Hello All,
I have recently been experimenting with a Canon SX260 HS for creating orthos and have discovered large discrepancies in the recorded altitude positions stored in the EXIF data. Over the course of a few weeks I would sometimes have data that appeared to be close to the altitude values I would expect but more often the altitude data is way out of whack. I tried letting the camera "warm" up, hopefully locking on a good satellite geometry but recently this has not been working. Are there other issues I should be exploring (camera mounting/shielding etc,)? Has anyone else experienced large variances of accuracy with the altitude data and if so any tricks to improve performance? BTW, I'm flying this camera with a 3DR Iris.
Thanks so much!
Replies
How did you attach the camera to the IRIS? Does the camera work 'out of the box' with the IRIS?
I am thinking that the camera will only give the ellipsoidal height and will not give the orthometric height. Where I am the difference is almost 80 feet. I wouldn't think that the camera would have a geoid model in the hard drive. I will try it out tonight. Cheers,
WQ
Gents, thanks for the feedback. This seems to be a popular camera with many (at lease for fixed wings) but I guess it doesn't work as well underneath a quad. My next step will be to sync the logs to get better data but I agree with James that a better long-term solution is needed. Cheers!
I experienced exactly the same problems with my SX260.
I put it down to it being a rubbish GPS device which was designed for the public to record where they took photos. Most people are not worried if the GPS data is 5-10m wrong as they simply want to remember the rough location they took the photo.
My short term solutions was to geo-tag the images after the flight using the geo-tagging function in mission planner.
My long term solution: i am currently working on, and will utilize industrial cameras, instead of the ones you take on holiday with you! Going to be incredible when its finished :)
James, your industrial solution sounds interesting. What GPS source will you be using and how heavy of a camera?
In direct answer to your question, we are looking into using an RTK GPS (still undecided on the chip we shall use). This will negate the need for using ground targets when generating digital terrain models.
To elaborate further the project will essentially give the UAV a brain which will support externally triggered Gig-E, Firewire, Coaxpress, Camera Link and USB3 industrial cameras. All recorded images will be geo-tagged with centimetre precision GPS, and will be saved to easily removable SSD's. The project will produce a hand launched UAV with 1-2 hours endurance, with a maximum 2kg payload cube. The payload cube is going to be 200mm(W) x 200mm(L) x 240mm(H), so should be able to fit pretty much any cameras you want
Fairly soon i should be releasing some information as we are contemplating getting 3DR/ DIYDrones involved in the opensource aspects of the project. If you or anyone else is interested and wants some more info, please feel free to PM me. But just be understanding of the fact that this is currently not in the public domain and part of the project is closed source, so we re having to be careful who we talk to, and what is discussed.
Cheers
James
The project is looking for extra people, so if interested and you think you could help, get in touch
Hi James,
I'm definitely interested in learning more about your project and the type of help you're looking for. You can email me at michaelbroker3@gmail.com.
I personally think using a consumer camera for a technical job has its limitations. The camera was designed for GPS tracking on ground shooting only. So using it at moving higher altitude we cannot expect it to perform precisely as on ground.
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