GB2302228A

GB2302228A - Proximity fuze

Info

Publication number: GB2302228A
Application number: GB9104507A
Authority: GB
Inventors: Friedrich Motzko; Manfred Donabauer
Original assignee: Messerschmitt Bolkow Blohm AG
Current assignee: Airbus Defence and Space GmbH
Priority date: 1990-04-07
Filing date: 1991-03-04
Publication date: 1997-01-08
Anticipated expiration: 2011-03-04
Also published as: DE4011391C1; FR2731788B1; IT1263162B; ITMI910292A0; ITMI910292A1; GB9104507D0; GB2302228B; FR2731788A1; GB9102408D0

Description

1 TITLE.

2302228 A Proximity Fuse The invention relates to a proximity fuse having a timing means using a transmitter for generating scanning pulses and a receiving circuit which is coupled to the transmitter and in which the energy content of the reflected scanning pulses is filtered using range gates, at least one range gate preceding and at least one range gate succeeding the assigned triggering distance defined in time and the pulse part thus filtered out being in each case fed to integrators of which the integrated voltages are evaluated for the purpose of producing a triggering signal.

DE 30 20 996 C2 makes known an apparatus of this kind which serves to ascertain the triggering range in the case of a projectile moving towards a target. The process described operates reliably under normal conditions. If, however, the target cannot be detected during the approach flight by the time the triggering range is reached, for example when concealed by dense fog, then the apparatus fails to serve its purpose as no additional device is provided for the purpose of detecting the target when the distance of the projectile 2 therefrom has become less This invention seeks proximity fuse in such a 40880C/wsz than the said assigned range. to supplement the known way that a detonation signal can be generated particularly in the case of targets enveloped in an artificial fog.

According to this invention there is provided a proximity fuse having a timing means using a transmitter for generating scanning pulses and a receiving circuit which is coupled to the transmitter and in which the energy content of the reflected scanning pulses is filtered using range gates, at least one range gate preceding and at least one range gate succeeding the assigned triggering distance defined in time and the pulse part thus filtered out being in each case fed to integrators of which the integrated voltages are evaluated for the purpose of producing a triggering signal, the integrator output signal of a range gate succeeding the assigned triggering instant being examined in order to determine whether a preselected minimum amplitude is reached and/or a presele-c-table minimum time is exceeded.

The particular advantage of this invention resides in the fact that the efficiency of the known proximity sensor has been thereby considerably improved, since a triggering signal can now also be produced in the range 3 40880C/wsz between the assigned triggering range and the target itself. This applies in particular to cases in which the target is surrounded by an artificial fog or cannot be detected in the approach flight phase until the projectile is in close range.

An embodiment as an example of the invention is illustrated in the accompanying drawing and will be described below in detail.

The drawing shows a simplified schematic diagram of the known apparatus for determining the triggering range (in the area enclosed by broken lines). As a supplement to this apparatus the drawing shown two alternative versions of this invention.

As the circuit of the known apparatus is described in detail in DE 30 20 996 C2 the details given below will be confined to the additions of this invention.

In the first arrangement use is made of that part of the pulse from the receiver output signal 3 which is filtered by the range gate T2 and which, after the filtering operation, is conveyed to the integrator J2 to provide an input signal 1 for the signal processing circuit SV2.

The second version proposed has an additional range gate T3 actuated by a clock generator TG through a line 4. The part of the pulse filtered out from the gate T3 4 40880C/wsz is once again integrated in an integrator J3. The output signal 1 is now conveyed to a signal processing circuit SV3 of the same kind as the signal processing Circuit SV2. This version enables the time for the release signal in the close range below the assigned triggering range to be preselected more flexibly.

The signal processing circuits each comprise two evaluation operations for the integrated signal 1; the first determines whether the amplitude of the integrated signal 1 exceeds a certain preselected minimum and the purpose is to make certain that the pulse measured is in actual fact reflected from the target. The threshold preferred for this purpose is the back-scatter value which would be found under otherwise identical measuring conditions if a dense wall of fog were generally present. The second operation determines whether the integrated signal 1 is present throughout a certain minimum period and the purpose is to eliminate the influence of interference signals. The two evaluation criteria are preferably interconnected in such a way that a detonation signal (ZS,ZSZ) is only produced if they occur simultaneously.

The function of the extended circuit of the proximity fuse will be explained by reference to an example. The opto-electronic proximity sensor according - 5 40880C/wsz to the invention is suitable for use with a double hollow charge warhead. In the latter, in accordance with its function, the detection of the target and thus the detonation triggering of the signal processing times, at a distance of 4 m in front of the target, takes place so that in the case of conventional sensors no detonation can be triggered over a range of about 4. 5 - 0. 5 m in front of the target. As it is now usual to camouflage targets with artificially produced fog (of a thickness of about 3 - 4 m) the known proximity sensor requires the addition according to the invention. Taking visibility conditions into account the gate width, pulse width and optical adjustment for the signal processing circuit can be selected in such a way that a target can be reliably recognised over a range of about 4. 0 - 1. 0 m. By the aid of the detonation signal ZS or ZSZ produced, the propellant charge for the ejection of the preliminary hollow charge can be primed without further delay. The efficiency of the system is thus almost completely maintained.

- 6

Claims

40880C/wsz 1. A proximity fuse having a timing means using a transmitter for generating scanning pulses and a receiving circuit which is coupled to the transmitter and in which the energy content of the reflected scanning pulses is filtered using range gates, at least one range gate preceding and at least one range gate succeeding the assigned triggering distance defined in time and the pulse part thus filtered out being in each case fed to integrators of which the integrated voltages are evaluated for the purpose of producing a triggering signal, the integrator output signal of a range gate succeeding the assigned triggering instant being examined in order to determine whether a preselected minimum amplitude is reached and/or a preselectable minimum time is exceeded.

Z. A proximity fuse in accordance with Claim 2, wherein the threshold value of the minimum amplitude is greater than the measured reflection of a dense fog.

3. A proximity fuse constructed and arranged to function as described herein and exemplified with reference to the drawings.

7 4.

claimed.

40880C/wsz A warhead incorporating a fuse as described and Amendments to the claims have been filed as follows 1. A proximity fuse having a timing means using a transmitter for generating scanning pulses and a receiving circuit which is coupled to the transmitter and in which the energy content of the reflected scanning pulses is filtered using range gates, at least one range gate being actuated before and at least one range gate being actuated after the assigned triggering distance is reached, the pulse part thus filtered out being in each case fed to an integrator of which the integrated voltages are evaluated for the purpose of producing a triggering signal, and wherein the integrator output signal of a range gate actuated after the assigned triggering instant is reached is examined in order to determine whether a preselected minimum amplitude is reached and whether the integrated signal is present throughout a certain minimum period, in order to produce a further triggering signal.
2. A proximity fuse in accordance with Claim 2, wherein the threshold value of the minimum amplitude is greater than the measured reflection of a dense fog.
3. A proximity fuse constructed and arranged to I function as described herein and exemplified with reference to the drawings.
4. A warhead incorporating a fuse as described and claimed.