GB2121148A - Radar decoys - Google Patents

Abstract

Defence against radar guided missiles such as the Exocet missile is provided by metal-coated decoy balloons deployed by means of any available missile system, the balloon package which replaces the explosive charge of the missile comprising balloon ejection and inflation means. A proposed tactic is the deployment of decoy balloons in an inverted letter 'V' formation, and anchored ships may be protected on all sides by the deployment of a star pattern formation. Alternative decoy means may take the form of a cloud of metal particles or a spray of liquid metal such as mercury.

Description

SPECIFICATION Improvements to missile defence systems: a means of defence against the Exocet missile There is at present no adequate defence against radar guided missiles of the Exocet type.

In view of the present situation of ships of the British Task Force deployed around the Falkland Islands, the following method of defence is submitted. It is suggested that this method may be developed within five or six days and that examples of the invention may be rapidly flown out to the Task Force.

TECHNICAL FIELD The Exocet Missile is guided to its target by radar system, which detects the metallic mass of a ship. The aim of the hereunder disclosed defence method is to almost instantly provide decoy metallic masses, which when fired towards an approaching missile and then deployed may lure the approaching missile from its target.

DESCRIPTION The decoy metallic masses may take the form of rapidly inflatable balloons. The balloons may be made of very fine rubber or latex, such as the rubber produced by the Durex company. When carefully packed for inflation this material may require very little packing space. The rubber balloons may be packed within the empty warheads of ships' defensive missiles, the explosive charge having been removed. The package may include a high pressure cylinder for balloon inflation. Means may be provided for package ejection from missile at a required spot after missile firing, and means for instant balloon inflation.

The outer surface of the latex may be coated with a very fine metallic spray in order to produce a sharp radar image. The aim of the balloon design must be to provide a maximum of radar reflecting surface for a minimal quantity of latex material and for a minimal volume of compressed air or helium Some of the considerations to be taken into account must be the resistance of the latex to wind pressure and wave effects, and therefore its thickness, and the best shape of balloon; one that will continually present a large or suitable radar reflecting surface irrespective of wind direction.

In one airborne form of the disclosure, a number of helium filled balloons may be attached to a cable, at intervals of two or three yards, over a distance of ten to twenty yards. These balloons may be three to five yards high, one or two yards wide, and perhaps only one or two inches thick, thus requiring a small volume of gas. The ends of the cable may be provided with water drags. The reflecting surfaces may therefore resemble the reflecting surfaces of a ship. However, the luring effect may not require a large area of surface but only a continuity in length and height. It may therefore be sufficient to provide a gas-filled belt about a foot high and about twenty yards in length, to decoy an approaching missile.

One sea borne form of the disclosure may consist of four lengths of inflated rubber joined at a common centre, which may enclose an inflated rubber axle. These lengths may measure from ten to twenty yards, each being about two or three yards in height and one or two inches in thickness.

The rubber axle may form the central part of an inflated rubber frame having the shape of a parallelepiped, permitting the assembly to float with the four lengths more or less clear of the sea surface, in such a manner that any wind will cause the lengths to turn upon the axle like a paddle wheel, thus preventing damage by wind pressure.

In another form of the disclosure, the radar reflecting surface may entirely cover an inflatable frame, which may however be at low pressure and therefore rather supple to wind effects. inflatable frames may take the form of a cube or that of a sphere, which will always present the same reflecting surface no matter what the wind effects.

The radar reflecting surface may be stretched over the inflatable frame, in the form of sheets of latex or silk. These sheets will not be necessary if radar detection provides to be a question of extension in length and height and not a question of area of reflecting surface.

At any one spot, a balloon package ejected from a missile, when inflated, may not provide a reflection of dimensions or area sufficient to decoy an oncoming missile. In this case it may be convenient to fire two or three balloon package missiles to eject at the same spot.

BEST MODE OF OPERATION It is assumed that an oncomingExocet missile can be detected approaching its target at least thirty or forty seconds before it reaches the target area, and that this time period is sufficient to fire missiles in the direction of the attacking missile.

The proposed tactic is to fire at least six missiles at the attacking missile. Two missiles may be set to each eject a balloon package at a suitable maximum distance from the ship to be protected, one package being ejected a little to the left of the oncoming missile, the other being ejected a little to the right, at a distance of perhaps two or three miles from the ship that is a target.

The balloons may then become inflated within ten seconds. The computer of the oncoming missile will then be forced to make a selective decision, and, if the right reflection characteristics can be determined for these balloons, the computer will be tricked, and the oncoming missile will veer to the left or right of its correct path. Two more missiles may each be set to eject a balloon a little nearer the target, and a little more to the left and to the right of the correct path, and so on for another pair of defensive missiles, in such a manner that an inverted letter 'V' pattern will be formed between the target and the missile. The attacking missile will thus be caused to veer step by step further from its target, until vicinity and the erronous path will cause a miss.

The decoy metallic masses may take other forms, such as clouds of metal particles or perhaps a spray of liquid metal such a mercury, the essential tactic being the establishment of one or both arms of the inverted 'V' pattern.

Anchored ships may be protected by the deployment of a number of radar reflecting balloons in inverted 'V' patterns, thus forming a star shaped pattern around the ships.

Claims (1)

1. CLAIM

   A means for the protection of ships from radar guided missiles, by the provision of air or gas-filled balloons, which may be metal-coated by spraying to produce radar reflection, the balloons being constructed with latex or fine rubber to produce a decoy radar image, in order to attract approaching missiles while luring them from their intended target; including a deployment means, which may be the warheads of available missiles and installations, the warheads being emptied of their explosive charge; the balloons being ejected for inflation at a suitable point between the target ship and the approaching missile; a rapid inflation means such as air or gas-pressurized cylinders, and a deployment tactic, which is the deployment of six or more metal coated balloons in an inverted letter 'V' formation, in order to guide an approaching missile down an arm of the inverted 'V' and away from the target; the invention being substantially as herein described.