GPS
Positioning
is
weighted
more
heavily
as
long
as
the
GPS
parameter
(e.g.
DOP,
number
of
satellites,
signal
ations,
where
the
GPS
signals
are
poor,
reflected
from
with
a
higher
weighting.
quality)
indicates
good
and
reliable
performance.
In
situ
buildings
(multipath)
or
jammed,
the
DR
solution
is
used
Poor GPS
No GPS
Good GPS
GPS
DR
GPS
DR
GPS
DR
Extrapolation
Blending
Calibration
EKF
EKF
EKF
Position,
Velocity,
Time
Position,
Velocity,
Time
y,
Time
from
e
clock
Position,
Velocit
real-tim
Altitude
held
constant
Fig re 30: Dead Reckoning Blending
u
(sensor
based)
positions
are
reported.
The
position
is
calculated
based
on
the
signals
of
the
turn
rate
sensor
and
speed
sensor,
with
reference
to
the
last
reception,
the
S
and
sensor
based
•
situation,
the
GPS
position
values
are
used
to
calibrate
the
DR
sensors
or
to
perform
sensor
integrity
checks
(to
establish
if
the
sensors
are
well
calibrated).
•
No GPS:
During
GPS
loss,
only
DR-
known
GPS
solution.
•
Poor GPS:
In
urban
canyons
with
fast
changing
sky
visibility
or
during
degraded
GPS
ANTARIS
®
4
DR
Technology
performs
a
calculation
by
blending
the
GP
positioning.
Good GPS:
With
good
GPS
performance
and
optimal
sky
view,
the
GPS
position
has
a
higher
weight
than
the
DR/sensor
based
position
on
the
overall
navigation
solution.
In
this
GPS
Modules
-
System
Integration
Manual
(SIM)
(incl.
Reference
Design)
GPS
Fundamentals
GPS.G4-MS4-05007-A1
Page 34
