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cessnapilot
03-26-2009, 12:42 AM
At least tenfold improvement can be achieved in the accuracy of the H48C 3-axis accelerometer by using scale factors and biases for the 3 axis of the sensor. The determination of these parameters can be done, for· example,· with the three attached applications. The procedure is described in details at the end of the attached PDF document and the applications are:

----"H48C_AcquireSteady.spin"--- is for collecting raw calibration data for different steady poses of the accelerometer.

----"H48C_LeastSquares.spin"---- is a robust least-squares of error driven parameter optimizer. Using this one can find the scale factors and biases for a given sensor.

--------"H48C_VerifyCalib"-------- is to verify the correctness of the obtained calibration parameters for a sensor.

I have calibrated five H48C sensors up till now with these programs and in each case the accuracy of the sensor was increased to be about or better than 1%. So the 10% (rather optimistic) datasheet accuracy can be sharpen at least tenfold.

In the sensor industry a tenfold accuracy improvement is usually accompanied with a similar 'improvement' of the prices. So with this calibration we can greatly enhance the value of our H48C sensors. These upgraded H48C sensors are ready for an other >tenfold improvement in accuracy and· precision when mounted in a 6DOF IMU sensor array. Averaging, error compensation, temperature compensation and en-route dynamic calibration will achieve that goal easily.

If you have any questions regarding the supplied programs or the calibration method, do not hesitate to ask.