Eurocopter AS 532UL Cougar – Horizon
One of the great concerns to NATO planners during the Cold War was the prospect of swarms of Warsaw Pact tanks quickly breaking through allied defences on the East German border and then running amok on the wide-open plains of North Germany en-route to the Channel Ports. The need existed for a system that could accurately identify vehicles on the ground and then pass targeting information to defending systems. Eventually this requirement was filled by mounting a Side-Looking Airborne Radar on an aircraft - the Grumman OV-1D / RV-1D Mohawk. After the Cold War had ended this concept lead to the Northrop Grumman E-8C J-STARS, RAF’s Sentinel R1 that will enter service in 2007 and the NATO AGS programme.
One of the lesser known programmes to use an airborne radar to identify potential targets is the Eurocopter AS 532UL Cougar Horizon system. The French Army had a long-standing requirement for a system that could assist in identifying vehicle targets for their artillery to engage. Rather than try and develop a fixed-wing system, the French Army decided to mount a radar on their standard battlefield helicopter, the Eurocopter Cougar and create the Horizon – Helicopter Observation and Radar Investigation of Zone. Four helicopters were equipped with the Thompson-CSF Target multi-mode pulse Doppler J-Band radar mounted below the rear fuselage in a retractable rotating antenna and associated electronics. The radar’s antenna has very low side-lobes and frequency agility for resistance to electronic countermeasures, including anti-radar missiles. The radar operate primarily in moving target indicator (MTI) mode, has a range of about 100nms / 160kms from its optimum operating height, a resolution of 10 meters and a target velocity of about 5-170mph. Typically the Horizon would pop-up to its optimum operating height – 8,000 to 15,000ft, from which it can scan nearly 8,000 square miles in 10 seconds, survey the movements of up to 4000 wheeled or tracked vehicles, before descending down rapidly again to get below radar cover. Defensive equipment includes an EW suite consisting of a Thales RWR (Fruit) and a missile-approach warning system (Damien) along with an MBDA countermeasures dispenser (Saphir). The crew of four consists of two pilots, a flight engineer and a radar operator.
The data obtained by the radar is transmitted via a Thales Agatha data-link to the Horizon ground station, with a typical delay of less than two seconds. The operator in the Horizon ground station can enhance the data, validate or invalidate the contact, add some maps or technical data (the crew can also do this in flight) and then send the results to wherever they are required via the Syracuse French military telecom satellite. Currently the French Army are equipped with four Horizon helicopters and two air deployable ground stations delivered between 1996 and 1997, however, the original Orchidee programme which eventually lead to the Horizon system called for a total of 20 Horizon helicopters, but with the end of the Cold War and subsequent draw-down in defence budgets, this number is was scaled back into the Horizon programme and is unlikely to ever be achieved. The Orchidee programme also called for the fitting of a direct datalink to J-STARS, but unfortunately when the Orchidee programme was cancelled this requirement was omitted from the subsequent Horizon programme, something that must have been deeply regretted by many people.
In fact, as the role for which it was originally intended disappeared, the French Army have been keen to find new ways of employing Horizon, less as a tactical and more as a theatre asset. However, as the Horizon was developed solely with when the French Army in mind, when it was first used in support of NATO operations it proved difficult to cross-cue data obtained by the Horizon with data from J-STARS and other sources, in other words Horizon tended to operate in a classic ISR ‘stovepipe’.
The real problem with the Horizon system is that there simply aren’t enough of them to make much of a difference, because the Horizon squadron, attached to the 1st Combat Helicopter Regiment at Phalsbourg, Lorraine, only consists of four helicopters and two ground stations. As a result, in the planning phase of an upcoming operation, although they might well be offered to a theatre commander as an available asset, the possibility of mechanical failure, combat loss or the loss of just one helicopter would seriously degrade the unit’s overall capabilities and, as a consequence, make it unlikely the Horizon system would be given a pivotal role in any critical operation. There is no doubt that the Horizon system works effectively and in the right environment can be a considerable operational asset, however, had the system been originally built with the capability to share data directly with the E-8C J-STARS and other NATO ground assets and if a larger buy of helicopters and ground stations had taken place, the Horizon system would have been requested by NATO commanders much more frequently. Nevertheless, as it is currently equipped it would appear that Horizon is destined to remain a niche French system that lacks the ‘critical mass’ necessary to make the bigger operational impact it actually deserves.
By 2008, in a time of pressure on the French defence budget, the high maintenance cost of keeping the Horizon programme operational was being seriously questioned, particularly as the specific threat that the system was designed to detect had disappeared. Additionally, it was considered there was little likelihood that there would be a need for the Horizon system in the future when quite small UAVs, carrying either electro-optical or synthetic aperture radar systems, can now undertake the task. Eventually in May 2008 it was announced that the four Horizon helicopters and two ground stations would be mothballed, however, I seriously doubt whether these unusual helicopters will ever see operational service again. Although well intentioned, the Horizon programme was just too small and 'French specific' to be of much use when the Cold War ended. The Horizon programme is an example of how, when political/military circumstances quickly change, a niche system suddenly becomes almost obsolete. Also, whenever a new military aerial surviellance system is being planned, if interoperability with other similar systems is not built-in from the start, this may well limit the systems true operational capability, as well as its overall effectivesness and length of service.
Updated May 2008