Roy Braybrook |
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| The V-1 is a useful starting-point for a discussion of present and future cruise
missiles, as it highlighted many of the economic and operational considerations that apply
today. Its merits included day/night all-weather operation, simplicity and low cost of
construction. Approximately 32 000 were made. It was difficult to defend against, since it
had a high speed (644 kilometres per hour), represented a small target and cruised above
the effective reach of light anti-aircraft artillery. On the down side, around 25 per cent of V-1s crashed before reaching Britain, due to poor reliability. Guns and fighters each destroyed about 25 per cent of the remainder, and balloons accounted for a further three per cent. Of the 5000 V-1s launched against Antwerp from October 1944, only 211 reached the target area, largely due to the effectiveness of proximity-fuzed shells. Today's cruise missiles naturally provide major improvements over the V-1 in most respects, although not all are capable of day/night all-weather operation. To achieve a reasonable degree of immunity from air defence systems, the modern missile can employ defensive routing, avoiding known threat areas and making use of the natural screening provided by valleys and mountains. It can also have reduced signatures, and use low altitude, high speed cruise. Navigation accuracy can benefit from the combination of inertial and satellite systems, and by automatically comparing sensed ground profiles and imagery with digitally-recorded maps. In turn, precise knowledge of missile location over a known landscape allows it to be flown low without the use of active sensors. Accuracy in the terminal phase can benefit from human or automatic target recognition. Preliminary damage assessment can be provided by data-linking missile imagery to an aircraft or a communications satellite. The following discussion considers how some leading cruise missiles exploit modern technologies in order to enhance penetration capability, range and navigation accuracy, and to provide improved attack profiles and damage assessment. Warhead technology will be considered separately in Armada 4/99. The Simplest (Corresponding table in this region)The simplest form of a relatively long-range guided weapon is a fixed-geometry glide missile such as the Boeing Jdam (Joint Direct Attack Munition) or the Dasa AFDS (Autonomous Free-flight Dispenser System). A highly effective way to extend range is to add wings of high aspect ratio, which prior to release must be stowed aft in order to permit multiple store carriage. By spreading the aerodynamic lift across a much wider span, the lift-related drag of the missile is reduced, and the glide-slope angle (as dictated by lift/drag ratio) is improved accordingly.
Examples of unpowered air-to-ground missiles with
flip-out high aspect ratio wings include Israel Military Industries' Msov (modular
stand-off vehicle), South Africa's Kentron Raptor 1, and America's Raytheon AGM-154 Jsow
(joint stand-off weapon) pronounced "jay sow."
Tomahawk: The cruise missile that has accumulated
most operational use is the BGM-109 Tomahawk, for which Raytheon is now the single source
(originally developed by General Dynamics and McDonnell Douglas). Some 288 were fired
during Desert Storm, and others have since been used against Iraqi targets (including 23
in June 1993). In August 1998, 66 were fired against terrorist targets in Afghanistan, and
13 against a target in the Sudan.
The Tomahawk can cruise high or low, but its
speed is given as Mach 0.50 to 0.75, and press reports suggest that Mach 0.55 (675
kilometres per hour) at low level is typical. In relation to manned aircraft attack speeds
this is slow, but the Tomahawk can employ evasive routing.
Alcm: The Boeing AGM-86B entered service on the B-52
in 1982, and is in broadly the same weight and range categories as the BGM-109A.
Navigation is provided by a combination of inertial and radar altimeter-based contour
matching. The AGM-86B is supplemented in the US Air Force nuclear weapon inventory by the
stealthy Boeing AGM-129A ACM (Advanced Cruise Missile), which reportedly provides major
advances in range, survivability, accuracy and targeting. Deliveries began in 1990, but
procurement is believed to have been restricted to 1000 units.
In 1998, Boeing was awarded a contract to
upgrade 28 AGM-86Cs to Block IA standard, with jam-resistant eight-channel GPS receivers
and other improvements. The Block II upgrade of the AGM-86C was planned to have a hard
target penetration warhead in the form of either the Royal Ordnance Broach or Lockheed
Martin Advanced Unitary Penetrator (AUP-3M). However, recent reports indicate that there
are problems in achieving the desired impact angle and the necessary accuracy. The Block
II may thus be limited to a 900-kilogram blast-fragmentation warhead. |
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| Lasm: The Gulf War encouraged the development of a range of air-to-surface
and surface-to-surface missiles. One example in the latter category
is Raytheon's proposed Lasm (land attack standard missile), which would
provide the US Navy with mid-range fire support, filling the gap between
gunfire and Tomahawk. The Lasm is currently based on the Standard Missile
2 (SM-2) Block II and III, although the Block IV would reportedly provide
over twice the range. It has Raytheon's GPS-Aided Inertial Navigation
System (Gains) in place of the semi-active radar seeker of the surface-to-air
missile. In baseline form, LASM has a modified Mk 125 warhead that scatters
fragments horizontally from a vertical descent, instead of throwing
them forwards. However, various submunition warheads are also being
studied. LASM appears to be regarded as a viable interim system for
the Navy, pending development of a longer-range ballistic missile. Slam: In a shorter range category the Boeing AGM-84E Slam (stand-off land attack missile) is already available as a derivative of the Harpoon anti-ship missile series. The Harpoon was designed for operation from aircraft, ships, submarines and shore installations. It first flew in 1972, and over 7000 have been ordered, including over 3000 for foreign services. The Harpoon carries a 222-kilogram blast warhead and employs inertial midcourse and active radar terminal guidance.
The Harpoon Block I entered service in 1976 and in 1980 was given a sea-skimming capability to meet British requirements. A similar domestic version was delivered in 1982 as the Block IB. The Block IC of 1984 provided extra range, waypoint navigation and counter-countermeasures improvements. The collapse of the former Soviet Union led to termination of plans to manufacture the stretched Block ID, which would have provided more range and a re-attack capability. However, re-attack is provided by the current Block IG, deliveries of which began in 1997. From 2000 the standard production Harpoon will be the Block II, equipped with the integrated inertial and satnav system from the Jdam. This version will provide capability against shore targets and ships in coastal waters or in harbour. Denmark is buying 50 retrofit kits, and the US Navy has earmarked funding for 300.
Uran & Raduga: The Russian counterpart of the Harpoon is the
Zvezda Kh-35 Uran AS-20/(SS-N-25), which is used in both air- and ship-launched forms. The
first export order is believed to have been for the Indian Navy's Delhi Project 15
destroyer. In broadly the same range class is the heavier air-launched Raduga Kh-59ME
(AS-18). In a somewhat longer-range category, Raduga has offered for co-operative
development the Kh-65SE anti-ship derivative of the strategic nuclear missile.
In addition to new-build Slam-ERs, at least 600 Slams
already in the US Navy inventory are to be upgraded to this standard. The ER is due to
enter service this year on Navy F/A-18s. Automatic target recognition based on stored
imagery from satellites or other sensor platforms is due to be added by next year,
producing the Slam-ER+. Future plans include a ship-launched version, real-time targeting
direct from the sensor to the launch platform, and a 450-kilogram warhead.
Storm Shadow/Scalp EG: The next member of the
Apache family is known as Storm Shadow in the context of the British EF2000, Harrier GR7
and Tornado GR4, and as Scalp EG (Emploi Général) when arming the French Mirage 2000,
2000-5 and Rafale. It retains the same engine as Apache, but has an increased fuel
capacity and a Royal Ordnance Broach tandem warhead. Inertial mid-course navigation is
updated by a Sextant GPS receiver and a terrain reference system. In the terminal pop-up
attack a Marconi/TME Ibis imaging-infrared seeker with Matra BAe Dynamics processing
provides automatic target recognition. |
| Wide angle view | |||
| Imaging infrared | Contoured image | Geometrical reference model | Correlation factor |
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| Narrow angle view | |||
| Imaging infrared 6°x4° | Contoured image | Geometrical reference model | Correlation factor |
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Is seeker technology, both in terms of algorithmic processing and resolution, ripe enough for accurate supersonic attack? These two simulated sequences of an attack from a Matra BAe Apache/Storm Shadow illustrate the difficulty. After radar navigation close to target, imaging infrared angle is narrowed to reduce processing time. |
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Kepd 150: A lighter variant with reduced range (Kepd 150) has been proposed for Sweden's JAS39, and a captive flight of a ballasted mock-up took place on that aircraft in August 1998. LFK has proposed an active radar ship-launched version (KEPD 150-SLM) as a Harpoon replacement for the German Navy, but there are doubts whether that service can fund such a programme.
Future customers for anti-ship missiles may well demand more range than the current generation (a trend exemplified by the 270 kilometres of the KEPD 150-SLM), but there is no consensus of opinion on whether the missile should be supersonic or subsonic and stealthy.
Mupsow: The Mupsow is a South African development on which Kentron has been working under contract from the Air Force since 1991. According to Kentron, full-scale development has now reached an advanced stage, with several glide launches having been performed. No powerplant has been selected so far. Payload would primarily be anti-runway, but unitary high explosive and, more interestingly, "Broach-like" types are envisaged.
France is the leading Western power to advocate the
development of a supersonic anti-ship cruise missile, although Aerospatiale is also
working as a minor partner of Norway's Kongsberg in the subsonic NSM (New anti-Ship
Missile) programme. In October 1998 the Délégation Générale pour l'Armament (DGA)
signed a definition study contract with Aerospatiale for the ANF (Anti-Navire Futur),
based on the Vesta ramjet technology demonstrator, three flight tests of which are
scheduled by 2002.
The ANF will be the West's first supersonic anti-ship missile, but Russia already has two such weapons in service and new supersonic and hypersonic designs in development. The Mach 3 Zvezda-Strela Kh-31A (AS-17) is light enough to be carried by the MiG-29, but is claimed to be effective against vessels of up to 8000 tonnes. It has been ordered by China and India, and a sea-skimming target derivative (MA-31) jointly developed with Boeing has been tested by the US Navy.
The much heavier 3M-80E (SS-N-22), designed
by Raduga and manufactured by Progress, likewise uses a combination of rocket and ramjet
propulsion. It cruises at 2800 kilometres per hour, reportedly at a height of 20 metres,
descending to seven metres in the terminal phase. In addition to its active radar mode, it
can employ anti-radiation and home-on-jam modes. Assessed by Nato as the most potent
challenge to existing shipboard defences, the 3M-80 entered service in 1980 on
Sovremenny-class destroyers. |
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