 66 sont tous les deux alimentés par le générateur 69. Ces transducteurs sont disposés sur la surface du cristal de façon que les ondes acoustiques qu'ils émettent dans le cristal provoquent la formation d'un faisceau de sortie 52 parallèle au faisceau 51 mais différent de celui-ci. La fréquence F2 du rayonnement du faisceau 52 est décalée par rapport à la fréquence F, du faisceau 51 de la valeur f2 de la fréquence acoustique émise par le générateur 69. On a par exemple.When the two rocker circuits are in their second stable equilibrium position, the transducers 65 and 66 are both powered by the generator 69. These transducers are arranged on the surface of the crystal so that the acoustic waves which they emit in the crystal cause the formation of an output beam 52 parallel to the beam 51 but different from the latter. The frequency F 2 of the radiation of the beam 52 is offset with respect to the frequency F, of the beam 51 of the value f 2 of the acoustic frequency emitted by the generator 69. We have for example.

Figure imgb0001
Figure imgb0001

La modulation du faisceau continu 2 émis par l'émetteur laser 1 s'effectue en provoquant, par le circuit de commande 29, une commutation séquentielle des deux circuits à bascule 67 et 68 sur leurs positions d'équilibre stable.The modulation of the continuous beam 2 emitted by the laser transmitter 1 is effected by causing, by the control circuit 29, a sequential switching of the two flip-flop circuits 67 and 68 to their positions of stable equilibrium.

C'est ainsi par exemple que, le circuit à bascule 67 restant sur sa première position d'équilibre, le circuit de commande 29 provoque une commutation alternative du circuit 68 sur sa première et deuxième positions d'équilibre, à un rythme qui permet de découper dans le faisceau laser continu des impulsions de courte durée, de manière que le faisceau 51 soit formé d'une suite d'impulsions.Thus, for example, the rocker circuit 67 remaining in its first equilibrium position, the control circuit 29 causes alternating switching of the circuit 68 to its first and second equilibrium positions, at a rate which makes it possible to cutting short pulses from the continuous laser beam, so that the beam 51 is formed of a series of pulses.

En référence de nouveau à la figure 1, ces impulsions sont envoyées vers le missile 7, après réflexion sur le miroir 3 suivant le faisceau 6. Les impulsions sont renvoyées par le missile et captées par le récepteur 15 qui délivre un signal de retour sur sa sortie 37 reliée au circuit 21. Celui-ci possède une horloge pour mesurer l'intervalle de temps qui s'écoule entre l'émission d'une impulsion laser vers le missile et sa réception sur le récepteur 15. Le circuit de télémétrie 21 délivre donc à sa sortie l'information de la distance du missile.Referring again to FIG. 1, these pulses are sent to the missile 7, after reflection on the mirror 3 along the beam 6. The pulses are returned by the missile and received by the receiver 15 which delivers a return signal on its output 37 connected to circuit 21. The latter has a clock for measuring the time interval which elapses between the emission of a laser pulse towards the missile and its reception on the receiver 15. The telemetry circuit 21 delivers therefore when it leaves the missile distance information.

La commutation séquentielle des circuits à bascules 67 et 68 peut comporter également, le circuit 68 par exemple restant sur sa deuxième position d'équilibre, une commutation alternative du circuit 67 sur sa première et sa deuxième position d'équilibre. Cette commutation alternative permet de découper dans le faisceau laser continu des impulsions de courte durée, de manière que le faisceau 52 soit formé aussi d'une suite d'impulsions (voir figure 2).The sequential switching of the flip-flop circuits 67 and 68 may also include, the circuit 68 for example remaining in its second equilibrium position, an alternating switching of the circuit 67 to its first and its second equilibrium position. This alternative switching makes it possible to cut out pulses of short duration from the continuous laser beam, so that the beam 52 is also formed of a series of pulses (see FIG. 2).

Le faisceau 52 est réfléchi par le miroir 54 suivant un faisceau 53. L'opérateur oriente la lunette de visée 22 vers la cible et, en même temps, dirige le faisceau 53, parallèlement à l'axe 34 de la lunette, également vers le cible.The beam 52 is reflected by the mirror 54 in a beam 53. The operator directs the telescopic sight 22 towards the target and, at the same time, directs the beam 53, parallel to the axis 34 of the telescopic sight, also towards the target.

Le cible 55 renvoie vers le circuit de réception 56, analogue au circuit 21, une partie de l'énergie des impulsions du faisceau 53 et le circuit 56 délivre, aux moments désirés et à intervalles de temps réguliers, l'information de la distance de la cible.The target 55 sends back to the reception circuit 56, similar to the circuit 21, part of the energy of the pulses of the beam 53 and the circuit 56 delivers, at the desired times and at regular time intervals, the information of the distance from target.

Le système de mesure 27, de type connu, délivre à sa sortie deux informations définissant la position angulaire du missile par rapport à un trièdre de référence lié à la lunette orientable 22.The measurement system 27, of known type, delivers at its output two pieces of information defining the angular position of the missile relative to a reference trihedron linked to the orientable telescope 22.

Le calculateur 28 reçoit sur ses entrées 39 et 40 les informations des distances respectives du poste 35 au missile et à la cible, et sur son entrée 41, les deux informations définissant la position angulaire du missile. Le calculateur 28 est capable de déterminer à partir de ces deux informations l'angle que fait la direction du missile avec celle de la cible.The computer 28 receives on its inputs 39 and 40 the information of the respective distances from the station 35 to the missile and to the target, and on its input 41, the two information defining the angular position of the missile. The computer 28 is capable of determining from these two pieces of information the angle which the direction of the missile makes with that of the target.

Le calculateur 28 a donc tous les éléments pour résoudre le triangle formé par les points qui correspondent respectivement au poste 35, au missile 7 et à la cible. Ce calculateur est capable de déterminer une trajectoire du missile, partant de sa position actuelle et aboutissant à la cible. De préférence, cette trajectoire est déterminée de façon que le faisceau laser reste au dessus de la cible, puis revienne vers celle-ci seulement à la fin du parcours. De cette manière, le poste de guidage est difficilement détectable par l'adversaire.The computer 28 therefore has all the elements for solving the triangle formed by the points which correspond respectively to station 35, missile 7 and the target. This computer is capable of determining a trajectory of the missile, starting from its current position and ending at the target. Preferably, this trajectory is determined so that the laser beam remains above the target, then returns to it only at the end of the journey. In this way, the guidance station is difficult to detect by the opponent.

Le calculateur 28 est capable en outre d'élaborer des signaux de pilotage capable de commander le réglage des organes 33 du missile 7, de façon à guider le missile sur la trajectoire déterminée.The computer 28 is also capable to develop piloting signals capable of controlling the adjustment of the organs 33 of the missile 7, so as to guide the missile on the determined trajectory.

Ces signaux de pilotage sont transmis au circuit de commande 29 du modulateur 30A afin de provoquer une modulation, suivant ces signaux de pilotage, de la suite d'impulsions laser du faisceau 51. Cette suite d'impulsion est modulée en position, la modulation consistant à décaler l'instant d'émission des impulsions successives.These control signals are transmitted to the control circuit 29 of the modulator 30A in order to cause a modulation, according to these control signals, of the series of laser pulses of the beam 51. This pulse sequence is modulated in position, the modulation consisting to offset the instant of emission of the successive pulses.

Les figures 3A, 3B, 3C et 3D sont des diagrammes établis pour une commutation séquentielle donnée des circuits à bascules 67 et 68.FIGS. 3A, 3B, 3C and 3D are diagrams established for a given sequential switching of the flip-flop circuits 67 and 68.

La figure 3A montre, en fonction du temps, l'amplitude A51 de l'énergie du faisceau 51, lorsque, le circuit 67 restant sur sa première position d'équilibre, on provoque une commutation alternative du circuit 68 sur ses deux positions. Cette commutation est effectuée de façon à obtenir une suite d'impulsions de courte durée, ces impulsions étant modulées en position, c'est-à-dire décalées dans le temps suivant les signaux de pilotage élaborés par le calculateur.FIG. 3A shows, as a function of time, the amplitude A 51 of the energy of the beam 51, when, the circuit 67 remaining in its first equilibrium position, an alternating switching of the circuit 68 is caused to its two positions. This switching is carried out so as to obtain a series of short duration pulses, these pulses being modulated in position, that is to say shifted in time according to the control signals produced by the computer.

La figure 3B montre en fonction du temps l'amplitude A52 de l'énergie du faisceau 52 lorsque, le circuit 68 restant sur sa deuxième position d'équilibre, le circuit 67 est commuté alternativement sur ses deux positions. Cette commutation est effectuée de façon à obtenir une suite d'impulsions de courte durée disposées entre les impulsions successives du faisceau 51.FIG. 3B shows as a function of time the amplitude A 52 of the energy of the beam 52 when, the circuit 68 remaining in its second equilibrium position, the circuit 67 is switched alternately to its two positions. This switching is carried out so as to obtain a series of short duration pulses arranged between the successive pulses of the beam 51.

Enfin les figures 3C et 3D montrent en fonction du temps la fréquence acoustique du courant d'alimentation des transducteurs 66 et 65. On voit sur ces deux derniers diagrammes que la fréquence f2 du courant délivré par le générateur 69 varie en fonction du temps, lorsque ce courant est appliqué à l'entrée du transducteur 65. Cette variation s'effectue suivant une rampe de montée suivie d'une rampe de descente; ces rampes sont linéaires et de même durée, et leurs pentes sont égales et de signe opposés. La variation de la fréquence f2 permet d'incorporer dans le circuit de réception 56 des moyens pour mesurer la vitesse de la cible par effet Doppler. Grâce à la forme en rampes symétriques de cette variation de fréquence, il est possible de comprimer la durée des impulsions à la réception suivant une technique connue, ce qui améliore les performances de la télémétrie et de la mesure de vitesse de la cible.Finally, FIGS. 3C and 3D show as a function of time the acoustic frequency of the supply current of the transducers 66 and 65. It can be seen in these last two diagrams that the frequency f 2 of the current delivered by the generator 69 varies as a function of time, when this current is applied to the input of the transducer 65. This variation takes place along an upward ramp followed by a downward ramp; these ramps are linear and of the same duration, and their slopes are equal and of opposite sign. The variation of the frequency f 2 makes it possible to incorporate in the reception circuit 56 means for measuring the speed of the target by Doppler effect. Thanks to the symmetrical ramp shape of this frequency variation, it is possible to compress the duration of the pulses at reception using a known technique, which improves the performance of telemetry and speed measurement of the target.

Le faisceau 51 est envoyé sur le missile par réflexion sur le miroir 3, suivant le faisceau 6. Le récepteur 31 du missile capte la suite d'impulsions modulées en position portées par le faisceau 6, et le circuit de traitement 32 délivre à sa sortie les signaux de pilotage qui sont transmis à l'organe de pilotage 33, de façon à guider progressivement le missile vers la cible.The beam 51 is sent to the missile by reflection on the mirror 3, along the beam 6. The receiver 31 of the missile picks up the series of pulses modulated in position carried by the beam 6, and the processing circuit 32 delivers at its output the piloting signals which are transmitted to the piloting member 33, so as to progressively guide the missile towards the target.

Le dispositif décrit ci-dessus en référence aux figures 1 et 2 est donc capable de guider un missile sur une cible. Ce dispositif utilise un seul laser 1 à partir duquel on forme, grâce à un modulateur 30 deux faisceaux distincts (51 et 52). Le faisceau 51 permet d'assurer les fonctions d'écartométrie, de télémétrie et de transmission d'ordres au missile. Le faisceau 52 permet de mesurer la distance de la cible et éventuellement sa vitesse.The device described above with reference to Figures 1 and 2 is therefore capable of guiding a missile at a target. This device uses a single laser 1 from which, thanks to a modulator 30, two separate beams (51 and 52) are formed. The beam 51 makes it possible to perform the functions of deviation measurement, telemetry and transmission of orders to the missile. The beam 52 makes it possible to measure the distance from the target and possibly its speed.

Le type 30A de modulateur représenté sur la figure 2, qui comporte deux transducteurs, présente l'avantage de former deux faisceaux (51 et 52) parallèles entre eux et de direction indépendante de la fréquence du générateur, ce qui facilite l'exploitation optique des faisceaux issus du modulateur.The type 30A of modulator represented in FIG. 2, which comprises two transducers, has the advantage of forming two beams (51 and 52) parallel to each other and of direction independent of the frequency of the generator, which facilitates the optical exploitation of the beams from the modulator.

Un autre mode de réalisation 30B du modulateur 30 est représenté sur la figure 4. Il comporte un cristal 73 à effet Bragg disposé sur le trajet du faisceau 2 émis par l'émetteur laser 1. Contre ce cristal, est appliquée la sortie mécanique d'un seul transducteur électromécanique piézoélectrique 74. Un circuit à bascule 75 est relié à l'entrée électrique du transducteur 74 et au circuit de commande 29 du modulateur. Le circuit à bascule 75 comporte deux entrées reliées respectivement à deux générateurs de courant 76 et 77 de fréquence acoustique f, et f2.Another embodiment 30B of the modulator 30 is shown in FIG. 4. It comprises a Bragg crystal 73 arranged on the path of the beam 2 emitted by the laser emitter 1. Against this crystal, the mechanical output of a single piezoelectric electromechanical transducer 74. A rocker circuit 75 is connected to the electrical input of the transducer 74 and to the control circuit 29 of the modulator. The flip-flop circuit 75 comprises two inputs connected respectively to two current generators 76 and 77 of acoustic frequency f, and f 2 .

Le circuit à bascule 75 comporte trois positions d'équilibre stable, une première position dans laquelle l'entrée électrique du transducteur 74 n'est reliée à aucun des générateurs de courant, une deuxième position dans laquelle l'entrée électrique du transducteur 74 n'est reliée qu'au générateur 76 de fréquence ft, et une troisième position dans laquelle l'entrée électrique du transducteur 74 n'est reliée qu'au générateur 77 de fréquence f2.The rocker circuit 75 comprises three positions of stable equilibrium, a first position in which the electrical input of the transducer 74 is not connected to any of the current generators, a second position in which the electrical input of the transducer 74 does not is connected only to the generator 76 of frequency f t , and a third position in which the electrical input of the transducer 74 is only connected to the generator 77 of frequency f 2 .

Le circuit de commande 29 du modulateur 30B commute séquentiellement le circuit à bascule 75 sur ses trois positions d'équilibre.The control circuit 29 of the modulator 30B sequentially switches the flip-flop circuit 75 to its three equilibrium positions.

Lorsque le circuit à bascule est sur sa première position, le rayonnement laser 2 sort du cristal suivant un faisceau 51 de fréquence FI égale à la fréquence du rayonnement émis par l'émetteur laser 1.When the rocker circuit is in its first position, the laser radiation 2 leaves the crystal in a beam 51 of frequency F I equal to the frequency of the radiation emitted by the laser transmitter 1.

Lorsque le circuit à bascule est sur sa deuxième position, le faisceau laser 78 qui sort du cristal est dévié angulairement par rapport au faisceau 51. Ce faisceau 78 n'est pas utilisé dans le fonctionnement du dispositif; il est obturé par un matériau absorbant 79.When the rocker circuit is in its second position, the laser beam 78 which leaves the crystal is deflected angularly relative to the beam 51. This beam 78 is not used in the operation of the device; it is closed by an absorbent material 79.

Lorsque le circuit à bascule 75 est sur sa troisième position d'équilibre, le faisceau laser 52 qui sort du cristal est dévié angulairement par rapport au faisceau 51 et sa fréquence estWhen the rocker circuit 75 is in its third equilibrium position, the laser beam 52 which leaves the crystal is deflected angularly with respect to the beam 51 and its frequency is

Figure imgb0002
Comme l'angle de déviation dépend de la fréquence du courant d'alimentation du transducteur et comme f, est différent de f2, les trois faisceaux 51, 78 et 52 sont distincts l'un de l'autre.
Figure imgb0002
 As the deflection angle depends on the frequency of the transducer supply current and since f is different from f 2 , the three beams 51, 78 and 52 are distinct from each other.

Lorsque le circuit 29 commute alternativement le circuit à bascule 75 entre sa première et sa deuxième positions d'équilibre, des impulsions sont formées dans le faisceau 51. Les impulsions successives ainsi formées sont décalées dans le temps de façon à effectuer une modulation en position suivant les signaux de pilotage élaborés par le calculateur. Ces impulsions sont illustrées par la figure 5A qui représente les variations en fonction du temps de l'amplitude A51 du rayonnement du faisceau 51.When circuit 29 switches alternately the flip-flop circuit 75 between its first and its second equilibrium positions, pulses are formed in the beam 51. The successive pulses thus formed are shifted in time so as to effect a modulation in position according to the control signals produced by the calculator. These pulses are illustrated in FIG. 5A which represents the variations as a function of time of the amplitude A 51 of the radiation of the beam 51.

Lorsque le circuit 29 commute alternativement le circuit à bascule 75 entre sa deuxième et troisième position d'équilibre, des impulsions sont formées dans faisceau 52. Ces impulsions sont illustrées par la figure 5B qui représente les variations en fonction du temps de l'amplitude A52 du rayonnement du faisceau 52.When the circuit 29 alternately switches the flip-flop circuit 75 between its second and third equilibrium position, pulses are formed in beam 52. These pulses are illustrated by FIG. 5B which represents the variations as a function of time of the amplitude A 52 of the beam radiation 52.

Les figures 5A, 5B et 5C concernent un exemple de commutation séquentielle du circuit à bascule, et la figure 5C montre les variations en fonction du temps de la fréquence f du courant d'alimentation du transducteur 74. Cette fréquence oscille entre la fréquence f, et la fréquencef2. Comme il est visible sur la figure 5C, la fréquencef2 varie dans le temps suivant une rampe linéaire de montée suivie d'une rampe linéaire de descente de même durée, afin de permettre la mesure de la vitesse de la cible et d'utiliser un circuit de réception 56 capable d'effectuer une compression de la durée des impulsions.FIGS. 5A, 5B and 5C relate to an example of sequential switching of the flip-flop circuit, and FIG. 5C shows the variations as a function of time of the frequency f of the supply current of the transducer 74. This frequency oscillates between the frequency f, and the frequency f2. As can be seen in FIG. 5C, the frequency f 2 varies in time along a linear ramp of ascent followed by a linear ramp of descent of the same duration, in order to allow the measurement of the speed of the target and to use a reception circuit 56 capable of compressing the duration of the pulses.

Claims (4)

1. A laser device for guiding a missile (7) to a target (55), the missile being launched towards the target and including flight controller means for modifying the direction of its movement, the laser device comprising:
- a guidance station (35) including:
. an automatic missile pointing system comprising:
+ a laser beam generator (6), including a transmitter (1) for transmitting laser radiation at a frequency ft, this generator being provided with beam pointing means (3, 5) for pointing the beam (6) towards the missile which returns a portion (9) of the beam energy in the opposite direction;
+ a deviation measuring system (13) fitted with an electro-optical receiver (15) disposed to receive the returned portion (9) of energy, the receiver being suitable for delivering a deviation measuring signal in response thereto representative of the angle of error between the position of the missile and the axis of the beam; and
+ a servo-control circuit (20) suitable for controlling the beam pointing means (6) to reduce the angle of error; means for measuring the distance of the missile, the means comprising:
+ a modulator (30) constituting a part of the generator, the modulator being suitable for receiving the laser radiation delivered by the transmitter (1) and for delivering laser pulses at the frequency F1 in response thereto; and
+ a missile telemeter circuit (21), connected to the modulator and to the output of the electro-optical receiver to measure the time interval between the transmission of a laser pulse at the frequency F1 and its return to the receiver after being reflected from the missile, this time interval being representative of the missile distance;
. means for measuring the distance of the target (55);
. an aiming sight (22) which can be pointed towards the target (55);
. angle measuring means (27) for delivering information on the angular position of the missile, this position being determined by the pointing means, the angular position information being relative to the direction in which the sight is pointed;
. a computer (28) connected to the missile telemeter circuit, to the means for measuring the distance of the target, and to the angle measuring means, this computer being capable firstly to determine a path for the missile towards the target on the basis of the information on the distance to the missile, on the distance to the target, and on the angular position of the missile, and secondly capable of generating guidance signals suitable for controlling the flight controller means to guide the missile along said path; and
. a modulator (30) control circuit (29) connected to the computer to modulate the laser pulses at the frequency F, with the guidance signals;
- and a laser beam receiver circuit disposed on board the missile and connected to the said flight controller means, the circuit being capable of receiving the modulated laser pulses at frequency F, and of delivering the piloting signals in response thereto;
characterized in that the beam (6) being a first beam (51),
- the modulator (30) is also adapted to deliver a second beam (52) at a second frequency F2 different from the frequency Fi ; and
- the means for measuring the distance to the target (55) comprise:
. a reflector (54) fixed to the aiming sight (22) to direct the second beam towards the target (55); and
. a pulse receiver system (56) for receiving pulses from the second. beam (52) as reflected by the target (55), the system being fixed to the aiming sight (22) and connected to the computer (28), and being capable of measuring the time interval between transmitting a laser pulse of frequency F2 and its return to the guidance station (35) after reflection by the target, the time interval being representative of the distance to the target (55).
2. A device according to claim 1, characterized in that
- the modulator (30B) comprises:
. a Bragg effect crystal (73) disposed on the path of the laser radiation (2) at frequency F" at the output from the laser transmitter (1);
. an electromechanical transducer (74) having a mechanical output applied against the crystal (73);
. a trigger circuit (75) connected to the modulator (30B) control circuit (29) and to the electrical input of the transducer (74), the trigger circuit having two inputs and three positions of stable equilibrium; and
. two current generators (76, 77) operating at different acoustic respective frequencies f, and f2, the generators being connected to respective ones of the inputs to the trigger circuit (75), with the electrical input of the transducer being connected to neither of the generators when the trigger circuit is in a first equilibrium position, with the electrical input of the transducer being connected solely to the current generator of the frequency f, when the trigger circuit is in its second equilibrium position, and with the electrical input of the transducer being connected solely to the current generator of the frequency f2 when the trigger circuit is in its third equilibrium position;
- and the modulator (30B) control circuit (29) being adapted to sequentially switch the trigger circuit (75) between its three equilibrium positions in such a manner that when the trigger circuit is in its first position the laser radiation leaves the crystal in a first direction and at a frequency F" when the trigger circuit is in its second position the laser radiation is deflected relative to the first direction to leave the crystal along a second direction, and when the trigger circuit is in its third position the laser radiation is deflected relative to the first direction and leaves the crystal along a third direction and the frequency F2 of said radiation differs from the frequency F, by the value f2, the laser radiation (78) deflected along the second direction being unused, the first laser beam (51) being constituted by the radiation leaving the crystal along the first direction, with the pulses of this first beam being formed therein by alternating the trigger circuit (75) between its first and its second position of equilibrium, and the second beam (52) being constituted by the radiation leaving the crystal along the third direction, with the pulses of this second beam being formed therein by alternating the triggger circuit (75) between its second and third position of equilibrium.
3. A device according to claim 1, characterized in that
- the modulator (30A) comprises:
. a Bragg effect crystal (64) disposed in the path of the laser radiation at frequency F1, at the output from the laser transmitter (1);
. two electromechanical transducers (65, 66) having their mechanical outputs applied against the crystal (64);
. two bistable circuits (67, 68) connected to the modulator control circuit (29) and to respective electrical inputs of the transducers (65, 66), each bistable circuit having an input and two positions of stable equilibrium; and
. a current generator (69) operating at an acoustic frequency f2, connected to the inputs of both bistable circuits (67, 68), with the electrical input of each transducer (65, 66) being disconnected from the current generator when the bistable circuit (67, 68) connected to these transducers (65, 66) is in a first position, and with the electrical input of each transducer being connected to the current generator when the bistable circuit connected to this transducer is in its second equilibrium position;
- and that the modulator (30A) control circuit (29) is adapted to sequentially switch the two bistable circuits (67, 68) between their equilibrium positions in such a manner that when both bistable circuits are in their first position the laser radiation leaves the crystal in a first direction and at a frequency F" when only one of the bistable circuits is in its second position and the other is in its first position the laser radiation is deflected relative to the first direction to leave the crystal along a second direction, and when both bistable circuits are in their second positions the disposition of the transducers (65, 66) on the crystal (64) is such that the laser radiation is deflected relative to the first direction and leaves the crystal along a third direction parallel to the first direction, and the frequency F2 of said radiation differs from the frequency F, by the value f2, the laser radiation (70, 71) deflected along the second direction being unused, the first beam (51) being constituted by the radiation leaving the crystal along the first direction, with the pulses being formed therein by alternating one of the bistables between its first and its second positions, while the other bistable is in its first position, and the second beam (52) being constituted by the radiation leaving the crystal along the third direction, with the pulses of this second beam being formed therein by alternating one of the bistables between its second position and its first position, while the other bistable is in its third position.
4. A device according to any one of claims 2 and 3, characterized in that the frequency f2 varies as a function of time according to a rising slope followed by a falling slope of the same duration, the slopes being linear and having the same gradient but opposite signs.
EP85101158A 1984-02-07 1985-02-05 Laser device for guiding a missile on a target Expired EP0151480B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8401842 1984-02-07
FR8401842A FR2559252B2 (en) 1984-02-07 1984-02-07 LASER DEVICE FOR GUIDING A MISSILE ON A TARGET

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EP0151480A2 EP0151480A2 (en) 1985-08-14
EP0151480A3 EP0151480A3 (en) 1985-09-11
EP0151480B1 true EP0151480B1 (en) 1988-09-21

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EP85101158A Expired EP0151480B1 (en) 1984-02-07 1985-02-05 Laser device for guiding a missile on a target

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EP (1) EP0151480B1 (en)
DE (1) DE3565177D1 (en)
FR (1) FR2559252B2 (en)

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Also Published As

Publication number Publication date
FR2559252B2 (en) 1986-12-05
US4634271A (en) 1987-01-06
DE3565177D1 (en) 1988-10-27
EP0151480A3 (en) 1985-09-11
FR2559252A2 (en) 1985-08-09
EP0151480A2 (en) 1985-08-14

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