GB2356240A

GB2356240A - A sensor controlled weapon

Info

Publication number: GB2356240A
Application number: GB8232918A
Authority: GB
Inventors: Harry Koetser
Original assignee: GEC Avionics Ltd; Marconi Avionics Ltd
Current assignee: Allard Way Holdings Ltd
Priority date: 1982-11-18
Filing date: 1982-11-18
Publication date: 2001-05-16
Anticipated expiration: 2002-11-18
Also published as: GB2356240B; GB8232918D0

Abstract

An array of infra-red detectors 8 are illuminated by an image of a field of view containing a potential target. The number of sensors illuminated by the target is indicative of its apparent size. An altimeter 11 controls a logic circuit 10 so as to detonate the weapon in respond to the illumination of different selections of sensors for different altitudes. In this way the weapon is made sensitive to targets of apparently larger size at low altitudes than at high altitudes since at high altitudes targets appear to be relatively small the weapon is in fact made to respond to targets of constant real size whatever its altitude.

Description

2356240 A SENSOR CONTROLLED WEAPON This invention relates to a sensor

controlled weapon. It arose in the design of a particular weapon which is fired from a gun or dropped from an aircraft over an area of ground or sea and which has a sensor device capable of identifying a particular feature in the said area as being a target constituting a possible threat. On identifying such a target the weapon detonates thereby firing a projectile at the target.

One form of sensor, which is preferred in some circumstances, is an infra-red detector which distinguishes between infra-red sources of different sizes and assumes that a source of greater than a particular intensity whose size lies between particular limits constitutes a threat. The inventor has recognised that a problem with such sensors is that, whether dropped from an aircraft or fired from the ground, they do not have a constant altitude whilst over the target area and the range of the target therefore varies. Since a target appears larger at a close range than at a distant range, the target-size discriminating capability of existing sensors is limited. The invention provides a sensor controlled weapon adapted to move through the air and comprising: a 25 projectile arranged to be fired from the weapon; an array of sensors; means for focussing an image of a field of view on the array of sensors; a logic circuit connected to outputs of the sensors and designed to respond to receipt of signals from a particular 30 selection or selections of sensors by firing the projectile; and control means for cont rolling the said selection or selections to which the logic circuit responds. The said selection is preferably controlled i n such a way that the logic circuit responds to sources having a larger apparent size when the weapon is at low altitudes than when it is at higher altitudes. Thus, the real size of sources to which the logic circuit responds can be made to remain constant for all altitudes of the weapon. The control of the selection can be performed by an altimeter; or by a timer if the altitude of the weapon at different times can be predicted.

One way in which the invention may be performed will now be described by way of example with reference to the accompanying drawings in which:Figure 1 illustrates a self-forging fragment weapon constructed in accordance with the invention; and Figure 2 illustrates a view from below of an array of sensors also shown, in elevation, on Figure 1.

Referring to Figure 1, the illustrated self-forging fragment weapon comprises an outer casing 1 having an internal partition 2. Below the partition 2 is a compartment 3 containing an explosive, and above the partition 2 is a compartment 4 containing a detonator 5 and a sliding sensor assembly 6. The assembly is normally stored within the compartment 4 but is urged by a spring (not shown) to the illustrated position where it partly extends from the casing 1. It assumes this illustrated position after the weapon has been ejected from a mortar or ejected from a cylindrical holder carried by an aircraft.

Infra-red energy from a field of view is focussed by a lens 7 onto a detector assembly 8 which includes ten detectors 8A to 8J arranged as shown in Figure 2.

Ten outputs (indicated on Figure 1 by line 9) of the respective detectors are passed to a logic circuit indicated schemmatically by the block 10.

An altimeter 11 produces signals on lines 11A, 11B, 3 11C, 11D and 11E, when the casing 1 is at respective different increasing heights: i.e. an output is produced at 11A at a low altitude, at 11B at a higher altitude and so on until the highest altitude when an output is produced at 11E. The outputs 11A, 11B, 11C, 11D and 11E set the logical operations of the logic circuit 10 which operates as follows:

At the lowest operational heights of the weapon, i.e. when a signal appears on line 11A the logic circuit 10 is set to produce a detonating signal on line 12 when element 8E only is illuminated.

When the altimeter produces a signal on line 11B the logic circuit 10 produces a signal on line 12 when elements 8E, 8F and 81 only are illuminated.

When the altimeter 11 produces a signal on line 11C the logic circuit 10 produces a signal on line 12 when elements 8C, 8F, 8H and 8E only are illuminated.

When the altimeter produces a signal on line 11D the logic circuit 10 produces a signal on line 12 when elements 8B, 8D, 8J, 8E and not BA, 8G and 81 are illuminated.

When the altimeter 11 produces a signal on line 11E the logic circuit 10 produces a signal on line 12 when elements 8A, 8G, 81 and 8E are illuminated.

In this way the weapon is made to respond to -targets of selected size. Furthermore by selecting different combinations of detectors 8A to SJ for different altitudes the weapon is made-to respond to targets of larger apparent size (i.e. occupying a larger angle of view) when at low altitudes than when at high altitudes. It thus remains responsive to a relatively constant real target size at all altitudes at which it is required to operate.

The signal on line 12 operates the detonator 5 which causes the explosive in compartment 3 to drive a concave cover plate 13 in the same direction as the optical axis of the lens 7. In doing so the plate 13 is forged into an elongate shape in a manner known in the field of self-forging fragment weapons.

The invention is believed to be particularly applicable for defence against a target on the ground such as a military vehicle which constitutes or contains a relatively high intensity source of infra-red radiation the size of which enables it to be distinguished from other features which do not constitute a threat. In alternative systems, also in accordance with the invention, light sensitive devices could be used instead of infra-red, and in either case the lens 7 shown in the drawing (which is intended as a schemmatic representation of an optical focussing system) could be replaced by a reflector or system of reflectors. Also of course the invention is not applicable exclusively to self-forging fragment weapons but could be used with advantage in many systems where an inexpensive method of obtaining an indication of range in order to distinguish between targets of different siz is required.

Claims

1. A sensor controlled weanon adapted to move through the air and comDrising: a projectile arranged to be fired from the weapon; an array of sensors; means for focussing an image of the field of view on the array of. sensors; a logic circuit connected to outputs of the sensors and designed to respond to receipt of signals from a particular selection or selections of sensors by firing the projectile; and control means for controll- ing the said selection or selections to which the logic circuit responds.

2. A weapon according to claim 1 in which the control means is an altimeter arranged to make the logic circuit respond to a selection of sensors covering a relatively wide angle of view when the weapon is at a relatively low altitude and vice versa.

3. A weapon according to claim 1 in which the control means includes a timer and means for setting the timer in accordance with a planned trajectory of the weapon so that the logic circuit is made to respond to a selection of sensors covering a relatively wide angle of view when the weapon is at a relatively low altitude and vice versa.

4. A -onapon according to claim 1 and substantially as described with reference to the accompanying drawings.

/0 Amendments to the claims have been Med as follows 1. A sensor controlled weapon adapted to move through the air and comprising: a projectile arranged to be fired from the weapon; an array of sensors; means for focussing an image of the field of view on the array of sensors; a logic circuit connected to outputs of the sensors and designed to respond to receipt of signals from a particular selection or selections of sensors by firing the projectile; and control means for changing the said selection or selections to which the logi(- -:ircuit responds, whilst the weapon is moving. 2. A weapon according to Claim 1 in which the control means is an altimeter arranged to make the logic circuit respond to a selection of sensors covering a relatively wide angle of view when the weapon is at a relatively low altitude and vice versa. 3. A weapon according to Claim 1 in which the control means includes a timer and means for setting the timer in accordance with a planned trajectory of the weapon so that the logic circuit is made to respond to a selection of sensors covering a relatively wide angle of view when the weapon is at a relatively low altitude and vice versa. 4. A weapon according to Claim 1 and substantially as described with reference to the accompanying drawings.