South Africa has to decide if it wants to go ahead with a plan to develop a local space-based satellite navigation augmen- tation system within a matter of months to avoid the risk that the preliminary work already done would become outdated, and skills acquired would lapse, and training would need to be repeated and skills reacquired. This would, of course, increase costs and add further delays.

The South African National Space Agency (Sansa) has already done quite a lot of preliminary work on a South African Space-Based Augmentation System (SBAS), in cooperation with European Union (EU). Such a system would be most beneficial to the entire aviation sector, from commercial to general aviation. While a number of satellite navigation systems are in operation or planned – most famously, the US Global Positioning System (GPS) – there are various factors which degrade the performance of such systems, including interference from the ionosphere (which varies significantly, depending on location) and the number of satellites that can be observed from a location.

Sansa space operations chief engineer Eugene Avenant reports that Phase A of the proposed local SBAS – concept development – is nearly complete. That should, ideally, be imme- diately followed by the start of Phase B – concept implementation. (Phase B would be divided into two parts: B1 and B2.) “We’re in a little bit of a holding pattern at the moment” he notes. “We don’t know how long we’ll be holding. We can’t start Phase B unless the budget is guaranteed. If it is not, and if we have to stop Phase B after starting it, then conditions can change and we would need to redo Phase B to start all over again, and so waste time, effort and money.”

The decision to proceed with Phase B cannot be made solely by Sansa or its home Ministry, the Department of Science and Technology (DST). “The DST has been involved from the ‘technology push’ side, but the DST would not be the user,” he explains. “Most of the users of the SBAS would be within the Department of Transport.” An integrated government approach to the issue is thus essential. “Sansa is a sort of systems developer. We’d establish the infrastructure. But all the time we’d have to work with [Air Traffic and Navigation Services, under the Department of Transport, responsible for air traffic management and air traffic control in South Africa]. They’d operate the system. It would have to be a cooperative approach.”

In addition, there would be the need to simultaneously cooperate with partner agencies in the EU. Sansa’s aim is to use technology developed for the European Geostationary Navigation Overlay Service (Egnos). “We’re not going to reinvent the wheel,” he affirms. “We’ll also take a lot of the safety cases from Europe and certify only when we’re different.” Egnos cannot simply be extended to Southern Africa because the two regions are not covered by the same constellation of satellites at any given moment.

In addition, it will also be necessary to get South African industry involved in the project at some point: local manufacture of at least some of the equipment required for the SBAS will be necessary and beneficial. But there will also be a need to involve foreign enterprises as well. An SBAS will require the use of transponders on geostationary orbit communications satellites. However, South Africa has no such satellites and currently has no communications satellite policy. (Nigeria has one, owned by the national space agency; Egypt has three, all owned by an Egyptian Stock Exchange-listed company.) Currently, one transponder is available on the Nigerian satellite. “For the SBAS, South Africa might have to piggyback on a commercial satellite programme, but decisions will have to be made quite soon,” he cautions. It is not usually possible to get long-term access to communications satellite transponders at short notice.

“How do we get the clock ticking again?” asks Avenant. “We need a consortium in government, and together draw up a policy for an SBAS in South Africa and submit it to Cabinet. A policy doesn’t guarantee funding but you won’t get funding without a policy. We have to have a Cabinet-approved policy by the middle of next year so we have a medium-term budget proposal to put in for 2015. The world is moving towards global interoperable [GPS aug- mentation] systems. We will have to decide when we want to join this community. The rest of Africa is playing catch-up with us, but they’re not far behind us now.”