Crotale Low-altitude Surface-to-Air Missile System

Development

In 1964, South Africa placed a development contract with the French company, Thomson-Houston (later Thomson-CSF) for a mobile, all-weather, low-altitude surface-to-air missile system. The Electronic Systems Division of Thomson-CSF was prime contractor for the complete system including the radar and electronics and Matra was responsible for the missile. The South African government paid 85 per cent of the development costs of the system, which it calls the Cactus, and the remaining 15 per cent was paid by France. After trials in 1971 the first of seven platoons was delivered to South Africa with the final one delivered in 1973. In February 1971, the French Air Force placed an order for one acquisition vehicle and two firing units which were delivered in 1972. After extensive trials with these units the French Air Force ordered the Crotale (Rattlesnake) system for airfield defence and by late 1978, 20 batteries had been delivered. Lebanon ordered the Crotale in the late 1960s but the order was cancelled before the systems were delivered. In 1975, Saudi Arabia ordered a new version of the Crotale, mounted on the chassis of the Giat Industries AMX-30 MBT known as the Shahine, for which there is a separate entry in this section, as the system has a number of improvements over the standard Crotale. The Saudis also ordered the standard Crotale in late 1978 and an upgraded version in 1990 for their air force.

As produced, Crotale is normally mounted on a P4R (4 x 4) vehicle and can also be shelter-mounted for use in static defence (qv Shelter- and container-based surface-to-air missile systems section). The first Crotale, produced in 1969, was called the 1000 series. This was followed by the 2000 series in 1973 with IFF and TV camera, the 3000 series (originally designed for the French Air Force with automatic TV tracking) in 1978, 4000 series with radio datalink in 1983, the 5000 series in 1985 and the improved Crotale in 1994. Crotale 3000 fire and acquisition units are not ready for action as soon as they come to the halt but have to be connected together by cables at a maximum distance of 800 m apart. The 4000 series has the LIVH (Liaison Inter Vehicule Hertzienne) radio link and mast which not only allows them to come into action faster but also to have up to 10,000 m between the acquisition units and 3,000 m between the acquisition unit and its firing units. The evolved system includes a better ECM performance and the passive tracking (by FLIR) of targets and missiles in both day and night conditions. The 5000 series was designed for a French Air Force modernisation programme and included the addition of an optical tracker and new antenna that extended the surveillance range to 18,000 m. The system was also modified to accept two Matra BAe Dynamics Mistral missiles on either side of the two container-launcher canisters to help defeat saturation attacks but these were never fielded in practice. In November 1988, at the second ASIANDEX exhibition in Beijing, the China Precision Machinery Import and Export Corporation (CPMIEC) revealed the FM-80 land-mobile shelter-mounted surface-to-air missile system on two-axle trailers. The FM-80 is very similar in concept to the Crotale shelter-mounted version and its naval equivalent. Details of FM-80 are given in the Shelter- and container-based surface-to-air missiles systems section under China.

Description

The basic Crotale has an all-weather capability. A typical platoon consists of one Acquisition and Co-ordination Unit (ACU) and two to three firing units, with a battery having two platoons. All the operators, have one ACU vehicle to two firing units with the exception of Libya and Bahrain, which have one ACU vehicle to three firing units. The system cannot operate on the move but takes less than 5 minutes to become operational once it has stopped. Once the target has been detected the missile can be launched within about 6.5 seconds. The system has been designed to combat targets flying at a speed of M1.2 at an altitude of 50 to 3,000 m and an equivalent radar area of 1 m{2} fluctuating. Data are transmitted from the Crotale 4000 ACU to the Crotale 4000 firing units via a cable that allows operations up to 800 m away or via a radio link.
Both vehicles have an all-welded steel hull with the driver at the front, electronics and operators in the centre and the thermal motor at the rear. There is a door in the right side of the hull which opens to the rear. Energy is provided by the thermal motor. An alternator, driven by the thermal motor, produces power, the output of which is rectified and then fed to a series of DC motors which in turn drive each of the four roadwheels by epicyclic reduction gears. Sufficient electric power is provided for all the vehicle's electrical systems including the electronics, air conditioning system and the hydraulic circuit which operates the three levelling jacks, steering, suspension and brakes. Each roadwheel station has a hydraulic and pneumatic suspension system designed by Messier. This acts as a pneumatic spring, suspension spring and shock-absorber simultaneously. The position of each jack is controlled by a selector valve connected to a differential gear and the driver has a lever which enables him to select one of five positions.

The ACU carries out target surveillance, identification and designation. Mounted on the top of the vehicle is a Thomson-CSF E-band Mirador IV pulse Doppler radar with fixed-echo suppression which rotates at 60 rpm and has a maximum detection range of 18.5 km against low-level targets with speeds of between 35 and 440 m/s and altitude limits between zero and 4,500 m. The system also has an IFF interrogator-decoder, a non-saturable extractor, real-time digital computer, display console and a digital datalink for transmitting information to the firing units. The computer, which is the same as that installed in the firing unit, is used to generate accurate data for confirmation of threat evaluation. Thirty targets can be processed per antenna revolution with the 12 most dangerous targets automatically evaluated and tracked by the system. Once the target has been detected, the computer triggers the IFF interrogator and the final threat information is displayed. The target is then allocated to one of the firing units and target designation data and operational orders are transmitted by the datalink which also supplies information from the firing unit on operational status, for example, the number of missiles available.

The firing unit has a J-band monopulse 17 km range single target tracking radar mounted concentrically with the launcher turret, which carries four ready to launch missiles, two each side. The system also has an I-band 10 antenna beamwidth command transmitter, differential angle-error measurement infrared tracking and gathering system with a +-5 wide field of view (and in French Air Force systems a further narrow field of view mode for passive operations), an integrated TV tracking mode as a low-elevation back-up, an optical designation tripod-mounted binocular device (which is controlled manually by a handlebar arrangement and used primarily in a heavy ECM environment or whenever passive operation is required), digital computer, operating console and a digital datalink. All the vehicles are fitted with an inter-vehicle link network to transmit data and orders by cable and for radio communication by a VHF radio link. The radar can track one target and guide one or two missiles simultaneously. The missiles, fired 2.5 seconds apart, are acquired immediately after launch by the 1.1 tracking beam of the radar with the help of infrared detection and radar transponders during the gathering phase. Initially the transponder was the 8,000 m range Thomson-CSF Stresa but this was replaced in 1990 by the Thomson-CSF RTKu M Ku-band which has an extended operational range of 10,000 m or greater and uses a solid-state transmitter with integrated processing. There is also a TV tracking mode possibility. Guidance signals are transmitted to the missiles by a remote-control system.

No spare missiles are carried on the vehicle and fresh missiles are brought up by a truck and loaded with a light crane. A well-trained crew of three can load four missiles in about two minutes. The missile is designated the R440 and weighs 84 kg, has an overall length of 2.89 m, span of 0.54 m and a diameter of 0.15 m. The missile complete with its transport/launch container weighs 100 kg. The HE high-energy focused fragmentation warhead in the centre of the missile weighs 15 kg, has a lethal radius of 8 m for the 2,300 m/s velocity fragments and is activated in the original R440 missiles by either the infrared proximity fuze (the fuze is commanded to activate 350 m before interception) or back-up contact fuze. The missile has an SNPE Lens III rocket motor with 25.45 kg of solid propellant powder. The missile reaches a maximum speed of 750 m/s in 2.8 seconds. The Naval Crotale fires a slightly modified missile, the R440N fitted with a Thomson-CSF FPE pulse-Doppler I/J-band proximity fuze. For 1 m{2} radar fluctuating cross-section targets with velocities of 50 and 250 m/s respectively the engagement parameters in Table 1 apply.

Table 1. Velocity 50 m/s 250 m/s Head-on target (maximum operational intercept range) >10,000 m 9,500 m (minimum operational intercept range) 500 m 500 m Crossing target (maximum operational intercept range) 9,700 m 5,500 m (minimum operational intercept range) 500 m 2,000 m Target altitude (maximum) >5,000 m 4,500 m (minimum) 15 m 15 m {ct} The Single-Shot Kill Probability for a single missile is 0.8 and for a salvo of two 0.96. The missile is itself capable of the following performance:

Range Manoeuvrability* Flight time 5,000 m 27 g 10 s 6,000 m 18 g 13 s 10,000 m 8 g 28 s 13,000 m 3 g 46 s

Note: * The manoeuvrability (or load factor) of the missile in terms of time is the maximum number of g which can be applied to the weapon in pitch and/or yaw when under guidance. The maximum range to which Crotale has been guided against a slow moving target (for example, helicopter) is 14,600 m. Minimum flight time is 2.2 seconds (the time required to arm warhead section)
. In early 1987, TDA tested a new HE fragmentation warhead for Crotale. This uses a time-space convergence technique to ensure that the warhead fragments arrive coincidentally within a 40 cm band at a distance of 5 to 8 m irrespective of the missile/target miss distance. The fragments are capable of penetrating up to 10 mm of steel plate within this range or severing the aluminium alloy body of a missile.

SPECIFICATIONS :

R440 Missile
Length: 2.89 m
Diameter: 0.15 m
Wing span: 0.54 m
Launch weight: 84 kg
Propulsion: solid propellant rocket motor
Guidance: command control
Warhead: 15 kg HE fragmentation with contact and proximity fuzing Max speed: 750 m/s
Max effective range: see text
Min effective range: see text
Max effective altitude: 5,000-5,500 m (depending upon target velocity)
Min effective altitude: 15 m
Reload time: 2 min (full 4-round load)

Status : Production as required (over 250 ground systems, 25 naval systems and some 7,000 missiles by 1997). Pakistan 11 acquisition units and 23 missile batteries for Air force

Marketing is now being concentrated on the Crotale NG covered in the previous entry and on the improvement of delivered Crotale systems to cope with the modern battlefield threat, that is ECM resistance and enhanced operational characteristics (using new planar antenna, associated data processing and ECCM devices, fully automatic optronic target and missile tracking mode and hypervelocity VT-1 missile). The naval version, Navale Crotale, has been sold to the People's Republic of China, France and Saudi Arabia.

COMPANY NAME : Thomson-CSF Airsys