Dino - do your flight lines really need to be followed very accurately? Or are your pilots good enough to follow a path to within metres?
The following applies to a full sized helicopter system:
We've used a standard mapping GPS to set up flight paths and have them followed, just using waypoint-to-waypoint track following. This requires a lot of pilot training and a very good relationship with the navigator/instrument operator. It is also very hard work for a pilot to keep a helicopter flying straight and level - although making their navigation screen bigger (ie an ipad/rugged tablet) and using some moving map software (eg oziexplorer, or something like:
http://itunes.apple.com/au/app/igmap-fswidgets-moving-map/id379872511?mt=8)might help.
But - we don't worry about following flight lines super accurately because the pilots can't physically do it. To compensate all the data we collect are geolocated using an onboard dual-frequency GPS+IMU. If we're flying grids we aim to also collect redundant data to further offset the fact that flight lines are not very accurate (metres), and cannot be followed very accurately anyway (metres to tens of metres).
So if you're relying on the pilot following a line I think you're in trouble, your apriori camera positions will potentially be way off. Quick and dirty solution might be to use something like a Nikon DSLR and its GPS extra bits, so you can have each image tagged with a (good but not great) GPS timestamp and position.
Adding ground control probably goes a long some way to fixing this. My (small) experience so far with photoscan is that it is best to give the images decent apriori camera locations, then use ground control to tighten everything up a bit. However, my datasets generally do not have much, if any, ground control. I'm relying very much on the camera centres and a couple of known objects at one end of a flight.
Hope that helps!
Topic: OT: GPS guide for aerial mapping in full scale aircraft (Read 9719 times)
