ADIS16480 AD [Analog Devices], ADIS16480 Datasheet - Page 19

• Manufacturer Part Number: ADIS16480
• Description: Ten Degrees of Freedom Inertial Sensor
• Manufacturer: AD [Analog Devices]

Data Sheet
MAGNETOMETERS
The registers that use the x_MAGN_OUT format are the primary
registers for the magnetometer measurements. When processing
data from these registers, use a 16-bit, twos complement data
format. Table 38, Table 39, and Table 40 provide each register’s
numerical format, and Table 41 provides x_MAGN_OUT digital
coding examples.
Table 38. X_MAGN_OUT (Page 0, Base Address = 0x28)
Bits
[15:0]
Table 39. Y_MAGN_OUT (Page 0, Base Address = 0x2A)
Bits
[15:0]
Table 40. Z_MAGN_OUT (Page 0, Base Address = 0x2C)
Bits
[15:0]
Table 41. x_MAGN_OUT Data Format Examples
Magnetic Field
+3.2767 gauss
+0.2 mgauss
+0.1 mgauss
0 gauss
−0.1 mgauss
−0.2 mgauss
−3.2768 gauss
ROLL, PITCH, YAW ANGLES
The EKF_CNFG (Table 94) register contains two bits, which
define the output format of the angle estimates. The first one
is EKF_CNFG[4], which selects the output format. When
EKF_CNFG[4] = 0; the output data is in the format of a
quaternion vector (See Table 42 through Table 45) and Euler
angles (See Table 47 through Table 49). When EKF_CNFG[4] =
1, the output data is in the form of a rotation matrix (see
Table 42 through Table 50).
Description
X-axis magnetometer data; twos complement,
±3.2767 gauss range, 0 gauss = 0x0000,
1 LSB = 0.1 mgauss
Description
Y-axis magnetometer data; twos complement,
±3.2767 gauss range, 0 gauss = 0x0000,
1 LSB = 0.1 mgauss
Description
Z-axis magnetometer data; twos complement,
±3.2767 gauss range, 0 gauss = 0x0000,
1 LSB = 0.1 mgauss
Decimal
+32,767
+2
+1
0
−1
−2
−32,768
Hex
0x7FFF
0x0002
0x0001
0x0000
0xFFFF
0xFFFE
0x8000
Binary
0111 1111 1111 1111
0000 0000 0000 0010
0000 0000 0000 0001
0000 0000 0000 0000
1111 1111 1111 1111
1111 1111 1111 1110
1000 0000 0000 0000
Rev. 0 | Page 19 of 40
Quaternion
This four-element hypercomplex number defines the attitude of
the body frame, relative to that of the navigation frame. The
Qx_Cxx_OUT registers (See Table 42 through Table 45) contain
the value for each element (q0, q1, q2, q4). The element, q0, is
the scalar part of the quaternion and represents the magnitude
of the rotation. The vector portion of the quaternion is defined
by (q1, q2, q3)
rotation takes place, in adjusting the body frame to that of the
navigation frame. When the orientation is in its reference
position, q0 is equal to one and q1, 2, and q3 are equal to zero.
These registers update at the same data rate as the gyroscopes
and accelerometers.
Euler Angles
The Euler angle names are yaw (ψ), pitch (θ), and roll (φ).
See Figure 19 for the axial association of these angles. These
three elements represent the most intuitive way of describing
orientation angles. The process of translating body frame
data to the navigation frame can be broken down into three
successive translations. These translations follow as the yaw
rotation about the z-axis, followed by the pitch rotation about
the y-axis, and finally the roll rotation about the x-axis. Reverse
this sequence to resolve a reverse rotation. Difficulties in this
process arise due to the singularities that occur whenever the
pitch approaches ±90° thus making the roll indistinguishable
from the yaw. For applications that may approach these limits,
the quaternion or rotation matrix output may be more appro-
priate. When the
three Euler angles are equal to zero. The update rate for these
variables is the same as the gyroscopes and accelerometers.
T
, which identifies the axis about which the
ADIS16480
is in its reference position, all
ADIS16480