How Runaway Drones Close Airports (and Why We Should Put SIMs in Them)

Back in 2020 in Latvia, connection was lost with an unregistered, experimental drone, mid-flight: it was somewhere, but no one knew where.

The ''runaway drone'', as it was called in the press, had its tanks full for a 90-hour total flight time, and was lost for over two weeks. This incident created chaos, and resulted in the Latvian authorities having no choice but to shut down the region’s airspace for several days.

Losing a 5,5 m wide and 3,5 m long drone, weighing 26 kilograms, and flying as fast as 70 kilometers an hour is an uneasy experience. After days of intense, but futile searching, the drone was finally found by pure chance by some passers-by who spotted it hanging in a tree in a forest, about 20 kilometers from Riga, the capital city of Latvia. 

This autumn another drone went MIA during a military training operation. This unmanned aerial vehicle (UAV) was a smaller counterpart of the first stray drone but was nonetheless a large unit, measuring 1,4 m in length and 2,8 m in width, weighing six kilos. Once again, this case posed serious issues to the local airspace and once again, the Latvian National Armed Forces asked for the public’s help in finding the stray drone. 

These are only two examples of drones going missing, despite the high-level equipment and state-of-the-art technology that was put into them. In this article, I explore a solution that could have prevented such cases from happening.

One of the issues in search of both missing Latvian drones was that there was no registered flight path for them. As a result, no one really knew which direction the drones were flying, significantly expanding the search area. While drones of this size are commonly equipped with a GPS tracker, their signal strength depends on several factors, including atmospheric conditions and signal blockage.

Signal blockage means that GPS accuracy worsens near objects like buildings or trees, so the technology might not be fully reliable in urban areas and areas covered by forests. That, in turn, limits the possibilities to develop drone solutions for urban environments, such as medicine delivery or organ transportation, to name a few.

For these reasons, drone technology being tested in the real world needs a backup. And that backup could be the infrastructure that’s already in place – mobile communications networks.

Drones have become vital assets in several industries, including energy, construction, and telecommunications. But one piece remains missing for now — cellular connectivity. Almost none of the drones in use today are connected to a wireless network. 

With wireless cellular connectivity, the potential of drones increases exponentially, allowing the drone to go much further from the pilot or even fly autonomously. Already with 4G LTE connectivity, drones will be able to have a seamless backup connection to the controller, offering more reliable information gathering and control even in tricky settings. Deployment of 5G will allow for an even greater upgrade, accessing the ultra-low latency and massive capacity of these new networks.

Some mobile operators, including the Latvian Mobile Telephone (LMT) are already actively investing in expanding the possibilities of mobile networks within the drone industry. At the 5G Techritory Forum, they conducted a live BVLOS (beyond visual line of sight) demonstration controlling a drone with a hook-on GPS device that transmits on the mobile network (in other words, a SIM card) from tens of kilometers away with no line of sight to it. The experiment demonstrated the network's capability to determine exactly where the drone was at every moment.

The location of a drone, which is transmitting its location over the mobile network, is detected by its proximity to a collection of mobile towers on the ground. For this to work, there must be decent network coverage, which nowadays isn't much of a problem anymore, even in the rural areas. Note: it’s important to have high network coverage at an altitude of 120 m (the ideal drone flight height) – in that case, losing a drone is less likely.

Increasingly more mobile operators globally are advocating for drone manufacturers to use backup solutions to GPS technology. One of such backup systems could be GPS hardware with a SIM card that would allow data verification in mobile networks independent from the performance of main drone systems.

In 2019, Deutsche Telekom teamed up with the German air traffic control company Deutsche Flugsicherung (DFS) to provide UAVs tracking using mobile networks. This was done to ensure the safe operation of drones covering large distances. In January 2020, Vodafone UK called for drones to be fitted with SIM cards to give them cellular network connectivity to reduce irresponsible drone use, the like of which closed Gatwick Airport in December 2018. More recently, Verizon announced billions of dollars of investments in 5G infrastructure and testing 5G connectivity for drones.

But if the solution is so straightforward, why aren’t all drones equipped with SIM cards to enable mobile network connectivity? There are two main reasons – first, regulations still exist in many countries that restrict BVLOS drone flights. Second, additional hardware and software required for this upgrade might add weight to an aircraft and consume more power. That said, the rise of 5G could mitigate both of these issues. 

To conclude, I believe that the day when UAVs will fly in a new, safer reality is coming. To achieve this faster, we have to start repurposing and adopting the technologies we already have.

If all drones were equipped with SIM cards, it would make flying drones BVLOS safer and allow us to start using their true potential faster. Until then, we may still hear new ''runaway drone'' stories and won't be able to blame the policymakers, as we are so fond of doing, for slowing down the commercialization of this technology.