People watching the inauguration of the Tokyo Olympics this week were treated to a special spectacle. Apart from the usual fireworks display there were 1824 drones lighting up the sky, seamlessly transitioning between the Olympics logo and a revolving globe. The drone display caught the eyes of millions around the world, leaving them with awe and inspiration.

Drone light shows or drone displays are not new. They have been featured in the recent G7 summit, Dollywood, Chelsea’s celebration of their Champions’ League victory, President Biden’s Inauguration and more. They’re not new to the Olympics either, the Winter Olympics in 2018 had a show with 1218 drones. Both events for the Olympics were organized by Intel’s drone light show division.

Drone light shows have even been used as aerial QR codes to advertise games and even music releases. With increasing adoption, these are bound to become ever common and prevalent in our modern cultural landscape.

Given the press and attention that the recent Olympics show has got, it’s a good time to understand how they work and what goes behind the scenes of these modern-day spectacles.

Naively, one might think that conducting a drone light show is quite simple -

Reality is often more involved than that and there’s a lot of complexity involved in having many drones flying in coordination so close to each other at the same time.

Traditionally, flying a drone has been a 1:1 process with one pilot controlling one drone. Almost every drone has capabilities which enables it to fly autonomously. The pilot only has to keep a sharp eye on the aircraft and intervene when required.

1:1 processes don’t scale well. The next obvious step is to have one pilot monitor several aircraft simultaneously, creating a 1:many process. This is possible with advancements in safety and the autonomous capabilities of drones. Skydio, which makes drones with state of the art autonomous drones, calls this stage 4 of autonomy. Stage 4 is when there are multiple drones controlled by the same pilot.

Drone light shows are like that. There’s a couple of trained remote pilots on-site who are ready to take over any drone if required. Each pilot can monitor anywhere from 25 drones to several hundreds in the case of larger shows. Intel claims that in recent shows, a single operator can monitor an entire show containing 400 drones.

I use the word “monitor” because the entire show is fully programmed beforehand. There’s little for the pilot to do, and certainly not control multiple drones simultaneously. That would be an absolute nightmare and a recipe for disaster. The reason that one pilot can monitor so many drones is because of some interesting advancements in drone technology. 👇

There are three major problems in flying a lot of drones in the same space and making them dance in beautiful patterns.

The first one poses a dilemma - to create detailed patterns, you want the drones to be as close to each other as possible. But if you get them too close, you run the risk of them bumping into each other and raining down from the sky.

Drones use GPS sensors (technically GNSS sensors) to know where they are. The typical ones have an accuracy of 3-5 meters. That’s acceptable for a single drone flying alone. But when you’re commanding hundreds of drones to precise positions a meter or two away from each other, the inaccuracies add up and you run the risk of having a collision.

The drones used in light shows have advanced GPS sensors that use a clever technique to have higher accuracies. These are called RTK receivers and work on a technique called Differential GPS. That’s technical jargon for having a fixed GPS unit on the ground and using its data to increase the accuracy of other GPS units nearby. So essentially, the drones in the air “correct” their GPS positions with reference to the one fixed on the ground.

This is some really cool technology! I’ve worked with RTK receivers before and they are so accurate, they can tell apart the fingers in an outstretched hand by placing a receiver on each finger. Compare that to your phone’s GPS that struggles to stay in the correct lane in a 50-meter highway. RTK receivers on the other hand, can be accurate to 2 centimeters or fewer!

The second problem is how you make them not bump into each other while flying in three-dimensional space doing intricate patterns. This is a hard problem and some of the brightest minds of our generation are working on efficient techniques and algorithms that makes planning flights for multiple drones easy. There’s even recent research on swarm flying with in-built collision avoidance.

Planning for hundreds or thousands of drones involves a lot of computation power and Intel has built custom software and algorithms that run on powerful hardware. These flight plans are calculated well in advance and are sent to each drone which then use the RTK GPS units to follow the plan as precisely as possible.

Reality has enough murphy-ness in it and it wouldn’t be prudent if the light show organizers can’t handle common types of failure appropriately. The drones are built with mechanisms to detect several kinds of system failure and are programmed to retreat safely away from the rest if such an event occurs.

In the case that they do fall out of the sky (which has happened multiple times), the drones are equipped with guards that protect people from the fast spinning propellers. In 2018, an Intel Shooting Star drone during an indoor light show fell out of the sky on the head of a TechCrunch reporter. He wasn’t hurt, but described the feeling as -

later adding -

The incident occurred indoors and were likely not using RTK technology as GPS doesn’t work very well indoors. But it shows to how easy things can go wrong. The organizers at intel were aware of the rogue drone, so their system did detect this little shooting star that became a meteorite.

Are they going to be the future of fireworks? Yes! Drone light shows are

But also they’re not quite there yet. While it can be argued that they’re probably a lot safer than fireworks, the cost of a show is what ultimately drives adoption. The pricing page on Intel’s website lists the cost for shows based on number of drones.

That’s a lot of money. Fireworks are multiple orders of magnitude cheaper, and will continue to dominate festivals and celebrations until the price of drone light shows come down. There’s plenty of competition to Intel in the drone light show market coming up every year. As Intel learned the hard way in the CPU market, increased competition will lead to price cuts that benefit the consumer. I reckon that in the next decade, the prices for drone light shows can become cheaper by an order of 10 or more.

The number of drones in a single light show is increasing every year and new records are being broken. The latest record-breaking show had 5200 drones! If the trend continues, we’ll see much more impressive shows and the cost for smaller shows coming down. I dream that by 2050, orders for drone light shows will be in the tune of Megapixels.

Listen to some peaceful birdsong with serene scenery in this drone shot from Reddit user P2591 - An early morning over the river.

Every week I also share something that’s not about drones but is hard to pass by. This week’s pick is a classic essay by Paul Graham -What you can’t say.

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Keep flying,

Nihal

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