We have been working to develop a well oiled solution for Aerial Survey and Photogrammetry over the last few moths. While there are a number of off the shelf solutions out there which produce great results, we are looking for something that will cover larger areas at a higher resolution. We started with the X5 as it could be hand launched and was a good platform that flew at higher airspeeds and could progress us into the X7. Here is some of our progress;
The X5 is running on APM 2.6 and has prove extremely reliable and stable. The camera used is a canon IXUS 132 running CHDK and shooting on an intervalometer script. The main purpose of the X5 was to learn about vibration dampenning and apature and ISO settigs to produce clear images. This took a significant amount of effort, however we are at the stage where 2 out of 3 images are photogrammetry quailty.
Our test baby has had a few hard landings (things were laid out a little neater when we started) . We are very excited about the recent interest and work being done on laser altimetry in recent months. We are also currently testing one of these devices as flying wings are extremely hard to land manually (especially when they are loaded up with gear). You can see the APM in the middle of the plane, 5.8GHz live video and 900MHz telemetry transmitters, and the IXUS 132.
We found the X5 reasonably easy to hand launch WITH A WELDING GLOVE (it will cut your hand to shreds - not if...when). You can see the camera poking out of the front of the plane. Images are good, however, to get the plane to navigate the survey grid well, it becomes a little twitchy which means that a high number of the images are not taken pointing straight down. Navigation accuracy (Nav Constants and Pitch and Roll constants) v's image quality is a trade off. Others may have found the perfect solution..we haven't. (Yes we are investigating some of those gimbals). We found the ideal cruise speed with a 4S 5000mAh battery was about 12m/s and we are getting about 30 mins of flight time.
We have been using Agisoft Photoscan which works really well and appears to be more flexible than Pix4U. We have no surveyed ground control in the images, and we have no geotags in the photos as we were running an intervalometer script. However, it was great practice flying and processing, changing settings and trying again. You cans see that you lose images when the camera is not pointing down and loose some of the survey area. We have found that it is better to not use bad images and have gaps, rather than use them and distort the good data.
Once we had some confidence in what we were doing, we unleashed the BEAST!
First of all, the X7 is more streamlined than the X8, but doesn't have anywhere near the same room for hardware. If we were to do another flying wing, we would try the X8. We are running the X7 on Pixhawk and have a nikon J2 taking photos. The J2 is triggered from the Pixhawk via an infrared LED shutter controller.
The Nikon is snug in expanding foam with its lens fitting nicely into the camera hole in the X7. With decent batteries and a big camera, you simply can't launch the X7 by hand, so we have built our own heavy duty catapult powered by 4 spear gun rubbers;
It took a while to settle down the nav and flight constants for the X7 but it flies beautifully once tuned. It cruises at around 15m/s and is far less twitchy than the X5. Photos are higher resolution and a lot sharper. We love it as an aerial photogrammetry platform, however landing is still an issue. As well, as we are only running 4s batteries, it's always touch and go as it comes off the end of the catapult. We are still playing with battery/motor/prop combos to get the optimised take off and duration.
Again, using Agisoft Photoscan, (with Geotags, but no ground control), the results were extremely pleasing;
We are still playing and tuning, but our focus at the moment is;
1) ground control -we are looking at a network gps system where you can drop a bunch of transceivers around the survey area and have them log back to a central PC where only one of the transceivers is located in a surveyed location.
2) AUTO LANDING....WOULDN'T IT BE NICE !
3) We have purchased a 757 Ranger to try slower speeds, but significantly longer endurance to see if it improves the sharpness of the images.
Anyway, this is what we are up to. Would love to hear comments from anyone else out there chasing photogrammetry.
Comments
Darren,
After a great deal of testing we have found that to get great imagery, you need a damped gimbal mount for the camera. We have been doing a great deal of testing with the Havok http://australiandroid.com.au/products/havok and a canon S110 and have had great results.
We have also moved away from the X5 & X7 and are working on our own plane with an integrated gimbal for longer endurance mapping. The main issue we are having is the size of data and the length of processing required for an hour's worth of photos. We have a purpose built photo crunching PC, but it still takes 6 hours to process 300 photos.
Hi, it's been a year since your blog post. I was wondering how your testing panned out ?
Thanks a lot guys for the support and concern, Special thanks to Chris Anderson for the tip, I noticed they are going to release the newer version at the end of July for an affordable price.I'll be waiting for it Chris, ;-).
On the other hand, I already had buy the airframe and everything else, and doing some modifications to it, I'll e uploading them to the forum shortly. Again thanks a lot guys. Happy flying
Yes, we have also moved on from the X5 and X7. We tested a number of off the shelf airframes, but nothing could provide the required features so we decided to develop our own. We are concentrating on a multi-rotor for mining stockpile measurement and a long endurance, hand launched fixed wing for aerial survey.
been there, done that...
we developed the Aeromapper X5 based on the skywalker X5 for mapping, including a parachute landing system that worked flawlessly every single time:
http://www.gizmag.com/aeromapper-x5-autonomous-uav/28501/
Although it is possible to make the X5 work for mapping, it is the worst possible airframe out there for this purpose.
I suggest consider more conventional aircraft.
@Michael Have you tried LIDAR-Lite for autolanding? It should give you as good an altitude reading as the eBee optical flow, and allow you to time your flare precisely. The latest APM:Plane code supports that.
Oh, yeah, I fotgot to mention, I'm learning to fly in a Nitro-gas Nextar along with my father. Also have a trainer Cessna 180 for that. So I'm learning, it's just that it seems that I wanted to run before walk :/. Any ways, I'm on it allready, so if you have any good tips I would appreciate them a lot, Thanks for your time Ausdroid, really appreciated!
Not sure. Haven't flown one, but looking at it, it doesn't have the angles wing tips that make it stable for beginners. Alternatively, just buy a $100 RTF from hobbyking and learn how to fly.
Thanks pal I though so, I do have a XUAV-mini Talon, how abou that one?
1) Building and flying a plane
2) The autopilot system
3) The camera system (including stable, clear images)
4) Image stitching software
There's no easy path. There's no question that the X5 is the hard way. If I was you, I would buy a cheap plane like the blixer and transfer all of your RC gear. It will be slower, more stable and much easier to fly.
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