Hey guys,

I took my Inspire 1 for a spin last weekend, and just before I took it off I calibrated the IMU while the inspire was sitting on the grass. I'm not sure if it was 100% level, but was wondering what the proper procedure is to calibrating the IMU, and how often it should be done. My flight seemed to go well, so I'm wondering if I should recalibrate it again at home before taking it out the next time, or if I should be fine leaving it.

If you really want to nail it, place it on a known-level hard surface (use a carpenter's level).  A poured-concrete floor is usually good for this (but check it).

part of a pre-flight procedure it's to check your IMU.
If it's off, you have to do a calibration.
ALWAYS CHECK IMU and calibrate compass before flights

IF it's off by .01, do you do a IMU calibration in the field before take off? What do people usually do? I've got my inspire set up, and I think I might just put it in my car with it ready to go so I can take off (after checks of course) once I get to location tomorrow.

Goodwill Posted at 2015-5-15 14:51
IF it's off by .01, do you do a IMU calibration in the field before take off? What do people usually ...

I have about 250 flights with my Inspire and my Phantom 2 Vision + together. On all this flights I have done compass calibration maybe 3 times on the Phantom and the same on Inspire. The same with the IMU - I have just done the calibration a few times ( after FW updates ). I do not tell others to do it like this - but I have had no problems with my Phantom or my Inspire so far. (Except from pilot error )
I am thinking - what is not broken - do not fix it.

nilsblix@gmail. Posted at 2015-5-15 15:02
I have about 250 flights with my Inspire and my Phantom 2 Vision + together. On all this flights I ...

Thanks, that was what I was thinking as well. My flight on the weekend went pretty good, so I don't think I am going to mess around with the settings, if it ain't broke, then no need to fix it.

What are the numbers for the compass supposed to be?

IMU calibration always in a level surface away from metal objects or electric power cables and away from cell phone antennas. this is what i do and its always perfect. have in mind that usually On level surfaces in a town there is always metal nets underneath. avoid it or find a all plastic table and put it on it.
compass calibration away from metal objects. even the metal zip of your jacket can affect the quality of calibration. i do IMU once every 10 flights and compass every working day. not every time.
this is WHAT I DO and its always perfect.
DO NOT FORGET TO BE AWAY FROM ANY METAL OBJECT AND ESPECIALLY THE HIDDEN ONES UNDERNEATH TOWN' S LEVEL SURFACES. . . . . .ALL PLASTIC TABLE IS THE BEST SOLUTION. TRUST ME ON THIS.   

nilsblix@gmail. Posted at 2015-5-15 15:02
I have about 250 flights with my Inspire and my Phantom 2 Vision + together. On all this flights I ...

+1.  I only calibrate IMU and compass whenever I update firmware.  I also consider calibrating the compass if I've traveled to another area where the magnetic declination is significant.

Goodwill Posted at 2015-5-15 15:23
What are the numbers for the compass supposed to be?

It is not easy to say exactly what the compass values should bee, but I can refere from another tread in another forum :
" if you look in any of the Naza publications a figure of between 750 to 2250 is acceptable (1500 optimum) with a vector range of -500 to +500.
However, after trawling through the Inspire publications/videos I can find no such recommendation for an 'optimum value'
Hearsay and urban legend recount figures of between 1400 to 1600 (that magic 1500 number in the middle again) as being the holy grail but I have not seen an official stance on this."

http://www.inspirepilots.com/threads/compass-mod-values.1601/

nilsblix@gmail. Posted at 2015-5-15 17:37
It is not easy to say exactly what the compass values should bee, but I can refere from another tr ...

Hi Friends.

For information regarding values, I found this video helpful when I first got my Inspire 1.



Regards.
Muzzy.