

Prenav "hello world" drone drawing cubes inside a building [video] - alain94040
http://www.prenav.com/blog/2015/8/26/hello-world

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Animats
Very nice. But there's no information about what they use as a position
reference. GPS with a pseudolite, maybe?[1] If you have a clear line of sight
to your local reference transmitter, 1cm repeatability isn't that hard. If
not, you need a much more complex system.

They're at my favorite local intersection, Industrial Rd. and Commercial St.

[1]
[http://gps.stanford.edu/papers/Thesis/StewartCobbThesis97.pd...](http://gps.stanford.edu/papers/Thesis/StewartCobbThesis97.pdf)

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ipsin
_The precision comes from custom software and hardware we 've created,
including a robot on the ground that's equipped with a camera and laser
rangefinder to guide the drone along a pre-defined path._

That's relative position, which seems adequate for what's exhibited here.

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pudquick
This makes me a little sad to learn that's the method involved.

All the timelapse video now proves is that the drone was in the proper
position to flash its light.

Out of position (as measured by the precise laser rangefinder)?

Then don't flash the light yet, drift/adjust, check again, repeat until
correct - then flash.

It's not precision as much as it's "eventual precision".

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scr
We're more focused on the "go to this point in 3d space and take a picture"
use case, so we don't care as much about the shape of the path in between the
points. It is however a totally smooth to the 4 derivative path we are
planning and executing to get to that new position, so its quite
mathematically pure... Wind and actuator dynamics get in the way of perfect
planning though. We did some work on more continuous velocity paths, which are
more in line with my computer graphics and cinematography background, but
those will have to wait for a future video. =)

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scrumper
But you care a bit about that path if you're up close to cell towers or power
lines, surely? You at least care that your path doesn't cross a minimum
distance threshold from the object.

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scr
Well, sure. I don't really mean we don't care about the path, we care quite a
bit about the path, mainly that it gets from point A to point B directly and
doesn't hit things, and that it is somewhat as smooth as possible (easy on the
actuators to follow). We have a 3d map of the environment we build from the
ground robot to directly test against while we are flying to make sure we
don't hit things.

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bdamm
Really cool technology, I can see many applications.

I would love to see their business case math.

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kaffeemitsahne
Reminds me of this quadrotor lightshow, with music by OPN:

[https://www.youtube.com/watch?v=cseTX_rW3uM](https://www.youtube.com/watch?v=cseTX_rW3uM)

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higgins56
so many real-life applications to this tech. awesome. Nicely produced
introduction video. good job, guys.

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amelius
I can see this being used mostly for advertisement :/

Wait a second, these videos are not real-time!

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jameshart
That can be solved by just using more drones.

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haser_au
Really impressive. Plenty of real-world applications for this.

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socrates1998
Nice, impressive.

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markhall
Impressive demonstration of precision!

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kriro
Very cool.

AstroScript Pilot Program :D

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chillingeffect
Off-topic: the cheapest home on zillow available in San Carlos, CA (where
Prenav is located) is $698k + $458 monthly HOA fee for 1,040 sq st.

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ChuckMcM
It would have been more interesting if you had mentioned why this was
important. FWIW, the San Carlos CalTrain station is an easy walk to these guys
so you pretty much could live anywhere from San Francisco (SoMa) to Gilroy and
be able to work here with a public transit based commute.

