AN3182

Calculating tilt angles

Doc ID 17289 Rev 1

13/18

Equation 6

Equation 7

Figure 8.

Tilt angles from a tri-axis accelerometer

The second way is to use trigonometric Equation 8 and 9 to calculate pitch and roll tilt angle,

which produces constant sensitivity over 360° of rotation, as shown in Figure 9.

Equation 8

Equation 9

Figure 9.

Tilt sensitivity of a tri-axis accelerometer

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

=

β

g

A

arcsin

1

y

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

=

γ

g

A

arccos

1

z

⎟

⎟

⎠

⎞

⎜

⎜

⎜

⎝

⎛

+

=

α

=

2

z1

2

y1

x1

A

A

A

arctan

Pitch

⎟

⎟

⎠

⎞

⎜⎜

⎜

⎝

⎛

+

=

β

=

2

z1

2

x1

y1

A

A

A

arctan

Roll