I want to put up a tower to get a line of sight wimax internet connection. There are lots of trees blocking the signal so I need to find out how high my antenna needs to be to get over the trees. I could rent an aerial manlift but that is at least $500/day. What I am thinking is that I could buy a quadcopter and take pictures as the drone flies around in the area I would put up the antenna. If the trees are less than 100 feet it could work. I can't afford a tower over 100 ft. In order for this to work I would need the following: GPS that gives accurate altitude reading Camera that can be set up to shoot horizontal (level) Ability to point the camera to a compass heading (digital compass not required but helpful) Camera image quality not terribly important. What are my options and price points for such a machine?
If you only need the manlift for a day it may be cheaper - especially since you do need a bit of experience to properly pilot. Or, you may consider contacting a local R/C club and seeing if any member with a Phantom Vision would help you out. In terms of quads which could do the job - or close to it - off the shelf.... Phantom- I think the vision would definitely do the job - but it's $1200. However, it may be that the cheaper Phantom Fc40 ($520 or so) would do the job.....they both have an app which works on your phone or tablet and I assume most of the parameters (altitude, heading) are on the screen display. screen shot from vision enclosed.....I'm not 100% positive that the FC 40 is the same, but it makes sense that it would be. The AR Drone with the GPS may also do the job.... http://ardrone2.parrot.com/apps/flight-recorder/ Assuming you don't crash or lose them, the quads could probably be resold at a loss of only about 20% when you were done.
You've probably considered this, but a nice size helium balloon with a small lightly cam (you could rig up a self level of some sort) - and you measuring the string - may do the job. Keep in mind GPA is only accurate to about 6-10 feet, although it's possible that some quads are using barometric and other assists to be closer.
Looking at the ARDrone, I see that it uses ultrasonics to measure altitude if not using GPS. This may be adequate for my needs. I need to know altitude relative to the ground anyway, not absolute altitude. Can the ARDrone measure height accurately in the 100 ft range?
ARDrones ultra-sonics are only good at 20 feet or less......with the GPS add-on they are accurate +/- 30 feet (this is not due to an bad GPS, but due to the government restriction on civilian GPS accuracy). you could do it the old school way, how I was taught in grade school science class.....http://www.zoom-one.com/distance.htm
Actually civilian GPS can be as accurate as military but requires augmentation such as NDGPS or WAAS. To get really accurate GPS readings (+/- 1 cm) the antenna needs to remain completely motionless for several minutes. How "rock steady" do these things hold position (assuming near zero wind)? A laser range finder would work but I would guess that's way out of my price range. Measuring the height with a protractor might be possible but tricky. How would I locate the spot on the ground directly under the quad?
I'd say with no wind that the Phantom may hold within a meter or so but not too much closer....but the Vision model may have a more advanced barometer in it that helps both the hold and the accuracy. My experience is with a stock Plantom (orig. model).
Can you see the top of the trees? Taking a 45 degree angle walk away from the base of the tree until the top of the tree is visible at a 45 degree angle to the ground. The height of the tree is the distance to the base. Your making an equilateral triangle. You might have to fiddle a bit with baseline heights and locations etc. Hope this helps (and sorry it doesn't involve a drone!) Assumptions: 1, The ground is level 2, The base is directly below the highest point; i'e one angle is 90 deg and the other is 45 degrees.
