UM001
83
6.2.3
Gyro Compensation
Gyro Compensation
Register ID : 84
Access : Read / Write
Comment : Allows the gyro to be further compensated for scale factor, misalignment, and bias errors.
Size (Bytes): 48
Example Command: $VNRRG,84,1,0,0,0,1,0,0,0,1,0,0,0*7E
Offset Name
Format
Unit
Description
0
C[0,0]
float
-
4
C[0,1]
float
-
8
C[0,2]
float
-
12
C[1,0]
float
-
16
C[1,1]
float
-
20
C[1,2]
float
-
24
C[2,0]
float
-
28
C[2,1]
float
-
32
C[2,2]
float
-
36
B[0]
float
rad/s
40
B[1]
float
rad/s
44
B[2]
float
rad/s
This register contains twelve values representing the gyro compensation parameters. The gyro
measurements are compensated for changes in bias, gain, and axis alignment that can occur during the
installation of the chip on the customer’s board using the following model. Under normal circumstances
this register can be left in its factory default state. In the event that there are significant changes to the
gyro bias, gain, and axis alignment during installation or during the life of the part; these registers allow
for further compensation. Note that this gyro compensation is separate from the compensation that
occurs during the calibration process at the factory. Setting this register to the default state of an identity
matrix and zero offset will not eliminate the gyro gain, bias, and axis alignment that occur during factory
calibration. These registers only need to be changed from their default values in the event that changes
in bias, gain, and axis alignment have occurred at some point between the times the chip was calibrated
at the factory and when it is used in the field.
{
𝑋
𝑌
𝑍
} = [
𝐶00 𝐶01 𝐶02
𝐶10 𝐶11 𝐶12
𝐶20 𝐶21 𝐶22
] ∙ {
𝐺𝑋 − 𝐵0
𝐺𝑌 − 𝐵1
𝐺𝑍 − 𝐵2
}
The variables {GX, GY, GZ}
IMU
are components of the measured angular rate. The {GX, GY, GZ}
Comp
variables
are the new acceleration measurements outputted after compensation for changes during sensor
mounting. All twelve numbers are represented by single-precision floating points.
