MPU9150 accelerometer accuracy and calibration

Hello,

I know there are similar topics on this in the forum, but I haven't found a n answer yet.

The readings I have obtained on the accelerometer while the sensor is completely stationary has measurement error of +-5mg. We intend to use the MPU to do dead reckoning with slow linear acceleration.

This +-5mg accuracy is very undesirable for us and I have read people were able to achieve +-1mg on the same device with calibration. I have searched through the forum and tried various approaches without success. For example, the use of very low cutoff frequency for lpf (5~10Hz) was suggested to reduce noise (see link below)

https://invensense.tdk.com/developers/forum/viewtopic.php?f=3&t=1064&hilit=accelerometer+accuracy

I added to the example code in the self-test to set up the lpf accordingly, but didn't observe any improvements on the accelerometer.

Other suggestions were to turn off gyroscopes to reduce cross-talk, which we cannot do as we need the gyro and quaternion data.

As of right now, my configuration is as follows
acc FS = +-2G
sample rate (ODR) = 200Hz
lpf = 5Hz
DMP enabled
raw_accelerometer, calibrated_gyro and quaternion are being pushed into the FIFO.

I would greatly appreciate it if someone can offer suggestions on calibrating the accelerometer to increase its accuracy to close to +-1mg.