6
4. INTERNAL BLOCK DIAGRAM
The following picture shows in a simplified form the internal logic of the EXLs3 unit.
The task of the unit is to
measure
in real-time the linear
acceleration
and the
angular velocity
at which
the unit itself is subjected (inertial measurements).
The unit can at the same time measure the magnitude of the surrounding
magnetic field
.
All measurements are performed by
tri-axial
sensors, so both
magnitude
and
vector direction
are
acquired.
After the
compensation
of
sensor’s raw data (i.e. offset and gain error removal), data and are processed
in order to calculate the
orientation
of the unit related to a earth reference frame in real-time.
Compensated inertial data together with
Orientation
data are packed and sent wirelessly to the host PC a
the desired
sampling rate
.
The produced stream can also be saved in the internal flash drive, as standard CSV file, in order to be
retrieved afterwards via USB connection for off-line post-processing and/or analysis.
3-axis
Digital
Accelerometer
3-axis
Digital
Gyroscope
3-axis
Digital
Magnetometer
comp
comp
comp
ORIENTATION ESTIMATION
Linear Acceleration
(m/s²)
Angular Speed
(rad/s)
Earth Magnetic
Field (µT)
RAW DATA
COMPENSATED DATA
DATA
PACKING
AND
TIME-
STAMPING
BLUETOOTH
RADIO
DATA-LOG
ON INTERNAL
DRIVE
(CSV FILE)
HOST PC