Rapier (missile) - Operation

Operation

The original Rapier took the form of a wheeled launcher with four missiles, an optical tracker unit, a generator and trailer of stores — the whole system along with crew delivered by two Land Rovers designated as the Fire Unit Truck (FUT) and the Detachment Support Vehicle (DSV). The launcher consists of a large cylindrical unit carrying two missiles on each side, the surveillance radar dish and "Identification friend or foe" (IFF) system under a radome on top, the guidance computer and radar transmitter and receiver electronics at the bottom, and a prominent parabolic antenna for sending guidance commands to the missiles on the front.

By 1980 each Royal Artillery fire unit consisted of a 101 FC 1 tonne 24v Land Rover towing the Rapier Launcher and carrying 4 missiles on board, a 109" 3/4 ton 24v FFR (Fitted For Radio) Land Rover towing a 1 ton MST (Missile Supply Trailer), containing up to a further 10 missiles. Whilst trained to operate Blindfire, it was not normally deployed on UK exercises.

The search radar was of the pulsed Doppler type with a range of about 15 km. The aerial, located at the top of the launcher, rotated about once a second, looking for moving targets that are "visible" due to their doppler shift. When one was located, a lamp would light up on the Selector Engagement Zone (SEZ), a box containing 32 orange lamps arranged in a circle about the size of an automobile steering wheel. The radar operator could also blank out returns from other directions, providing jamming resistance.

The optical tracker unit is made up of a stationary lower section and a rotating upper section. The lower section houses the operator controls, while the upper section houses the tracking optics. The operator's optical system is a modified telescope containing a Dove prism to prevent the image 'toppling' as the optics rotate in azimuth. This system means that, unlike a periscope, the operator does not have to move in order to track the target. The upper section also contains a separate missile tracking system that is slaved to the operator's optics, based on a television camera optimized for the IR band.

Upon detection, the optical tracking system would then be slewed to target azimuth and the operator would then search for the target in elevation. The operator's field of view would depend on the target range, "wide" at about 20 degrees or "track" at about 4.8 degrees. When the target was found the operator switches to "track" and uses a joystick to keep the target centred in the telescope. Once a steady track was established the missile was fired. The TV camera on the tracker was tuned to track the four flares on the missile's tail. Like the operator's telescope, the TV system had two views, one about 11 degrees wide for the initial "capture", and another at 0.55 degrees for tracking.

The difference between the line-of-sight of the operator's telescope and the missile's flare was calculated by the computer in the base of the launcher, and guidance updates sent to the missile over the guidance link, received on small antennas on the rear of the mid-body fins. The operator simply kept the telescope's crosshairs on the target using the joystick, and the missile would automatically fly into the line-of-sight, a system of operation known as SACLOS.

The missile contained a small 1.4 kg warhead with a contact fuse and a single-stage solid-rocket motor that accelerated the missile to about 650 m/s. Engagement time to the maximum effective range was about 13 seconds. Response time from the start of the target detection to missile launch is about 6 seconds, which has been repeatedly confirmed in live firing.