SANSA helping SANDF’s secure communications

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The South African National Space Agency (SANSA) has for several years been providing space weather data to the South African National Defence Force (SANDF) so that it gets optimal High Frequency (HF) radio signal performance, and has now released an app that assists it, and other users, make best use of HF frequencies depending on space weather.

SANSA said its software engineers have made the forecasting easier than ever by developing a visual, intuitive tool called Ionospheric Characterisation, Analysis and Prediction (IOCAP). “Before, operators relied on unintuitive tables of raw data – a wall of numbers, so to speak – to make sense of how space weather conditions might affect the way HF signals travel (or propagate),” SANSA said.

“These products are technical, and very hard to read, so people wanted an operational solution,” said SANSA’s Piet van Zyl, responsible for developing the IOCAP tool.

Technical operators who cut their teeth on HF communications are adept at interpreting the “wall of numbers” software, and it is still ideal for research. But younger operators, not as clued up on the underlying science yet, need something visual and intuitive for forecasting. “It’s a formidable thing to study,” said Van Zyl.

“We created a canvas with a dual-map system so that you can zoom right down to street-level,” said van Zyl. The IOCAP tool also makes use of colour-coded charts to help the operator make sense of the numbers.

“Having created a much more immersive environment for users, the IOCAP tool also removes the need to worry about complex settings – the default is intuitive and works well. The developers devised what they call the triangle of prediction, which uses colour to display how useful a prediction may be,” SANSA said.

The IOCAP tool considers the difference between the specifications of radios and antennas used at either end – often many hundreds if not thousands of kilometres away from each other. After the elements on both sides are calculated, the tool gives the best possible frequency at any given time.

The IOCAP tool also helps train new operators on how to make sense of the scientific theories behind the frequency predictions. “They see the science behind it all demonstrated practically in an operational setting in front of them; this makes it an extremely valuable training tool.”

A SANDF colonel said all he needs now is his “radio and this software,” as opposed to the many tables he would need before, said Van Zyl.

Other improvements include being able to make two paired frequency predictions for the two transmitters of a circuit in one step, and predictions for communication with moving receivers such as on a ship or a vehicle.

Van Zyl hopes the tool will be implemented successfully in the SANDF – he said it would be a great example of a modern, convenient, innovative, and proudly South African product.

HF signal propagation is sensitive to the volatile changes in space weather that occur in the ionosphere, so the SANDF needs accurate forecasts of the conditions that might affect usable frequencies for HF communications.

The 11-year solar cycle affects communications. At present there are few sunspots, but these will build to a maximum with more solar activity over the next five to six years. SANSA monitors space weather and gives warning of when solar flares occur – solar flares in the past have damaged satellites and other communications infrastructure.



Although satellite communication use has risen dramatically, HF radios are still widely used by the military and are useful in cases where the cell phone communication infrastructure has been damaged or has been overloaded, such as after natural disasters.