Aerosonde Robotic Aircraft

Visit to Aerosonde Thursday 9 September 1999

Tom Worthington

Draft 1.0, 16 September 1999,

The photos

Aircreft Diagram Engine Avionics
  1. Fitting the wings to the Aircraft: Also note the carbon fibre of the front payload section and red storage batteries.
  2. Diagram: showing location of the battery, avionics, fuel, engine and propeller.
  3. The Aerosonde uses a model aircraft engine, modified to run on aircraft fuel and to increase efficiency
  4. Avionics: One box contains the electronics for controlling the aircraft, including GPS satellite navigation, inertial gyroscope navigation, a 9600bps digital radio link.
Front Door of Aerosonde Stained Glass at Front Door Ceiling Panels in the workshop.
  1. Front Door of Aerosonde
  2. Stained Glass at Front Door
  3. Ceiling Panels in the workshop: The ornate wall and ceiling panels contrast with the high technology nature of the enterprise.


Aerosonde is a small robotic aircraft designed for collecting meteorological data. It is claimed to be the first robotic aircraft to cross the North Atlantic Ocean and smallest aircraft to do so (3,200 kilometres in 26 hours). The Aerosonde's development by the Aerosonde Robotic Aircraft Pty Ltd in Melbourne illustrates some of the potential and the frustrations of high technology development in Australia. In September 1999 I visited Aerosonde's staff in Melbourne and here describe the aircraft and suggest how it has potential as an observation platform for military and civilian applications.

Aircraft Characteristics

Some specifications from the Aerosonde home page [NOTE: Aerosonde became part of Textron Systems Australia in 2007]:
Table 1. Aerosonde Robotic AircraftTM Mark 2 Specifications
Weight, wing span 13-14 kg, 2.9 m
Engine 26 cc, Avgas 100LL, 1kw normally aspirated
Navigation GPS, DGPS, automatic storm/front tracking
Staff for Launch and Recovery 3: Controller, Engineer, Pilot/Maintenance
Staff for Flight Operations 1 Person for 2-3 aircraft
Ground Equipment Proprietary Staging Box, Personal Computer GPS Antenna,
Flight Fully autonomous, under Base Command
Takeoff, Landing Car roof rack, belly, Autonomous or with pilot
Ground & air communications UHF to Aerosonde, VHF to FSU and other aircraft , Dial modem link to remote command
Speed, Climb 18 - 32 ms-1, Climb 2.5 ms-1
Range, Endurance >3000 km , >30 Hrs
Altitude Range 100 m - >5000 m (intermediate weight)
Mean Time Between Failures 200 h
Payload Maximum 2 kg with full fuel load
Standard Instrumentation
Temperature, Pressure, Humidity, Wind 3 Vaisala RSS901 Sondes <0.1oC, <0.2 hPa, <2% Humidity, Proprietary wind <0.5 ms-1

What these specifications don't convey is how small and light the aircraft is. The wingspan is about the same as my outstretched arms. The wing and twin tail assembly can be easily lifted with one finger. The fuselage is made of composite material (carbon fibre and glass resin), which looks like fragile packing material, but is designed to be strong enough to fly the aircraft into a cyclone. The fuel tank would be too small for a hedge-trimmer, but holds enough to cross a continent.

Why Was I there?

In 1996 I transmitted photographs to the Internet from a hot air balloon over Canberra. This was done as a publicity stunt, using a consumer digital camera, laptop computer and GSM mobile telephone. After the flight I speculated on how the equipment might be built into a model aircraft and used as a low-cost surveillance platform over a city.

In 1998 I read a press report that something called an of the Aerosonde had crossed the Atlantic. It was startling to read that it was Australian designed and backed by the Bureau of Meteorology, not an organisation one would think of being involved with aircraft design.

In July 1999 I left the Department of Defence to become an independent contractor and researcher. In my first non-defence presentation I nominated the Aerosonde as a technology which could be developed in Australia for military and civilian activities:

Low Cost Surveillance Platform: In place of high cost surveillance aircraft, the use of small pilot-less aircraft could be developed. The Australian Bureau of Meteorology already has done work in this field.

There currently exists a gap in the military market for surveillance aircraft for military and civilian use. There are large, long range, long duration surveillance aircraft (based on civilian passenger aircraft design) and small, short range pilot-less craft (which look like model aircraft). However, technology now makes possible small, long range, long duration pilot-less craft. The BoM's Aerosonde robotic aircraft , has flown non-stop 3200 kilometres across the Atlantic Ocean.

Small long range aircraft could be used for military observation, early warning and communicates relay, in place of large manned aircraft. They would also have application for civilian crop observation, bush fire and flood observation.

This proposal drew a sharp reaction from the Defence Science and Technology Organisation (DSTO), who considered funding Australian organisations to research, test and export such IT products for dual military and civilian use as "bizarre". This reaction may have been because the proposal was to transfer funding for the work from DSTO and due to problems with their Global Hawk project.

More positively, in response to the item, I received an invitation from Dr. Greg Holland, Program Leader and one of the originators of the Aerosonde concept, to visit and see the aircraft. Greg was away when I visited, so Brian Taylor, Business Manager, gave me a tour of the Aerosonde facilities.

Global Hawk

On 1 March 1999 the Minister for Defence, announced a $A30 million agreement for DSTO to work with the USA on Global Hawk. The Global Hawk is the size of a business jet and designed to fly for 38 hours, at altitudes of 20km (65,000ft), with high-resolution radar, optical and infra-red sensors, and a satellite communications and navigation system.

If it could be made to work, the Global Hawk would be a far more capable system form major military operations than something based on the Aerosonde, but perhaps less practical for current requirements. In any case, on 30 March DSTO explained that the Global Hawk has crashed during a developmental flight in the United States and there have been few reports of progress from DSTO since then.

Aerosonde Melbourne

Aerosonde has 16 staff, 12 of whom are at two locations in Melbourne and 4 at its subsidiary Aerosonde North America. I visited the temporary business HQ and technical facilities at Hawthorn East, Melbourne. In doing the usual on-line background checks, which I do before visiting any on-line organisation, I discovered the worrying fact the office wasn't listed in the phone book. A web search showed a restaurant at that street address. This was easily explained on arrival, as the restaurant had a few months before moved out of the building.

Aerosonde is located in "KAWARAU", a national trust listed historic building. Like the Australian Technology Park in Sydney, Aerosonde appears almost embarrassed about being located in an old building with character, rather than an anonymous modern steel and glass structure. Unfortunately whilst there is the pleasure from working in an historic mansion, its limitations mean that Aerosonde are moving to new premises in the near future to allow all the Australian operations to be under one roof.

The historic building has a 3m satellite dish out the back and a 2m radome on the roof, used for meteorological satellite receiver R&D by an associated company (I don't know how they got the dish on the roof past the historic houses people). Passing through the impressive stained glass entrance, the production area & laboratory is located at the back of the building in a carved wood panel room, with ornate fireplaces and wood and plaster patterned ceiling.

Sitting incongruously within the ornate walls is a modern robotics workshop. Like the Robotic Systems Lab at the Australian National University, Aerosonde is a curious mixture of old fashioned engineering, with gears and motors, plus advanced computer technology. There were parts for about a dozen Aerosondes around the room, nose cones, wings and fuselages. One aircraft was on a frame being assembled for a project.

One of the most interesting comments from my visit was when I asked what I could take photos of and if there was any commercial-in-confidence technology I shouldn't mention. Brian's response was: "you can photograph anything, the confidential stuff is in the software".

The Aerosonde looks like a large model aircraft, similar to those flown by hobbyists. Some of the components, such as servo motors to control ailerons are model aircraft components. The engine is a model aircraft one, heavily modified for efficiency and to run on standard aviation gasoline. However, what makes it more than a model and makes it a robot is the software.

The Aerosonde's software allows it to fly autonomously, after manually controlled take off. The aircraft will fly a pre-programmed route, but can also deviate from this to follow interesting meteorological events, such as a storm-front. The aircraft can be given new instructions in mid air via a digital radio link. It can send back data when in radio range, or store it up for later retrieval.

Business Model

It would be reasonable to assume that Aerosonde is in the business of building and selling robotic aircraft. But while they would presumably happy to sell you some, the business model is actually to operate them for others.

In the long term they envision a global aircraft operation, with a central control facility in Melbourne. Aircraft would be serviced around the world and after launch controlled by the global center.


The Aerosonde's advantages are also its limitations: it is a small, relatively slow propeller driven aircraft with only one engine. It would take many hours to reach a remote location and can't carry much of a payload. The aircraft is difficult to detect on radar and difficult to see, which makes it hard to use where there are conventional aircraft present. Aerosonde is a small start-up company with ambitious plans, but needs support to realise its ambitions. A major issue is if it should stay in Australia battling with limited resources, or move to the USA with better Government and industry backing.

Aerosonde for Military Observation in East Timor

When in July I proposed the Aerosonde be developed in Australia for military and civilian activities, this was as a long term R&D project. However, Australia now has a need for a long range military surveillance platform to assist peace keeping operations in East Timor.

While Australia has military surveillance aircraft, these are limited in number and their potent attack capabilities may make them politically unacceptable in a peacekeeping operation. Smaller fixed wing and rotary aircraft expose their crew to risks. A small remote controlled aircraft would be a non-threatening and safe way to asses the situation.

Aerosonde are at pains to point out that their aircraft was developed for collecting meteorological data, not military intelligence. The aircraft is not yet equipped with a camera or other surveillance equipment but could be rapidly converted to carry modern sensor packages. However, this may not be as easy as it looks and someone would have to provide the funds to adapt the aircraft.

While the range and endurance are suitable, the payload and communications are limited. An Aerosonde could fly from Darwin to East Timor, remain on station for about eight hours and return. A high end commercial video camera with two or more hours recording time could easily be fitted to the Aerosonde for such a mission.

The specifications allow a payload of maximum 1 kg with full fuel load, complete with all standard avionics and meteorological sensors. The standard communications are a 9600bps frequency agile radio link with a range of about 150km. Satellite links are being investigated, but have not yet been fielded due to the continued delays in the Iridium system.

A project to properly design, develop, test and field a surveillance system would normally take months, if not years. However, given the current pressing circumstances, I suggest a prototype could be made operational in a few days or weeks, using the expertise at the Faculty of Engineering and Information Technology at The Australian National University and other institutions.

The obvious option is to fit a consumer camcorder to the aircraft. This might be done by cutting a hole in the bottom of the aircraft and the camera fitted, perhaps in a commercial underwater housing, to provide some protection. The camera would have a fixed view and be turned on and off by the aircraft's on board computer.. The videotape (or disk) data would be viewed on return. There would be no way to obtain real-time images in flight.

The second alternative would be the one I proposed in 1996: the optics and sensor from a still digital camera and an on-board computer. Current model consumer digital cameras have 2 million pixel image units, x12 zoom lenses and limited motion recording capability. This could be controlled by a small one board computer using commercial off the shelf software (perhaps Linux based).

The conventional solution to transmitting the images would be a high speed satellite link. However, instead the existing link could be used, with technology developed for use of the web. The on-board computer could transmit low resolution images and allow the ground operator to select images, or sections of images for higher resolution transmission (the same way you can click on images in this web page). The user interface could be implemented with an on-board web server and use the PNG progressive image display format, which I suggested for military use following Exercise Tandem Thrust 97.

The Aerosonde aircraft could be launched from Darwin, or another mainland Australian base by a local crew, fly autonomously to the target and then be controlled by local personnel with a digital radio linked to a lap-top computer. Alternatively the aircraft could be launched from the deck of the HMAS Jervis Bay.

Further Information

Copyright © Tom Worthington 1999.