your position is our focus
3.1.2 Input Signals/ Sensors
3.1.2.1
Turn rate sensor (Gyroscope)
The
gyroscope
indicates
the
turn
rate
of
the
device.
The
gyro
output
signal
is
connected
via
an
A/D
converter
to
the
DR
module
and
sampled
at
40
Hz.
The
integration
of
the
gyro
signal
over
one
measurement
period
is
equal
to
the
relative
turn
of
the
device
during
this
period.
There
are
three
major
parameters
of
the
gyroscope:
•
Gyro Bias
:
Describes
the
offset
of
the
gyro
signal
at
a
turn
rate
of
0
[deg/s].
+/-25.0
[deg/s]
is
the
maximum
allowed
Gyro
Bias
Offset.
•
Gyro Scale Factor
:
Describes
the
relation
of
the
typical
gyro
sensitivity
[V/(deg/s)]
of
the
real
measured
output
voltage
[V]
to
the
actual
turn
rate
[deg/sec].
This
value
has
an
upper
limit
of
1.2,
and
a
lower
limit
of
0.8.
This
means
that
the
implemented
gyro
can
vary
by
+/-
20%,
from
the
typical
gyro
sensitivity.
•
Gyro Bias as function of the temperature
:
Any
differences
from
the
Gyro
Bias
Offset
over
the
entire
temperature
range
are
stored
in
a
lookup
table,
called
Temperature
Compensation
Table
(TC).
This
table
covers
a
temperature
range
of
–40
deg
Celsius
to
+80
deg
Celsius.
Turn
Rate
w
[deg/s]
+100
Gyro
Voltage
0
-100
2.5
5.0
0
Gyro
Bias
Offset
typical
Gyro
Sensitivity
Gyro
Scale
Factor
real
Gyro
Sensitivity
Figure 8: Gyroscope Signals
Gyro-
scope
A
D
DR
module
Figure 9: Gyroscope Signals Flow
!
Note
The
mounting
angle
of
the
gyro
influences
its
performance
significantly.
The
angle
of
incline
should
not
exceed
the
maximal
value
referring
to
the
turn
axis
of
the
vehicle.
Consult
the
datasheet
of
the
gyro
carefully
to
choose
the
appropriate
mounting
technique
as
well
the
right
parameter
settings
(e.g.
Gyro
Sensitivity,
Polarity,
max
angle
of
inclination
etc.)
Z
axis
Y
axis
X
axis
z
axis
Angle
of
incline
Gyro
Gyro
Figure 10: Mounting of the gyroscope
LEA-4R
/
TIM-4R
-
System
Integration
Manual
/
Reference
Design
Receiver
Description
GPS.G4-MS4-05043
Page 17
