Calculating tilt angles

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Calculating tilt angles

Low-g MEMS accelerometers are widely used for tilt sensing in consumer electronics and

industrial applications, such as screen rotation and automobile security alert systems.

Another popular application for low-g accelerometers is tilt-compensated electronic

compasses for map rotation and personal navigation devices. This application note

describes how to obtain accurate tilt measurements with respect to local Earth horizontal

plane, by compensating for a few non idealities that may cause angular tilt calculation error.

For detailed information and device specifications, refer to the respective accelerometer

may also be used, in accordance with their respective specifications.

1.1

Theory of operation

Figure 1 shows the single sensing axis of the accelerometer for tilt measurement.

Figure 1. Tilt measurement using a single axis of the accelerometer

The accelerometer measures the projection of the gravity vector on the sensing axis. The

amplitude of the sensed acceleration changes according to the sine of the angle

 between

the sensing axis and the horizontal plane.

Equation 1

Using Equation 1, it is possible to estimate the tilt angle,

Equation 2

where:



A = acceleration measured



g = Earth’s gravity vector