Comment by Tom Yochum on April 22, 2009 at 8:33am

We are using the Atomic IMU with the goal of using it for attitude determination. We are very early in the project, so we don't have any results yet. We are currently finishing the code to do the initial alignment, and we should have some IMU data collected to test it with soon.
How familiar are you with computing the attitude from IMU measurements? I hope you are aware that the IMU does not provide your roll, pitch, and heading; it provides the sensed accelerations and angular rates in the body frame. You need to write software that will collect and integrate the IMU readings to output the attitude. This is a difficult task, and so far it appears that only one person has accomplished this. I would recomend purchasing his UAV DevBoard if you don't want to create this work for yourself.

Comment by Tom in ON on April 22, 2009 at 8:56am

You may find used FMA sensors at http://www.rcgroups.com/for-sale-wanted-201/

Developer Comment by William Premerlani on April 22, 2009 at 8:58am

Garry,
If you decide to use the UAV DevBoard, let me know, I could give you some tips for using it. The code is open source, so you could adapt it to your needs. I agree with Tom, collecting and integrating IMU readings to an accurate estimate of attitude is difficult. The method that Paul Bizard and I developed, based on Mahoney's work, is called "Direction Cosine Matrix", it works rather well, as you can see from the video. It provides zero drift operation. The results are forever as accurate as when you start. It uses accelerometer information to correct for pitch-roll drift, and a GPS to correct for yaw drift.
If you decide to use the board, you would probably want to extend the existing firmware to send the attitude information out through the board's spare serial port.

Comment by Tom in ON on April 22, 2009 at 9:01am

Also here: http://paparazzi.enac.fr/wiki/Infrared_Sensors

Comment by Garry Qualls on April 26, 2009 at 8:00pm

Thanks for all the input! I think I'll wait it out for the FMA sensors to be in stock. In the mean time, I'll work on my own flying skills and maybe play around with the Ardupilot on a RC car. I'm going to go ahead and order a UAV Devboard and try using it as my IMU in the near-term.

As far as rolling your own code to integrate IMU outputs to track your attitude, there is at least one open source project that integrates GPS, pressure sensors, gyros, accelerometers, and magnetometers to get a vehicle state (for the now-out-of-production Crossbow MicroNav). If you go to this Sourceforge page and download "MNAVFIRM v1.4" you can see how they do it. If you have any basic questions about that code, I may be able to help, but I think there are others hanging out in these forums who know that particular platform inside and out.

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