FR2612288A1 - Over-flight munition with tilting charge - Google Patents

Abstract

The present invention relates to a munition for direct firing, with direct attack and/or attack in over-flight of a target, such as for example an armoured vehicle, of the type comprising an axial militiary charge, whose tilting under the transverse action of at least one impulse mechanism, is controlled by over-flight detection means for the target. The munition is characterised in that it comprises over-flight detection means 6 for a target, consisting of at least one radial infrared detector, and ogive detection means 10 consisting of an axial infrared detector. Each of the impulse mechanisms is controlled by an infrared detector, which is associated with it, and the over-flight detection means comprise six identical infrared detectors, each having a field of approximately 60 DEG in the plane perpendicular to the trajectory.

Description

OVERFLOW CHxRGE OVERVIEW MCNYmo
The present invention relates to the technical sector of ammunition for ground-to-ground weapon with a tight shot, particularly of the rocket type, with direct attack and / or over flight of a target, such as for example an armored vehicle.

 armored vehicles being better and better protected against aggression by anti-tank weapons, armor whose structures become more and more complex increasing in efficiency, we see appearing new weapons systems attacking armored vehicles in overflight (attack from the roofs) since, to stay within acceptable mass limits, the armor of this area will always remain less efficient than on the sides and especially on the front of the tank. Ammunition based on this principle flies over the armored vehicle and attacks it when it passes vertically: therefore it must have specific and efficient detection devices.

 Many configurations for ammunition of this type have been proposed, relating both to the active charge and to the target detection rroyens which equip them.

 With regard to over-flight detection of the objective, electro-mechanical systems, electromagnetic or magnetic systems with induction coils are known. These detection means require complex signal processing, most often involving the memorization of the characteristics specific to certain types of armored vehicles for the various influences detected. On the other hand, the documents showing these detectors generally do not sufficiently describe the essential cooperation between the detection means and the orientation of the active charge equipping the projectile, the terminal effect of which is exerted during the overflight of the goal.

 the military charges used capable of attacking a target a few meters away are ineffective at impact and must therefore be triggered at a sufficient distance from the target. Some systems propose to project a hollow charge against the target, but when you know the speed of the projectile, this seems perfectly impractical.

Regarding the orientation of the military charge towards the armored vehicle, the whole of the proposed systems revolve around two ideas
- a preoriented load which eliminates any tilting device but which has two major drawbacks: first the load must rotate very quickly to be certain that during the flight over the axis
of the charge will intercept the target at least once or not
turn at all and stay downward. Then, this available
sition prohibits frontal attack or requires the addition of a second
charge,
- a tilting load which has the advantage of using the volu well
me ammunition, so allow to have a high-performance charge,
and which authorizes the frontal attack since the load is oriented in the direction of movement of the ammunition. However, this provision
is only viable if the load switching system is sufficient
fast branching and low crowding.

patent FR 2,552,871 shows for example an anti-projectile
tank acting in overflight, presenting several loads modular forms
tilting after detection. the tilting means are constituted
by side powder impellers, each comprising a plate
explosive located between a rigid plate and an ejec inner plate
table. But this document, as it was said above, does not specify
the nature of the proximity detection means used to ensure
synchronization of the load tilt as a function of its distance
effective action.

The present invention overcomes the shortcomings and disadvantages
proposed configurations, and targets ammunition with means
detection in overflight ensuring, despite the rotation of the projectile and
after its tilting, the alignment of the vulnering axis of the load with
The target. The present invention also provides a mixed munition which can
assault a target, in particular an armored vehicle, by scm attack
mital or by lateral attack on impact with the same effectiveness
doing. 'minition
ammunition
The subject of the present invention is therefore a / for taut shooting, with
direct attack and / or hovering over a target, such as for example a
armored vehicle, of the type comprising an axial military charge, the
tilting under the transverse action of at least one impeller is com-
rnarxé by detection means over the target, characterized in
what it includes means of detection in overflight of the target cons
titrated by at least one radial infrared detector.

Preferably, each of the lateral impellers causing the
tilting is controlled by an infrared detector which is pro
pre. Furthermore, the ammunition may include detection means
of warhead also constituted by an axial infrared detector. the
the aforementioned infrared detectors preferably operate in the
band from 8 to 12 microns,
Other advantages and characteristics will appear on reading the following description of an embodiment of the ammunition
according to the invention, without limitation, with reference to the drawing
on which
- Figure 1 is a longitudinal schAmatic view, partially
exploded, of a munition according to the invention,
- Figures 2 to 4 illustrate various phases of operation
in overflight or in direct frontal attack,
- Figures 5 and 6 show, respectively in cross sections
dirty and longitudinal, the overflight sensors acting radially
before ammunition tipping and commanding the latter and,
- Figures 7a to 7d show the details of the die
warhead guard fitted to a munition according to the invention.

the main components of the ammunition according to
the invention, of the known type called tilting load, are shown from the rear to the front with reference to Figure 1 where have been omitted
known means of propulsion, any rocket type propellant that can be used.

The folding tail 1 is fixed to a rear body 2. A
block 3 consisting of a security and arming device ensures all
Cuban pyrotechnic misalignments in storage and allows the ammunition of the ammunition during firing, both pyrotechnically and elec
tripping (erasing of electrical safety, commissioning of
power sources).

 One set includes six explosive impellers 4 arranged on the periphery of the meeting, near the arming device 3 for construction facilities.

This munition being of the tilting charge type, the military charge is in the axis of the ammunition and impellers are responsible for causing it to tip when the munition flies over the target. the impellers used are for example explosive systems as described in
the patent FR 2 552 871. They have the advantage of allowing a tilting
in a time of the order of 10 ms and are of sufficiently small dimensions that the munition can comprise several. Depending
the speed of this type of projectile (150 to 200 m / s) and its speed
of rotation (15 to 20 t / s approximately) it is necessary to have six impellers around the projectile to be certain that there will be a well placed one to position the load in the direction of the target. To do this and as explained below, each irruisor is associated with an infrared sensor responsible for determining the instant of overflight.

 A homogeneous electronic unit 15 groups together all the processing circuits which are, for example, coated in a protective resin.

A flyover detection block 6 is described below. In a known manner, the military charge comprises a priming block 7 of the
pyrotechnic charge and the pyrotechnic charge itself d. Finally, the warhead 9 has a warhead detector 10 which will be described later.

The system detection function must trigger the different target attack sequences according to two typical scenarios
- the attack in overflight, when the trajectory does not pass by the volume of the objective (ammunition represented in Al figure 2).

 - direct attack, when the trajectory intersects the volume of the objective (ammunition shown in B1 figure 2).

 These two cases correspond to different shooting sequences.

Indeed, in the case of the overflight attack, the detection must intervene a first time to activate the impeller to topple, ent of the military charge (position A2), then a second time to trigger can fire when, by following the tilting, the object appears well placed on the firing axis (position A3).

 In the case of a direct attack, the first sequence becomes useless and the firing must take place before impact, as soon as the target appears at good range for the optimal effectiveness of the hollow charge (ammunition B3).

 The detection function must be equipped to process a signature characteristic of the active target with a good capacity for discriminating false alarms. the choice fell on an infrared detection in the 8 to 12 micron band which delivers the maximum signal to detect the perimeter of the target taking into account the temperatures encountered.

 the overflight detector is shown in FIGS. 5 and 6.

 The field angle along the pitch axis (angle α) is obtained by considering the shooting parameters. For example, if we admit that the average speed on the trajectory is of the order of 150 m / s and that the tilting time on a quarter turn occurs in 10 milliseconds, we see that to obtain optimal efficiency, it the tilting must be brought about 1.5 m from the target point. If we accept that the perimeter of the objective is a rectangle of 6 X 3 m, we see that the flyby detector must trigger the tilting sequence at about 1.5 m from the point targeted.

 This function is performed using an irailticellular detector with an optical field of 180. tilting thus takes place in substantially the same vertical plane for a height between h = 3 m and h = 6 m (Figure 2). In fact, if we admit that the triggering occurs when the target is intercepted by the front half of the field, we obtain a dispersion of the order of 75 cm which, with respect to the dimensions of the target, is completely acceptable.

 In the plane perpendicular to the axis of the projectile, detection is carried out according to six independent fields of 600 each so that the indexing between the detection zone and the tilting sector can satisfy the requirements of good probability of reaching te of the target. As soon as two consecutive fields detect the target (Figure 4), the firing signal of the corresponding tilting impeller intervenes. Given that the tilt is 10 milliseconds and that the rotation speed is 20 revolutions per second, an offset of a few degrees is necessary for the accuracy of the shot.

 The aim of the direct or frontal attack detector 10 is, for the two possible types of attack, to determine the optimal moment of fire of the military charge. In one case, its role is to allow precise aiming. It is designed to recognize the correct centering of the target. In the second case, it functions as a proximity rocket. It is constituted by a conventional detector with three quadrants, known for example in pyroelectric technology, which, placed at the head of a warhead, scans the space placed in front of it at an angle of 450 in total. the signal processing circuit emits the firing order when the three cpadrans see the target simultaneously. This detector actually works differently depending on the type of attack (see Figure 3). In overflight attack (case A3), it pivots and its sweeping movement reveals the target in its field. In direct attack (case B3), the perceived energy increases until the target is seen "full-frame". The energy received then stabilizes, which makes it possible to determine the optimum point for firing.

 The processing logic, which is different for each of the two functions envisaged, is automatically selected according to whether the switching sequence has taken place or not. While flying, it is possible to find a configuration or the warhead detector sees the target. But the energy received will decrease to disappear, which gives an indication of the moment of appearance of the target in the field of the overflight detector.

 the processing circuits of the two detectors are common and grouped in an electronic assembly which can advantageously use a microprocessor device. Such a circuit simplifies the tilting system. It then suffices from three impellers to 1200 instead of six, the function being fulfilled as the case may be, by firing one of the three impellers remaining in the axis or, to relocate one of the three suppressed impellers, by firing of the two impellers located on either side of the firing axis. The supply of electrical energy is made from a source having a capacity for long-term storage, such as for example a lithium bootable battery, a battery thermal, or a fast-charging accumulator, charged a few seconds before firing.

 The hover attack detector (Figures 5 and 6) occupies a full section of the master-couple. The optical assembly is very simple. It is made up of six identical modules, each having a total field of 600 with a selective infrared filter in the 8 - 12 micron band.

Each module includes a sensor 11 whose field, greater than 600, is collimated to 600 in the plane perpendicular to the trajectory by collimators 2 and in the pitch plane by an afocal modulator comprising several slits 3 providing a field of angle i = 180. These sensors mounted on a support 4 are electrically connected to the processing circuit 5 located immediately behind this assembly.

 Another embodiment is obtained by the use of a mirror with six hexagonal planes 6 realizing the six sectors of sensitivity by returning the rays to a flat mosaic of six sensors 7. The modulator constituted by the slots aims to eliminate the point sources seen from a small angle. For example, with eight slots per sensor, i.e. 48 slots for the whole, all the signal sources seen at an angle less than 3,750 generate a frequency of 960 Hz which is easy to eliminate with electrical filtering. Those seen from an angle greater than 7.50 will give an unmodulated signal, therefore unfiltered. Furthermore, knowing that, with the parameters selected, the section takes place after a swept distance between 17 and 50 cm (from Figure 2), the signal establishment time with a projectile speed of 150 m / s is between 1.13 and 3.33 ms, which allows a response time of the electronic assembly and detector of a third of this time, ie 0.37 to 1.11 ms, therefore a bandwidth of 140 to 420 Hz, which is compatible with the frequency p-oduite by the afocal modulator, clearly higher than the maximum frequency of the bandwidth of the detector.

The direct attack detector (figures 7a to 7d) placed at the head
of warhead 9 has its field angle l mited at the selected value (γ = 45)
by the collimator effect of its necaric environment or by a
lens 18: sensitive infrared sensor 19 in the 8 to 12 yrn band
consists of a mosaic of three cells (item 20) or by a
single cell with three sensitive areas (item 21) for example or by
any other means enabling the three sectors of sensitivity to be obtained
to 1200. the sensor outputs are connected to the electronic block of
signal processing by a flexible electrical connection such as a flexible printed circuit 22. It is preferable to place it at the level of the warhead, if
possible in the sensor housing, charge amplifiers
the constraint of pyroelectric infrared sensor technology.

The whole is embedded in a protective resin 23. The field of view
retained from 450 ensures firing at a distance of the order
50 cm in frontal attack.

Claims (13)

RETURNS 1 - ammunition for direct fire, direct attack and / or overflight of a target, such as for example an armored vehicle, of the type comprising an axial military charge whose tilting under the transverse action of at least one jogger is control by means of detection in overflight of the target, characterized in that it comprises means of detection in overflight of the target constituted by at least one radial infrared detector. 2 - Ammunition according to claim 1, characterized in that it carries warhead detection means constituted by an axial infrared detector. 3 - ammunition according to claim 1, comprising explosive impellers, characterized in that each of the impellers is controlled by an infrared detector associated with it. 4 - Ammunition according to one of claims 1 to 3, characterized in that the infrared detectors operate in the band from 8 to 12 mi crons. 5 - Ammunition according to one of claims 1 to 4, characterized in that the detection means in overflight ccmçce: tent six identical infrared detectors each having a field of about 600 in the plane pepen- dicclire to the trajectory. 6 - Ammunition according to one of claims 1,3 or 4 characterized in that the overflight detection means comprising a set of plane mirrors cooperating with a plane mosaSque of infrared sensors, to form areas of sensitivity in the radial plane of ammunition. 7 - Ammunition according to claims 5 or 6, characterized in that the thrust axis of an impeller is offset by a fixed angle relative to the field axis of the detector which is associated with it, in the longitudinal plane of ammunition. 8 - Ammunition according to one of claims 5 to 7, characterized in that the overflight detection means comprise an afocal modulator allowing the elimination of small sources by electrical filtering. 9 - ammunition according to claim 2, characterized in that the warhead detection means are constituted by an infrared detector with several quadrants. 10 - Ammunition according to one of the preceding claims, characterized in that it ccaçorte a security and arming device common to the explosive boosters and the military charge, and controlling the electrical functions. 11 - device according to claim 11, characterized in that the safety and arming device is actuated by the double effect of acceleration and ejection during launch. 12 - Ammunition according to one of the preceding claims, characterized in that it comprises an electronic circuit for processing microprocessor signals, powered by a bootable electrical source. 13 - Ammunition according to claim 12, characterized in that the electrical connection between the electronic processing circuit located at the rear of the ammunition and the warhead detection means is constituted by a flexible connection.