Effects of cellphone/batteries/magnets/acceleration on IMU [VectorNav video]

One quick comment: the vectornav doesn't have a built in gps for correcting heading drift, so its built in kalman filter needs the magnetometer to avoid drifting. Even if you had a gps, these things could be used indoors or stationary where the gps isn't able to help with heading drift anyway. So I think it's an absolutely fair representation, as long as you understand their product and what they are showing. They also offer a temp calibrated version of their IMU. I know that a good filter can estimate bias, but I've also see that a good filter will converge *much* faster when fed non-biased sensor data.

For the product I am involved with, we just grab the raw sensor data from the vectornav + gps and feed it into our own kalman filter -- we aren't using their built in filtering, but their temp calibration really helps our filter lock in on true heading much much faster than the non-temp calibrated version.

Yuan Gao: also don't fly your quadcopter near electric motors. :-)

MRI machines: long ago I used to work in the MRI building of GE Medical systems -- this was back in CRT days and all our monitors got misaligned and the color guns each by a different amount. We had one conference room where you could throw paper clips at the white board and they would dance around on the order of feet before coming to rest somewhere random stuck on the wall. Pretty powerful crazy stuff.

The vectornav is not cheap, but you get really nice clean raw sensor data, you get a built in kalman filter if you choose to use it (that is very tunable), and temperature calibration -- which is more important than most people realize if you want fast IMU convergence and solid stable results. That said, you can get around the sky for much less money, but if you need accurate attitude estimation for camera pointing or georeferencing type work, it's worth the extra money to get some really nice sensors and feed that into a high end kalman filter.

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Comments

Gareth Rens January 3, 2012 at 1:47am

I see your point :)
Gareth Rens December 29, 2011 at 10:51pm

The last time I MRI'ed my quad, it didnt fly so well... ;)
Gareth Rens December 29, 2011 at 10:45pm

Also, not a good idea to use magnets to keep your dome on...
Curt Olson December 29, 2011 at 7:46pm

One quick comment: the vectornav doesn't have a built in gps for correcting heading drift, so its built in kalman filter needs the magnetometer to avoid drifting. Even if you had a gps, these things could be used indoors or stationary where the gps isn't able to help with heading drift anyway. So I think it's an absolutely fair representation, as long as you understand their product and what they are showing. They also offer a temp calibrated version of their IMU. I know that a good filter can estimate bias, but I've also see that a good filter will converge *much* faster when fed non-biased sensor data.

For the product I am involved with, we just grab the raw sensor data from the vectornav + gps and feed it into our own kalman filter -- we aren't using their built in filtering, but their temp calibration really helps our filter lock in on true heading much much faster than the non-temp calibrated version.

Yuan Gao: also don't fly your quadcopter near electric motors. :-)

MRI machines: long ago I used to work in the MRI building of GE Medical systems -- this was back in CRT days and all our monitors got misaligned and the color guns each by a different amount. We had one conference room where you could throw paper clips at the white board and they would dance around on the order of feet before coming to rest somewhere random stuck on the wall. Pretty powerful crazy stuff.

The vectornav is not cheap, but you get really nice clean raw sensor data, you get a built in kalman filter if you choose to use it (that is very tunable), and temperature calibration -- which is more important than most people realize if you want fast IMU convergence and solid stable results. That said, you can get around the sky for much less money, but if you need accurate attitude estimation for camera pointing or georeferencing type work, it's worth the extra money to get some really nice sensors and feed that into a high end kalman filter.
Anish December 29, 2011 at 2:20pm

MRI machines boy those have superconductive magnets, ur quads wont escape :)
Gareth Rens December 29, 2011 at 1:52pm

But as always, "marketing puke" prevails!
Gareth Rens December 29, 2011 at 1:51pm

To be fair, he was using a Neo-dymium rare earth magnet. Those things are pretty hardcore. They stop my watch and it doesnt have a compass in it ;)

This reply was deleted.