For a long time, drones were at the mercy of the wind. A drone flying away just because a gust of wind hits the drone is a thing of the past. These days, even some of the cheapest drones on the market have static hovering capabilities.
Today, most drones can hover in one spot. They are very good at holding a steady hover, and in some cases, they hover so still it looks unnatural to the human eye.
Why would you want a drone to hover in one spot?
One of the reasons why it was important to develop drones that can hover in one spot is because of the dangers that “flyaways” created. Flyaways occur when the drone flies away from the pilot, out of the pilot’s control.
These flyaway situations often happen because the drone cannot hover.
A situation where the drone would fly away is when the connection is lost from the remote controller to the drone, and the pilot can no longer control the drone.
Many times this happens if the pilot’s line of sight to the drone becomes obstructed by a mountain, building, or tree.
What used to happen, is the drone would begin flying in the last direction that the pilot gave it. This often resulted in drones entering restricted airspace, crashing into private property, or, worst case, crashing into a person.
Now, if a pilot’s remote controller becomes disconnected from the drone, the drone will do one of three options that the pilot can set.
The most common option is to hover. This gives the pilot time to move to a spot where they can regain connection.
The ability for the drone to hover saves the pilot money, saves aircraft control stress, and saves property owners from damaged property.
To conduct drone mapping, the drone MUST hover in one spot. This is because drone mapping usually calls for the flight to be automated. There are usually five phases of an automated flight.
- Take off: the drone flies directly upward to a set altitude
- The drone hovers momentarily, establishing its location in reference to the automated flight plan
- The drone flies over its route.
- The drone hovers momentarily at its waypoints
- The drone lands
Without the ability to hover, the drone could lose its positioning along the set flight plan, or worse, execute the flight in completely the wrong area.
Part of flying is landing, and the landing process often is automated. Part of the automated landing process is hovering in one spot before slowly making your descent.
The drone hovers approximately two feet off the ground as its sensors check for a proper place to land.
If the drone was not able to hover in place, its sensors would detect that the area underneath the drone is safe to land, but then it might drift and land on an uneven surface.
That is why hovering is crucial to a safe landing. Just like with any aircraft (other than FPV drones), a slow, controlled descent is usually best.
Thankfully, modern drones are able to hover and hold their position to the point where it’s almost uncanny.
An extremely common use case for drones hovering in one spot is to balance out the effect that wind has on the drone.
If you are shooting a drone video, such as a hyperlapse, overhead shot, or aerial traffic study, the drone will often need to stay in one spot. This alone is a reason why you would want the drone to hover in one spot.
However, with some skill (and no wind), you could pilot the drone so that it stays in one position, but it would be very difficult. If there was even a small gust of wind, the drone would be pushed, and you might undercompensate or overcompensate for this movement.
With the drone’s ability to hover in one spot, the pilot is able to sit back and not worry about a gust of wind.
Obviously, it’s not safe to fly in high winds, but if you are flying at the beach, you’ll often encounter high winds. This is highly unavoidable, and with the drone’s ability to hover in one spot, those gusts are no problem at all.
Some of the technology that allows the ability to hover in one spot while negating turbulence actually transfers to the stability of the drone during flight.
How does a drone hover in one place?
Several factors allow a drone to hover in one spot.
Advances in technology, from the onboard computers’ reaction to outside forces, to the physical build of the arms and propellers, to the most important advancement: the GPS location.
The onboard computer/sensors
One of the most all-around useful advancements in drone technology is the onboard computer’s ability to compensate for outside forces.
If the drone’s onboard computer senses that the drone is being pushed upward and right from a gust of wind, it will provide less power to the motors on the left side of the drone to balance out the force applied.
This allows the drone to sit stationary in the air, whereas if there was no onboard computer telling the drone to decrease power to select motors, the drone would be pushed upward and right.
This also goes for downward-pushing air masses. If the drone is hovering, and a downward force is applied to the drone, the motors will spin faster, creating an equilibrium in the flight, and continuing to hover in one spot.
This technology has come a long way, and it makes up a large reason why hovering is possible.
The physical build
The lesser way the drone is able to hover in one spot is the actual build of the drone. It’s no secret that drones have been made to be smaller, quieter, and smarter over the years.
Part of the reason why drones can hover is because of the even weight placement of the build. Many drones of the past were built with uneven weight distribution.
Nowadays, you’ll find that the drone is often perfectly balanced. In some cases, such as with the DJI Mavic series, the camera is mounted on the front, and the battery is set from middle to back. This balances the drone well.
But other drones, such as larger quadcopters like the Matrice series or even hexacopters and octocopters the drone are perfectly symmetrical.
The GPS location device
This is the game changer. This is the breakthrough that, for most of drone history, drones were lacking.
At the beginning of the article, we discussed the common problem of flyaways. This hardly ever happens anymore because of the internal GPS locator inside the drone.
GPS means Global Positioning System. Drones use GPS so that the drone’s internal onboard computer knows where the drone is located on Earth. This is vital to the drone’s ability to hover in one spot, because without it, the drone would not know the spot it needs to stay fixed in.
The GPS unit, in some cases, is so accurate that the drone can be used for aerial surveys, producing an aerial map with less than a centimeter of global positioning error.
If you’ve ever flown a Mavic Air 2 or a Skydio, or any drone made after that, you’ll know how still the drone can sit in the air. This wouldn’t be possible without the internal GPS unit.
Of course, GPS has only gotten better and more widespread in the drone market since its introduction to the masses.
When GPS first came onto the unmanned aircraft scene, its accuracy was not as sharp as it is now.
Along with that, the sensors and onboard computer were not as advanced either, meaning the drone could hover in one general area, but not one spot.
For instance, the hobby drones of the early 2010s that were equipped with GPS might stay in a five-foot radius of their original position but could rarely achieve a perfect stationary hover.
This stands in stark contrast to the drones of today that, if the controls are not touched, will hover in one spot until the drone’s battery dies.
Unmanned Aerial Operations (link)