Top radar man sees a future for aerostat-mounted units in SA


Francois Anderson is one of South Africa’s top radar experts and having come from a time when radar tracking technology was an integral part of air defence systems he now sees “a dramatic change” in national radar requirements and utilisation.

“South Africa today no longer finds itself in a Cold War-like situation and government’s requirements for radar have changed. What we are now focussing on is how best to protect South Africa’s porous borders, game reserves and protected areas from illegal immigrants, drug traffickers, pirates, poachers and other criminals.
” We have more than 4,400 km of land borders and a coastal border of a further 2,800 km, with limited people and equipment with which to safeguard them. Persistent wide area surveillance systems utilising radar technology to monitor the situation day and night as well as in all weather conditions, can go a long way to keep an eye on our borders and assist the SA National Defence Force and other law enforcement agencies to deploy forces efficiently and effectively,” Anderson said.

A project he is passionate about is AwareNet – a wide area persistent surveillance technology demonstrator being developed by the CSIR for these types of applications. Its sensor technologies are being optimised specifically for southern African requirements and conditions. The system will allow experimentation with new technologies under real-world conditions and the demonstration of the resulting capabilities to private and government stakeholders in defence, safety and security.
“South Africa, like many countries, has a problem with stolen goods, firearms, cigarettes and particularly drugs, which are smuggled over borders, either in vehicles or by boat or in light aircraft able to fly below the coverage of normal land-based radars,” Anderson said.

The problem with land-based radar systems, even when radar stations are set up high on mountain tops, is their coverage against surface-based and low-flying targets is limited by the horizon as well as by the terrain casting radar shadows, for instance behind topographical features, such as lower hills or neighbouring mountain ranges, that obscure the line of sight.
“The Aware Net concept uses airborne radars in a wide area persistent surveillance network. The higher up the radar, the more it is able to see. We considered using manned aircraft and unmanned drones for this purpose, but those large enough to carry long range radars, are expensive to fly and can only act as a platform for a persistent surveillance system for a couple of days at a time. As a much more affordable alternative with the required long endurance, we are looking at using aerostats on which to mount radars and other sensors,” he said.

An aerostat is a lighter-than-air blimp-shaped airship tethered to the ground by a cable which gains lift through a combination of buoyant gas and aerodynamic forces. When fitted with a special lightweight radar system, relatively affordable aerostats flying at heights up to 1 500 m above the surface are capable of providing low-level coverage up to ranges of 150 km for periods of up to a month at a time.
“Aerostat-mounted sensor systems have great potential as force multipliers because they operate in real time and can persist for long periods. Over the past two decades aerostats have already been used effectively by the US military in Iraq and Afghanistan. They are also being deployed by an increasing number of countries in border safeguarding roles. In addition, aerostats are perfect platforms on which to mount wideband communications repeaters providing coverage over a wide area.”

To date, Anderson and his team have secured the bulk of the funding required to acquire an aerostat for the AwareNet project from the Department of Science and Technology. The balance of the funding has been pledged by other interested government departments and organisations.
“Once we have acquired the aerostat, we want to put it to work monitoring 300 km stretches of South Africa’s coastal and northern borders to demonstrate its capability to provide real-time, reliable, affordable and effective radar surveillance over a wide area,” he said.

With the SA Air Force currently looking at ways of expanding and refurbishing its aged radar network and the African Union emphasising the need for maritime safety, security and protection around Africa, Anderson believes aerostat-borne radars may well prove to be an effective solution in those areas with a lack of appropriately located high mountains.
“If we can successfully demonstrate the usefulness and readiness level of this technology to decision-makers in government and the private sector, I believe aerostat-borne radars can help provide South Africa with affordable, reliable and versatile wide area persistent surveillance solutions.
“With an appropriate mix of mountain-based and aerostat-based radars we should be able to cost-effectively cover all of South Africa’s land and coastal border zones. My hope is that we can attract sufficient funding to invest in this project to further develop the technology, build a full-scale technology demonstrator and reduce the perceived technology risk. If this can be used to convince decision-makers to opt for this type of solution, a resultant South African product promises to contribute greatly to the satisfaction of the challenging requirements for safeguarding our country and our continent’s borders, our game reserves and our protected areas, while saving foreign exchange and contributing to South African job and wealth creation,” he said.