GB2216995A - Stabilised weapon system - Google Patents

Abstract

A stabilised weapon system for use on board a ship comprises a missile launcher mounted on a stabilised platform which may be controlled by gyroscopes and accelerometers fixed either to the hull of the ship or to the platform itself. A radar, infra-red or similar target sensing system is mounted on the same platform as the missile launcher and produces signals indicative of target position. These are compensated for ship movement, detected by the same or further gyroscopes, and the target location used to control the missile launcher. The provision of a combination of sensor and launcher on the same stabilised platform avoids disparity errors between the two systems, provides considerable saving of space on what is likely to be a crowded deck, and minimises or eliminates the need for transformation of co-ordinates between the two systems. <IMAGE>

Description

A Stabilised Weapon System This invention relates to a stabilised weapon system for use on board a ship or other marine platform subject to the instability of sea movement.

Ship-borne missile launchers are known in which the launcher is mounted on a platform stabilised with reference to local earth axes. A target sensing system is provided as a separate entity and mounted on the ship, perhaps remote from the launcher, for best target sensing capability. The effect of ship movement on the sensor can be overcome by providing a dedicated stabilised platform, as for the launcher, or by detecting the ship movement and compensating the output signals of the sensing system accordingly. Such systems have a number of disadvantages but are nevertheless accepted. The disadvantages include a need to transform co-ordinates between the sensor system and the launcher system and an uneconomic use of space which is commonly at a premium in such situations.

According to the present invention, a stabilised weapon system for use on board a ship or other marine vessel comprises a missile launching device, a sensor system for locating a target and providing directional information for the control of the missile launching device, and a common stabilised platform on which the launching device and the sensor system are mounted and with reference to which they are controlled.

The launching device may be rotatable in azimuth on the platform and the sensor mounted on or close to the azimuth axis of the launching device.

The sensor system may be of such extent and positioned at such a distance from an elevation axis of the launching device as to permit an angle of elevation of the launching device of at least 600.

A stabilised weapon system according to the invention will now be described, by way of example, with reference to the accompanying drawings, of which: Figures l(a) and 1(b) are elevation and end-view of a pair of missile launchers and a sensor platform having a common stabilised platform; Figure 2 is a block diagram of the total system components; and Figures 3(a) and 3(b) are diagrams illustrating sensor platform and launcher proximity relationships.

Referring to the drawings, Figures 1(a) and 1(b) show in elevation and end-view an arrangement of a common stabilised platform 1 supporting a pair of missile launchers 4 and a platform 3 for a sensor system. The stabilised platform 1 is mounted on the deck 7 of a ship by means of a gimbal system 9 which permits motion about two orthogonal axes. A control mechanism (not shown), including jacks 6, maintains the platform 1 in a horizontal position for all possible combinations of pitch and roll of the ship during normal operation.

A column 2 is rigidly mounted on the platform 1, so that the column 2 is vertical when the platform 1 is horizontal. The sensor platform 3 is mounted at the upper end of the column 2. Sensors (not shown), which may be radar or electro-optic devices, or both, are mounted on the sensor platform 3. The sensors are capable of searching and tracking approaching missiles or aircraft. A turntable and mounting frame 5 supports the missile launchers 4 and is capable of rotating in azimuth about the axis of the column 2. The sensors are mounted on or close to the azimuth axis of the launchers 4. The mounting frame 5 also allows the missile launchers to be trained in elevation from the horizontal to a high angle of elevation, to project missiles along the tracks 8.

Figure 2 shows in block diagram form the inter-relation of different parts of the system. The platform 1 is stabilised with respect to a roll reference 17 and a pitch reference 18, both references being provided by instruments in the ship. The reference signals are applied to servo-mechanisms 15 via the transducers 16.

The servo-mechanisms 15 control jacks 14, which determine the inclination of the platform 1 with respect to the deck 7 about the two orthogonal axes of the gimbal mount 9 (Figure 1).

The sensor system 10 is linked to the missile launchers 4 by a surveillance and tracking control means 11 which drives an elevation servo 12 and an azimuth servo 13 to direct the launchers to the direction in which the enemy missile or aircraft is found by the sensor system 10 to lie, or to such other angle as is optimum for a successful counter-attack against these targets.

The mounting arrangement is designed to allow the sensors to be mounted in close proximity to the launcher, which minimises or eliminates the need for the control means 11 to transform co-ordinates in directing the defending missiles against their targets, since the common mounting determines a co-ordinate system stabilised in angular reference to local earth axes which can be used by both sensors and launcher. In applications where the deck space of the vessel is restricted, the use of the stabilised platform 1, with the sensor and launcher mountings centred above the same point on the deck, enables the equipment dimensions to be as small as possible without risk of interference between the line of fire of the missiles and the sensors, or undue proximity of the sensors to the efflux from the missiles shortly after launch.The use of the mounting method described is particularly advantageous when targets may be engaged at high elevation angles, i.e. at least 60 degrees from the horizontal. It is also possible that one or more of the sensors having limited angular coverage may be mounted directly on the launcher, but having no axial freedom independent of the launcher.

The use of a stabilised platform means that there is no requirement for any of the sensors or for the launcher itself to have an extended elevation angle scan in order to accommodate ship motion.

The sensors and launcher can use the same set of angular co-ordinates, since the common mounting permits the use of the same horizontal reference plan to which they are both referred by a direct mechanical relationship. Also, no independent control channels are needed for the servo-mechanisms 12 and 13 to take account of ship motion.

Further, the ability to mount the launchers close to the supporting column reduces the moment of inertia of the launcher turntable. This lowers the power requirement of the corresponding servo system, and maximises the slew rate of the system to allow a faster response rate than existing configurations.

The common platform 1 is stablished with sufficient accuracy to avoid the need to couple into the sensor system errors in the direction in which the launchers are pointing from the true target direction. Other forms of stabilised platform, such as a tripod mounting with legs of adjustable length, are suitable as an alternative to the platform mounted on a gimbal system.

As an alternative to the arrangement described with reference to Figure 1, the system may be configured so that the sensors are mounted on the turntable/frame 5 and the launcher on the upper platform 3.

The use of a stabilised platform for the sensors and launching device, provides a number of advantages over an arrangement in which the column 2 is mounted directly on the deck 7. In such an arrangement, the launcher has to be spaced further from the axis of the column, or a longer column is needed in order to allow for ship motion, since the defending missile must clear the sensor platform at high launch elevation angles when the ship deck is at its maximum pitch and roll inclination. The requirement is illustrated by Figure 3. Figure 3(a) shows the arrangement with a stabilised platform where the maximum elevation angle E for the launch of missiles provides a clearance from the upper sensor platform of c, independent of the deck inclination I.If a column of the same length is directly mounted on the deck (Figure 3(b)), as in prior art systems, the clearance c is reduced at the same elevation angle E due to the deck inclination I. To achieve the same clearance as in the stabilised platform arrangement, it is necessary to space the launcher further from the axis of the column, or to use a longer column so that the separation of the sensors and the launcher is greater. This increases the requirement for deck space or increases the height of the equipment.

Although the embodiments described have referred to a pair of missile launchers, the system may incorporate a launcher capable of firing a single missile or several missiles in parallel tracks. The system may also include guns firing conventional projectiles in place of, or in addition to, missile launchers.

Although described for use on board a ship or other marine vessel, the stabilised platform system may be suitable for use on other forms of transport, such as land vehicles, where the mounting surface on the vehicle is subject to a changing attitude with respect to the surrounding terrain.

Claims (4)

1. A stabilised weapon system for use on board a ship or other marine vessel, and comprising a missile launching device, a sensor system for locating a target and providing directional information for the control of the missile launching device, and a common stabilised platform on which the launching device and the sensor system are mounted and with reference to which they are controlled.

2. A weapon system according to Claim 1, wherein said launching device is rotatable in azimuth on said platform and said sensor system is mounted on or close to the azimuth axis of the launching device.

3. A weapon system according to Claim 2, wherein said sensor system is of such extent and is positioned at such a distance from an elevation axis of said launching device as to permit an angle of elevation of the launching device of at least 60".

4. A weapon system substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.