GB2180043A - Guided depth bomb - Google Patents

Abstract

A depth bomb in missile form is guided to travel to a station above a target and then vertically downwards, preferably after a 90 DEG turn, through air and water under power from the bomb's thrust motor. Thrust vector control and/or control surfaces on the bomb fuselage control direction. Possible guidance methods are shown in Figs. 2/3. <IMAGE>

Description

SPECIFICATION Improvements in or relating to guided missiles The present invention relates to guided missiles. It provides a guided depth bomb.

In the attack of a submarine from an aircraftasign- if icant amount oftime, called losttime, can elapse between detecting and determining the position of a submarine and the arrival atthesubmarineofa depth bomb. Typicallythistime is made up ofthe time taken to withdraw sonar equipment from the water and to flyto a station above thetarget, orthe time taken to fly the weapon to the station above the target, plus the time taken fortheweapon to drop, usually on a parachute for store stability purposes, to the water surface, plus the time taken for the store to sinktothetarget.

A guided depth bomb according to the present invention has; a thrust motor; directional control means; navigation means arranged to control the direction control means and thus to directthe bomb to travel to a station above the target and then to direct itto travel substantially vertically downward, includ- ing underwater, under powerfrom the thrust motor; awarhead; and meansfortriggering the warhead.

The navigation means and direction control means are preferably arranged to turn the bomb through 90 or thereabouts when the above target station has been reached, from a horizontal direction configuration to a vertically downward configuration.

This may be achieved by arranging for a somewhat quarter elliptical trajectory, but in the more likely context of low altitude launch, a rather more sudden turn is preferred.

In one embodiment of the invention the nagivation means incorporates means permitting just prior to launch, the inputthereto of a signal from an external control as to the location of the above target station, the navigation means being arranged to control bomb direction and altitude thereafter.

In another embodiment of the invention the navigation means incorporates computer means for determining the above target station location in relation to an initial location and direction ofthe bomb,and the below station target range, arranged to control the navigation means, and having an input arranged to accept a signal relating to target location from an external supply.

In another, less preferred embodimentfromthe point of view of interferability of the guidance means, the bomb incorporates a receiver arranged to accept guidance signals, eg radio or light signals, from an external source during flight.

Thewarheadtriggermeans may comprise a hydrostatic fuze, a proximity fuze or contact detection means.

The bomb is likely to be arranged to be helicopter borne, in which case a helicopter mounted computer associated with sonar or other target location apparatus, can constitute the source of external signals for guiding the bomb. Fixed wing aircraft and ships provide possible alternative bomb and control signal source carriers.

The direction control system is preferably a thrust vector control device arranged to control motor thrust direction with respect to the bomb longitude.

Alternatively or additionally it may comprise control surface on the bomb fuselage.

A guided depth bomb in accordance with the present invention will now be described by way of example with reference to the accompanying drawings, ofwhich: Figure 1 is a schematic section of a guided depth bomb; Figure2 is a flow chart of a simple bomb guidance system, Figure 3 is a flow chart of a bombborneguidance system; Figure4is a block diagram of a simple bombguidance apparatus; and Figure 5 is a block diagram of a bomb path optimiser.

As shown in Figure 1 the guided depth bomb has a fuselage 10 with fins 11 and cruciform array. Atthe nose of the fuselage is a warhead 12, behind which is a sensor 13, guidance apparatus 14, rocket motor 15 and thrust vector control apparatus 16, in serial array. The warhead 12 includes a hydrostaticfuze (not shown), while the sensor 13 includes attitude and rate gyros.

In a simple guided bomb embodiment, forwhich the guidance apparatus 14 is illustrated in Figure 2, the guidance apparatus 14 is arranged to receive from the store carrier (eg a helicopter) signals as to direction and turnovertime. The apparatus 14 isthen arranged to execute a programme in which the alti tude ofthe weapon is controlledto turn-overtime, then the weapon is turned to a vertically downward trajectory, an appropriate signal from the apparatus to that effect being passed to the thrust vector control 16.

The store carrier, in the case ofthis simple embodiment, is equipped with a computer which isarran- gedtoacceptsignalsin respectofthe range and track ofthetarget, azimuth direction, altitude and target depth, to compute firing time and water entry aim point, and to pass the said appropriate signal to the apparatus 14.

In a more complex embodiment,forwhich the gui- dance apparatus 14 is illustrated in Figure3,the apparatus 14 is arranged to accept signals relating to target range, track and depth derived from say a sonar, and signals relating to carrier attitude and altitude from appropriate carrier sensors (such as altimeter, direction and level detectors). The apparatus 14then computes the best time to fire, the required direction and the time to turn the weapon over, and passes appropriate signals to the weapon motor 15 andthrustvectorcontrol apparatus 16.

The guidance apparatus 14 in the simple embodi ment is set out in g reater detail in Figure 4. This shows that the apparatus has input signals in respect ofthe missile attitude demands azimuth and vertical control, and of any required post-firing corrections and of the time to elapse before the turnover man- oeuvre is initiated, means to resolve these space axes signals in terms of the missile axes for a missile that may be freely spinning, means for determining appropriatey and z attitude signals, converting these into thrustvector control signals and for passing them to the x andy nozzle angle controls, and means for nulling thrust vector control upon water entry.

Aflowdiagram by which the carrier or, in the more complex missile embodiment of Figure 3,the appar atus 14 determinesthe timefrom missile firing to missileturn-overisshown in Figure 5.

Claims (7)

1. A guided depth bomb having a thrust motor, directional control means, navigation means arranged to control the direction control means and thus to direct the bomb to travel to a station above the target and then to direct itto travel substantiallyver tically downward, including underwater, under powerfrom the thrust motor, a warhead, and means fortriggering the warhead.

2. A bomb as claimed in claim 1 and wherein the navigation means and direction control means are arranged to turn the bomb through 90' when the abovetargetstation has been reached, from a horizontal direction configuration to a vertically downward configuration.

3. A bombasclaimed in claim 1 orclaim 2 and wherein the navigation means incorporates means permitting just priorto launch, the input thereto of a signal from an external control as to the location of the above target station, the navigation means being arranged to control bomb direction and altitude thereafter.

4. A bomb asclaimed in claim 1 or claim 2and wherein the navigation means incorporates computer means for determining the above target station location in relation to an intitial location and direction ofthe bomb, and the below station target range, arranged to control the navigation means, and having an input arranged to accept a signal relating to target location from an external supply.

5. A bomb as claimed in anyone of claims 1 to 4 and wherein the warhead trigger means comprises a hydrostaticfuze.

6. A bomb as claimed in anyone ofthe preceding claims and wherein the direction control system is preferably a thrustvector control device arranged to control motor thrust direction with respect to the bomb longitude.

7. Aguided depth bomb substantiallyas here- in before described with reference to any ofthe accompanying drawings.