Just a quick photo a buddy took of my QAV400 multirotor in the air at Cannon Air Force base in Clovis, NM. He brought me out for a project where we did some filming and stills for Falcon Containers out of Austin, TX.
We’re getting ready to do some lower altitude mapping at about 150′. The question was raised what size the ground control points need to be to show up in the imagery. My initial estimate is probably 2’x2′ would suffice. I had some posterboard laying around in the garage and decided to do a field test. Unfortunately I didn’t have enough to make up a 2×2 GCP so I opted for a 1’x1′ piece of posterboard with a X on it. The X was made with two 1″ strips of duct tape. Given the fact I was completely unprepared all I had was fluorescent orange duct tape to create the X with. I was a bit concerned given how reflective this duct tape was and the fact I was flying right at midday. Here is a photo of the ground control point:
There was a bit of wind so the clamps were used to hold the GCP in place. Now this GCP did not have an actual geolocation associated with it. I just picked a random spot and set it down since the test was mainly to see if the sizing was okay. Here you can see the an image taken from the UAV at 150′. Make sure you click on the image below so that you can see it full size in a new window:
You’ll notice the GCP has a bit of glow to it. The posterboard and duct tape are fairly reflective, but you’ll notice that the edges of the duct tape are pretty visible. I’m confident if this were a non-reflective material with a non-reflective black X this GCP would work perfectly. If this were enlarged to a 2’x2′ GCP as I originally thought then it would be even easier to georeference, but you may lose a little bit of accuracy. I’ll continue to share thoughts as we continue to experiment with ground control points for various UAV surveying applications.
I always enjoy the UAV “shadow shots” that happen during takeoff and landing. Here is one of a recent hand launch before a 50 acre mission.
The other day I was able to do some aerial mapping for a friend’s property in Dripping Springs, TX. This was a 50 acre flight so that we could get some aerial perspective of an area of the property where he had cleared some brush. Below are some photos on the ground and the from the UAV. The aerial photos were taken from about 250′ AGL. The Longhorns were taking a little nap when we pulled up but the UAV didn’t spoke them at all.
I was looking through my photo archives and stumbled across several great photos a buddy of mine took. These photos were taken on a trip back from Melrose, NM to Austin, TX. We stopped in West Texas to get some video footage of a wind farm. You can see a zoomed in shot and then one zoomed out to get some perspective. It’s pretty nerve-racking to fly this close to a wind turbine as I didn’t want to damage my QAV400 rig or the wind turbine!
It’s pretty amazing to me how our landscape is constantly changing. The before and after shots below show a new build in our neighborhood that doesn’t exist in Google Maps….yet. So when I took the UAV up this past week I was able to get a aerial photo of this new home that was built since the last time Google updated their satellite imagery. It’s neat to be able to see this type of “realtime” imagery at a much higher resolution than what Google Satellite offers.
I’ve been flying our neighborhood lately mainly trying to get good aerial imagery and elevation data. I’ve been processing all my imagery with Pix4D which is an amazing package, but I’m still trying to get my head around the whole DEM dataset. Also, trying to figure out how to work with the .las LIDAR files that it outputs. Here is a sample preview of the aerial mosaic and the DEM. Right now I’m sold on Pix4D over PhotoScan, but I’m only using PhotoScan Standard at the moment. I hope to evaluate PhotoScan pro in the near future.
This venture has been a long time coming. Unmanned Airlines is a combination of my passion for the RC space that was instilled in me by my dad when I was 10 years old. This was the car that got it all started:
You remember that one??? I can’t tell you what a fun build that was and how much I enjoyed working on it with my dad. He was a petroleum engineer and was so meticulous in everything he did. The Hornet was assembled with much care and the labels were painstakingly put on the shell of the car. It made the “maiden” drive all that much more enjoyable.
Flash forward almost 30 years and I’ve been spending every spare moment building & flying RC planes and multirotors. It’s been an incredible journey and I’ll be sharing random findings related to UAVs, aerial photography, autonomous flight, remote sensing, and much more on this site. I hope to evolve this into something more than just a hobby one day, but in the meantime I’m having a blast with it.