Even light helicopter drones, like this Schiebel Camcopter S-100 and its side-pylon mounted Picosar, are now able to join the ‘Sar League’ in which membership was hitherto restricted to the larger Male and Hale drones. (Schiebel) (Persistent Threat Detection System), with the company’s 56K aerostat flown at 2500 ft. Tars: Lockheed Martin is also responsible for the US Air Force Tars (Tethered Aerostat Radar System), using the company’s 420K aerostat, with an envelope made by ILC Dover. Flown at 15,000 ft, it gives the Lockheed Martin L-88 radar a range of 370 km. Marts: Employed for communication relay, the Marts (Marine Airborne Re- Transmission System) was developed by Darpa for use by the US Marine Corps in Iraq. The Tcom 32M aerostat takes a 225- kg payload to 3000 ft, giving a radius of 125 km. Jlens: A major advance in aerostats will be achieved by the Raytheon/Tcom Jlens (Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System), which – in combination with the US Army’s IAMD (Integrated Air and Missile Defense) – is intended to provide deployed forces with the detection and tracking of potential threats and targets, including large-calibre rockets, drones and moving surface vehicles. The Jlens will employ the Tcom 74M aerostat, which can carry a 1600-kg payload to a normal operating height of 10,000 ft, with an endurance of one month. The 74M is designed to operate in 130 km/h winds, and survive winds of 170 km/h. Each Jlens system (or ‘orbit’), of which 14 are planned, will employ two aerostats, one with a surveillance radar and the other with a fire control radar for the new interceptor missile, which will have a range of up to 400 km. The Jlens programme was motivated by the failure of US forces to detect the five HY-2/C-201 Silkworm cruise missiles fired at their positions in Kuwait during the 2003 invasion of Iraq. It is currently proceeding on the basis of a $ 1.4 billion design and demonstration contract, awarded to prime contractor Raytheon. This contract includes the delivery of two Jlens orbits. The decision on Jlens low-rate initial production is now due in FY12, and the last orbit is to be delivered in 2019. The programme is expected to total around $ 6.4 billion, each orbit costing approximately $ 360 million. <strong>Sensors</strong> Long gone are the days when the drone’s primary observation weaponry consisted of downward shooting wet-film still and cine cameras whose precious booty had to be laboratory processed before being handed over to the analysts. Digital cameras came of age in the early 1990s and with them the means to transmit live (or almost live) imagery down to base. Now video cameras easily fit into a thimble and are used in the cheapest of drones, the body and wing of which are carved out of polystyrene foam, which makes them almost expendable. After the wet film era, and together with the inception of their electronic counterparts, the next significant step that was afforded by the miniaturisation of electronics was stabilisation, which itself led to what are commonly referred to now as stabilised turrets, or balls. Granted, the ‘older’ cameras could be slewed, but hardly locked on – particularly in space-restricted aircraft like drones, including the larger types. With stabilisation came a host of amenities. First and foremost of course, are clearer pictures, since not only is the relative displacement of the ground target relative to the platform compensated, but so are the bumps, leaps and side-slips of the aircraft in low-altitude turbulent air. Secondly, proper stabilisation came to the rescue of lock-on. Lock-on (which means that, upon command from the ground operator, the camera will keep staring at a given spot) is obtained by an electronic analysis of the pixels in the cross-hairs area. If the ‘target’ is a darker spot and the movement of the camera’s cross-hairs slips into an area of brighter neighbouring pixels, the processor will send commands to the platform to drive the camera back to its original darker spot. If one imagines the number of electronic commands that such a procedure requires, say in one second, one can just as easily understand the benefits derived from a camera that is readily ‘kept still’, because there is a limit (made up of contrast threshold and judder speed) beyond which the lock-on system will simply give up. Finally, stabilisation allows one to obtain a permanent and accurate reading of the three-dimensional geographical co-ordinates of the spot the crosshairs are locked onto and, datalink allowing, these and the pictures are received and read live on the ground. Not only does this enable target data to be forwarded to command for an artillery intervention, or to a bomber aircraft, it also allows the drone to directly and steadily illuminate the target with a laser beam (if the turret is so equipped) to provide a spot for surface- or air-launched laser-guided weapons to home onto. The ultimate refinement is what Flir, for example, terms «Geo-lock», meaning that should the ball be locked onto an object and that an obstacle (a tower, chimney or tall building) temporarily cross the aiming path, the system will anticipate the platform’s motion to immediately and seamlessly re-lock onto the original target once the obstacle is cleared. Evidently, reaction times and the number of sensors housed are what make the difference between the various systems available on the market, but also of course, their size and cost. As usual, it is the mission that drives the requirement, which in turn drives the type of stabilised platform and hence the type and size of drone that is finally required. The most complete stabilised turrets are those that can simultaneously house a day and low-light camera (CCD), an infrared camera, a rangefinder and a laser target designator. The leaders in the field of drone Northrop Grumman has completed flight testing of its Vader, a ground target moving indicator synthetic aperture radar that is able to detect slow moving small objects such as men and animals walking over a wide area. (Northrop Grumman) 34 armada Compendium Drones 2010
Compendium by C4ISR Issue 5/2010 C4ISR systems Network-centricity Fixed/mobile assets Command centres Intelligence analysis The new Compendium C4ISR will provide timesensitive information on modern network-centric warfare techniques. Also distributed at: AUSA, Washington, DC Euronaval, France Military Airlift, UK Idex 2011, UAE Send your signals – provide a coherent message in the new C4ISR Compendium! Advertising deadline 27 Aug 2010 Ad material deadline 1 Sep 2010 Issue date 24 Sep 2010
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