AGU Data Dump

Disclaimer: This post is as much for my own benefit as anyone else's. I needed to write down all the things that are swirling around in my head after AGU and I thought it might be interesting enough to others to put up here.

First, AGU went really well. Here you can see the poster I presented.

I had the great opportunity to network with a lot of people working in the UAV field and there were quite a few people who had a great deal of interest in what we are doing. I was able to meed John Dandois of Ecosynth and the University of Maryland (ecosynth.org), one of the true pioneers of using UAS technology in ecology. They are doing really great work on the same sorts of things as us and I definitely see the possibility of some collaboration in the future. I also met people from University of Arizona, Oregon State University, University of Alaska-Fairbanks, Norway, and San Francisco State University who are all working with UAV and ultra high resolution imagery. These connections all have the possibility for learning quite a bit from the mistakes of others and for them to learn from ours. Additionally, I had the chance to meet with some vendors, which is part of what I wanted to cover here.

I spoke with guys from Google Earth Engine and Microsoft Research. Earth Engine is really cool in that you can run some pretty advanced data analysis in the cloud, which would take a lot of the load off of us when generating really complex products with vast amounts of data. Then, with the ability to tie Earth Engine into Maps Engine, where we could upload imagery and have it processed by Google into more manageable pieces, the prospects for a really powerful data management, visualization, analysis, and dissemination tool start to become clear. This is something that I will be working with over the next few days and I am pretty excited about the prospects. Hopefully a grant from Google which will provide us access to these tools will really open up our possibilities in the data visualization area.

Microsoft Research has an interesting GIS program called Layerscape which looks to be much more user-friendly than something like ArcGIS and, as you might expect, it comes with all the necessary bits and pieces to disseminate the maps once you have made them. It looked pretty cool but it remains to be seen whether it will be able to beat the Google offerings and be worthwhile.

I also spoke with a couple hyperspectral imager vendors and people who are operating hyperspectral units on UAS, which got me thinking about these kinds of things again. I found a couple companies which have really impressive offerings, namely Resonon (resonon.com). I heard from a researcher I was talking to that the Resonon systems are actually fairly inexpensive, which would be huge for us if true.

Well, thats all for now, hopefully I have even more exciting stuff to share next time.

Drones in the news

Well, I thought I would take a moment to stray from our normal pseudo-scientific ramblings to talk about a few cases of drones in the news recently. First, I'll present to you an op-ed from the New York Times which was written in response to Jeff Bezos' announcement of Amazon Prime Air, a possible future delivery service that you have probably heard of already. Take a moment to read the op-ed and then continue on to what I have to say about it.

The op-ed is nothing more than vacuous drivel coming from someone with no more understanding of drones than of quantum physics, string theory, or (apparently) logic. After confessing her fear of skies thick with drones (never mind that our skies are already thick with planes with 9.8 million manned flights crossing our skies in 2012), she shows the value of her hand almost as soon as she starts, "So if they can’t land on my head, why do they make my head hurt? Maybe because they are redolent of President Obama’s unhealthy attachment to lethal drones..." I suppose she can't be bothered with the fact that the aircraft in the sky today have the military to thank for much of their development (First jet aircraft? Luftwaffe). To reject the use of drones based on their military application is tantamount to rejecting air travel because airplanes can be (and frequently are) used to drop bombs on people. In fact, if she could trouble herself to look at the numbers, she would see that of all the weapons released by aircraft in Afghanistan from 2009-2012 (18,559), only 6.8% of them were released by drones. How is it that they are public enemy No. 1, the evil machines raining death on the Middle East when they account for 7% of the lethal air power used and the other 93% gets a free pass?
After she finishes with her journalistic masterpiece about the potential lethality of these innocuous little aircraft she makes an entirely unrelated and unsupported statement about the "unhealthy attachment to indiscriminate surveillance" of our spy agencies. This is a matter of opinion, and many people agree, but it is quite out of context and not entirely applicable here. Not even the Snowden leaks could produce evidence of surveillance on Americans in America (by drone or otherwise), which is the only type of surveillance restricted by our laws. Our spy agencies act within our laws, so if you want them to act differently you might consider changing the law. I will readily concede that the idea that spy agencies may be tempted to spy on us from above is not unfounded but neither is the idea that drones could revolutionize our daily lives in ways that we cannot yet predict. The Wright brothers gave rise to next day air freight, intercontinental air travel and, yes, even drones. Do you think they would have expected that?
And, as if her murderous privacy-invading drone point wasn't clear enough (It was plenty clear, just not logical) she goes on to provide some tenuous link to the latest episode of Homeland. I won't even bother addressing the absurdity of connecting reality to a TV drama.
After all of that nonsense she does manage to put together part of a factual and sensible statement. She says that Bezos is simply putting on a PR show and catering to our desire for instant gratification. This may be true, but that is his job; he has built his entire company on the foundation of providing anything you want as soon as you want it. The highly successful Amazon Prime is centered around providing anything Amazon sells in 2 days at no additional charge. Can you blame the man for pushing the delivery time envelope? Further, while the items she might order would be argyle sweaters, some of us (like us in the lab) order things that we can't get locally and need yesterday. Turning 2 day shipping into 30 minute shipping has the potential to turn 2 wasted days into barely enough downtime to eat lunch. And her implication after this that other companies following suit is also a bad thing is equally off base; why is a coffee being delivered by drone any worse than a sandwich or a pizza being delivered by bike or car?
She then goes on to mention lobbying and movie producers and some stuff about jobs. To be quite honest I'm not sure what she was doing here. She provides some of the biggest reasons drones should be integrated into the airspace (100,000 jobs, $90 billion industry) with no explanation, no support or rejection. Then, with a similar nonsensical transition, she returns to Amazon's drone delivery and a quote from Politico (a political news outlet with presumably as much drone expertise as our dear friend Maureen or Barney the Dinosaur) that highlights the danger of operating drones in a city. Sure, current generation drones probably aren't reliable enough to safely conduct this sort of task, but does that mean the drone of 5 years from now will still be incapable? Does our current track record of dizzying rates of technological advancement suggest that we will make no meaningful progress in this area in the next few years?
Next, she is on to another "drones will take away your last shred of privacy" argument. I would refer her back to the second paragraph for a refresher on why this isn't a sound logical argument.
Finally, she goes back to breaking down her own case with a few of the multitude of valuable uses of civilian drones before making another absurd reference to Hollywood as if it has any relevance to reality. Her op-ed ends just as weakly as it started; same old fearmongering tactics, new half-baked examples. I understand that people are afraid of change but have we not seen for a hundred years or so that our fears are generally alleviated by overwhelming benefit?

Phew, ok, now that I have that out of the way, I'd like to turn to some brighter news. First, Lian Pin Koh, the director of ConservationDrones.org, recently gave a talk at TED in Edinburgh, Scotland. His talk is certainly inspiring and shows the real power of the aircraft we work with, but I was a little disappointed that I wasn't invited to speak. I'm kidding, kinda. While the work they are doing is impressive it in no way exceeds our accomplishments and I would even say that we are quite a few steps ahead of them, as we are much more advanced in the area of multirotor-based imaging. They have gotten their aircraft out to more places and collected more data, which definitley counts for something, but the systems they have developed do nothing that ours can't. This is actually heartening for me, as it shows that the progress we have made over the past 16 months is really meaningful and basically TED-worthy.

Finally, I'll share a few stories of us in the news. We have already gotten some good attention as a result of these and I really think it will help us as well as drone development in general.

WFU News

Science Daily

El Comercio (Peruvian equivalent of the New York Times)

Old Gold and Black Newspaper

Consumption Resumption

I have to admit I just sat here for about 5 minutes trying to think of a good word that rhymed with presumption and assumption. Anyway, as the title might suggest, I'm bringing back our earlier discussion of power consumption. When I left off last time I noted that slowing down by about 30% can more than double our flight range. This got me thinking, what other small tweaks can we make to get big gains; the low-hanging fruit, if you will.

I started to think about motors and propellers and their efficiency. With that in mind, I pulled up eCalc, a great online tool for calculating all sorts of things about your aircraft, motor, propeller, and ESC. The big thing I was interested in was efficiency of the motor/propeller combo. I set out to model what we currently fly, an MK3638 motor with an 11x6 propeller. Here is the graph I got:

As you can see, the efficiency of this motor/propeller combo (the blue line) peaks at about 90%. It's 87.8% to be exact. It also has a nice thrust-to-weight ratio of 0.66:1. Those number are both quite good. The only problem is that the 87.8% efficiency doesn't happen until you draw 24.1 A. This is a problem because we generally cruise at 5-10 A. As you can see in the figure, the efficiency in that range is pretty bad in that range (well lets just face it, for an electric system its abysmal). At 10 A the efficiency is about over 77% and in the butter-zone, 7.5 A, it drops to less than 75%.

So, what is the diminution solution? Enter, the Tiger MT-2814-10. This motor spins at 770 RPM/V, just like the MK3638, but the way it is wound does something interesting with it's efficiency curve:

Again, the peak efficiency of this setup is quite good, 86.2%. It also has a decent thrust-to-weight ratio of 0.60:1 (with a change to a 12x6 propeller). The icing, though, is that it's 86.2% efficiency peak falls right in the middle of our cruise range, 8.8 A. This means that with a simple motor/propeller change we should gain more than 10% efficiency at cruise. For such a simple change that is a pretty impressive gain.

So, we ordered the motor and a propeller and for $60 we have (hypothetically) added 10% efficiency. I got it mounted up yesterday and spend a bit of time today balancing the propeller and motor. It is now ready to fly and, as an added benefit, it puts almost no vibration into the airframe (look here for a bench test after mounting and balancing which shows that there is no longer any "jello" in the video). Now, all we need to do is get it airborne and see how it goes.

"It just won't flat spin"

Yesterday was an outstanding day. We joined some other local FPV flyers for a small fly-in at the RAMS RC club (the field where we normally test our planes). We took the DAO, the Phoenix, and my plane (an FPV Raptor), which I'll just call the Raptor for now until another name presents itself. We were also joined by Kevin Wang, the newest member of the lab, a freshman who is interested in computer science and wants to work with us to enhance our systems. We set out to do a few things:

1. Get me some flight time on the Raptor, both LOS and FPV
2. Return the Phoenix to the skies
3. Do a long range flight with the DAO, simulating a flight to Pilot and back.

On all three counts we succeeded. From this point on I'll tell the story with pictures.

We arrived and promptly set up the "Christmas Tree Farm," our array of tripod mounted antennas and video monitors. As you can see here, the skies were pretty clear and the wind was light from the North (from the direction of Pilot).

Kevin got to learn from the best.

The Phoenix was revived and ready for action.

I wasted no time getting the Raptor ready to fly.

The Raptor took to the skies after an FPV takeoff and gave us great FPV views of Pilot under the wispy clouds. The flight was a completely uneventful (a good thing) 40 minutes of FPV bliss. After I had my fill of flying I brought her in for a landing under FPV.

The DAO, unmodified since our 7.25 km flight, was sent skyward with Tim at the controls.

Our flight plan was to travel out to the west of Pilot, pass it, and return. Pilot is the large dark green forested area at the top, west of Pinnacle. As you can see, we returned a little short (about 2 km) of our target. At about 12.6 km we started to get some spotty reception on our Dragonlink. We made it out 12.8 km from home. Surprisingly, the FPV system (800 mW 1.3 GHz tx, RMRC rc w/ SAW upgrade, homebrew half-wave dipole on tx, and homebrew biquad on rx) gave us totally rock solid link for the entire journey (except for turns when the bank angle turned the tx antenna out of polarization). The RFD900 telemetry system and yagi also gave us perfect performance, with Mission Planner reporting 98% RSSI the whole time. We plan to remedy our Dragonlink reception issues by flying higher and using the Moxon (more directional) antenna.

If you happened to be on the observation deck at Pilot, this is what our flight path would have looked like.

Here you see Pilot from the DAO shortly after takeoff. Range to Pilot here is ~13.5 km.

Pilot mid-flight, just about to pass over the bend in the Yadkin River and leave it behind for bigger, better things. Range to Pilot here is ~9.75 km.

Pilot again mid-flight, passing over some farmland. Range to Pilot here is ~7.75 km.

Pilot shortly before turning back for home. Range to Pilot is ~3.0 km. Range to home is ~12.5 km.

And she returned home safely. The RAMS is the green grassy area just below the center in this picture.

After flying the DAO, it was time to see what the Phoenix could do. Here you can see it leaving Tim's hand on its re-maiden. Unfortunately, the settings in the transmitter had not saved after Marcus changed them and the ailerons were reversed. This led to a very quick but spectacular return to earth with minimal damage.

After some quick repairs to the tail and the necessary adjustments to the transmitter, the Phoenix was sent skyward again. She flew like a bat out of hell. She has tons of power, can almost hover, knife edges well, but doesn't like to fly inverted. Also, according to Marcus, "It just won't flat spin." I should go ahead and note here that we were not, in fact, having fun but were testing the full range of flight capabilities of the aircraft. The big news here is that we have another functional aircraft which will be useful for testing new features, firmware, techniques, etc so we don't have to use the DAO for that anymore.

Here are the DAO and Phoenix after flying, in good shape and ready to fly again.

Stay tuned for video from the DAO long range flight and the Raptor.