News24 | Wake-up call for SA drone operators after solar storm headache

• Hermanus drone operator Louis McCarthy was disrupted by a solar storm last month.
• Massive explosions on the sun sometimes send large clouds of charged particles to Earth, which can disrupt electrical equipment.
• McCarthy plans to err on the side of caution going forward, and suggested other drone operators in South Africa should also be aware of the potential impact of the sun on their operations.
• For more financial news, visit News24 Business.

On a solid November day for drone flying, Louis McCarthy had to explain to his client that a massive solar explosion 150 million kilometres away had interfered with the data he collected.

While it may sound like a ‘dog ate my homework’ kind of excuse, it is a fairly well-documented phenomenon that solar storms can cause disruptions to drone navigation systems and the instruments they use.

It was a risk that McCarthy was aware of and prepared for.

McCarthy is a licensed drone operator and the founder of Aerocam, a drone company that offers a range of services, including topographical surveys, LiDAR surveys and solar and wind farm inspections.

In November, McCarthy experienced a fairly rare disruption to his operations, which may be important for other drone operators to note.

On 7 November, McCarthy had intended to fly to conduct a LiDAR survey for a client, but chose not to, despite the good weather on the ground that day.

LiDAR surveys are conducted to provide extremely accurate data on the shape of the ground in a given area. A device shoots thousands of laser pulses at the ground every second to collect data that is used to build a 3D map of the area.

Drones are particularly adept at maintaining their position and can operate at low altitudes, making them ideal for the job.

McCarthy chose not to fly because he had observed that the KP index, an internationally recognised scale ranging from 0 to 9 that quantifies geomagnetic activity resulting from interactions between solar wind and the Earth’s magnetic field, had exceeded the safety threshold he had established for flying.

The South African National Space Agency (Sansa) had sent out a notice the day before, warning that a strong geomagnetic storm risked disrupting navigation systems.

Essentially, a big explosion on the Sun, called a coronal mass ejection (CME), had sent a cloud of charged particles towards Earth, which interacted with our atmosphere.

CMEs, when directed at the Earth, can cause aurora, a spectacular light display that occurs when the charged particles interact with gases in our upper atmosphere.

However, CMEs can also cause trouble for electronic equipment and GPS navigation systems, as the strong electric fields can interfere with equipment and make it more difficult to pick up satellite signals that are crucial for GPS.

McCarthy said that he elected not to fly because the KP Index on the day was above the threshold considered to be safe.

“If we look at anything from seven to eight, that’s way beyond what we’re comfortable flying with,” he said.

The next day, the KP index was lower, so they decided to fly. McCarthy said there was a slight flare-up while they were flying, and the KP Index reached 5.7. This was still below the safety threshold of six that they used.

There is no internationally accepted KP index threshold for safe drone usage. What is safe may depend on the type of equipment being used.

McCarthy said that while a KP index score of 5.7 isn’t high enough to degrade the command and control between the operator and the drone, it was enough to disrupt the data they were collecting.

New safety threshold

Because LiDAR scans measure signals down to the millisecond, the drone’s GPS must be extremely stable. McCarthy explained that the data tears if this isn’t the case.

While there are some ways to correct this, tearing means you are less sure whether the data you collect is 100% accurate.

He said the data collected on Saturday had to be salvaged using post-processing software, and they had to return on a quieter day to collect additional data.

The incident last month was not the first time McCarthy experienced disruptions from the sun.

He recalled an occasion a few years ago when he decided not to fly because the drone struggled to lock onto more than seven satellites while flying a mapping mission.

He explained that the drones they use connect to various satellite constellations for GPS positioning. The drones use satellite data to determine their location.

While there isn’t an official limit on the number of satellite connections needed to ensure the GPS system on a drone works optimally, seven is considered below normal.

McCarthy said nine is the minimum Aerocam connects to before flying, adding it is normal to connect to about 20 satellites.

He saw videos of other operators overseas landing drones 20 meters off-target due to solar storm interference last year.

The incident in November led McCarthy to change the safety threshold he uses to decide whether to fly or not.

“It was an extremely important learning curve for us […]. We have now gone and actually readjusted our safety threshold down from where we were previously.”

McCarthy said that while they used to fly if the KP index was below six, they will now no longer fly if the KP index is above 5.2.

Check the space weather

He strongly advised that drone operators in South Africa take note of the space weather on a given day before they decide to fly.

“My advice would be to, if you’re going to fly on the day, very quickly, you go to Sansa’s website, and you just check the space weather for the day, and if things are flashing red [...] then perhaps reconsider flying that day.”

Sansa regularly updates a webpage showing the local K index, which is the localised version of the KP index, for Hermanus.

It is best to use localised data, as the intensity of solar storms can be greater at the planet’s poles, meaning global data may not accurately reflect local conditions.

Sansa maintains a world-class space weather forecasting facility in Hermanus, which provides a valuable source of data due to its positioning near the southern tip of the continent.

Sansa spokesperson Daleen Fouche said anyone working with technological systems needed to be aware of space weather and how it may potentially affect their operations.

“I don’t think people realise how incredibly dependent we have become on space technology systems, and any one of those systems can be affected by space weather.”

She urged anyone who thinks they may have experienced some disruption from a solar storm to share their experience with Sansa.

“It’s still a very new area, and we are really looking for ways to expand our understanding of the impacts.

“We are extremely grateful to Louis and his team for contacting us and working with us to truly understand the impacts that it has on the drone industry,” she said.