Land Warfare 2011: NZ UAVs | ADM October 2011
Nick Lee-Frampton | Wellington
Some five years after the New Zealand Army adopted an indigenously designed and developed Unmanned Aerial System (UAS), the electrically powered Kahu (Hawk) has progressed to providing operational intelligence, surveillance, target acquisition and reconnaissance (ISTAR) both domestically and overseas.
Developed originally from research by the Defence Technology Agency (DTA), the Kahu UAS has progressed to certified and rigorous training and the Army’s UAS battle lab has expanded the ways in which Kahu is used and deployed.
The DTA’s Sensor Systems Group started core research on UAS in 2000. The NZ Army and Navy expressed an interest in small, inexpensive UAV systems for use in patrol or small unit operations and in 2005 DTA was tasked to develop a system for experimentation. A major goal was to produce an autonomous system that required minimal operator intervention and training.
The Kahu UAS consists of five major components: a lightweight airframe optimized for long duration flights; advanced autopilot suitable for any small UAV; the ground control station for high level control and mission planning; the vision module to provide image stabilisation and geo-referenced mosaicing; and the payload, options for which include EO/IR sensors and/or an environmental sensor package.
Just a few months ago the Army flew the lithium-ion polymer battery powered Kahu to a height of 13,000ft, although the height was limited by airspace restrictions rather than UAS capability.
Moreover, during the recent Exercise Viper, Kahu achieved more than 30 flights in 14 days in spite of winds of more than 40 knots.
Versatility was enhanced with the UAS being launched and recovered by one ground control station (GCS) while live imagery and flight data was received by a second GCS in another location several kilometres away.
In another variation, Kahu was launched from a mobile GCS which then shut down and was driven five km away from where it recaptured and recovered the orbiting UAS. This indicates the customary crawl, walk, run approach is making real progress: some four years ago the UAS battle lab controlled Kahu from a moving Light Operational Vehicle (LOV) equipped with a GCS.
ADM understands the GCS can be transitioned from a static two-man team to a LOV mounted installation in some 15 minutes, so clearly there is flexibility when it comes to control of the UAS.
Flexibility too in terms of duration for the NZ Army says it has achieved more than four hours of continuous surveillance on a single location, using two Kahus and two GCS.
Another development is the use of a parachute to land the 3.9kg Kahu safely. According to the Army, use of the ‘Parachute Flight Termination System’ has reduced attrition and damage to the UAS when landing from some 50 per cent to less than five per cent.
A further refinement is the Army’s trial of a bungee launch system. Normally launched by hand, using a bungee launch system will be significantly more effective for take-offs, both at high altitude and in low winds.
Skycam developed the bungee launcher for their 7kg Skyclops UAS, which has a 3m wing span and a wider fuselage than Kahu.
As well as improved methods of launch and recovery and expansion of the GCS parameters, Kahu now comes with a fully gimballed camera, able to move through 360° and thus providing far greater coverage than the static downward facing camera used hitherto.
ADM asked Skycam for further details on the launch and recovery systems and the wing design of Skyclops but the company said it was not at liberty to discuss such matters.
Last year Skycam told ADM that Skyclops was expected to have three times the endurance of Kahu and to cruise 18 km/h faster. Which equates to some six hours and almost 80kmh respectively.
Subject: Air