In true timely fashion, Digital Aerolus, a global leader in autonomous technology for any vehicle that flies, drives, dives, or swims, has developed the first indoor drone with C-band ultraviolet (UVC) lights, created specifically to combat the spread of the COVID-19 (SARS-CoV-2) virus with a 99% disinfection rate.

By using its patented technologies, the Aertos 120-UVC can fly stably inside buildings and sterilize areas, thereby reducing exposure of frontline workers to infections. Digital Aerolus’ industrial drones do not use GPS or external sensors, allowing them to operate stably in places other drones cannot go – including small and confined spaces.

The Aertos 120-UVC flies above a surface that it illuminates using 36 optically intense 265 nm LED UVC lights. At 6 feet above a surface and just 5 minutes, this is enough UVC intensity to provide a greater than 99% disinfection rate of a 2 meter by 2 meter surface. These drones are scheduled to be available in volume in May.

We had a chance to interview the co-founder, Jeff Alholm, about this innovative drone technology.

Alice Ferng, Medgadget: What is the UVC power intensity needed to inactivate viruses? Can you talk more about the exposure time needed for virus inactivation?

Alholm, CEO of Digital Aerolus:
We know
from studies with other coronaviruses that inactivation using UVC depends on
exposure time and intensity. As a general rule, delivering 3 milli-joules of
265 NM UVC to a square centimeter area will achieve a disinfection rate
exceeding 99%. These results are not derived from our studies, but from those
of our UVC LED supplier, Crystal IS/Klaran, and decades of pathogen
sterilization using UVC energy in various industries.

the replication mechanics of a virus on a surface critically depends on the
exposure time and distance from the UVC source. We mount our UVC LEDs on a
moving airborne vehicle.

energy emitted in the wavelength range centered around 265 NM is generally
considered the gold standard for effective UVC disinfection. There are multiple
variables in every disinfection situation. As a general rule, if a greater than
3 milli-Joules of energy can be delivered to a cm by cm surface, then a greater
than 99% disinfection rate is achieved.

correct UVC fluence or dose (d) is calculated using the following equation:

Dose (d) = UVC Intensity (i) x Exposure time (t)

Intensity (i) = Power emitted from UVC light source or sources + distance of
emitters (in this application 36 emitters pointing down from the Aertos
120-UVC) toward the surface being sanitized X (times). Exposure time (t) = time
of exposure.

Medgadget: What’s the UV operating frequency range, and why is UVC the most effective for this application? Was this technology based on any prior studies?

UVC disinfection systems are
broadly deployed and sanitize much of the world’s water. Drone-based UVC
disinfection–our delivery of the UVC energy makes this product unique.

via UVC emitters is not new, but there is a new class of small LED sources that
have recently become available for broad deployment. Using our stable indoor
platform to deliver UVC disinfection is what is unique. By combining our steady
industrial drones with these small but powerful UVC sources, allows more
organizations to deploy UVC disinfecting tactics quickly and remotely. We
believe that some businesses and organizations need immediate, deployable, and
practical access to this technology to kill pathogens.

UVC in the 265-nanometer frequency range provides an extremely high rate of
disinfection. There are multiple variables in every disinfection

provide a broadly applicable example, we have calculated the time and distance
from the Aertos 120-UVC to accomplish a greater than 99% disinfection rate.

Here is
one example to help understand the Aertos 120-UVC capabilities:

Figure 1. Ray tracing simulation from the Aertos 120-UVC LED array.

● The
Aertos 120-UVC contains 36 optical intense 265 NM LED UVC sources arranged in
an array pointing down from the UAV (there are options to the Aertos 120-UVC
that has additional emitters pointing up).

● When
the platform flies 2 meters (~6.6 feet) above a surface for three minutes, it
provides higher than a 99% disinfection rate in the red center of the green box
shown below, or if flown for 5 minutes, the entire 2 by 2 meter (~6.6 by 6.6
foot ) square is covered.*

Besides just the surface, the entire area inside the Figure 1 ray tracing
representation is covered, roughly 150 cubic feet.

Similar simulations show that a greater than 99% disinfection rate is achieved
over a smaller surface area by flying just 18 inches for 30 seconds.

● As a
general rule, if a greater than 3 milli-Joules of energy can be delivered to a
1 cm by 1 cm surface, then a greater than 99% disinfection rate is achieved.

Figure 2. Total energy projection per second on a 2 meter x 2 meter area.
*=These images are the output from Zemax OpticalStudio using data provided by Crystal IS/Klaran, the company providing the UVC light sources arrayed on the Aertos 120-UVC. Digital Aerolus will provide users with additional information and software resources to determine the correct UVC dose for each disinfection before the Aertos 120-UVC’s broad product launch in early May.

At 6 feet above the surface, how
concentrated is the beam? Coherence can be a big issue.

The above simulations above are
based on the data from this specific LED; it’s a lack of coherence is helpful.
The 36 emitters have a nice overlap of energy that can be seen in the surface
energy density plots. Overkill is always good, more energy is best, yet this
has to be balanced with sanitizing as much space as possible.

Medgadget: Can UVC inactivate COVID-19? How was this tested? Was it a partnership? 

COVID-19 is a disease caused by
a new virus (SARS-CoV-2) related to other well-characterized viruses. At this
time, the CDC continues to develop broad disinfection guidelines for this
virus. Recent research and protocols indicate that UVC energy centered around
the 265 NM wavelength is useful for COVID-19 disinfection, destroying its

light sanitation technology is currently used for surface and water
disinfection all over the world. As you know, UVC technology is not new. But
generally, UVC sources are large, cost-prohibitive or impractical to

We are working
with UVC LED manufacturer Crystal IS/Klaran, and we have worked closely to
integrate their UVC emitters properly. We have not entered into a formal

We are
working with the manufacturer’s engineers to determine the correct UVC doses needed
for a 99% disinfection rate, and the graphics I’ve provided come from Zemax
OpticalStudio software with data supplied by Crystal IS/Klaran.

At the
same time, before the May production rollout of the drone, we are gathering
additional data.

I want to make it clear that we are not trying to be experts on UVC or COVID-19 (SARS-CoV-2). We are engineers and scientists, not UVC experts. However, there are decades of credible research surrounding the effectiveness of UVC as a disinfection tool. We are working with proven UVC research and applying it to a new delivery application via our stable commercial drones.

Medgadget: Are there surfaces where UVC inactivation is not as ideal for or ineffective? 

We’re hoping to find out more
about disinfecting varied surfaces and spaces. 

now, the Digital Aerolus team will continue to focus on delivery mechanics and
processes. As soon as we can get information from additional users about how
the Aertos 120-UVC tool performs in the field, we’ll improve on the most effective
ways to deploy our Aertos UAVs for disinfection tasks. Hard surfaces are
straight forward to characterize. Cloth and other porous materials require more
time and data to describe accurately.  

Medgadget: Is there any harm to people if they are in the flight path? 

Drones are sophisticated
tools, and in general, require a pilot that has the skill and experience
necessary to complete the desired task. Since conventional drones only fly well
outdoors, deploying a drone indoors multiplies the complexity and the chance
for a collision. We designed the rugged Aertos 120-UVC to withstand crashes,
but there’s always the chance of a collision that damages the drone, property,
or a human. Proper procedures, training, and, when appropriate licensing,
should ever be observed. Our Aertos 120-UVC has protected ducts versus open
spinning blade or blade with inefficient blade guards.

the Aertos 120-UVC drone emits intense UVC light from 36 UVC LEDs. This
frequency of this energy is dangerous to humans: it damages DNA and other
organic molecules and leads to severe harm to the molecule. That’s bad for both
viruses and humans. All pilots and any spectators of UVC disinfection should
remain hidden from the UVC emitters while on. If around the energized emitters
for any reason, then proper eye and skin protection are required. The Aertos
120-UVC is designed to be flown remotely, and the UVC emitters are wirelessly
controlled during a flight to prevent the pilot from being exposed. We are all
familiar with the need to wear UV sunglasses, and proper covering to achieve
protection from sunlight containing UV A and B energy. UV-C is naturally
filtered by the atmosphere and is significantly more damaging to our skin and

Medgadget: If any of the UVC lights go out, does the efficiency and efficacy of inactivation decrease? By how much? Will the user be notified? 

If the intensity of the UVC
emitters changes, the efficiency changes. But have put 36 UVC emitters on our
drone, MORE than enough power to disinfect with a 99% kill rate, so that if an
emitter goes out, the disinfection will still be successful, requiring slightly
more time. 

By the
time production launches in May, we plan on having software tools available for
all customers to use so that they can determine effective doses for each

Aertos system uses four strip arrays of 9x UVC 265 NM high-intensity LEDs. At
any given time, a total of 36 LEDs can be illuminated. The efficiency decreases
in a linear relationship depending on how many LEDs are on. We will provide
periodic testing and maintenance methods, but the lifetime of these LEDs are
measured in many thousands of hours.

Medgadget: Are your drones explicitly built for a certain type of indoor space? How do they navigate around barriers? Are they programmed similar to a Roomba, and similarly – does it get stuck? (If it doesn’t use GPS or external sensors – how does it navigate a new area?) Is it fully autonomous, or can manual control be used? Is there remote-controlled video feedback? Tell us more about the imaging system – are there sensors to detect infected areas? 

For these UVC applications,
the Aertos will be operated in First-Person View (FPV) by a skilled pilot using
the cameras on the platform. We designed our drones around a unique set of navigational
and AI structures, we call these the Mind of Motion Framework and Folded
Geometry flight Code (MMF and FGC). Today’s Aertos platforms operate in what we
call semi-autonomous mode. Using AI techniques, we build a dynamic set of
kinematic models based on the environment that the drone is experiencing, along
with “watching” the pilot. These models allow us to do seemingly impossible
things: feeling and backing off from wall and ceilings effortlessly, adjusting
for wind or ventilation, correcting for drift and creating stability without
optical flow, magnetic bearings, maps, Lidar, or GPS. We are “instant on” and
can automatically balance / perch on a pipe of the edge of furniture or a
fixture to significantly increase flight times during operations.

Because of their rugged construction and flight technologies, our Aertos platforms are generally difficult to get stuck. We’re not aware of any technologies that can detect micro pathogens from a distance. That would be an unbelievable advantage. We currently fly two imagers, a fixed low-resolution FPV camera, and a much higher resolution gimballed array. In other Aertos models, we have IR capabilities along with higher resolution visible spectra cameras.

Medgadget: What’s the use time for the drone (battery life)?

Generally, we expect 10 minutes
of flight time for our traditional missions but typically fly back at 8 minutes
to play it safe. These times depend on many variables: the altitude and
humidity of the environment, how long the UVC LED arrays are on, and how long
the platform can perch. If perched or balanced operating time can be extended
to over 30 minutes. Since piloting a drone is a strenuous task that requires
concentration, 10 minutes of non-perching flight time is an acceptable mission.

Medgadget: How many of these have gone into production? Do you already have buyers lined up? Where will these drones be first deployed and used? 

Mr. Alholm: We are currently bringing up volume production for the Aertos 120-UVC drones in May. The platform is a slight variation on a platform we sell daily, our Aertos 120 industrial drone. We have a significant distribution and support network supporting our current and future Aertos customers.

will begin taking preorders and have this new product on its website this week.
Besides our existing reseller network, we are talking to other potential
partners and drone service providers to support our growing customer base. Yes,
we have orders, and we are flying the Aertos 120-UVC today. 

Medgadget: Anything else you’d like to add about the company, its goals, plans, or vision moving forward? 

Digital Aerolus’ mission is to
combine artificial intelligence with advanced mathematics to create software
and the base technologies for vehicles that fly, drive, dive, or swim. The
company’s first commercial products using these technologies are the Aertos
industrial inspection drones. This includes our newest product, the Aertos

Our current
and future autonomous systems equip vehicles to look at the world differently –
in a predictive, and not just a reactive, way. We believe this approach will
make the world a safer and more efficient place. The Mind of Motion Framework
is particularly powerful: it quickly processes avalanches of input data to
predict potential threats and then to effect changes based on a
quickly-changing environment and risks. MMF integrates complex operators of all
orientations, accelerations, velocities, probabilities, interactions, and
noise. Then, it projects how the host vehicle should behave. MMF is managing
the world continuously in real-time, coherently and concurrently, for vision,
autonomous behaviors, various sensor data, and flight/drive operators. It maps
the probability of interactions and collisions for all projected objects,
including the platform, and projects a probabilistic cloud of interactions
based on real physics. Other approaches to autonomous navigation management are
simply at a disadvantage.

This is
truly transformative. When drones are no longer limited to flying only
outdoors, when robotic avatars can make intelligent and human-like decisions,
when machines can perform dangerous tasks instead of people, the world is a
safer place. And, we’re helping build that world.

Link: Digital Aerolus homepage…

Purchase page: CDW (drone distributor)

More: Interviews of Jeff Alholm by CGTN and Authority Magazine…


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