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ADIS 16480: startup bias calculation error

Question asked by abueno@servicevision.es on Nov 6, 2014
Latest reply on Sep 17, 2015 by NevadaMark

Hello,

  we are doing tests with the adis 16480, and almost everything is fine. We are only using the outputs from the gyro and the accelerometer, doing all the calculations in our code, so we are planning to use in the future the 16485 or similar.

  The fact is that doing tests, we have noticed that if the adis is not perfectly stable at startup, the gyro bias changes: I read values above 100 (or above 1000) when the gyro is steady (if I power up with the adis steady, the output is perfect 0 when the gyro is steady).
So it seems that the adis is calculating an internal bias at startup, and I am not able to overwrite it. I have read (not at the data sheet, only seen at the forums) that the device must be steady during 2 secs at startup, in order to calculate the correct initial positions.
I understand that this may be needed for the EKF calculations, but not for the raw gyro values. This makes the 16480 unusable if your initial conditions are not perfect steady.

  I have read in the forum that if the initial conditions are not controlable, the use if the 16485 or 16488 are a better choice, but as the behaviour of the gyro ouptuts seems to be the same, I don't know if there will be the same initial bias calculation. As I said, in the data sheet does not indicates nothing about this initial bias or startup time or conditions.

 

  Is it possible to know exactly what are the restrictions in the startup, for the different devices?

 

  Thank you

 

  Alex Bueno

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