Hi, it all depends on how accurate you want your survey to be. In a research project that I am carrying on in Italy we used UAVs to obtain 3D of the beach, of course using RTK GPS to measure targets on the ground. The final vertical accuracy of our survey is around 10 centimeters, which is not very different from what other authors have obtained in different environments.

Hi! I agree on Alessio's statement: your application requirements are crucial. I invite you to read our open-access publication about Unmanned Aerial Systems (UAS) on Photogrammetry and Remote Sensing (link attached), so you get an overall feeling on types of platforms, applications and uses in this context.

Article Unmanned aerial systems for photogrammetry and remote sensin...

I lke that paper, I actually referenced it in two papers I have under revision, great work!

I also agree on Alessio; photogrammetric survey with UAV platforms allows to obtain 3D models with high levels of detail and accuracies, but the topographic measurements of ground control points is essential.

In the last two years many researches have been carried out about the accuracy of UAV photogrammetric applications; you will find some interesting results in http://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XL-1-W2/ and in http://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XXXVIII-1-C22/ .

I also attach my last paper about this topic that will be present at ISPRS Technical Commission V Symposium "Close-range imaging, ranging and applications" next week.

I am also working in the field of uav-based remote sensing. The fact that the accuracy is already rather high regarding products that were produced by UAV-based mapping approaches, I completely agree (see also the paper for our work carried out in morocco).

Refering to the question, which included commercial feasibility is clearly to be answered with yes in general.

I would be more interested in which field you intend to apply the UAV-based remote sensing? The economic factors clearly rely on more than only the accuracy of the product. Therefore it would be interesting if you may provide some more details to the initial question stated.

Article Unmanned Aerial Vehicle (UAV) for Monitoring Soil Erosion in Morocco

An interesting question... while I haven't published on this yet, I'm seeing 1%-2% error in 3D reconstruction when flying 36 mp DSLR cameras at 100' (30m) above roads when assessing potholes, ruts, corrugations, etc... on a 75cm high traffic cone, that translated into +/- 1.5cm accuracy - quite good, and probably sufficiently high quality for photogrammetric work.

www.mtri.org/unpaved

I really do appreciate the response of all researchers above (Alessio, Pere, Mauro, Sebastian and Colin). Your materials presented overwhelmingly pronounces on the accuracy element. My own requirements are in the 10-15cm RMSE range. The applications include roadway engineering, building construction, drainage design. Achievements in the +/- 1.5cm range is very impressive and could expend to possibilities of deformation and monitoring.

There is another thing to take into account though. Using UAVs for commercial applications requires, depending on the state, licenses and permits. In the US laws are pretty restrictive and commercial operations are not really allowed. In Italy, where I also own a company that does commercial works with UAVs, the civil aviation has de facto banned flights since April, unless you decide to take a path of painful authorizations. In Germany and France it's a bit better. So, before starting any commercial venture, I would suggest anyone to check what are the authorizations needed in the specific area of work.

As the others have indicated, and demonstrated with their publications, high-accuracy photogrammetric measurements can be obtained using a wide range of systems. The cheaper ones generally require ground control points to improve the accuracy and some post processing of data but the more expensive systems can produce the same results without the ground control stations and post processing so if you are working in an area where you can put out ground control points you can use an inexpensive system. The quality of the lenses you are using is a factor to consider and good quality DSLR lenses have minimal distortion and are as good as the larger and more expensive medium format systems.

Your questio is the"question of the question" in this moment in the world of geomatics, sometimes it seems that UAVs capabilites are over evaluated, anyway

UAVs represent the last frontier for the acquisition of the territory with high resolution and low-altitude flight. They have the possibility to install different sensors make them usable in urban areas, for analysis of risk environment and for the estimation of the changes of land use, as an example. Regarding photogrammetric measurement in order to produce high accuracy topographic mapping, We agree with other collegues and friends (ciao Mauro!) that with an UAV, to know the accuracy that you can obtain you have to consider a lot of parameters, like focal lens, flight altitude. From our preliminary tests, if you considered a camera with a focal lens around 18 mm and a flight altitude around 40 m, you can obtain accuracy around 1 cm. One critical item is the plannign of the acquisition. See the link for our first results.

Regards Eng. Martina Mormile & me

Here is the link.

http://server-geolab.agr.unifi.it/public/completed/2014_EuJRS_47_477_496_Baiocchi.pdf

Did You use self-calibration camera ?