The South African National Space Agency (Sansa) is working on a local version of what it hopes will be a more accurate satellite navigation system, which it aims to launch in 2020.
Sansa says its scientists and engineers are developing Satellite-Based Augmentation Systems (SBAS) - which typically use multiple ground stations at precisely-surveyed locations to take measurements from orbiting navigation satellites.
SBAS is designed to supplement existing global positioning systems (GPS) and Sansa says the system brings "better accuracy, integrity, continuity and availability to a navigation system". It also compensates for continuity and availability challenges of global navigation systems, and improves positioning and timing data for aviation.
Eugene Avenant, chief engineer at Sansa Space Operations, notes SBAS is a significant improvement from a functional perspective. "Navigation satellites tell you where you are, but an SBAS system confirms the information is correct and safe for functions such as landing planes in bad weather and operating vehicles without drivers," he says.
Global benchmarks
According to Sansa, the development of a new SBAS came after abandoned attempts to extend the European Geostationary Navigation Overlay Service (EGNOS) so that it could serve SA.
"There was talk for a few years of extending EGNOS to SA, but a technical review showed there was little benefit, because Europe and SA do not see the same constellation of navigation satellites at any one time, resulting in poor performance for the South African extension," says Sansa in a statement.
"We concluded that it was better to build our own and to share it with other neighbouring African states," Avenant adds.
EGNOS is operated by the European Space Agency, while other regions running SBAS include India's GPS-aided geo-augmented navigation and the Wide Area Augmentation System, operated by the US Federal Aviation Administration.
Japan is covered by its Multi-functional Satellite Augmentation System, while Russia and China have also proposed SBAS systems which have yet to be implemented.
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