MotionFX output used for dead reckoning

[AMahm.2]

We are trying to use data from MotionFX output in order to do dead reckoning.

We are using linear acceleration which is as per our understanding equal to:

acceleration - gravity acceleration

Linear acceleration is being integrated in order to get velocity, but the velocity doesn't get back to zero when the device is stationary. We expect it to get to zero when acceleration is zero in the image below (note that data is acquired by placing the sensor on a leg and walking with it).

We are using a 100Hz sampling rate and 9DOF output.

MotionFX algorithm works pretty well in our setup in terms of device orientation in space (quaternions), but we are having mentioned issues with using it for dead reckoning.

We are using the following parameters for knobs setup:

modx = 1

LMode = 1

ATime = 0.900

FrTime = 0.667

MTime = 1.500

Gbias is being determined by setting start_automatic_gbias_calculation flag and reading values after 10 seconds.

My question is, is there anything we can do to improve the dead reckoning process by changing the algorithm params, or is there anything else we can do?

[Miroslav BATEK]

There is no solution which can allow to integrate sensor data to obtain drift free velocity. 

Even if military grade IMU is used, errors in integration process of acceleration are minimized, but, cannot be eliminated

[Macneacail]

You can do integration over very short time steps, but you need to determine the real zero from a stationary point.

You have temperature drift in the acceleration and a lot of other problems/