FR2678060A1 - Method and device for selectively firing a horizontal-action weapon - Google Patents

Abstract

According to the invention, it comprises a firing circuit, an acoustic detection subassembly (36) sensitive to the acoustic vibrations generated by a target and delivering an electrical detection signal when a target comes into the vicinity of the action field of the weapon, an optical locating subassembly (37) sensitive to the infrared radiation and delivering an electrical locating signal when a target comes substantially into the firing axis of the weapon, characterized in that it furthermore comprises a control sequencer subassembly (48), equipped with a counting device (46), interposed between the detection subassembly (36) and the locating subassembly (37) on the one hand, and the firing circuit on the other hand, so as to control the firing circuit according to a predetermined firing program. WEAPON;FIRING

Description

The subject of the present invention is a method of selective firing &

  horizontal action weapon according to which an electrical detection signal is emitted when a target passes in the vicinity of the weapon's field of action, a localization signal is emitted when a target passes

  substantially in the firing axis of the weapon and the simulated emission

  The electrical detection and location signals constitute a necessary condition for the emission of an electrical control signal authorizing the control of the setting to

gun fire.

  The present invention also relates to a

  device for implementing such a method.

  A device for implementing

  such a process is described in French Patent No. 1,590,594.

  Such a device which ensures the selective firing of a weapon with horizontal action, at a distance and without mechanical contact with the target to be destroyed, comprises: a) a low-consumption standby assembly

  of energy which explores the characteristic seismic frequency band

  of the type of vehicle to be destroyed and provides an alert signal when a vehicle of this type is detected, and b) a very narrow field infrared device, which is activated when an alert signal is produced

  by the watch unit and which generates an electrical impulse

  stick when the vehicle detected on the firing axis.

  As soon as the infrared device has generated

  an electrical impulse, the ignition power circuit

tion of the primer is fed.

  Such a system, in addition to the presence of a seismic detection subset, which is relatively unselective, present, the drawback of automatically triggering the firing of the weapon as soon as

  the infrared locator has emitted an electrical signal.

  Thus, no possibility of predetermined inhibition of the system

  is not possible, and taking into account additional information

  There are no plans to conceal the authorization to authorize the firing. According to an unpublished French patent application, No. O of P V 129 804, a system intended to ensure the selective firing of a weapon with horizontal action, from a distance and without

  mechanical contact with the target to be destroyed, includes a sub-

  acoustic type selection set, which calls for the harmonic analysis of the acoustic spectrum generated by a

  vehicle and a location device, of the infrared type.

  In such a system, the acoustic selection sub-assembly emits an electrical signal which triggers the start-up

  the infrared locator, which locator emits a pulse

  electric soot during the passage of the vehicle detected on the firing axis As in the case of the device which is the subject of French patent No. 1,590,594, the firing of the weapon is triggered automatically

  as soon as an electrical impulse emitted by the loca-

  Infrared reader Thus, the simultaneity of the presence of electrical information emitted by the selection subset

  and electrical information emitted by the locating device

  Infrared readout automatically triggers the firing of the weapon without any means being provided to predeterminedly inhibit the triggering of the weapon in the event that, despite the simultaneous presence of information from the subset of detection and information sent by the location device, certain additional conditions

  are not met.

  v The present invention specifically aims to remedy the aforementioned drawbacks and to allow for the taking into account of a certain number of additional conditions to authorize the initiation of the firing of the weapon, and in particular to delay the firing of the weapon of a predetermined number of

  Passage of targets in the field of action of the weapon.

  This object is achieved by a method of the type mentioned at the beginning according to which, in accordance with the invention, the very triggering of the firing of the weapon is carried out

  from the electrical control signals according to a program

  predetermined tion so that the actual firing of the weapon can be deferred by a predetermined number of signal transmissions

electric controls.

  So; unlike the known firing methods and devices, according to which the firing of the weapon occurs when the first vehicle of a column crosses the zone of action of the weapon, the method according to the invention makes it possible to postpone the firing of the weapon by a predetermined number of vehicle passages, although each of the Vehicles gives rise to the emission of a control signal when it passes within the scope of the weapon When several mines are placed one after the other in a minefield, the process according to the invention

  presents a considerable advantage insofar as a program-

  Different mation can be chosen for each of the different mines so that it is possible to let a selected number of vehicles enter the minefield before any

ignition is not carried out.

  According to a particular characteristic of the method according to the invention, an electrical safety signal is emitted when the weapon is in the "armed" position and the simultaneous emission of the electrical detection, location and safety signals constitutes a necessary condition for authorizing the command

of firing the weapon -

  According to the invention, various other additional conditions can be taken into account so that the firing control signal is only emitted when the target to be destroyed is placed in a position of

  maximum vulnerability compared to the horizontal action weapon.

  Thus, according to a particular characteristic of the invention, the control of the firing of the weapon is inhibited if the order of appearance of said electrical signals which can simultaneously authorize firing does not correspond to a

  predetermined chronological order.

  The control of the firing of the weapon can in particular be inhibited if the electrical locating signal

  appears before one of the detection or safety signals.

  It is advantageous that the electric detection signal is delivered by a device sensitive to the acoustic vibrations generated by the target, and that the electric signal

  of location is delivered by a device sensitive to the ray-

infrared.

  Preferably, the electrical locational signal

  reading is delivered by the device sensitive to infrared radiation with a delay proportional to the size of the flux

  infrared and subject to environmental temperature.

  The present invention also relates to a selective firing device for a horizontal action weapon, in particular -10 for implementing the method defined above, of the type

  including a firing circuit, -a subset of d 4 tec-

  Acoustic sensitive to the acoustic vibrations generated by a target and delivering an electrical detection signal when a target arrives in the vicinity of the field of action of the weapon, an optical localization sub-assembly sensitive to radiation

  infrared and delivering an electrical location signal when

  that a target arrives appreciably in the firing axis of the weapon, character-

  This is further characterized in that it further comprises a control sequencer sub-assembly, provided with a counting device, interposed between the detection and localization sub-assemblies on the one hand, and the

  firing circuit on the other hand, in order to control the circuit-

  firing according to a predetermined firing schedule.

  The device according to the invention preferably also includes a safety circuit delivering an electrical safety signal to the control sequencer sub-assembly when

the weapon is in position "armed.

  If the optical localization subset is itself

  -passive, the selective igniter with influence constituted by the device-

  selective firing of horizontal action weapon in accordance with the invention is completely passive and makes it possible to carry out, in a discreet and efficient manner, both a selection of vehicles, by means of acoustic sub-assembly, a location of vehicles # by means of the optical sub-assembly, and programming

  firing, by means of the counting sub-assembly.

  The authorization to fire a weapon is given by the simultaneous presence of two influence information and one armament security information, which are respectively the output signal from the acoustic detection sub-assembly, which indicates the proximity of a vehicle of the type to be destroyed or

  neutralize, the output signal of the localization subset

  tion, which indicates the presence in the firing axis of the weapon, of the selected vehicle and the signal delivered by the safety circuit The presence of the sequencer sub-assembly of

  control, fitted with a counting device, makes it possible not to trigger

  expensive firing, in the presence of three selection, location and safety information, only for a certain

  predetermined number of vehicles selected, passing successively

  vement in the firing axis of the horizontal action weapon.

  According to a particular embodiment of the invention, the sequencer sub-assembly for controlling the firing of the weapon comprises an AND gate, a first input of which is connected to the output of the acoustic detection sub-assembly and, a second input is connected to the output of the location sub-assembly, and a programmable counter, connected to the output of the AND gate, the firing circuit being itself connected to the output of the counter so that a control signal from the AND gate is only transmitted by the counter to the firing circuit when the counter has received a predetermined number of

  control signals, said number corresponding to the program-

predetermined tion.

  In the case where the device according to the invention comprises a safety circuit, said AND gate comprises a

  third input connected to the safety circuit.

  According to a particular embodiment of the invention, the acoustic detection sub-assembly comprises an acoustic sensor, a preamplifier circuit, a filtering circuit and an amplifier circuit to which a comparator circuit can be added to compare the signal from the

  amplifier circuit at a predetermined amplitude threshold.

  The acoustic detection sub-assembly is

  advantageously provided with a pulse duration control circuit

  sions which only delivers an output signal if the signal from the aforementioned amplifier circuit, or from the comparator circuit,

  is present for a period greater than a predetermined time.

  An information delay circuit can be arranged at the output

  of the pulse duration control circuit.

  According to a particular embodiment of the provision

  compliant with inyentiqn, the duration control circuit

  pulse circuit includes an inverter circuit and a mono circuit

  stable arranged in parallel and to which the signal from the information delay circuit is applied, and an AND gate of which a first input is connected to the output of the inverter circuit and a second input is connected to the output of the circuit

monostable.

  The simultaneous roles of the frequency selection, amplitude comparison, pulse duration control and information delay circuits help to improve the selectivity of the acoustic detection system and reinforce

  immunity to possible spurious signals.

  The optical localization sub-assembly preferably comprises an infrared detector, an alternating current amplifier connected to the output terminals of the infrared detector

  and a threshold comparator circuit connected at the output of the amplifier

alternator current.

  The optical localization sub-assembly can have increased efficiency and precision by the addition of circuits making it possible to introduce a delay, proportional to the importance of the infrared flux and taking into account the time of

detector response.

  Thus, according to an advantageous characteristic of the present invention, a DC amplifier is connected

  at the output terminals of the infrared detector, an integrated circuit

  connected to the output of the DC amplifier and

  has an integration time-greater than the corresponding period-

  in the passage of a target in the field of sight of the

  optical localization assembly, and the output of the integrating circuit is connected to the reference input of the threshold comparator circuit. According to another embodiment, the output of the

  threshold comparator circuit is connected to a single circuit

  stable whose metastable period is determined by a circuit

  resistance-capacity, the resistive element of the resistance circuit-

  capacity being constituted by a thermosensitive component, the variation of resistance of which is directly linked to the variation of temperature and a shaping circuit is connected in

exit from the monostable circuit.

  According to yet another characteristic of the invention

  tion, so that the command to fire the weapon is inhibited if the electrical locating signal appears before one of the detection or safety signals, the optical locating sub-assembly is connected to the sub-assembly of firing control by means of a circuit comprising in series a monostable circuit and a circuit for shaping the

  leading edge of the pulse emitted by said monostable circuit.

  Other characteristics and advantages of the invention

  will appear better on reading the description which follows

  of some embodiments of the invention, given only by way of nonlimiting examples, with reference to the appended drawings in which: FIG. 1 is a block diagram of an exemplary embodiment of the acoustic detection sub-assembly included in the device according to the invention; Figure 2 is a schematic representation of an infrared detector usable in a device according to the invention; Figures 3 and 4 show the evolution of the amplitude of the signal delivered by the infrared detector of Figure 2 as a function of time, in the case where the background temperature seen by the detector is respectively high

and weak; -

  Figures 5 and 6 are block diagrams of two exemplary embodiments of the optical localization sub-assembly included in the device according to the invention;

  Figure 7 shows the operating diagram

  ment of the optical localization sub-assembly shown in Figure 6 and shows the shape of the signals at different points in the circuit of Figure 6; Figure 8 is a schematic overview of the device according to the invention; FIG. 9 illustrates the simultaneous use of several devices in accordance with the invention, each associated with a different weapon,

8 2678060

  Figures 10 to 12 show the form of signals applied to the control subassembly of the device according to the invention, in three different operating cases; FIG. 13 represents the shape of the signals applied to the control sub-assembly when the order of arrival of the signals is normalized; FIG. 14 is a block diagram of an exemplary embodiment of the localization sub-assembly, making it possible to standardize the order of arrival of the signals at the control sub-assembly according to the operating diagram of the

figure 13.

  All heavy vehicles such as armored vehicles on tracks or on wheels generate acoustic noises or vibrations during their movements due to the engine, undercarriage, etc. The harmonic analysis of the acoustic spectrum of a given vehicle highlights a number of frequencies

  characteristics for which the amplitude has a peak.

  According to the invention, the detection of vehicles to be destroyed or neutralized is carried out on the basis of the exploitation of this acoustic spectrum by means of an acoustic detection sub-assembly 36 of which an exemplary embodiment is shown.

figure 1.

  The sub-assembly 36 uses all the frequencies of the spectrum in which the characteristic frequencies generated by the vehicle to be destroyed can be situated and includes a sensor 11 which transcribes into electrical signals the sounds emitted by any vehicle using the passage zone controlled by the selective firing device Sensor 11 is weak

  energy consumption and ensures a permanent acoustic watch.

  The sensor 11 may consist of a conventional voice coil microphone having a bandwidth which includes the

  characteristic frequencies emitted by the vehicles to be destroyed.

   n generally, the sensor I 1 must be able to detect the presence of sound frequencies between 80 and 500 Hz The analog electrical signals emitted by the sensor 11 when a vehicle is detected are transmitted to a preamplifier circuit 12 The signal from the preamplifier 12 is then filtered by the circuit

  bandpass filter 13, to eliminate the frequency spectrum

  these frequencies due to unwanted noise generated by

  for example by light vehicles, aircraft, get there.

  The signal from the filter circuit 13 is then applied to the

amplifier circuit 14.

  In order to prevent a vehicle passing outside the range of the weapon from being detected, the electrical signals corresponding to noises of too low noise level are

  delivered using a comparator circuit 15 The comparator circuit

  rator 15 connected to the output of the amplifier circuit 14 delivers & its output, in the form of a logic signal, pulses only when the signal from the amplifier circuit 14 exceeds

a given threshold.

  The pulses from the comparator circuit 15 are directed to a holding circuit 16 which delivers information at its output only if the pulses from the comparator circuit 15 are present at the input of the holding circuit 16 for a time greater than one predetermined time Tl, for example a few seconds, corresponding approximately to the passage time of a land vehicle of the type to be destroyed

  in the field of action of sensor 11.

  The logic information delivered by the holding circuit 16 is simultaneously applied to an inverter circuit 117 and to a monostable circuit 18 The output of the inverter circuit 17 and the output of the monostable circuit 18 are each applied to an input of a gate Et ' 19 The set of circuits 17, 18, 19 plays a safety role and causes a slight delay in the transmission of information from circuit 16, which corresponds to the detection of sound frequencies characteristic of a vehicle type to destroy If the logic information delivered by the holding circuit 16 is "1" when a characteristic sound frequency has been detected, the AND gate 19 is provided to deliver an electrical detection signal on the subassembly 48 of control of the firing of the weapon when at its inputs are present simultaneously a logical information "O" coming from the inverter 17 and a logical information "O" coming from the monostable circuit 18, -this e last information corresponding to

  the information from circuit 16 reversed and delayed by a time t 2 of for example 2 seconds.

  Frequency selection circuits 13, amplitude comparison 15, pulse duration control 16

  and information delay 18, contribute to perfecting the selection

  activity of the system and reinforce immunity to any parasitic signals picked up by the sensor 11. In the case where for example the sensor 11 detects a parasitic acoustic vibration generated by the passage of an aircraft, the frequency of the vibration emitted can be included

  in the spectrum selected by the filter circuit 13 and the am-

  lo plitude of the vibration may be such that the corresponding electrical signal is greater than the threshold chosen for the comparator 15, but the duration of such a signal remains less than the time T 1 fixed by the variation circuit 16 (and chosen to correspond to the passage of a land vehicle) so that no information is delivered at the output of the circuit 16, and therefore at the output of the

gate AND 19.

  The monostable detection sub-assembly described above makes it possible to detect the presence of a vehicle of the type

  to destroy in the vicinity of the field of action of the weapon The command-

  of the firing of the weapon must however intervene when the vehicle is very precisely in the firing axis of the weapon, so that a subset of localization of the vehicles on the firing axis must necessarily be added to the acoustic detection sub-assembly to participate in controlling the

Firing.

  In the context of the present invention, the localization

  tion of vehicles is ensured by a static interception device using infrared detection of the signature of the vehicles themselves We know that any body other than 00 K

  emits characteristic radiation in the infrared spectrum.

  This radiation depends in particular on the emissivity (nature, color, surface condition) and on the temperature of the body which emits it. The detection of the characteristic infrared spectrum emitted by a vehicle provides a mode and entirely passive means, therefore

  undetectable, to detect the presence of a vehicle.

  Conventional infrared detection devices generally include an infrared detector intended to monitor a determined area in the field of an associated optical system and an electronic amplifier followed by a threshold comparator which must be adjusted so that when a moving target engages in the field of the optical system, an electrical signal taken at the output of the infrared detector leads to authorize the initiation of firing at the optimum instant when the target passes in the firing axis of the weapon. If the emissivity factor of the target is considered constant, the variation in infrared flux received by the infrared detector 20 (FIG. 2) is proportional to the surface of the target 1 seen by the detector 20, and to the difference of the powers10 fourth of the absolute temperatures of the bottom 200 and of the target 1. The bottom 200 is the area of terrain located in the field of view of the detector 20 and corresponds to the hatched part of FIG. 2. The detection threshold is adjusted for an average background temperature, for example 200 ° C., and must take into account the fact that the detectors capable of picking up a natural infrared gradient emitted by a moving target have,

  due to technological constraints, required mechanical constraints, and the part of the spectrum used, a certain response time or delay in establishing the electrical signal20 which they provide.

  However, difficulties appear when the bottom temperature differs greatly from the average temperature considered, and in particular when the bottom temperature is high. This appears more clearly if one refers to Figures 3 and 4, which represent the evolution of the amplitude U of the signal delivered by the detector 20 as a function of time, from the instant when the presence of the target begins to be taken into account by the detector 20, respectively in the case where the bottom temperature 200 is high and in the case where the bottom temperature is reduced In FIGS. 3 and 4, U represents the variation of the amplitude of the signal corresponding to the infrared flux due to the target 1 when the latter is fully present in the field of action of the detector 20 U represents the threshold from which the presence of the target in the field

  of action of the detector 20 gives rise to the emission of a control signal by the location sub-assembly It appears clear-

  ment in FIGS. 3 and 4 that the higher the temperature of the bottom 200, the greater the amplitude U and the more the time tos required to reach the threshold Up is reduced. Thus, in the case of FIG. 3, the threshold Us is reached very quickly s so that a control signal is emitted by the locating subassembly at the moment when the target only begins to penetrate the optical field of the detector 20, and can help trigger the firing of the weapon even before the target optimally intercepts the firing axis, so that it

  is reached only in front parts, generally not very vital.

  -In accordance with the invention, the difficulties p Z recited are mitigated by the fact that it is provided in the subset of

  localization the introduction of a delay proportional to the importance

  tance of the infrared flux and taking into account the response time

of the detector.

  According to a first embodiment of the localization sub-assembly 37, represented by FIG. 5, a detector 20 delivers a continuous electrical signal, of amplitude proportional to the perceived infrared flux which, in the absence of target in the field of action of detector 20, comes only from the bottom

  The signal from detector 20 is transmitted to an amplifier.

  DC current generator 21, the output of which is connected to an integrator circuit, 23 the integration time of which is greater than the period corresponding to the passage of a target in the field of view of the optical system The output signal from the integrator

  23 is used to bias the reference input 24 of a comparative circuit

threshold threshold 26.

  As soon as a target appears in the field of view of the optical system, the amplitude variation of the signal picked up by the detector 20 is applied to the input of the amplifier 21 and to the input of an amplifier. alternative 22 whose output

  is connected to the input 25 of the threshold comparator circuit 26.

  In this case, the assembly constituted by the continuous amplifier 21 and the integrator 23 is insensitive to the variation in amplitude of the signal from the detector 20 and the reference input 24 does not change state. circuits 21 and -23 only takes into account the slow variations in infrared flux due to slow changes in the bottom temperature, the period of which is greater & the period corresponding to the passage of a target in the field of view of the optical system On the other hand, the alternating amplifier 22 delivers an output signal on the input 25 of the co-processor 26 E, if this latter signal is found to be of an amplitude greater than the reference level of the input 24, a logic status signal "1 l appears on output

  of circuit 26 and constitutes one of the input information of the sub-control unit 48 (FIG. 8).

  According to a second embodiment of the localization sub-assembly 37, which is shown in FIG. 6, it is considered that the difference in temperatures between the bottom and the target remains substantially constant whatever the temperature 1 o of the bottom. if the target evolves within a variable temperature environment, its average temperature increases in substantially identical proportions As the average infrared flux is a function of the temperature, the delay applied to the emission

  a control signal can be directly controlled by the temperature

  rature of the environment In FIG. 6, the detector 20 is connected to the input of an alternating amplifier 22 whose output is connected to a threshold comparator circuit 26 A monostable circuit 28 is connected to the output of the comparator 26 and has a metastable period, the duration of which is determined by a circuit

  outdoor RC 27 comprising a capacity 27 a and a resistor element

  tif 27 b consisting of a heat-sensitive component, the varia-

  resistance is directly linked to the variation in temperature

  ambient temperature Thus, the duration of the metastable period is subject to ambient temperature A shaping circuit

  29 is connected to the output of the monostable circuit 28.

  Figure 7 shows the shape of the signals in different

  annents points of the localization subset of figure 6 and

  allows you to understand how it works From the moment you

  rition of a target in the field of view of the optical system, the variation in the amplitude of the infrared signal picked up by the detector 20 is transmitted in the form of a continuous electrical signal 30 to the input of the AC amplifier 22, of which

  the output signal 31 satisfies the input of the comparator circuit 26.

  If this signal has sufficient amplitude, the circuit detected

  threshold sensor 26 delivers a logic status signal "1" 32 The circuit

  cooked monostable 28 is itself connected so as to change state only in the presence of positive edge of signal 32 The output signal 33 of monostable circuit 28 has a duration function of the metastable period of circuit 28, and therefore function of the ambient temperature The trailing edge of the signal 33 is calibrated by means of a shaping circuit 29 in the form of a signal 34 which is applied to the control sub-assembly 48 of FIG. 8 and contributes to authorize the control of the firing of the weapon. A third sub-assembly is provided to deliver an additional electrical signal which contributes to authorizing the control of the firing of the weapon with the detection and localization sub-assemblies. This is a circuit ensuring the safety of , which introduces an additional delay

  fixed, determined so as to allow the stabilization of the circuits

  electronic circuits of the igniter device after switching on The control of the safety circuit can be carried out simply by means of a safety jumper which, when in place, short-circuits a capacitor tank intended to contribute to the supply in energy of the setting device

  fire The presence of the safety jumper prevents said condensation

  energy storage tank, while the removal of said jumper authorizes the charging of the tank capacitor through a resistor From the moment of arming which corresponds to the removal of the safety jumper, the load of

  reservoir capacitor is performed with a certain delay, deter-

  undermined by its capacity and the value of the resistance through which it charges At the end of this charging time, the safety circuit delivers information in the form of logic signal "1", which is applied to the control sub-assembly of firing. In the case where the device is returned to the "disarmed" position by replacing the safety jumper before the safety circuit has delivered a signal "1", that is to say before the capacitor is not fully charged, the latter discharges completely through an associated diode so that the weapon and its igniter are again neutralized The entire device according to the invention is

  represented in the form of a block diagram in FIG. 8 The acoustic detection sub-assembly '36, the localization sub-assembly

  Optical station 37 and the safety circuit 38 are each connected to an input of the control sub-assembly 48, the selected output of which 47 is connected to an igniter or switching circuit.

  fire; not shown, which triggers the firing of the weapon.

  The control sub-assembly 48 comprises an AND gate 35 with three inputs, connected respectively to the detection system

  tion 36, the locating system 37 and the security system 38. An electrical control signal is thus emitted at the output of the

  AND gate 35 whenever logic information "1" is present simultaneously on the three inputs of AND gate 35 The control signal is then applied to a counter 46 with multiple outputs

  tiples The counter 46 counts the number of pulses emitted by the AND gate 35 and each pulse delivers a signal on the output corresponding to the number of pulses then recorded by the counter Thus, the triggering of the firing of the weapon it will only intervene during the N command pulse emitted by the AND gate 35, if the N output 47 of the command sub-assembly has been selected to connect it to the weapon igniter The firing of the weapon is thus deferred by a certain number of passages of vehicles in the field of action of the weapon, said number being programmed at the time of installation of the device by the choice of the output of the control sub-assembly which must be connected to the firing circuits of the weapon In FIG. 8, the output 47 selected corresponds to the number 3 The firing

  will therefore be triggered when a signal appears on output 47, that is to say at the moment when counter 46 counts the third pulse emitted by AND gate 35.

  The igniter device according to the invention thus makes it possible to let engage a selected number of vehicles in the minefield where the igniter is placed before firing on one of them. Thus, vehicles which have already entered the minefield is not warned or warned too late of the presence of mines The destruction or immobilization of a single vehicle placed in the middle of a column can make it possible, in particular in the case of crossing a bridge, to prevent the advance of the following vehicles while prohibiting the retreat of those who have already passed through. 35 A set of mines fitted with the device according to the invention and judiciously programmed can also have maximum efficiency as shown in FIG. 9 which

  shows schematically an example of use of a set of several mines provided with an igniter according to the invention.

  In FIG. 9, the first five vehicles of a column, referenced 1 to 5, pass through an area prqtégé by five mines referenced 6, to 10, all equipped with the firing device according to the invention If the mine 6 is programmed on 5, mine-7 is programmed on 4, mine 8 is programmed on 3, mine 9 is programmed on 2, mine 10 is programmed on 1, and if the five vehicles enter the next mined zone the direction shown in Figure 9, mine 6 will destroy

  vehicle 5, mine 7 will destroy vehicle 4, mine 8

  will destroy vehicle 3, mine 9 will destroy vehicle 2 and mine

destroy the vehicle 1.

  Thus, the control sub-assembly 48 not only precisely determines the moment when a vehicle of the type to be destroyed is exactly in the axis of the firing of the weapon, from information supplied by the detection sub-assemblies, location and security, but still allows to postpone the effective firing of the weapon by a certain number

  predetermined vehicle crossings, so that the decian-

  The firing of the weapon is not automatically linked to self

  risation of control of the firing provided by the detection and localization sub-assemblies, as in the case of known devices. According to the invention, the selectivity of the firing device can be further improved by the fact that the order

  chronological appearance of electrical signals that can auto-

  riser ignition is taken into account in the emission of the signal

door 35.

  It is for example interesting that the firing is inhibited when a demining operation, by explosives, for example,

  lying in the line of sight is effective.

  Figures 10 to 12 illustrate three possibilities of operation of a device according to the invention in which the chronological order of arrival of the electrical information 41, 42, 43 respectively from the safety sub-assembly 38 #

  of the detection sub-assembly 36 and of the localization sub-assembly

  tion 37 is not taken into account for the emission of a signal

control via ET gate 35.

  FIG. 10 illustrates the case of normal operation of the electrical signal 43 coming from the location sub-assembly

  infrared is applied last to the AND gate 35 and authorizes at the instant t O the emission of a control signal at the output of the AND gate 5.

  The figure It illustrates the case of a mine clearance by explosives carried out in the firing axis of the weapon In this case, the noise is

   u with a delay time relative to the lightning, so that it is the signal 42 delivered by the detection sub-assembly 36 which is applied the

  at the AND gate 35 and authorizes at the instant t the emission of a control signal at the output of the AND gate 35.

  FIG. 12 illustrates the case where the vehicle to be destroyed or neutralized evolves with a strong head wind, so that the noise generated by the movement of the vehicle propagates along an eccentric lobe towards the rear of the vehicle. is the signal 42 coming from the detection sub-assembly 36, which, generated last

  is applied last to the AND gate 35 and authorizes at the instant tc the emission of a control signal by the AND gate 35 At this instant, the vehicle may have crossed the firing axis of the weapon , et20 triggering the firing of the weapon may prove to be ineffective.

  To avoid inadvertent firing of the weapon when a vehicle is not definitely present on the axis

  firing the weapon (in the case of FIGS. 11 and 12), in accordance with the invention, the order of arrival of the information necessary to satisfy the AND gate 35 is standardized.

  This can be achieved for example by means of a circuit such as that shown in FIG. 14 In FIG. 14, we can see a localization sub-assembly 37 as described above - with reference to FIG. 5 at the outlet of which are connected30 in series a monostable circuit 39 to temporarily store the signal from the comparator circuit 26 and a circuit 40 for shaping the front edge of the signal emitted by the mono-, stable circuit 39 The circuits 39 and 40 could naturally be

  * connected to the output of a localization sub-assembly 37 pre-

* feeling a completely different configuration than that shown in FIG. 5, and which can for example be in accordance with the diagram of

  FIG. 6 -The output of circuit 40 is connected to the input of AND gate 35 corresponding to the location sub-assembly 37.

  FIG. 13 illustrates the operation of the selective firing device in which the order of arrears of the firing control authorization information is

  normalized, for example using the circuit of FIG. 14.

  When a signal 43 corresponding to the presence of a target in the field of view of the optical device is emitted at time t 'by the localization subassembly itself, that is to say in FIG. 14 in output of comparator 26, this signal 43 is stored in memory by the monostable circuit 39 for a time T 2,

  which can be of the order of 20 seconds, corresponding to the.

  metastable period of circuit 39 The signal 45 from monostable circuit 39 is shaped on its front edge by circuit 40, so that 4 at the output of circuit-40 j it is delivered to the corresponding input of gate AND 35 a pulse 45 which does not authorize the emission of a control signal by the AND gate

  that if security information 41 and security information

  tection 42 are already present on the corresponding inputs of the AND gate 35 If this is not the case, as in FIG. 13, the control of the weapon is inhibited during the time T 2, so that during the appearance at time t "(such as t" -t 'T 2) of the signal 42 coming from the detection sub-assembly 36, the AND gate 35 does not emit any signal The weapon remains however potential, and if, when the time inhibition T 2 has elapsed, a signal 43 coming from the localization sub-assembly 37 is emitted while the signals 41 and-42 coming respectively from the safety circuit and from the detection sub-assembly 36 are present on the corresponding inputs AND gate 35, the latter will deliver

  at the output a control signal which will increment the counter 46.

  Of course, various additions and modifications may be made by those skilled in the art to the methods and devices which have just been described, only by way of non-limiting examples, without departing from the protective framework.

  defined by the appended claims.

19 2678060

  RE v ENDI, CATIONS 1 Method for selective firing of a horizontal action weapon according to which an electric detection signal is emitted when a target passes near the field of action of the weapon, a signal of localization - is emitted during the passage of a target substantially in the firing axis of the weapon and the simultaneous emission - of the electrical detection and localization signals constitutes a necessary condition for the emission of an electrical signal of control authorizing the control of the firing of the weapon, characterized in that the very triggering of the firing of the weapon is carried out from the electrical control signals according to a predetermined programming so that the firing effective of the weapon can be deferred by a predetermined number

  emission of electrical control signals.

  2 Method according to claim 1, characterized in that an electrical safety signal is emitted when the weapon is in the "armed" position and in that the simultaneous emission of the electrical detection, location and safety signals constitutes a necessary condition to authorize the order

firing of the weapon.

  3 Method according to one of claims 1 and 2, charac-

  terrified in that the command for firing the weapon is

  inhibited if the order of appearance of said electrical signals can

  before simultaneously authorizing firing does not correspond to

  a predetermined chronological order.

  4 Method according to claim 3, characterized in that the control of the firing of the weapon is inhibited if the electrical location signal appears before one of the signals

detection or security.

  5 Method according to any one of claims

  1 to 4, characterized in that the electric detection signal is delivered by a device sensitive to acoustic vibrations

generated by the target.

  6 Method according to any one of claims

  1 to 4, characterized in that the electrical location signal

  is delivered by a device sensitive to infrared radiation.

  , r) 7, A method according to claim 6, -characterized in that the elect zique localization signal is delivered by the device sensitive to infrared radiation with a delay proportional to the importance of the infrared Elux and controlled by the temperature of the environment, 8 Selective horizontal firearm firing device, in particular for implementing the method according to

  claim 1, comprising a firing circuit, a sub-

  acoustic detection assembly sensitive to vibrations

  ticks generated by a target and delivering an electrical detection signal when a target arrives in the vicinity of the weapon's field of action, an optical localization sub-assembly

  sensitive to infrared radiation and delivering an electrical signal

  locating stick when a target arrives substantially in the firing axis of the weapon, characterized in that it further comprises a control sequencer sub-assembly, provided with a counting device, interposed between the sub- detection and localization assemblies on the one hand, and the firing circuit on the other hand, in order to control the firing circuit according to a programming

of predetermined firing.

  9 Device according to claim 8, characterized in that it further comprises a safety circuit delivering an electrical safety signal on the sequencer sub-assembly of

  command when the weapon is in the "armed" position.

  Device according to claim 8, characterized in that the sequencing sub-assembly for controlling the firing of the weapon comprises an AND gate, a first input of which is connected to the output of the acoustic detection sub-assembly and, a second input is connected to the output of the location sub-assembly, and a programmable counter, connected to the output of the AND gate, the firing circuit being itself connected to the output of the counter so that a control signal from the AND gate is only transmitted by the counter to the firing circuit when the counter has received a predetermined number of control signals, said number corresponding to the programming

predetermined.

  Il Device according to claims 9 and 10, character-

  laughed in that the AND gate includes a third input connected to the

safety circuit.

  12 Salt device Qn one of claims 9 to 11,

  characterized in that the acoustic detection sub-assembly comprises an acoustic sensor, a preamplifier circuit, a filtering circuit and an amplifier circuit, 13 Device according to claim 12, characterized in that the acoustic detection sub-assembly further comprises a comparator circuit for comparing the signal from the

  amplifier circuit at a predetermined amplitude threshold -

  14 Device according to claim 12 or claim 13, characterized in that the acoustic detection sub-assembly further comprises a pulse duration control circuit which delivers an output signal only if the signal from the amplifier circuit ( respectively of the comparator circuit) is present for a period greater than

a predetermined time.

  Device according to claim 14, characterized in that the acoustic detection sub-assembly further comprises an information delay circuit arranged at the output of the

  pulse duration control circuit.

  16 Device according to claim 14, characterized in that the pulse duration control circuit comprises an inverter circuit and a monostable circuit arranged in parallel and to which the signal from the information delay circuit is applied, and an AND gate of which a first input is connected to the output of the inverter circuit and a second

  input is connected to the output of the monostable circuit.

  17 Device according to any one of claims

  9 to 16, characterized in that the optical localization sub-assembly comprises an infrared detector, an alternating current amplifier connected to the output terminals of the infrared detector and a threshold comparator circuit connected at the output

  of the AC amplifier.

  18 Device according to claim 17 # characterized in that the optical localization sub-assembly further comprises a DC amplifier connected to the output terminals of the infrared detector, an integrator circuit connected at the output of the DC amplifier and of which the integration time is greater than the period corresponding to the passage

  of a target in the field of sight of the localization subset

  tion and that the output of the integrator circuit is

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  connected to the reference input of the threshold comparator circuit.

  19 Device according to claim 17, characterized in that the optical localization sub-assembly comprises in

  in addition to a monostable circuit connected at the output of the comparative circuit

  threshold sensor, a resistance-capacitance circuit which determines the

  metastable period of said monostable circuit, the resistive element.

  of the resistance-capacitance circuit being constituted by a thermosensitive component whose variation in resistance is directly linked to the variation in temperature and a shaping circuit

  connected at the output of the monostable circuit.

  Device according to any one of the claims

  tions 9 to 19, characterized in that the subset of localizations

  tion is connected to the control sub-assembly of the

  fire via a circuit comprising in series a circuit

  cooked monostable and a front shaping circuit before

  the pulse emitted by said monostable circuit.