I wanted to ask if anyone knows of the best way to either tether a IRIS+ quadcopter so it will hover relatively stationary, or provide a system for indoor navigation for a room. I am currently working on a cyber security research project at a large university, and I have been tasked with having a quadcopter hover in the middle of a large room to provide an aerial vantage point. The building is a former nuclear reactor, so needless to say, GPS is not an option. I have experimented with several different styles of tethers, all of which have lead to oscillations back and forth across the center. The effect is lessened in AltHold mode, but it is still present, and concerning enough that I do not think it is safe for the cyber protection scenario. The eventual goal is that we could either fly the copter around to certain points in the room with an indoor navigation system, use the tether to "pull" the copter to certain points in the room, or have the copter fly in a direction and have the tether keep the range of motion limited enough for stable stationary points in the air. Does anyone have any recommendations? Anything would help, thanks in advance!
First off, you're going to need a much more accurate positioning system for indoor flight. There's a few options here: optical flow, lidar, stereo cameras, sonar.
@Austin: do you have a timeframe and budget for this project?
I know I do, I was wondering if someone could recommend a specific system that would provide some benefit in my situation, and how I should go about applying that system. Any thoughts? Thanks!
The timeframe is as soon as possible, and the IRIS+ is an accessory to the main cyber security project, so I do not have too much of a budget to play around with. I am not really actively looking to develop a full system for my needs, but if you have something in mind, or even something already in the works, I am all ears. Thanks!
LOL! No time and no budget? An interesting challenge! We'll have something available soon but I can't make any delivery promises so perhaps this isn't a solution for you on this project.
Start with a single sonar and work your way up @Stephen's list.
At the moment, the APM has built-in support for using the previously-listed items for accurate height control. For horizontal position control using those items, you would need to develop the software yourself.
Have a look at http://diydrones.com/profiles/blogs/precision-land-arducopter, they've got precision flight with the APM using cameras (though still very much in the experimental stage).
Thank you so much for the help!
For everyone interested, I have decided to use the PIXFlow with LIDAR as defined in the wiki for non-GPS loiter. As for navigation, I am setting up multiple RPi based access points with sort range wifi adapters in key locations around the test room, and I am polling signal strength using an onboard raspberry pi computer. This will allow me to get a relative "position" in the room, and provide some loose reference points to maneuver around the room. I will then guide the copter to different locations using this system. Thank you so much for the help everyone, if you have any questions or want an update, I will gladly give you one. Thanks!
You can use a precise (+-2cm) Indoor "GPS": http://marvelmind.com/.
Here a couple of demos: