God is my Co-Pilot……or is it Drone Deploy?

God is my Co-Pilot……or is it Drone Deploy?
3D Model 1


Recently I was approached about one of my previous blog posts on Vineyard Surveys https://theuavguy.wordpress.com/2014/09/26/drones-above-the-vineyards/ by a Drone Startup based in San Francisco, Drone Deploy. In my previous blogs I’ve stated the importance of a whole system approach to UAV work with a smooth end-to-end flow. It’s not about the drone, or how sexy it is. It’s using the drone as a tool to get actionable data that can be used to improve your crop yields, reduce your survey times, in a sense make you work more efficiently with less workload. What Drone Deploy suggested is that they had taken the processing section of the workflow and automated it. From my experiences and from talking with other UAV operators, it’s clear flying and capturing useful images/data is 20% of the time, the rest of the 80% is data processing, analysis and decision making. However Mike Winn, CEO and founder (Jono Millin and Nicholas Pilkington are also founders) at Drone Deploy told me that they had devised a product that would take the data as the drone is flying, yes as it’s flying, and start processing as it’s flying, and 15 to 30 minutes after landing you would have all the processed data available. Really? This seemed too good to be true, as such I set off on this investigation to see how well Drone Deploys system worked.


What is Drone Deploy?
I first came across Drone Deploy in May 2014 at the sUBSExpo in San Francisco, where they presented their Co-Pilot hardware and software post-processing system. The premise behind the presentation is that Drone Deploy gathers your images as they are taken and uploads them to the cloud, where they are then processed on extremely fast and optimized servers designed for this application. The results are the presented via the cloud to the user by any device with a web browser interface. In this way the cloud processing can achieve image post processing times unobtainable with your normal system at home or office.
So I hear you ask, how do you get the images from the aircraft to the cloud? Well Drone Deploy have addressed this by using a cellular module, the Co-Pilot (thus the blog title,) which runs at LTE data-rates to allow images to be pushed to the cloud from the camera as it is taking the images. So you start to realize now how much work Drone Deploy have put into the Co-Pilot and the associated cloud processing. The Co-Pilot itself has the LTE module for image transfer to the cloud, a Wifi module that talks to the survey Camera and a telemetry link that talks with the Flight Controller. That’s pretty cool. Why? Because the Co-Pilot takes the GPS coordinates from the flight controller when the camera is triggered, and stamps it onto the image. As such none-GPS cameras can be used to generate Orthomosaics, which can later be overlaid onto Google Earth. However what’s even cooler, is that the LTE link is bi-directional. What’s the advantage of this? It allows you to talk to the aircraft from your smart device via a web-browser, which really doesn’t seem like a major deal. But what Drone Deploy have done is integrate the flight controller mission planning into their own web browser mission planner. This allows you to plan a mission, fly the mission, and look at the post-processed mapping/survey data on the same device just by using a web browser, no telemetry links etc. Also Drone Deploy have addressed multiple markets and platforms with their Web-based mission planning and data viewing App. First they support both fixed-wing and rotary aircraft including helicopters and multirotors. Secondly, they have devised mission planning categories for surveying, agriculture, construction and 3D modeling. Chose the category to best plan your mission.

So what happens if you don’t have cellular coverage or if you don’t live in North America. Well Drone Deploy is working on both of those points. You can pre-plan a mission and fly without the cellular telemetry downlink. Once you are back where a cellular signal exists, trun on the UAV, and it will upload all the images to the Drone Deploy cloud and process them. Also in the future Drone Deploy is looking at adding WiFi/Bluetooth links to do in-field communication from your smart device to the UAV.

OK so what about international customers, again Drone Deploy has the foresight to see the UAv community as been global, and as such is rolling out deployment in the next months overseas. Keep watching.


What does a Drone Deploy Mission Look Like?
So here is a test case using a multirotor:
1. Put the multirotor at its takeoff point, turn on your transmitter, turn on the UAV camera and then connect the UAV battery. At this point the UAV will connect to the Drone Deploy cloud server and upload any updates if necessary.
2. Get out your smart device be it an Android phone, iPhone, laptop, tablet and log on to Drone Deploy website and enter your account information. You will then be taken to the Dashboard, which has all the missions you have planned off-line (you can plan missions in the warmth of your office/home) or missions flown with generated maps.
3. You now have the choice to plan a new mission, fly a mission you planned off-line, or re-fly a mission you have already flown.
4. Let’s plan a new mission. Pick a category, such as Agricultural.
5. You will be asked which aircraft profile and camera you want to use and your present location.
6. Draw a perimeter around your required survey area and define your required ground resolution per pixel or altitude.
7. Drone Deploy will then generate a flight path to optimize the correct image overlaps to allow correct stitching. What’s also important is that it only takes enough images necessary. Having too many extends processing time. As such normal rules are fly as high as you can, as fast as you can and get just enough images to allow quality data stitching and analysis. Drone Deploys figures that all out for you. As such the Co-Pilot also triggers the camera according to when it determines trigger points are in its computed flight path. Note, the flight path generation also checks flight duration versus aircraft capability. As such if the mission exceeds the aircraft endurance this will be flagged as a safety issue.
8. By now the multirotor status will be visible on the webpage and will report connection, updates, GPS-lock and finally FLY NOW.
9. You now click on the symbol “FLY NOW” and the Co-Pilot will go through a preset checklist, it will connect to the camera, check camera battery, check multirotor battery, ensure you have GPS-lock, and take a test image and down-load it from the copter to your browser. If all checks pass, the checklist is passed and you get the “Ready to Launch”. If any check fails, the copter will not launch, this is an inherent safety feature so you do not take off with low batteries, no GPS lock etc.
10. Now switch your transmitter to Auto, and press “Launch” on your browser screen. A notice will come up stating “Takeoff in 5 Seconds” The countdown will begin and at 0 the copter will takeoff and climb to survey height. It will then start to fly the mission.
11. During the flight, the images are downloaded to the cloud and processed as you fly. The images are also presented on your web browser screen along with aircraft speed, height and battery level. The flight plan is shown, with the aircraft progress, direction of travel and the direction it’s pointing.
12. The next bit is truly impressive. During the flight and as images are processed in the cloud, stitched results are placed in realtime, yes in realtime on the flight path of your web browser. From anyone who has used stitching software this is like a miracle to watch, realtime stitching whilst the copter is still in the air!
13. At the end of the survey, the copter returns to the take-off point (or the point you want it to land) and lands.
14. After landing large sections of the area will be stitched or even fully stitched. Results may even be available already. However results such as stitched Orthomosaic, ENDVI maps, Digital Elevation Models and 3D models will be viewable in approx. 15 minutes depending on mapping area.
15. So now power-off, pack-up your copter. Then get your smartphone etc. view the results as you are stood in the field, and using geo-referenced survey map generated from the mission go crop ground truthing etc.
16. On to the next site.

Note: Safety is paramount and Drone Deploy uses an extensive three dimensional geo-fence, that monitors aircraft deviation away from the expected flight corridor. Excessive deviations will trigger a return home and land. They also supply No-Fly Zones during mission planning.

It really is that simple and fast. Here is a video of the whole process using a preplanned flight, look how fast it takes (apologizes for iPad glare.)

And here is a video of 20 acres been stitched in realtime:


Test Bed

For the initial exercise a 3D Robotics Iris+ was used. The reasoning behind this decision was to prove out that a small consumer drone could fly a commercial survey mission. Remember my initial point “the drone it’s just a tool”. I see a lot of UAV manufacturers with excellent products, however the price tags are in the $15k to $30k price range. Again all the drone does is act as a camera platform, it’s the images from the camera that are the important bit. If you want quality data, focus on the payload system, and just use the drone as a tool to carry it. Could a $750 consumer drone do a full commercial UAV survey using Drone Deploy? Most farmers and agronomists want a ROI on new technology, so why not give them a tool they can get a feel for UAV’s in precision agriculture, but without breaking the bank account? Only one way to find out.


So next was the choice of camera and gimbal. Obviously, this is the tradeoff of resolution, weight, flight time and spectral coverage. The Iris+ can carry a GoPro Hero 3 or 4 either in a hard mount or using a Tarot Gimbal. To ensure good data a gimbal is used such that the camera is always pointed straight down in a NADIR position. This position and the brushless gimbal ensure the image is sharp with the correct overlap. However it is expected that the hard mount could be used and is a future investigation.


So now talking about the GoPro. Obviously we want to do vegetation health and stress analysis so we need some type of Near-Infrared, or Red Edge camera. This requires taking a stock GoPro, opening it up and removing the normal lens/filter used for RGB daylight photography/video:



(If you are not confident in doing this please use a vendor purchase from RageCams or IR-Pro instead.)
Once the old lens is removed, use a new replacable screw-in NIR-GB lens. There are number of lens that exist on the market from IR-Pro http://www.ir-pro.com/ and Peau http://www.peauproductions.com/main.html


So what results should you expect from a GoPro NDVI? The most important thing to recognize is that this is not a referenced NDVI camera. To go that route you are looking at much more expensive solutions. Here we are talking about a cheap scouting copter for farmer to take the first steps into UAV with a short ROI which does not break the bank, but can generate actionable data and can identify vegetation and crop issues, that are correlated to ground data. The holy grail of UAV NDVI is still that, you speak with anyone with experience in this field (bad pun) and they will tell you that although everyone holds NDVI up as the only metric. That’s untrue, in reality it’s using any combination of cameras to generate UAV images, which are combined with ground data to generate actionable data. Different crops work better with different cameras, processing, camera combinations i.e. NGB and FLIR for example. There is no single camera/formula which will work for all solutions. Of course resolution, imager size, rolling shutter effects etc. play into this as well, but the question here is, can you use a GoPro for NDVI that allows useful correlation with ground data.

So let’s do some comparisons. Below are 2 scenes, one of an open space, one of a plant, with photographs taken with a normal RGB Canon SX260HS, the GoPro with a IR-Pro InfraBlue22 NDVI lens, a Canon SX260HS with an older style Event 38 filter, and finally a Canon SX260HS with a new style Event 38 filter. That’s 8 photographs in all. Obviously you cannot vegetation health from the RGB, but it’s our reference to understand what we are looking at.
RGB Photographs


Now look at the GoPro NDVI photograph. You can see the vegetation is red/brown/pink, whilst the manmade objects are mostly as viewed by our RGB reference. However you see some pink tinge to the manmade objects.
GoPro Photographs

Looking to the older Event 38 filter, you can see that this has similar type of spectral separation, with some overlap between the vegetation and manmade objects. Here the manmade objects such as the road and buildings have a slight pink tinge to them, but less than the GoPro. This is due to the red notch roll-off, filter corner frequency.
Old Event 38 Photographs

Old_E38_Field Old_E38_Plant

On the newer Event 38 filters, you can now see good separation of spectral content, with manmade objects having no or little pink, and the vegetation been much better defined pinks/browns. This is because the new filter has a roll-off which is steeper and the corner is moved slightly up in the spectrum.
New Event 38 Photographs

New_E38_Field New_E38_Plant

As such you can see how 3 different NIR filters with good imagers, two with the same Canon imager, can generate significantly differently results. For today the flights are only concerned with the GoPro InfraBlue22 NDVI lens, but in later blogs I’ll be looking at filters for Canon Point-Shoot and the Sony Alpha range of cameras, as finally with an Event 38 GoPro lens using the filter shown in the above Canon SX260HS. At that time I’ll be looking to do a fly off of all the different lenses and cameras, thus showing the relative merits and drawbacks of each.
Now one curious point about having a GoPro InfraBlue22 NDVI lens, is that you can now shoot NIR video, and here is a sample. Again look at the ground color which is sparse due to the California drought, the accumulated water from the first rain in months, the vibrant color of the trees, and manmade objects like the path and buildings:
Now one question I have been asked a lot is, “can I fly a GoPro NDVI and look at the video to see crop health. In this way I won’t have to do all this image stitching and processing.” I’m afraid not, the GoPro InfraBlue22 is not really NDVI camera, what it does is captures NIR, Green and Blue spectra which then needs to be processed by software on a pixel by pixel basis to generate a NDVI image, using a NDVI, ENDVI, DVI formula. Many formulas exist and each formula has its own merits in terms of results for different crops, sun and cloud conditions, filter type etc. To get an NDVI image of a large area, you need to capture a set of overlapped still images in NIR-G-B (or other band combination dependent on filters), stitch them together and then process them according to a formula. If anyone has a NDVI video processing software let me know, or I’ve just given you your next Startup or Kickstarter idea.


Test Cases
Three test cases were flown. The flights were preplanned away from the field, then flown using just an Apple iPad with Internet connection whilst at the field. Two surveys covered 20 acres at an altitude of 80m and took approximately 9 minutes to fly, whilst the last survey covered 5 acres at 50m with an elapsed time of 5 minutes. The flights were flown with the GoPro 3 Black converted and using the IR-Pro InfraBlue22 NDVI lens, in a downward pointing NADIR position, in a Tarot Gimbal, flown on a 3D Robotics Iris+ multirotor. The test sites were chosen as they consisted of a number of plant habitats and included wild and mown meadow, manmade objects, seeded lawn with grounds keeper care. To act as a reference, the images from each survey were also processed in Pix4D Pro as well. Due to the nature of the test sites, stitching was not easy and this was intended to test the efficiency of the algorithms.


Test Case 1

Wild Meadow in drought with rolling hills with a general declining elevation away from the takeoff point. Mixture of wild meadow, mowed meadow, brush, with fences, paths and cattle. Flight covered 20 acres at an altitude of 80m and took 9 minutes to fly. 37% battery left.

Drone Deploy Flight Path


Drone Deploy Orthomosaic


Drone Deploy NDVI


Drone Deploy Digital Elevation Model


Drone Deploy 3D Model


Pix4D Ray Cloud


Pix4D Orthomosaic




Ground Photographs

Picture 1 – Looking South over the Survey Site


Picture 2 – Ground vegetation and brush


Picture 3 – The hole in the ground and the bump


Picture 4 – The path up the left side of survey area


Picture 5 – The road and banking to the right of survey area


Ground Truthing
Picture 1 shows a view looking over the survey sight. You can see the rolling nature of the meadow, which is made up of grass, vegetation and brush shown in picture 3. This is common grazing meadow. Interesting if you look towards the center of the photograph at the next hill, just to the left you will see an off-road vehicle track which bends around the hill. Now look at the Orthomosaic and NDVI to the right side and you will see a blue area which bends. This is the same feature, but why the blue? Well look more to the right towards the road and compare to Picture 5. You’ll see a bank, but on the NDVI where the bank is again a blue area. Now look at the Orthomosaic, NDVI, DEM and 3D model and in the middle you will again see a blue area. Looking at Picture 3 this can be seen to be due to a big hole in the ground. So what is causing the blue? Well the survey was taken in the afternoon in late December, with the Sun low in the horizon, as such the blue is from shadows. Now look at the NDVI to the left side and you see an area of blue, this is actually shadows from the dead brush shown in Picture 2.
The rest of the NDVI shows varying degrees of green which correlates to different densities of grass throughout the meadow. In Picture 4, you can see a path to the left of the hole, which is easily seen on the Orthomosaic, NDVI, DEM and 3D Model. And that is what’s interesting is the amount of data produced, from different vegetation densities, identifying elevation changes, depressions and water drainage areas, fence lines, paths etc. It’s data rich information from a single 9 minute UAV flight over 20 acres.


Test Case 2
Meadow in drought with wild and mowed areas, buildings and concrete path in survey area, see 3D model. Takeoff was from the top of a hill to the left center of the survey site, with the land dropping away in altitude in a rolling manner. Rain the previous days highlighted by areas of accumulated water in low lying basins. 9 min 10 sec flight at 80m with 41% battery left at landing.

Drone Deploy Flight Path


Drone Deploy Orthomosaic


Drone Deploy NDVI


Drone Deploy Digital Elevation Model


Drone Deploy 3D Model

3D Model_Bike

Pix4D Ray Cloud


Pix4D Orthomosaic




Ground Photographs

Picture 1 – Looking South of take-off point

IMG_0610 - Copy

Picture 2 – Looking North of take-off point

IMG_0612 - Copy

Picture 3 – Looking at depression in ground South of take-off filled with water

IMG_0619 - Copy

Picture 4 – Looking to the West of take-off point, towards mowed area, treeline and Sun


Ground Truthing
The DEM and 3D Model and good representations of the survey site, with the DEM showing the marked elevation changes, which can be seen by looking at the ground photographs. The buildings can be seen in Picture 2, and visible at the top of the mosaic and NDVI. The tarmac bike paths can also be clearly seen.
To the middle left of the NDVI image can be see a blue area. Closer examination shows this to be due to the shadow of the trees, look closer at the shadow shape. It can also be seen in the Orthomosaic. Looking around further, and comparing to the DEM, you can see that the significant areas of blue are all on the right side of elevation slopes in the DEM. As such these are again shadows due to elevation changes and plants/bushes. This observation falls in line with Test Case 1. In this case the survey was run in late December at around 3pm, where the Sun cast shadows. Another reason for blue is water. Look at Picture 3 with the depression filled with water, then look at the same location in the NDVI and Orthomosaic. So here you have similar colors for different reasons. Another point to watch out for.
Different plant and vegetation densities show up as different shades or colors. In this case more dense areas showed up as a stronger green, whilst mowed areas and paths were more of a darker green. You can see the differences by comparing Picture 4 where you can see unmowed/mowed with the Orthomosaic and NDVI imagery.


Test Case 3
Soccer field cared by ground keeping staff. Covers approx. 5 acres. Flight time of 5 minutes at 80m, with 62% battery left after landing.

Drone Deploy Flight Path


Drone Deploy Orthomosaic


Drone Deploy NDVI


Drone Deploy Digital Elevation Model


Drone Deploy 3D Model


Pix4D Ray Cloud


Pix4D Orthomosaic




Ground Photographs


Ground Truthing
From the Orthomosaic, NDVI from both Drone Deploy and Pix4D, the question is, what’s with the circle patterns? Well that’s a good question. Just looking at the ground photograph it’s hard to even see the pattern unless you already know it’s there. So what is it? To be truthful I can say what the difference is, but not why. The area within the circles appears to be of a different density of seeding, with more densely packed growth outside to inside the circles. As to why a circular pattern, I have no idea. There are no sprinklers to generate such a well defined pattern. At this time I’m going to approach the field owners to ask some questions.


Drone Deploy Observations
So let’s go over my observations from this investigation of Drone Deploy:
1. UAV data needs to be ground truthed. Without correlating ground and aerial data, you have no means to interpret what you are seeing. UAV images and in particular NDVI imagery however can highlight issue areas, and with experience seasoned UAV operators can pull on past knowledge to make educated assessments.
2. Drone Deploy is fast and simple. Its GUI is intuitive and actionable data is delivered in a simple to understand format. Drone Deploy is so easy to use via a tablet, a non RC experienced user can easily fly a survey, and get quality results in a very short time.
3. Stitching on the go, it’s unheard of and it’s not a gimmick. Having the ability to see maps generated as you fly means spotting issues with images whilst in-flight, or issues in the field straight away.
4. Actionable data, it’s not just a saying. Drone Deploy generates Orthomosaic overlayed on Google Earth which has great alignment. It’s amazing to watch as you zoom in the quality of detail in Drone Deploy area, compared to surrounding Google Earth imagery.
5. You get 4 sets of data in one go, Orthomosaic, NDVI, Digital Elevation model and 3D Model all in one . Also all the data can be exported and shared.
6. The GoPro does not have GPS and for this exercise I didn’t try to match the GoPro clock to the Pixhawk clock, so I could align using the Iris+ logs. Instead the Pix4D images were stitched with un-geotagged images. As such I was quite amazed at the speed and ability of Pix4D to stitch none geotagged images from a GoPro. At no time did Pix4D fail to stitch the images from any survey flight I flew.
7. Most parameters on the GoPro are controllable, except one, shutter speed. My expectation, and one raised by Agribotix in their blog in the past, is that the lack of shutter speed control with flight speeds of UAV’s would generate blurring. In fact this was not the case. You’d be unable to stitch images if this was the case.
8. Drone Deploy and Pix4D data correlates well, showing that both companies have done their homework on how to generate data that is quality, correct and actionable.
9. You can fly 20 acres with a consumer drone such as an Iris+, capturing NGB images to generate NDVI data whilst the aircraft is still in the air. Given the battery capacity left and flying at 107m it is feasible to cover 25 acres with such a setup.
10. NDVI data is not infallible, it is a function of camera quality, filters, Sun and lighting conditions. Be aware of the limitations of the technology you are using to get the best data available.


Drone Deploy Conclusions
Overall I’m very impressed with the Drone Deploy system. This is a disruptive technology in the commercial UAV space, where the UAV is viewed as a tool rather than pretty piece of sexy technology. In this space the UAV is just a part of the whole system, an important part, but the end goal is actionable data. Using a consumer drone from 3D Robotics, the Iris+, and flying a NDVI converted camera, Drone Deploy facilitated a number of 20 acre NDVI crop scouting flights, with actionable data available in minutes that correlated with ground data. On top of that Drone Deploy have made a system that a worker in the field with no previous experience of RC flight can be trained on a flown with a smartphone or tablet. Nothing else today exists to do this. I believe Drone Deploy has a very bright future.
If you are interested in learning more about this system, drop me an email at iain.butler@kextrel.com



I’d just like to personally thank the following people for making this investigation a success. Mike Winn for initially reaching out to me to discuss the vision of Drone Deploy. Jono Millin and Nicholas Pilkington for business and mapping support, and Jeremy Eastwood, Chase Gray and Manu Sharma for technical assistance. Best of luck and I’m sure that you will do well. Also congratulations on hiring Gretchen West.

In my next blog I aim to cover flying a number of different cameras on a 3D Robotics X8M platform with and without Drone Deploy. The cameras will range from GoPro, through Point and Shoot to high end consumer.





How to Crash your Drone in 30 Seconds……. Or Hopefully not with a Little Information

How to Crash your Drone in 30 Seconds…….Or Hopefully not with a Little Information


So if you’ve got a RC plane, Helicopter or Multirotor for Christmas congratulations, I’m sure you’re going to really enjoy it. I’m hopefully going to explain the opposite of the article title and give you some pointers so you don’t crash your new drone. It should also make your flying more enjoyable and less stressful.

Now for starters like anything most things there are a couple of rules that you need to understand. Generally drones are governed by the countries airspace authority, such as the CAA in the UK and the FAA in the USA. Policy, advisories and rules exist to separate RC aircraft from manned aircraft, keeping them apart and avoiding collisions. Globally airspace authorities are struggling to keep pace with the massive explosion of the hobbyist and commercial drone market. However the general rules are:

FAA know

  1. Fly no higher than 400 feet. Why? Manned aircraft do not fly below 400’, small drones no higher than 400’, therefore they avoid collisions. Never ever fly above 400’ AGL (above ground level) your risking people’s lives.
  2. Always keep your aircraft in sight, you need to be able to determine where is pointing, which direction it’s traveling and be able to recover it and fly it safely back to you. If you cannot see you don’t have correct situational awareness and you likely to crash or have a flyaway (more later.)
  3. Never fly within 5 miles of an airport or on the approach paths to an airport. Again it’s pretty commonsense, but worth mentioning.
  4. If you see a manned aircraft nearby, avoid any chance of flying nearby and if possible land.
  5. Do not fly over or near people. Well the reason is pretty obvious, loose control and you can really hurt someone, if your batteries run out of power, you’ve got a 2lb flying brick falling from 400’, yes it could really hurt.
  6. Don’t fly over Stadiums, this is generally restricted airspace during sporting or events. Again you don’ want your drone falling on people.
  7. Join a club and take a lesson.
  8. Inspect your drone for loose parts, good wiring connections, and tight propellers. Now is the time to find out your wing is loose, not 300’ up in the air.
  9. Do fly for fun, not commercially unless you have a commercial license.
  10. Normally weight restrictions apply, in the USA don’t fly a RC aircraft over 55lbs (unless waivered.)
  11. Don’t fly recklessly or dangerously. If you fly dangerously you can be arrested for reckless endangerment.
  12. Respect privacy. Drone privacy regulations are been formulated and discussed, but normal privacy laws apply. Doesn’t matter if it’s a drone, camera, telescopic, spying on your neighbors is illegal.

For the USA here is a short FAA video on small UAV policies. http://www.faa.gov/tv/?mediaId=997


OK so that is a quick discussion on the present policy, advisories and regulations, but let’s give you some hard learned lessons and pointers to help you fly safe. So how can you fly safer? Here are some pointers:

  1. When you get your drone, read the instructions cover to cover. Follow the instructions. This is where problems first start. You need to know what each knob, switch, lever on the transmitter does. You need to know the calibration procedures, most drones after been turned on need to be left untouched to calibrate the electronics, plus get things like compass and GPS calibrated. Imagine taking off with your compass wrong and GPS thinking you’re in Cape Town, South Africa, when you’re actually in Huddersfield, England? Well when you take off it’s going to start flying to South Africa! That’s called a “Flyaway”, where the drone just fly’s away out of your control (again flyways mentioned soon.)
  1. Join your local flying club, in the USA your local AMA @modelaircraft club. The people here enjoy RC flying and have lots of knowledge, people who can help train you and hold events like flying contests, fun fly days, BBQ’s etc. Contact your AMA club and attend.
  1. Buy a flight simulator, it really will save you money in the long term. Flight simulators from Real Flight http://www.realflight.com/ . Are very realistic in graphics and flight dynamics. You can learn to difficult maneuvers without crashing, and if you do you just hit RESET and you’re flying again. This really will save you lots of money and climbing trees. Flight simulators are particular important for RC planes where you need to learn takeoff and landings, this is where most crashes occur for beginners. It also teaches you about orientation. Normally a RC plane, copter follows the direction of your transmitter sticks when viewed from behind, however when the plane or copter is pointing towards you the transmitter stick movements are reversed! This is another reason for beginner crash, you’re up in the air and no idea front from back, and you’ve taken off in your back yard and stuffed it into that 40’ conifer tree. Trust me, get a flight simulator fly in manual mode, and avoid all those fancy stabilization modes for now. Fly until its subconscious. Once you have done that, go fly at your RC Club field with seasoned pilots. You’re still going to crash but no way near as if you hadn’t practiced on a simulator. Also the best way to improve is to avoid crashing on the simulator. Fly as if the aircraft was real. You’ll learn a lot faster, practice each simulator session with a set maneuver to improve in mind i.e. take-off, landing, level turns, loops, rolls etc.


  1. Fly in a big open space, not your back yard unless it’s big! Flying in a small area with limited beginner skills probably means you’re going to crash, your reaction skills and muscle memory haven’t had the correct training yet. You need to subconsciously react, normally if you have to think about which direction you’re pointed, or what to do, you’ve already crashed.
  1. Fly two mistakes high. It’s an old saying but very true. You’ll come to learn what you safety margin is, but your should be able to make two mistakes and recover before you crash. This is more applicable to planes, as nowadays Multirotor have stability recovery systems which recover if you let go of the sticks. Planes if you let go of the sticks they just crash (unless they have the new recovery systems now entering the market.)
  1. Never fly over your head or behind you. It’s the best way to loose orientation and crash. It’s also a safety issue, as any spectators should be stood behind you.
  1. Never fly into the sun. There is a reason WW2 fighter pilots dove out of the sun on their prey, you cannot see and will lose sight of your aircraft and probably crash.
  1. Always check your transmitter and aircraft batteries are fully charged before taking off. There is nothing like the fear of hearing the beeper as your transmitter batteries run out of power and you try desperately to land your aircraft before you lose connection and it flies off in to the sunset.
  1. Avoid Flayaways or recover from them. This can be caused by a number of issues such as firmware updates of your drone, bad GPS and compass calibration, incorrect switch settings etc. Main thing be very careful after doing a firmware update on your drone, and make sure you have completed the correct compass and GPS calibrations. Also be careful when flying with GPS when Solar Flare activity is high, this can disrupt GPS and cause flyaways. If your drone starts to fly where you don’t expect it do the following:
    1. Check your switch settings and move to correct positions.
    2. If that is OK, switch to MANUAL.
    3. If that doesn’t work, switch to RTL or LAND.
    4. If that doesn’t work turn off your Transmitter and the failsafe’s should kick in.
    5. Follow the Instructions for your drone about Flyaway recovery.


  1. For RC planes practice dead-stick landings, where you throttle the engine all the way back and land by gliding. It’s a good technique to learn for WHEN your motor quits in the future, either from a lack of gas or a low battery.
  1. For Collective pitch helicopters practice autorotation’s, where you cut the throttle and use the blades energy to keep you flying with a flare at the bottom for landing.
  1. Don’t try engine off landing on fixed pitch Multirotor, you’ll just dig a hole in the ground as it falls like a brick.
  1. Follow a checklist every time you fly, manned aircraft do it, it gets you into a routine of checks that no matter how obvious will help you spot issues before they become crashes.
  1. Always aim to land with >20% battery or fuel left. All you need is somebody to crash on your landing area and you’ll be glad you had that spare fuel. Plus it helps your batteries.
  1. Use small smooth control inputs, imagine you’re holding two glasses of water filled to the top. Don’t spill the water, make smooth small movements. Big fast movements over-control your aircraft and before you know it it’s in a death spiral or rocking violently from side to side. Smooth is king. If you’re out of control, center your controls, let the aircraft recover and then take control again.
  1. For RC planes always take-off into the wind and land into the wind, you get more lift and slower takeoff and approach speeds.
  1. For all aircraft monitor the wind and be prepared for gusts. If it’s too windy land.
  1. Practice crosswind landings on the simulator, A LOT, then try them at the flying field.
  1. Practice the basics before trying more complicated flight modes. The basics will save your aircraft when everything else goes wrong.
  1. Have fun, but be safe.


FPV Racer Photograph courtesy of Hovership

Merry Christmas





eXom – the drone that lets you focus on your work, not on flying

eXom – the drone that lets you focus on your work, not on flying
senseFly brings next-generation rotary UAVs to life at Intergeo 2014


Sensefly who is well known for its eBee Ag and eBee RTK fixed wing drones, but they have now moved into the Multirotor arena. Announced at Intergeo, Berlin, today the Sensefly Exom was launched to the public. The development has taken over two years, and Sensefly has added some new unique features to the quadcopters functionality which give the Exom unprecedented situational awareness.


In addition to seeing what its TripleView camera head sees, eXom’s five vision sensors also enable you to see in the direction the drone is moving – like the visual parking displays in modern high-end cars – for enhanced awareness and safe operation. These sensors work in harmony with eXom’s five ultrasonic sensors to ensure you always know the drone’s distance from nearby objects. Plus, eXom includes the extra security of automated proximity warnings, and shock-absorbent carbon fibre shrouding protects eXom’s rotors in case of surface contact.


In another first for a civil drone system, the eXom’s autopilot-controlled TripleView head allows you to view and record any type of imagery required – HD video, ultra-high-resolution stills, thermal data, or all of the above. All without needing to land in order to swap cameras. Since its head faces the front, eXom can fly up close to target structures for sub-millimetre data resolution. The head’s 270° vertical field of view also means eXom can document objects directly above it; crucial for challenging tasks such as inspecting underside of a bridge.

eXom’s unparalleled level of sensory intelligence means it is easily controlled, even in the most demanding situations (e.g. approaching a high target positioned hundreds of metres away), without the need for a remote control or piloting skills. Simply choose your flight mode:

Interactive ScreenFly mode – click or tap the on-screen video feed to define an object of interest. eXom’s intelligent autopilot moves the drone into position and directs its TripleView head automatically.
Autonomous mode – define the area to map using the drone’s eMotion software. The software automatically generates the drone’s flight plan, then eXom takes off, flies, acquires imagery and lands itself (similar to senseFly’s fixed-wing eBee drones).

With so many unique features in one safe, robust platform, senseFly is pioneering innovation in the civil drone field. “We are thrilled to announce the eXom and look forward to demonstrating this next-generation platform to Intergeo visitors,” said Jean-Christophe Zufferey, CEO and co-founder of senseFly. “We designed eXom to be unlike any other rotary drone; a fully-integrated imaging platform rather than just a remote-controlled aircraft with cameras attached. This allows users to focus on their work, not on flying.”




Drones above the Vineyards

Drones above the Vineyards

So what are drones good for? Well a lot actually as it turns out. For example, I had the privilege of working with a top California Vineyard before harvest time, to investigate how Multirotor UAV’s could be used in vineyards to improve efficiency and identify crop issues. In the following I’ll highlight the workflow used, the results and some tips learnt the hard way.

Which UAV platform and Remote Sensing Equipment to use?
First off is what type of UAV to use, well it’s not as easy as picking up a drone off a store shelf for starters. To have useful photogrammetry results a number of key issues needs to be addressed:
1. Lift capacity and Endurance – Although this seems obvious, the UAV has to lift itself, batteries and camera/s into the air and fly the whole survey route. Working backwards, the UAV choice is therefore influenced by the payload or in this case the camera. I’ll explain more on this later, but for this test the payload weight was 8.15oz or 231g, or a point and shoot size camera. Add onto this a gimbal of approx. 100g; we needed to lift approx. 330g for approximately 12 minutes. Looking through specifications, the 3D Robotics Y6 was capable of this scenario, using a 4S 6000mAh battery http://store.3drobotics.com/products/3dr-rtf-y6-2014 Another option was the 3D Robotics X8, however we also wanted a copter that could fold down for transport, as such the Y6 with its foldable frame was selected over the X8.

2. Autonomous Flight with Flight Planning – When flying large areas of crops, flying manual and getting the correct overlap on images is near impossible. As such the UAV needs to be flown in an autonomous mode. This requires that the area to be mapped is stored in an electronic flight plan in the UAV, and the UAV flies from each assigned point or waypoint at a specific speed, altitude and orientation. This also allows the mapping mission to be flown, time and time again, days, weeks and months later. This is important, as it allows images from different dates to be compared side by side, allowing crop analysis over time. As we were flying 3D Robotics Y6 we had a choice of Pixhawk or APM autopilots. The UAV was initially a Y6A with AMP2.6, however for this mission the UAV was converted to a Y6B (mainly as this was better supported) but still with an APM2.6. In the future we will look at using the Pixhawk for the Y6. The APM2.6 has a long history in UAV autonomous flight, so this was the chosen platform.

3. Camera – The data is only as good as the images, as such the camera is critical. This data quality is a trade-off in a number of factors, weight, resolution, control, imager size, cost etc. We have a defined weight of approx. 200-300g as an acceptable payload weight. This places us in the point and shoot category. The camera must also have an NDVI capability. Also the camera needs to be setup with the correct parameters and also be triggered by the UAV, which the APM2.6 can do. This combination led us to use the Canon series of point and shoot cameras. Presently the SX260HS, S100 and S110 can be converted for NDVI and are used by companies such as Agribotix, Sensefly, Roboflight, Quest UAV etc. To simplify operation, the camera used was the SX260HS, as this has an on-board GPS, allowing for each image to be geo-tagged with GPS coordinates. This helps with the image processing later. The Canon range of cameras also are supported by an application called CHDK, which is placed on the cameras SD card. This supplies the camera with additional functionality, such as triggering from the UAV, interval timing shots, setting white balance etc. The camera is also 12.1Megapixel, for flying at a height of approx. 100 feet, with a ground resolution of approx. 1cm per pixel. More than enough for crop analysis, and flying up to 400 feet still gives excellent imagery for analysis. Finally as previously mentioned, the cameras need to be NDVI capable. This was achieved using an Event 38 NGB, near infrared, green, blue filter with the red spectrum notched out.


A tutorial on how to convert the camera is defined here, the process is relatively simple.



And the results of the conversion can be seen in this blog:


Other camera filters exist from companies such as Max-Max:


So the remote sensor is a Canon SX260HS with GPS, fitted with an Event 38 NGB NDVI filter, with CHDK software mounted on the camera SD card.

4. Camera Gimbal – Flight time is a trade-off of thrust versus weight, as such the lightest simplest quality gimbal was researched. Gimbal categories can be split into 3 main areas, simple servo gimbals, high quality servo gimbals sometimes with gearing, and brushless gimbals. The purpose of the gimbal is to allow the camera to take high quality images of the crop. To do this a number of issues must be addressed. Firstly the gimbal needs to keep the camera pointing straight down. This keeps the overlap on the images which I’ll explain later, even when the UAV is tilted when flying forwards or into crosswinds. This also stops blurring, as the camera is stabile in pitch and roll, thus not been moved around by the UAV movements. An important factor in this is the gimbal movement should be smooth. Secondly, the camera needs to avoid any vibration that could blur the images; therefore the camera needs to be isolated from vibrations of the Multirotor. This is normally achieved using rubber isolation grommets between the camera gimbal and the airframe. Thirdly, it should be light and simple, the more complex it is the more chance it will go wrong in the field. Finally it should be cost effective.

Based on these criteria, we need a smooth movement gimbal in pitch and roll, good vibration isolation, simple and light, and approx. $300. Simple servo gimbals although simple and light, can have sloppy or sharp movement, whilst brushless gimbals are very smooth as they are required for video work, tend to be more complex and heavier. As such a high quality servo gimbal was chosen, the GUAI Crane II which cost $279. It does not have any associated electronics as per brushless gimbals, instead using the UAV flight controller for gimbal control. An advantage of this gimbal is that it also allows the gimbal to be removed easily from the isolation damper for packing/traveling.


5. Camera setup – Again, the final analysis is only as good as the data used, which means you need good quality images. For UAV aerial images, there are a number of trade-offs, such as ISO settings, the aperture, auto-focus, shutter speed, white balance, image stabilization, image capture time etc. The main aim is to get a sharp image with the least amount of noise. Also the image quality is affected by the light quality, with results changing between a sunny day and a cloudy day for example (see Agribotix for further analysis on this.) Normally the following setting work and were used, white-balance sunny day, zoom set to wide angle to maximize image view, auto-focus off to speed time between images and focus set to infinity, aperture set to automatic, image stabilization off, shutter speed set to a medium such as 1/800, ISO set as low as possible to avoid noise.
Summary of Setup
OK, so we have the UAV the 3D Robotics Y6, the 3D Robotics APM2.6 autonomous autopilot, a Canon SX260HS with GPS, fitted with an Event 38 NGB filter, mounted in a GAUI Crane 2 gimbal.


Plan the Mission
The flight planning software for the 3D Robotics Y6 is called Mission Planner (http://copter.ardupilot.com/wiki/mission-planning-and-analysis/) and can be used to devise flight plans, configure the UAV, plus monitor the UAV in flight using a telemetry link. One useful point when planning a mission is to use a site survey if nearby, to access the safety and understand the terrain or any obstacles or special circumstances that need to be taken into account. Once this is done, Mission Planner can then be used to draw the survey map.

This survey grid is then converted to waypoints with flight altitudes, and uploaded into the UAV.


On the Day
Meeting the vineyard owner, a survey site was identified of approximately 7 acres, which kept the UAV away from trees, power lines, workers and an on-site event which was been setup. The site was focused on the middle of the vineyard with some elevation change involved. This is very common situation in the Santa Cruz area, where the vineyards propagate through the Santa Cruz Mountain region. Normally this is also associated with the vineyard been surrounded by tall trees such as Redwoods, which in turn leads to a large bird population. The upshot of this is the vineyard headache of birds been pests, which leads to most Santa Cruz vineyards using netting to protect their crop. However on this day only some of the crop was netted, so the majority of work was over the un-netted area.
Here is the Y6 ready to fly:


Josh Metz, UAV Observer and Vineyard GIS Specialist @Geovine :


As mentioned before the site had been pre-planned via Google Earth and a number of possible missions planned and stored. Therefore all that was required was to upload the correct mission the Y6. Firstly the NDVI NGB camera was loaded, turned on and allowed to get GPS. The mission was then started a survey grid flown with no issues, except one.
When the mission was preplanned, the landing site was in the center of the vineyard, however the take-off and landing site was moved to the top of a hill to get better observability of the UAV during the flight. The exception was that the take-off site was changed, but the landing site did not reset correctly. The result was at the end of the mission, the UAV attempted to land at the other end of the vineyard in the old landing spot. This was easily overcome by going to manual and flying it back and landing by hand. However the moral is, when you program a mission to a UAV, always read it back to make sure all changes are correct. Also always pay attention, have an observer in my case Josh Metz, Vineyard GIS Specialist @Geovine , and always be ready to take control back.
After the NDVI RGB camera flight, the camera was swapped out for a normal RGB camera, and the mission flown again. Again, this is the advantage of autonomous flight, both NGB and RGB doing two flights but over the same flight path.

Processing Information
A number of software suites exist to process images and create NDVI information, two examples are AgiSoft (http://agisoft.ru/ ) and Pix4D ( http://pix4d.com/ ). Another interesting choice is from Agribotix which is a Cloud Based NDVI service for post processing UAV images http://agribotix.com/
This survey was based on Pix4D who kindly gave us a Demo License for this investigation. The purpose of this software is numerous. Firstly it corrects for camera issues, as such the camera model used is added as input data, the separate images are uploaded and then the software joins all the separate images together in a point cloud. From this a single large image is generated and then numerous other outputs such elevation models, 3D models, plus NDVI data plots as outputs. The output formats are numerous, with Geo-Tiff been a primary output. To help the software align the images, ground control points can also be added, which gives known reference point for the software to stitch the images together.
To get a complete stitched image, all the images must overlap. The required overlap is normally 60% to 80% to allow the software to stitch properly. As such you need lots of images, and the lower you fly, the more images you need. The downside of this is that you must process more images, which takes more time. This process requires a fast computer using lots of memory, such as an Intel i7 running 32 or 64GB of memory. So two lessons fly as high as you can, but no higher than 400’, and have a very fast computer.
Pix4D did an excellent job of stitching the NGB NDVI images together, but issues did occur with the RGB images, although this was not a software issue. The GPS on the Canon SX260HS RGB camera had not geo-tagged the images correctly. However just using the Pix4D ground control points, the software was still able to stitch the RGB images together.
NGB Point Cloud showing the UAV position when the image was taken.


NGB Mosaic Image, showing the separate images stitched together.


RGB Point Cloud, where the images were stitched using just ground control points with no GPS data.


RGB Mosaic with all the stitched images.


NDVI Image


The NDVI image was generated using the NGB bands processed by the Pix4D software. A quick explanation of the image brings to lights some details with NDVI imagery in vineyards. Firstly the dark blue is actually due to shadows on the ground between the vineyard rows. This was because the survey was flown in the morning around 10:30am, rather than noon with the sun directly overhead. The green indicates the ground. The red indicates the separate vines.

One of the main items to notice is where you have good vine virility and growth, you see red vines and the blue shadows. Where growth is low the vines in red are less obvious and the shadows (blue) less strong, and the ground (green) more merged together. Using this information it can be see that certain areas show lower growth and yields than other areas.

Correlating to Ground Data

After the data was processed, we went and talked with the vineyard owner, and compared ground data with our results. It was obvious from the discussions that the ground data and the UAV NDVI and RGB images both highlighted low yield areas, which were known to be lower than the rest of the vineyard due to soil type, irrigation etc. As such the UAV images with Pix4D processing were shown to have been able to correlate well to ground data.

It also became clear that the owner knew his vineyard very well, as it was approx. 17 acres, so he and his staff could walk the property and identify issues on the ground. As such UAV imagery only becomes effective as a business model when the property cannot be efficiently walked. At this point the UAV is indispensable in its ability to capture large areas and process data.

One advantage of UAV imagery that needs further investigation though, is that RGB images do not show yield issues that easily when the vines are netted, however preliminary analysis shows NDVI NGB images can show yield issues even when the vines are netted.

IMG_20140721_200505 (2)

Lesson Learned
1. Keep it simple
2. If it can go wrong it will go wrong
3. Preplan your mission, do a site visit or use Google Earth for site info
4. The higher you fly, the less images you need which means less processing time
5. The higher you fly, the larger the area you can map
6. Always check your images when in the field
7. Fly at noon to limit shadows from the vines
8. Use an observer
9. Crop analysis is 20% flying and 80% data processing
10. Image processing takes lots of computing power, get a fast processor with lots of memory
11. High quality images equates to high quality crop analysis, poor images mean poor data
12. Aerial images and analysis needs to be correlated with ground data to be effective
13. Normal photographs and video in RGB is almost as invaluable as NGB to the vineyard owner
14. Drone NDVI mapping becomes effective with vineyards greater than 50 acres
So we have shown how a UAV such as a 3D Robotics Y6, mounted with a simple Canon point and shoot camera modified with a NDVI filter, using powerful software such as Pix4D, can generate useful crop analysis for vineyards. We’ve pointed out lessons learned and are now ready to keep on helping the Santa Cruz Mountain Wineries stay the best in the World.




Gene Robinson the UAV Search and Rescue Legend

Gene Robinson the UAV Search and Rescue Legend


A couple of weeks ago I spent a day at the sUSBExpo in San Francisco, organized by Patrick Egan (Thanks Patrick great job.) Quite a few people have covered the Expo already, so I’m going to focus on it from a different angle. I had the privilege of attending the Search and Rescue Workshop presented by Gene Robinson. This was a sold out workshop, but even so Patrick managed to get in most people who wanted to attend.

Gene Robinson has been a pioneer in the use of UAV for search and rescue, starting more than a decade ago. This is truly a humanitarian focus and Gene runs all his SAR work through the non-profit RP Flight Service (http://www.rpflightsystems.com/MainPage.html) /RP Search Services (http://www.rpsearchservices.org/) and working with Texas Equusearch (http://texasequusearch.org/). He was recently awarded the Recipient of the Spectra Humanitarian UA Award. If any one person is an advocate of the peaceful community based role for UAV’s, it’s Gene.

Gene uses his own fixed-wing UAV called the Spectra, using a Robota Goose Autopilot (http://www.robota.us/Autopilot/b/8829483011?ie=UTF8&title=Autopilot). Normally he flies with a 12Mps digital camera. His philosophy is simple, keep it simple, always have a back-up, plan and practice. How do you see this in his operations? Well the Spectra is a flying wing, with only 3 moving parts, two elevon servos and an electric motor. This is a design and requirement based on experience of what works and Gene has lots of it. For example, will your autopilot work below freezing, will it work at 120’F in the desert, will you LiPo batteries have full capacity at launch when it’s cold, and should you change your propellers when flying at altitude? Gene explained all this and more, with a very straight forward and simple way, but drove the message home. Here’s another example, you’re on a search in a desert, are you going to be any good to the Incident Commander if you’ve got sunstroke because you haven’t got any cover?


And here is another important point he drove home, be professional. Do your emergency management training; learn the Search and Rescue team’s methodologies and protocols. Know what radios they use, how to use them etc. And practice, practice, and practice you’re flying. As Gene put it, “You only get one chance with an Incident Commander, if you throw your UAV and it bites the dirt, you’re done.”

It was absorbing to hear of the fire monitoring, and search and rescue missions he has been involved in and made a difference. The number of searches he mentioned where the ground searches had been through an area with a tooth comb, and not find the missing person, only for Gene to find them later. It’s not that the ground search teams are doing it wrong, it’s a resource issue. To find a missing person, you need to be able to see the feet of the searcher next to you, if you don’t your too far apart, and can walk straight past the person you are trying to find. So if someone is lost in Yosemite, how many ground searchers would you need?!

Another of Genes take away point, gather as much information as possible, what were they wearing etc. Here’s another fact, about 80% of missing people are wearing Jean’s. Blue is not a significant natural color in nature. As such Gene now uses image processing software that scours the images for specific colors like blue and other discrepancies, and can identify possible sites for further investigation. On that note, Gene needs help to improve his image processing software, if there are any Python programmers out there, drop Gene an email, http://www.rpsearchservices.org/contact-form.html


The sad part is, is that Gene now has issues with the FAA. Although RP Search Services is a non-profit and Gene pays for everything himself (that’s about $4000 of equipment he throws in the sky knowing he may never get it back, people come before machines and he’s willing to lose it to save lives) they consider him flying search and rescue as a commercial operation, which according to the FAA is illegal under there regulations (that is a whole other story.) As such Gene has retained Brendan Schulman, a pioneering UAV Attorney to take the FAA to court to resolve the issue. The heartache of the matter is that until this is resolved, Gene is not flying SAR within the USA. What is worse, a lot of missing children are small children, can you imagine having a resource such as Gene on hand to find your lost child, but the FAA forbids it?

The next Saturday morning we went on a birthday party with my young daughter in a forest. The first thing I did was take a picture of my daughter. My wife having known that I’d been to Gene’s workshop said “You didn’t do that as a birthday party picture did you?” We also taught her a new rule, if you cannot see our feet your too far away. She’s still checking our feet to this day.

Thanks Gene, you are a real gentleman and humanitarian. Thanks for the workshop, the knowledge and the peace you have brought to families of missing people.

Go watch the Movie from Maha Calderon about Texas Equusearch and Gene Robinson, http://www.civiliandronesmovie.com/home.html

And if you can support Gene Robinson please support with a donation http://www.rpsearchservices.org/support.html

You can also buy his book, “First to Deploy” http://www.rpsearchservices.org/learn/index.html






Which Aerial Platform to use for Precision Agriculture?

Which Aerial Platform to use for Precision Agriculture?

eBee Ag Drone With Case

In my previous post I discussed how UAV’s can help with Precision Agriculture. In this post I’ll discuss the platforms that can be used at this time, ranging from off the shelf complete packages, to do-it-yourself airframes.

So one thing to note is that no single platform is suitable for all applications. The type of platform is dependent on a number of factors such as land topography, area of coverage, environmental conditions such as wind, direction and cloud ceilings. For example a small vineyard with elevation changes in a mountainous region is going to require a different platform, than a large artichoke field which is flat and near a windy coastline. Both these scenarios require different platforms.

Multi-Rotors v Fixed-Wing

In general multirotors are great for small aerial PA projects, 0.2 sq mile. They have endurance of approximately 20 minutes allowing coverage of smaller areas, have good wind resistance to approximately 20 to 25mph dependent on model, can cope with rapidly changing land elevations, and can fly lower for higher resolution. Also the take-off and landing area requirements are significantly smaller. The downside as mentioned is their limited range, which means that for large areas multiple flights are necessary with associated image stitching and complication.

For medium to large areas, 4 sq miles, fixed wing platforms dominate. The reason is endurance, fixed-wings as the name suggest generate lift off their fixed-wings, so as long as they have enough forward motion to generate lift they stay airborne. In a multirotor all the lift comes from the motors and propellers. If both a multi-rotor and a fixed-wing use the same battery, the more efficient fixed wing will be able to fly much longer. Normally up to 3 times as long.

So what are desired requirements for an aerial platform?

Safety and Redundancy

Well for anything aerial safety is key, and the lesson learned from manned and RCMA (RC model aircraft), is that redundancy is key. On a multirotor, the lower the number of rotors you have, the more catastrophic the event if a motor or propeller fails. Losing a propeller or motor on a tricopter (3) or quad copter (4) will normally always result in a crash. Using Y6 (6), and hexacopter (6) formats allows for a motor/propeller issue, but for the platform to be landed. The same is true of X8 (8) and octocopters (8).

Another area of redundancy is servicing and repair. Multirotors as the name suggests are made from a number of motors which operate in tandem to control the flight of the UAV. Normally the motors are the only moving parts on a multirotor except for maybe a gimbal. As such there are less moving parts to fail. The safety concern with multirotors, is that they have no lift mechanism other than the motors and propellers. The problem here is that if the motors stop, they just fall out of the sky. On a fixed-wing, if the motor/s stops, the wing still generates lift and you can glide to a landing.

Now fixed-wing moving part failures tend to be catastrophic in failure, unless there are redundant actuators. On a generic fixed-wing airframe you have actuators that control roll, pitch, yaw and throttle. Normally that translates into two independent airelons for roll, two elevators which are normally joined for pitch and a single rudder for yaw. That equates to 4 actuators/servos and a throttle control. To increase safety this can reduce to two airfoil actuators and a throttle control. Here the pitch and roll are combined in what is termed an elevon system, where the left and right ailerons are moved in combination. Both airelons up induces a climb, both aileron down is a dive, left aileron down, right up is a right roll. Now if the left aileron is moved up and the right aileron is left neutral, the plane with roll left and pitches up. This type of control is normally associated with airframes that are called flying wings. To further increase safety, multiple actuators can be also placed on a single airfoil, as such if one fails, the other takes over as a backup.

So what we are doing here is reducing the number of moving parts that can fail, and where we cannot minimize anymore, then add redundancy in the form of parallel actuators or motors.

Another key area is auto-pilots, just like you Windows PC rebooting and installing updates without warning, you need to ensure you have a safety-critical autopilot. If you autopilot reboots in mid-air, on your multirotor the motors will stop and it will just fall out of the air, on a fixed wing it may glide off into the sunset. Other safety issues are flyways, this can be due to poor autopilot firmware, GPS glitches, power supply spikes etc. Ensure you are using certified autopilots with stable code, good supply distribution, and high quality GPS and even redundant GPS units. In some cases redundant telemetry, RC receivers and autopilots are also employed.

A final safety feature is geo-fencing. Here an invisible fence is placed around the flight path by the mission planning software. If a geo-fence is breached, such as due to a failure of GPS loss of lock, GPS glitching, lost telemetry link etc., that the platform returns to the takeoff site and either loiters allowing a manual landing or auto-lands.

Safety is key, this industries growth will be defined by how safe it is.


It’s great buying that cheap UAV or airframe from overseas, but what happens when you have a rough landing? Can you get spares readily? This is an important consideration, if you ding a wing, you don’t want to wait 2 weeks for international shipping. Makes sure you either have an inventory of spares, or have a nearby dealer who has a good supply.

Stability and Image Quality

It’s true that the fun focus is on the flying, but flying is only 20% of the overall work. The other 80% is flight preparation, post flight and then data retrieval and processing of the images. However you can have poor images due to poor camera choice, no gimbal or a badly stabilized camera gimbal, badly designed autopilot or inefficient stability algorithm, a badly setup multirotor with bad gain settings, poorly balanced propellers etc. All these issues can lead to inferior image quality. And as with most processes, if you put bad images in, you are going to get poor data out. As such although flight time is only 20% of the process, it is key to getting quality data.

So you need to look for a good camera which has approx. 12Mega pixel, with the best possible dynamic range, with integrated image stabilization. The cameras are normally modified with new filters for NIR etc. I’ll discuss cameras and modifications in the next blog. At present the go to camera is a Canon S110 with NIR using filters from people like Event 38. Other cameras such as the Canon SX260 and S100 are also used. You notice the predominance of Canon cameras, this is because they are easily modified for filters and updated with control software called CHDK.

For fixed wing operations having the camera hard mounted to the airframe is the norm. Normally due to the forward speed of a fixed-wing platform and the autopilot, it is normally flying wings level during image capture. On multirotors, due to wind effects, direction of travel, the airframe can be leaning into the wind/direction of travel, and as such a 2 axis gimbal is normally used. These gimbals can be servo or brushless, as this is still pictures a quality servo gimbal can work as well as a brushless gimbal, without the associated cost. The gimbal levels the camera and removes any autopilot sudden corrections.

Autopilots are very important for image quality, a poor autopilot can wander off path giving incorrect image overlaps, jerkiness in control response and just about spoil your day.

So based on the above information, I know there was a lot compacted into a small space, here are some picks for Agriculture UAV’s with some pros and cons:

Fixed-Wing Complete (with associated GCS)

senseFly eBee Ag https://www.sensefly.com/drones/ebeeag.html

Pro – Well integrated package using S110 cameras and PIX4D software. Very small.

Con – Integration costs approx. $25,000 including PIX4D software

Event 38 E384 http://www.event38.com/ProductDetails.asp?ProductCode=E384

Pro – Well sorted package based on 3D Robotics Aero, $2,399. $3700 extra for AgiSoft software

Con – Highwing design, more susceptible to damage, more moving parts

3D Robotics Aero https://store.3drobotics.com/products/3DR-Aero

Pro – Designed by 3DR around Pixhawk autopilot $1350, supported by Pix4D +$3000 annual

Con – Highwing, more susceptible to damage, more moving parts, no defined camera area

Ritewing Zephyr II with Ruby Autopilot http://www.ritewingrc.com/Zephyr_II_ARF.html

Pro – Proven design

Con – Ruby autopilot does not support waypoint navigation at this time

Fixed-Wing Airfarmes

Range Video RVJet http://www.rangevideo.com/en/18-rvjet

Pro – Very stable design for autonomous flight

Con – Long wing easy to damage, no defined horizontal camera area

Skywalker X8 as used by Robo Flight RF 1 http://www.roboflight.com/products/

Pro – Large stable flying wing, able to carry large payloads over long distances, has camera area

Con – Parts from overseas, very large

Phantom V2 Flying Wing http://pixhawk.org/platforms/planes/phantom_fpv_flying_wing

Pro – Small airframe, flying wing that can be taken apart, very stable, has camera area

Con – Parts from overseas

Fixed-Wing Autopilots (with associated Ground Control System and Mission Planning Software)

3D Robotics APM2.6 https://store.3drobotics.com/products/apm-2-6-kit-1

Pro – Established fixed-wing autopilot

Con – Running out of processing power and memory, surpassed by 3DR Pixhawk

3D Robotics Pixhawk http://3drobotics.com/pixhawk/

Pro – Carries on from where APM2.6 left-off

Con – Newer architecture

Roberta Goose http://www.robota.us/Goose/dp/B00EGT0ZCY

Pro – Very reliable, used by Gene Robinson for Search and Rescue

Con – Expensive $3995

Airware http://www.airware.com/

Pro – Modular autopilots for who range of UAV’s

Con – Very Expensive

Complete Multirotor for Scouting (with associated GCS)

3D Robotics Iris https://store.3drobotics.com/products/IRIS

Pro – Integrated proven design with support

Con – In-demand

DJI Phantom 2 Vision+ http://www.dji.com/product/phantom-2-vision-plus

Pro – Integrated proven design with support

Con – In-demand

Complete Multirotor with Lift capability for NVDI Cameras (with associated GCS)

3D Robotics X8 https://store.3drobotics.com/products/3dr-rtf-x8-2014

Pro – Proven Pixhawk X8 copter with PA mission planning and Pix4D software support, $1350

Con – Needs more hands on experience required with mission planning

3D Robotics Y6 https://store.3drobotics.com/products/3dr-rtf-y6-2014

Pro – Proven Pixhawk Y6 copter with PA mission planning and Pix4D software support, $1000

Con – Needs more hands on experience required with mission planning

Aerialtronics Zenith http://www.aerialtronics.com/products

Pro – Very professional high quality design

Con – Expensive at $25,000

DJI S800 http://www.dji.com/product/spreading-wings-s800-evo

Pro – Very professional high quality design

Con – Expensive at $10,000

DJI S1000 http://www.dji.com/product/spreading-wings-s1000

Pro – Very professional high quality design

Con – Expensive at $25,000

Multirotor Flight Controllers (with associated Ground Control and Mission Planning Software)

DJI A2 http://www.dji.com/product/a2

Pro – Established highend multirotor autopilot

Con -Cost

DJI Wookong-M http://www.dji.com/product/wookong-m

Pro – Established multirotor autopilot

Con -Cost

DJI NAZA V2 http://www.dji.com/product/naza-m-v2

Pro – Established entry level multirotor autopilot

Con – Recorded flyaways due to GPS glitching

3D Robotics APM2.6 https://store.3drobotics.com/products/apm-2-6-kit-1

Pro – Established multirotor autopilot

Con – Running out of processing power and memory, surpassed by 3DR Pixhawk

3D Robotics Pixhawk http://3drobotics.com/pixhawk/

Pro – Carries on from where APM2.6 left-off

Con – Newer architecture

OpenPilot Revolution http://www.openpilot.org/products/openpilot-Revolution-platform/

Pro – Open source firmware, proven

Con – Not as widespread as other autopilots at this time

Airware http://www.airware.com/

Pro – Modular autopilots for who range of UAV’s

Con – Very Expensive

So the question is do you spend $25,000 on a senseFly eBee AG or do you buy a 3DR Aero for $1350? Same with the multirotors, do you spend $25,000 for an Aerialtronics Zenith or $1350 for a 3DR X8. I guess it depends on how deep your pockets are.

Thanks for reading, next posting will be about cameras for PA.





How UAV’s can help in Farming – An Introduction

How UAV’s can help in Farming – An Introduction


No matter if you call then small Unmanned Aerial Systems (sUAS), Unmanned Aerial Vehicles (UAV) or the ubiquitous “Drone” moniker, UAV’s have massive potential in farming. Normally if you think about farming, you’d probably think about a farmer driving his tractor and caring for his cattle. My uncle owned a farm in rural Yorkshire in England, and I spent many summer working on his farm, so I thought I knew a little bit about farming. As it turns out I really had no idea.

Today farmers are at the forefront of technical innovation, and this methodology is generally termed “Precision Farming”. In Precision Farming (PA) tools are used to observe, measure and then react to variances within a crop. This allows farmers to determine if crops are under-watered, need pesticides etc. In this manner rather than treating a whole field/s, with water, pesticides, the areas that need treating can be identified and only they are treated. In this way, yields can be increased whilst using less resources such as precious water.

A good source for PA information is http://www.precisionag.com/

So what tools do PA use, how do they process the collected information, and how to they use that data to make decisions?

PA is formed around GPS and the ability to define exactly within a field, specific conditions that exist. By mapping these crop variances to a map location, then a recipe map can be derived which identifies what treatment the crop at location X,Y should have. As such, a single field can be broken down into lots of tiny sub-plots and the crop treatment tailored to that tiny sub-plot area.

Presently the observation is generally ground based, and uses such tools as GPS enabled tractors and combines monitor chlorophyll levels, water status and spectral monitoring. The collected data, is then processed to generate NDVI (Normalized Difference Vegetation Index) maps, where crop stress can be identified and treatment undertaken by GPS enabled seeders, sprayers etc.

Presently NDVI mapping is expensive due to it been time and labor intensive for land based systems, and expensive when employing aerial or satellite mapping. The major benefit of the UAV is in collecting data to generate these NDVI maps, in a short time, at a low cost and with good accuracy. It’s the latest tool in the PA toolbox.

Here is a quick explanation of NDVI, http://www.wikiagro.com/en/NDVI_-_Vegetation_Index

So how can UAV’s help? Well with the advent of multirotor aerial systems with autopilots, you can plan a NDVI survey flight in a relatively short time.

The key tools are:

1. A Multirotor or Fixed wing UAV to do the aerial survey http://3drobotics.com/landing-product/

2. NDVI capable camera with a GPS which can geo-tag the photograph http://www.event38.com/ProductDetails.asp?ProductCode=CAM-NGB260

3. Mission Planning Software, to plan the flight including take-off point, survey flight path including where to take the photographs, and where to land. Also for safety fail-safes are built into the mission, such that if a communication or telemetry link breaks or the UAV goes outside an expected flight corridor (geo-fencing) it returns and lands safely http://copter.ardupilot.com/wiki/mission-planning-and-analysis/

4. Post Analysis Software, which stitches the many photographs together and then processes them to show crop stress analysis http://pix4d.com/ Using this NDVI map the recipe map can then be derived.

Once you have these tools, it is relatively simple to plan and execute a mission. Today’s PA UAV’s are designed to be user friendly and operated via laptops, tablets or even smart-phones. The requirement to be able to know how to fly these multirotros is removed, thus removing the barrier to using them just as tools. Today you don’t need a Ph.D in Aeronautics to be able to capitalize on this technology. It’s been designed to be user friendly and safe, but also intuitive to use. If it’s not, why use it?

So this is a brief introduction to using UAV’s in PA. In the following blogs I’ll cover the 4 points above, picking a multirotor, NVDI cameras, planning a mission and then the post analysis. Also I’ll cover important aspects such as safety, UAV regulations and current news.