Good evening everyone. I am new to the site as well as UAVs. I am a licensed land surveyor who is looking to explore the possibilities of low altitude photogrammetry using some type of UAV. My question is simple, what type of drone do you guys recommend, a plane or rotor type vehicle? To give you some specifics, altitude will probably be at or below 300ft, area coverage should be less than 30-40 acres. Ground control will always be used.
I realize that the FAA won't give answers until 2015 so I am looking at taking this project in steps. Once I've decided on a vehicle, I will learn the basics of flight, then progress to GPS flight controls to control the flight path for mapping. I would then begin working with cameras to collect data in order learn the ins and outs of that part of the process. Finally, if/when the FAA allows commercial use, I may be ready to take the plunge on a system made for commercial use. However, at this time, I can not dump tons of money into a system on the hopes that I can get a return in the future.
With all that said, I'm looking for anyone with experience to help with the pros and cons of different types of vehicles. I would like to hear everything from flight times, camera stabilization, etc. Some things to consider is that every job will be completed in the dirt/mud as we are looking to compute volumes from DEM's on construction sites so landing and takeoff would have to be considered. Wind isn't necessarily an issue as I can always wait for good flying conditions before beginning a project.
So let's here it guys. I'm looking forward to purchasing a drone to begin my quest.
Replies
Hi John
As a fellow surveyor, I can sympathize with you situation.
You would need some redundancy in the craft to meet site safety standards, a hexa or octocopter instead of a quad. Some of our sites even require protected props. The downside is the fact that you lose flight time with the extra motors.
@ Josh - I went with a clone F450. It was cheap, ready to go, and has helped me become an okay pilot (at least to take control and bring it in without total disaster). It gets me around 5-6 min. without payload but I have since purchased an adapter to parallel a couple of batteries so hoping to get that 5-7 min with the camera.
@ Wes - you've gotten further than I have. I am currently playing with Agisoft Photoscan demo and just got a Pix4D demo but it only last 10 days. I like Agisoft but I definitely need to upgrade the computer for larger scale projects. I've downloaded sample data from 20 photos up to 600 photos to get a feel for processing time. The larger projects are taking a toll on my workstation (5+ hours). I've looked into a few online processes but the best they can do is to put the data into a world coordinate system even with GCP's, leaving me more processing to get the info. into the local site coordinate system. We may work on sites many times over several years so being able to use their established control is crucial.
I'm also working on a swinging 1 axis gimbal (basic pendulum with camera mount) to keep the camera vertical when the quad is pitched forward in flight. I may look at making the camera mount large enough to add some padding to help save the camera in the event of a crash. Haven't flown with the camera yet but have had the quad fly some short missions to see how well it tracks along the designated path and I must say I am impressed. It looks like it should do well enough to ensure the proper overlap needed for good processing.
Prices seem to be coming down and flight times seem to be going up for quads so I'm not too concerned with purchasing something better right now I can't legally use to get me money back. I've got a copy of a build where the guy is getting 28 minutes of flight time with a larger quad without payload. Even if that comes down to between 15-20 with camera, projects can get bigger with less hassle.
I am also a surveyor that has gotten the photogrammetry bug. I have gotten 6 to 8 min on my 3DR quad with a sx260 hanging from it. I have seen some great results. I am thinking about getting a event382 or getting the 3DR bixler. I am still on the fence. Also Agisoft and LP360 are great tools and I think I might be purchasing both pro versions in the next month or so.
I have been getting 20 acres done at 100 meters height with two flights of around 5 to 7 min each. My ground control is set with rtk in about 30 min to an hour depending on access and features.
I have had several crashes and have demolished 3 sx260 cameras. I am going to be building a Otterbox like case for the new camera I just bought today.
I have converted two cameras to the NIR, but have not gotten the chance to use them.
Message me if you want to bounce survey ideas around.
sorry I forgot to mention that I have used a skid plane, no land gear, and it will still smack the plane up. A skid landing is just a semi controlled crash.
Ive done extensive mapping with plane platforms. Easy to get up and easy to get down if you have a lot of room and a field to land in. Not good at all if you have trees, or no smooth areas to land. Multi rotors would work well on 40 acres or so, planes work well on bigger but its not a cake walk. And never believe the title "autonomous", that is very miss leading and a law suit waiting to happen.
You're absolutely right Jeff. I have read about people maxing out flight times with additional or larger batteries but no payload. It definitely looks like a plane is the way to go. I think the learning curve for a regular heli might be too much. Remember, we aren't RC hobbyist, rather surveyors trying to add a new tool the the mix. It looks like I'll start looking into a plane. Jeff, would you guys be willing to sell a complete set of parts (ie. flight controller, camera, etc.) to use on an air frame I may acquire in the near future. As stated, the FAA won't let us use this for commercial work anytime soon so I can use that time to buy a plane with radio and learn to fly the thing confidently. I may even play around with my Canon PS as well.
Thanks for the responses Keeyen and Jeff. Keeyen, I was afraid of the flight times with a multi-rotor. As discussed with Jeff, the only issue with planes is the landing. Job sites are always dirt and/or mud, rocks, etc. Every time I see a video somewhere over seas, they have a nice lush landing area that's easy on the equipment. I don't have that luxury. Is there no way to get 20-30 minutes from a battery setup with a multi-rotor. I would be willing to use multiple battery changes, just could get problematic if I have to do them every 10-15 minutes.
As you've mention you'll going to buy, I'll suggest using some kind of low cost system such as Event328 to start with. It will suit your purpose. Multi rotor system may not able to cover your area requirement with sufficient overlapping given the flight time for most multirotor is 10 to 15 minutes.