Howard Gethin/LONDON
Long-range precision strike remains an ability all commanders desire, but the cost and complexity remain high. Using manned strike aircraft allows a man-in-the-loop and lots of firepower, but is expensive and vulnerable, especially over a battlefield.
Artillery cannot strike in depth beyond about 40km (25 miles), even with extended range ammunition and, once a shell has left the barrel, the damage is all but done to friend, foe or bystander.
Commanders are now offered what is claimed to be a unique system. The Trilateral Fibre Optic Missile (TRIFOM) project will allow high value point targets to be attacked in depth, with hitherto unseen capabilities. The system, developed by France, Germany and Italy, is based around the Polyphem missile.
INTELLIGENT ARTILLERY
The Polyphem acts as intelligent artillery, but with a range of 60km (the initial requirement of 30km was extended). The TRIFOM requirement was for a weapon capable of attacking targets in depth, with a first-time direct hit. The weapon had to be non-specific (able to engage a range of targets), be highly mobile (with relocation possible in around 2-3h), supply real time information to the operator, be controlled all the way through the engagement, and only need a rough target location at launch - about 300-400m (1,000-1,300ft) accuracy.
The core of the system is the Polyphem's unique guidance, a high-resolution 3-5 micron imaging infrared camera sending data back to the operator in real time via a fibre-optic cable. The missile is fired from a launcher based on a container, with four launch vehicles, each with 12 missiles connected to a mission planning and command vehicle. Reaction time from set-up to launch is around 30min, with flight time to maximum range of around 6min.
The Polyphem is a 130kg (280lb) weapon, 2.7m in length, with a 20kg shaped charge warhead with preformed fragments. The missile is powered by a rocket booster, and a turbojet sustainer engine which starts when the weapon reaches 29,500ft/min (150m/s). At the rear of the missile is the tubular bobbin, which pays out fibre-optic cable for the datalink. Four large mid-mounted wings fold out after the weapon leaves the launcher.
The fibre-optic link presents the operator video data of the target, as well as passing commands from operator to missile. Fibre-optics offer the advantage of being jam-proof, as well as offering transmission rates as high as 200 megabytes/s. Unwinding a fibre at speeds of up to 35,430ft/min (maximum speed) has been the greatest challenge, concedes project manager Jean-Paul Roves.
"We have tested the bobbin out to 60km on a C-22 target and validated the system," he says.
The thin fibre-optic cable is potentially the most vulnerable part of the system, but Polyphem programme manager Frederic Donnaint denies the link has caused problems in flight over terrain. He points out that cruise altitude to the target is around 120-250m, well above the tops of trees or power lines.
The slow flight speed (which is selectable, between 23,600-35,400ft/min, or 250-375kt) would also render the missile vulnerable to short range air-defencesystems, although it has a smaller infrared signature than that of a rocket, and can attack from any direction to avoid defences, including steering through those en route to target.
Another potential problem is that the launcher will need to remain static during firing, with cable break likely if the launcher moves.
The TRIFOM programme began with an initial research memorandum of understanding by France and Germany in May 1991, leading to windtunnel tests of the missile in 1992. Italy joined the project in 1994. Ramp tests of the missile airframe were carried out in 1995, to check the survivability of the fibre-optic link in the harsh acceleration which is experienced during rocket motor launch.
Further benchtests were also carried out in 1995, including a 60km flight test on a C-22 target, a record distance for a fibre-optic link. The first canister launch was made successfully in Sardinia in January 1997. The missile made its first simulated attack flight trial in April 1997 (without a warhead), hitting the target.
Full system evaluation should be completed by the end of 2000, leading to project definition in 2001. The system will begin its development phase from 2002-5. Production is slated to begin in 2006.
The missile's data transfer ability allows almost unprecedented flexibility to the operator. Not only does he have a high resolution image all the way to the target, allowing the missile to be effectively an expendable unmanned air vehicle, but it can also be aimed precisely where it is needed.
As such, it can be aimed to "warn off" an adversary - an unlikely need in wartime, but extremely useful in high tension situations like peacekeeping missions, where a demonstrable threat of lethal force can be very useful.
The control issue is also invaluable because an engagement can be stopped by the operator with only a few seconds to go. Not only does this allow the prevention of "friendly fire" incidents, it also allows the operator to snap from low-value targets to better ones suddenly seen in the field of view in the terminal phase of the attack. Attack break-off can be carried out with the weapon as close as 280m from the target, according to Roves.
Typically, the target will be acquired between 3km and 8km, depending on size, around 20s to 40s from impact. A high level of automation is possible for the attack to reduce operator fatigue in the cruise phase. The system is designed to be fully automatic, with the operator merely validating the automatic engagement selection and adjusting the final aim point if need be.
TYPICAL TARGETS
Typical high value targets for the Polyphem will be armoured vehicles, air defence radar and missile sites, helicopters and enemy artillery systems. The small warhead does not make it suitable for attacking large structures or hardened targets, but the accuracy of the weapon makes a small ship a worthwhile target because a crucial part, like its main armament or sensors, could easily be selected for attack, leaving it essentially defenceless.
Although the system has hitherto been installed only in a standard German army truck-mounted container, other potential launch platforms could include light vehicles or small helicopters.
The German navy plans to use the missile on its new K-130 class corvettes, taking advantage of the missile's sea-skimming ability.
Source: Flight International
