AN4508 datasheet(9/13 Pages) STMICROELECTRONICS

tên linh kiện	AN4508

Giải thích chi tiết về linh kiện	Parameters and calibration of a low-g 3-axis accelerometer

PDF	13 Pages

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nhà sản xuất	STMICROELECTRONICS [STMicroelectronics]

Trang chủ	http://www.st.com

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9 / 13 page

DocID026444 Rev 1

9/13

AN4508

Least square method

Appendix A

Least square method

Let's consider accelerometer calibration at the 6 stationary positions shown in Table 1.

Equation 1 can be rewritten as:

Equation 3

Equation 4

where:



Matrix X is the 12 calibration parameters that need to be determined



Matrix w is sensor raw data LSBs collected at 6 stationary positions



Matrix Y is the known normalized Earth gravity vector

For example,



At Zb down position (P1 position),

, and assume that at Zb down

position, n1 sets of accelerometer raw data Ax, Ay and Az have been collected. Then,

Equation 5

where:

Matrix Y1 has the same row of [0 0 1].

Matrix w1 contains raw data in the format of LSBs.



At Zb up position (P2 position),

, and assume that at Zb up

position, n2 sets of accelerometer raw data Ax, Ay and Az have been collected. Then,

Equation 6



At Yb down position (P3 position),

, and assume that at Yb down

position, n3 sets of accelerometer raw data Ax, Ay and Az have been collected. Then,

Equation 7

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