Test Descriptions

34

Freescale

Sensor Fusion Library for Kinetis MCUs, Rev. 0.7, 9/2015

Freescale Semiconductor, Inc.

5.10 Orientation Magnetic Immunity (Static Device)

5.10.1

Intent

The test response of the stationary DUT to momentary changes in the local magnetic field is used to

measure the orientation magnetic immunity. Because the device is stationary, the accelerometer and

gyroscope readings remain relatively constant, changing only due to sensor noise.

5.10.2

Procedure

Setup as defined in Matlab Stimulus/Expected Response + Hardware-based Fusion. Matlab is used to

post-process data.

1. Starting point = device stationary, fusion outputs stable

2. 100 µT magnet moving at 0.25 m/s

3. Closest approach to magnetic sensor = 5 cm

4. Test to be simulated using environment specified in Matlab Stimulus/Expected Response +

Hardware-based Fusion. Magnetic interference may be modeled as a time varying field which is

consistent with the description above.

5.11 Orientation Magnetic Immunity (Moving Device)

5.11.1

Intent

This test measures the immunity of a linearly, with no rotation, moving DUT to a 100 µT magnet change

in the magnetic field. The outputs of all acceleration and magnetic sensors change during this test.

Gyro outputs should be constant throughout, with any changes attributed to noise only.

5.11.2

Procedure

1. Starting point = device stationary, fusion outputs stable.

2. Use a 100 µT magnet.

3. The DUT moves by magnet at 0.25 m/s with the closest approach to magnet=5cm.

4. Test to be simulated using environment specified in Matlab Stimulus/Expected Response +

Hardware-based Fusion. Magnetic interference may be modeled as a location varying field which

is consistent with the description above.

5.12 Error in Computed Gyro Bias

5.12.1

Intent

Measure how well the fusion library tracks slowly varying gyro bias.

5.12.2

Procedure

Test to be simulated using environment specified in Matlab Stimulus/Expected Response + Hardware-

based Fusion.

1. Starting point = device stationary, fusion outputs stable

2. Add 10 dps gyro offset as step function

3. Run test until computed gyro offset stabilizes