WO2000002000A1

WO2000002000A1 - Passive fail-safe device for mobile craft such as a helicopter

Info

Publication number: WO2000002000A1
Application number: PCT/FR1999/001584
Authority: WO
Inventors: Joël BANSARD
Original assignee: Alkan
Priority date: 1998-07-03
Filing date: 1999-07-01
Publication date: 2000-01-13
Also published as: ES2209448T3; EP1093561A1; EP1093561B1; DE69911608T2; FR2780774B1; DE69911608D1; FR2780774A1

Abstract

The invention concerns a passive fail-safe device for a mobile craft such as a helicopter (10), comprising at least a decoy dispenser (LL, LL') mounted adjustable on said craft, automatically controlled by a detector of hostile element (D) and a navigation unit (CN). The invention is characterised in that it comprises means for setting up a dynamic decoy library based on data supplied by said detector and by said unit, so as to define decoy sequences wherein the orientation and timing for launching said decoys are optimised.

Description

Passive self-protection device for a mobile machine such as a helicopter

The present invention relates to a passive self-protection device for a mobile vehicle such as a helicopter.

A constant concern in the field of armament techniques is to best protect mobile devices such as ships, land vehicles, planes and helicopters against "hostiles" such as trajectory-corrected rockets or missiles .

It is well known to use decoy launchers for this purpose, making it possible to fire cartridges containing, depending on the type of hostile, infrared decoys or electromagnetic decoys. The decoys drawn deflect the hostile from its target, thus avoiding partial or total destruction of the latter.

It is said that decoy launchers constitute passive self-protection devices because they do not make it possible to destroy the hostile.

Found in the prior art are launchers mounted mobile on their support, capable of pulling several lures in possibly different directions to increase the effectiveness of the decoy. We then implement decoy sequences.

In the case of mobile devices whose speed is much lower than that of hostiles, the adequacy of these decoy sequences to the different possible situations is critical.

The present invention aims to provide means for optimizing the decoy sequences for such devices, in order to improve their protection. This object of the invention is achieved with a passive self-protection device for a mobile machine such as a helicopter, comprising at least one decoy thrower mounted orientably on said machine, slaved to a hostile detector and to a navigation center. , remarkable in that it comprises means for developing a dynamic decoy library from the information provided by said detector and by said control unit, in order to define decoy sequences in which the orientation and timing of the shots of said launcher lures are optimized.

Thanks to these characteristics, it is possible to define optimized decoy sequences according to the nature of the hostile and the relative movements of the mobile machine and the hostile.

Other characteristics of the device according to the invention are defined in the appended claims, and will appear clearly on reading the description which follows and on examining the appended drawings given solely by way of example, in which:

- Figure 1 is a front view of the chassis of a decoy launcher of the device according to the invention mounted on a motorized gimbal, this chassis being shown in position "zero";

- Figure 2 is a partial side view of the assembly shown in Figure 1, the frame of the decoy launcher being shown in three positions: minimum roll position (dashed line), zero position (solid line), and position maximum roll (broken line);

- Figure 3 is a top view of the assembly shown in Figures 1 and 2, the frame of the decoy launcher being shown in three positions: minimum yaw position (dashed line), zero position (solid line), and position maximum yaw (broken line); - Figure 4 is a side view of a helicopter equipped with two decoy launchers of the device according to the invention (only one of them being visible in this figure); - Figure 5 is a front view of the helicopter of Figure 4;

- Figure 6 is a top view of the helicopter of Figure 4; FIG. 7 is a flowchart describing the operation of the device according to the invention;

- Figure 8 illustrates a decoy sequence.

In these figures, identical reference numerals represent identical or analogous members or sets of members. It will be noted that the following has chosen to describe the invention when it is incorporated into a helicopter, since it is a fact that it is particularly suitable for this type of mobile vehicle. That said, this choice is in no way limiting, and it should be borne in mind that the invention could also be advantageously incorporated into other mobile devices such as ships or land vehicles, or even into planes.

In what follows, the terms "top" and "bottom" are understood with respect to the vertical, represented where appropriate by an axis ZZ ', Z being located downwards and Z' upwards.

Referring now to Figures 1 to 3, where there is shown the frame 1 of a decoy launcher of the device according to the invention mounted on a motorized gimbal.

This chassis has substantially the shape of a parallelepiped box open on one of its faces 2. It is intended to receive a charger (not shown) comprising cartridges of electromagnetic or infrared decoys. In the case of a helicopter, it is preferable to use special cartridges with suitable payload, which also makes it possible to reduce the reaction forces when firing. The bottom of the chassis 1, opposite its opening, comprises electrical members (power amplifiers, etc., not shown) allowing the ignition of the decoy cartridges. These electrical components are connected to the interior of the helicopter by connection components (not shown).

The chassis 1 is rotatably mounted around a horizontal axis 3 on a plate 4, itself rotatably mounted around a vertical axis 5 on a support 6. The support 6 is fixed on an appropriate part 7 of the helicopter. A first electric motor 8, of the “torque” or “step-by-step” type, fixed on the plate 4, is intended to rotate the chassis 1 about its axis 3.

A second electric motor 9, similar to the motor 8, is fixed on the support 6 and is intended to pivot around the vertical axis 5 the assembly formed by the plate 4, the chassis 1 and the motor 8.

FIG. 2 represents three possible positions of the chassis 1, the plate 4 being in its “zero” position, that is to say in a middle position between its two extreme positions.

The position of the chassis 1 which is shown in solid lines is its zero position.

The position of the chassis 1 which is shown in phantom is an extreme downward position, also called the minimum roll position.

The position of the chassis 1 which is shown in broken lines is an extreme upward position, also called maximum roll position, symmetrical with the minimum roll position relative to the zero position. Typically, in the case of a helicopter, the minimum and maximum roll positions are each tilted at an angle α of about 60 ° relative to the zero position. FIG. 3 represents three possible positions of the chassis 1 corresponding to three possible positions of the plate 4.

The position of the chassis 1 which is shown in solid lines is its zero position. The position of the frame 1 which is shown in phantom is an extreme position in the direction of clockwise rotation, also called minimum yaw position.

The position of the chassis 1 which is shown in broken lines is an extreme position in the anti-clockwise rotation direction, also called maximum yaw position, symmetrical with the minimum yaw position with respect to the zero position.

Typically, in the case of a helicopter, the minimum and maximum yaw positions are inclined by an angle β of about 75 ° relative to the zero position.

Referring now to Figures 4 to 6, where there is shown a helicopter 10 equipped with two decoy launchers

LL, LL 'of the device according to the invention. Each of these two decoy launchers is mounted on a motorized gimbal such as that which has just been described.

However, for the sake of simplification, each decoy-cardan launcher assembly has been represented by a simple rectangle. The two decoy launchers are preferably placed symmetrically with respect to the main line 13 of the helicopter, at a sufficient distance from the air inlets 14 of the apparatus. They can be fixed on any sufficiently rigid part of the device, such as landing gear supports, as shown.

FIGS. 5 and 6 show the deflections of the roll and lace decoy launchers, corresponding respectively to FIGS. 2 and 3 described above.

The extreme angles of roll α and of yaw β shown are preferably respectively about 60 ° and 75 °. In this case, the decoy launchers then each have a maximum clearance of approximately 120 ° in roll and 150 ° in yaw, which a priori makes it possible to draw decoys in almost all directions of space.

Note on the one hand that the maximum deflections of the decoy launchers are likely to vary from one helicopter to another, and on the other hand that for a given helicopter, the authorized firing directions can vary according to a certain number of parameters.

For example, when a helicopter flies in formation, firing of decoys towards neighboring aircraft is prohibited.

According to another example, the firing of electromagnetic decoys towards the front of an advancing helicopter is also prohibited, in order to prevent any penetration of metallic flakes into the air intakes.

According to yet another example, shots into the mobile wing of a helicopter are prohibited when infrared decoys are used. As can now be understood, the management of shots from the orientable decoy launchers of the device according to the invention can quickly prove to be very complex, and in any case impossible to optimize manually. This is the reason why the invention also provides a system for optimizing the decoy sequences.

Referring now to Figure 7, where there is shown a flowchart describing this system.

The frames of each decoy launcher are shown diagrammatically in this figure by elements bearing the references

1 and the, and the two motors of each of the universal joints on which these frames are mounted are shown diagrammatically by elements bearing the references 8, 9 and 8 ', 9'.

As we can see, the optimization system includes a CT fire calculator interface with:

- a hostile detector D,

- a CN navigation center, - a static decoy library B,

- a PC control station,

- position encoders C8, C9 and C8 ', C9' of the motors 8, 9 and 8 ', 9'.

The hostile detector D, which can be a radar, makes it possible to identify a hostile by virtue of a plurality of antennas A1, A2, A3, A4 located at the periphery of the helicopter.

Ideally, one could choose a detector D of the Doppler effect type, in order to obtain information on the kinematics of the hostile.

The detector D is also of a type making it possible to identify the category of the hostile. Such a detector, available in the prior art, must at least make it possible to differentiate a hostile with electromagnetic guidance from a hostile with infrared guidance.

Ideally, detector D can also allow other characteristics of the hostile to be identified more precisely.

The information sent by the CN navigation center to the CT fire computer concerns essentially the attitudes (Euler angles) of the helicopter, its speed and the position of its center of gravity.

By reconciling the information provided by the hostile detector D with that provided by the central navigation station CN, the firing computer CT can determine the exact position of the hostile in the helicopter frame of reference, or even in a frame of reference absolute. The static decoy library B contains various subroutines which can be used by the CT computer to order decoy sequences. This library is static in the sense that the various subroutines are predefined.

The information sent by the PC control station to the CT shooting computer essentially depends on instructions imposed manually by the pilot and concerning the shooting conditions: activation / deactivation of the optimization system, firing prohibitions depending on the circumstances (flight in formation for example), etc.

The information sent by the position encoders C8, C9 and C8 ', C9' to the firing computer CT allows it to know at all times the orientation of the chassis 1 and the. These position encoders can be, for example, optical or potentiometric sensors.

When a threat arises, the decoy sequence optimization system works as follows.

Once the detector D has identified the category of the hostile, the CT fire calculator interrogates the library B to find the subroutine adapted to this category, then it calculates in real time the orientation and timing of the launcher's shots, taking into account the information provided by the hostile detector D and by the CN navigation center. The firing computer CT thus creates a dynamic decoy library from the static library B and information supplied by the hostile detector D and by the navigation center CN, making it possible to define a decoy sequence including the efficiency is optimized depending on the nature of said hostile and the relative movements of the helicopter and the ostile.

Thanks to the position encoders of the launcher motors, the CT firing computer knows their orientations at all times. By comparing these to the calculated orientations to be reached, the computer determines the movement orders to be sent to the engines of the decoy launcher.

The CT shooting computer also checks that the direction of fire to be achieved is compatible with the instructions imposed by the pilot, provided by the PC control station.

If the firing orientation to be reached is prohibited by these instructions, it can advantageously be envisaged for the firing computer CT to determine a new firing orientation which approaches the ideal firing direction.

Once the decoy launcher is properly oriented and the moment of firing is reached, the firing computer CT sends it a firing order.

FIG. 8 shows an example of a decoy sequence, in the case of a hovering helicopter and an infrared-guided hostile arriving on the starboard side of the helicopter. As can be seen in this figure, the hostile initially follows a trajectory 20 directed towards the turbines of the helicopter 10.

The LL launcher located on the starboard side of the aircraft pulls three lures L1, L2, L3 directed more and more towards the front of the helicopter, so as to gradually deviate the initial trajectory 20 of the hostile towards trajectories avoidance 21, 22, 23.

In doing so, the infrared signatures of the decoys are progressively separated from that of the helicopter, and the hostile is prevented from reaching its target.

To fix the ideas, the time interval separating each lure shot in this example can be of the order of half a second. The decoy sequence described above would no longer be suitable if the helicopter was advancing, because then the infrared signature of the helicopter would risk joining the infrared signatures of the decoys fired last. In this case, the dynamic library means exposed above would then make it possible to modify the decoy sequence according to the movements of the helicopter so as, for example, to deviate the trajectory of the hostile towards the rear of the apparatus. According to another example, if the helicopter did a U-turn, the dynamic library means described above would make it possible to switch directly from the starboard decoy launcher to the port decoy launcher, or vice versa, so as to ensure the continuity of the decoy vis-à-vis the hostile.

To increase the security of the device according to the invention, it is also possible to provide a degraded operating mode when the optimization system described above breaks down or when it is damaged, for example during a fight. In this degraded operating mode, the two decoy launchers are set to their zero position by electrical or mechanical means (not shown), and the firing orders are sent manually by the pilot via the PC control station.

It is now understood that the present invention makes it possible to define decoy sequences in which the orientation and the timing of the shots of the decoy launchers are optimized according to the nature of the hostile and the relative movements of this hostile and of the 'helicopter.

Of course, the invention is not limited to the embodiment described and shown which has been provided only by way of example. Thus, for example, one could consider placing more than two decoy launchers on the mobile machine.

Claims

1. Passive self-protection device for a mobile machine such as a helicopter (10), comprising at least one decoy launcher (LL, LL ') mounted orientably on said machine, slaved to a hostile detector (D) and to a navigation center (CN), characterized in that it comprises means for developing a dynamic decoy library from information supplied by said detector and by said central, in order to define decoy sequences in which the orientation and the timing of shots from said decoy launchers are optimized.

2. A passive self-protection device according to claim 1, characterized in that said means for developing a dynamic decoy library comprise a fire computer interfacing with said hostile detector (D), with said navigation center (CN) and with a static decoy library including predefined subroutines corresponding to different types of hostiles.

3. Device according to one of claims 1 or 2, characterized in that said dynamic decoy library is adapted to control decoy sequences making it possible to gradually separate the signatures of the decoys from that of a hostile, so as to deflect the initial trajectory of said hostile towards avoidance trajectories.

4. Passive self-protection device according to any one of claims 1 to 3, characterized in that it comprises means for implementing a degraded operating mode, making it possible to place said decoy launcher (LL, LL ') to its zero position and send fire orders to it when its servo is out of service.

5. A passive self-protection device according to any one of the preceding claims, characterized in that it comprises means for prohibiting certain directions of fire. β. Passive self-protection device according to any one of the preceding claims, characterized in that said decoy launcher (LL, LL ') is connected to said mobile machine (10) by a motorized gimbal, allowing said lure launcher to be oriented in yaw and roll. 7. A passive self-protection device according to claim 6, said mobile machine (10) being a helicopter, characterized in that it comprises two decoy launchers (LL, LL ') arranged symmetrically with respect to the line of faith (13 ) of said helicopter. 8. A passive self-protection device according to claim 7, characterized in that each of said decoy launchers has a displacement of approximately 150 ° in yaw and 120 ° in roll around its zero position.