ADIS16480 AD [Analog Devices], ADIS16480 Datasheet - Page 28

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

ADIS16480
REFERENCE FRAME
During the power-on initialization and reset recovery opera-
tions, the
references for use in the orientation computation. During this
process, the gravity vector becomes the accelerometer reference
and the magnetometer reference computation includes the
following steps: measure horizontal and vertical components
of the magnetic field and align the horizontal component to
magnetic north. This also measures the inclination, which
removes this requirement from an external system. The resulting
reference frame is a local ENU inertial frame formed by the
y-axis pointing at magnetic north, the z-axis pointing up, and
the x-axis completing the right-hand frame by pointing east.
REFERENCE TRANSFORMATION MATRIX
The reference transformation matrix, R
programmable alignment function for orientation alignment
to a local navigation frame. Another common name for this
function in navigation system literature is the coordinate
transformation matrix.
When this matrix is equal to an identify matrix (factory
default), the local navigation frame matches true level, with
respect to gravity, and magnetic north. The tare command
automatically calculates and loads the matrix values that
establish the current ADIS16480 orientation as the reference
orientation. When the ADIS16480 is in the desired reference
orientation, initiate the tare command by setting GLOB_CMD[8]
= 1 (DIN = 0x8003, then DIN = 0x8301, see Table 146).
Each element in this matrix is associated with a register that
provides read and write access. See Table 84 through Table 92,
for these registers. Use these registers to define the local
navigation frame, based on system generated requirements.
Each element is the cross product of the unit vectors that
describe the axes of the two frames, which are equal to the
cosines of the angles between the axes. Units of rotation vary
by ±1. When writing to these registers, write to R33 last because
a write to the upper byte of this register causes all nine registers
to update inside of the ADIS16480.
R
IJ
=
ADIS16480





R
R
R
11
21
31
R
R
R
12
22
32
R
R
R
sets the accelerometer and magnetometer
13
23
33





IJ
, provides a user-
Rev. 0 | Page 28 of 40
Table 84. REFMTX_R11 (Page 2, Base Address = 0x62)
Bits
15
[14:0]
Table 85. REFMTX_R12 (Page 2, Base Address = 0x64)
Bits
15
[14:0]
Table 86. REFMTX_R13 (Page 2, Base Address = 0x66)
Bits
15
[14:0]
Table 87. REFMTX_R21 (Page 2, Base Address = 0x68)
Bits
15
[14:0]
Table 88. REFMTX_R22 (Page 2, Base Address = 0x6A)
Bits
15
[14:0]
Table 89. REFMTX_R23 (Page 2, Base Address = 0x6C)
Bits
15
[14:0]
Table 90. REFMTX_R31 (Page 2, Base Address = 0x6E)
Bits
15
[14:0]
Table 91. REFMTX_R32 (Page 2, Base Address = 0x70)
Bits
15
[14:0]
Table 92. REFMTX_R33 (Page 2, Base Address = 0x72)
Bits
15
[14:0]
Description (Default = 0x7FFF)
Sign bit
Magnitude, binary, 1 LSB = 1/2
Description (Default = 0x0000)
Sign bit
Magnitude, binary, 1 LSB = 1/2
Description (Default = 0x0000)
Sign bit
Magnitude, binary, 1 LSB = 1/2
Description (Default = 0x0000)
Sign bit
Magnitude, binary, 1 LSB = 1/2
Description (Default = 0x7FFF)
Sign bit
Magnitude, binary, 1 LSB = 1/2
Description (Default = 0x0000)
Sign bit
Magnitude, binary, 1 LSB = 1/2
Description (Default = 0x0000)
Sign bit
Magnitude, binary, 1 LSB = 1/2
Description (Default = 0x0000)
Sign bit
Magnitude, binary, 1 LSB = 1/2
Description (Default = 0x7FFF)
Sign bit
Magnitude, binary, 1 LSB = 1/2
15
15
15
15
15
15
15
15
15
Data Sheet