Sensor to Shooter: Heron UAV puts in 80 hours of maritime surveillance | ADM Aug 08

Customs’ recent trial of the Heron mid-range UAV saw the aircraft undertake some 80 hours of maritime surveillance over large areas of the Gulf of Carpentaria, the northern section of the Great Barrier Reef marine park, and the Torres Strait.
by Julian Kerr

The trial was the first time a large UAV - the Heron is nearly eight and half metres long and has a wingspan of 16.6 metres - had been on the Australian civil aircraft register.

It was also the first time a large UAV had flown both visual and instrument flight rules in non-controlled Australian airspace.

Brendan Kosmer, Capability Development Technical Manager of Australian Customs, told ADM, “On the longest flight the UAV was taken to 15,000 ft, although it’s capable of flying quite happily to more than 30,000 ft.

"While we were flying under civil regulations we still had a fair bit of freedom in the sense we had aircraft detection capability and the ability to communicate, so to all intents and purposes to ATC (Air Traffic Control) and other airspace users we were just another aircraft."

A report on the trial was has been delivered to Customs and the cost- effectiveness of this type of UAV will be evaluated against other methods of surveillance.

According to Kosmer all the objectives of the four-week trial had been achieved, notwithstanding its delayed start from August last year until May.

This was caused by what he described as technical difficulties with the platform experienced by its manufacturer Israeli Aircraft Industries (IAI), who won the competitive tender for the trial with a bid of $5.5 million.

Informed sources attributed the nine-month delay to problems in integrating the sensor suite onto the aircraft.

Some $9 million was originally allocated for the trial, and the balance of the budgeted amount has been returned to government.

Kosmer emphasised Customs’ interest in mid-range technology – which in the case of the Heron provides a platform with a maximum speed of 207 kph, a range of 3,300 km, a service ceiling of 32,800 ft, and a sensor payload of up to 250 kg.

While the trial was structured to carry out wide area and targeted surveillance, the post-trial analysis is looking at the advantage of midrange UAV technologies compared to alternative surveillance assets; communications capabilities; the suitability of mid-range UAVs for various operational scenarios; and their cost-effectiveness compared to other surveillance resources which are available or currently being deployed.

Customs trialled the small Aerosonde UAV in 2004 but concluded its 5 kg payload was not sufficient to conduct the types of surveillance required.

These requirements were detailed in the tender document for the recent trial as wide area surveillance focusing on programmed missions that: develop maritime domain awareness through the detection, classification, identification and reporting of non-alerted targets; satisfy client surveillance requirements; and provide a deterrent effect.

Targeted surveillance, as set out in the tender, encompasses the detection, classification, identification, reporting and tracking of specified targets.

The latest trials were based from the commercial airfield at Weipa, on the Cape York coast, under the direction of Customs using a single IAI ground station and IAI pilots, sensor operators and technicians.

According to Kosmer, this technology would normally operate with a crew of three or four.

However, for the purposes of the trial, IAI provided what he described as a “significant” number of specialists to deal with any issues and as a result the trial progressed smoothly.

Although the Heron is capable of autonomous takeoff and landing this was not a trial requirement.

Since this mode would have required additional ground survey and infrastructure, manual operation was chosen to save both time and money.

(Should communications with the ground station be lost, the Heron can autonomously return to base and land).

Two test flights were undertaken, the first to check the airframe after assembly and the second to test the sensors.

Both flights were under observation by the Civil Air Safety Authority (CASA) to verify airworthiness and to confirm the correct functioning of the ELTA 2022 maritime surveillance radar aircraft detection capability.

This multi-mode radar incorporates simultaneous 360 degree surface and air search capability for detecting vessels and aircraft - a critical requirement for the trial to progress forward.

Other surveillance sensors included in the Heron’s payload were a stabilised electro-optic/infrared sensor for target classification and identification; the SAAB R4A Automatic Identification System (AIS) for maritime vessel identification; and a VHF relay for both aviation and maritime frequencies.

Eight operational trial flights took place, most under 10 hours but one of about 15 hours which was close to the UAV’s maximum endurance with the full sensor suite aboard.

Kosmer said each flight focused on a particular aspect of UAV and sensor capabilities.

The aircraft flew a predetermined flight path, but was not limited to that particular route.

“It wasn’t a case of let’s get as much data as possible on as many things as we can while flying; it was a case of let’s test the sensors until we’re satisfied we understand how they work so we can then use that information for consideration of UAVs in future scenarios”, he commented.

The trial flights were generally conducted below 10,000 ft, with most of them below 4,000 ft.

“We worked with IAI to determine the optimum attitudes depending on what we were hoping to achieve on particular flights – after all, they’re the ones who have been operating UAVs for many years.”

Line of sight communications from the ground control station to the UAV extended to about 40 nautical miles depending on the altitude being flown.

Commercial satellite links were used beyond that distance, with data being received back from the aircraft with a time lag of about half-a-second.

The UAV located and tracked various civilian vessels of opportunity, some of which were then spoken to via the marine VHF relay aboard the Heron while the UAV was at ranges of 50 to 300 miles from the ground control station.

’Hot handovers’ to or from the UAV and Coastwatch aircraft were not undertaken because of time constraints and operational requirements but, according to Kosmer, “We know it can be done, that’s procedural, it doesn’t involve specific UAV technology beyond what we’re already trialling”.

Weather conditions ranged from clear skies through to strong winds and rain, which meant the UAV had to be flown at lower altitudes to improve visibility for confirming vessel identification.

“We actually pursued surveillance in what you’d call unfavourable conditions to see how the system performs in adverse weather”, Kosmer said.

“If you get torrential downpours you’ll be affected by downdraft just like any other aircraft. Because the Heron has quite a long wingspan it may be affected by turbulence, but there wasn’t any weather encountered during the trial that made it necessary to return home."

The results of the 2006 North West Shelf UAV trial, involving a Mariner-configured Predator B UAV and an Armidale class patrol boat, were taken into account in structuring the latest tests, Kosmer said.

“Having knowledge of that allowed us to maximise outcomes to avoid duplication of what had already been done.

“However, the NW Shelf trial was Defence-led and had Defence-orientated aims and outcomes to achieve.

"Ours was a Customs trial tailored to outcomes that will provide valuable information for the use of UAVs in civil applications."

Copyright - Australian Defence Magazine, August 2008