your position is our focus
‘noise’
that
may
interfere
with
the
antenna
performance.
For
further
information
about
Antenna
designs
refer
to
Note
LNA
required
for
passive
antennas.
Activ
tenn
ise
amplifier.
They
can
be
directly
connected
to
RF_IN
.
If
an
active
antenna
is
connected
to
RF_IN
,
the
integrated
low-noise
amplifier
of
the
antenna
needs
to
be
supplied
with
the
through
the
power
cons
inner
conductor
will
be
separated
from
the
RF
signal
and
routed
to
the
supply
pin
of
the
LNA
(see
Figure 60
).
Section 3.4.
Passive
antennas
do
not
require
a
DC
bias
voltage
and
can
be
directly
connected
to
the
RF
input
pin
RF_IN
.
Sometimes,
they
may
also
need
a
passive
matching
network
to
match
the
impedance
to
50
Ohms.
Note
Some
passive
antenna
designs
present
a
DC
short
to
the
RF
input,
when
connected.
If
a
system
is
designed
with
antenna
bias
supply
AND
there
is
a
chance
of
a
passive
antenna
being
connected
to
the
design,
consider
a
short
circuit
protection.
All
ANTARIS
®
4
receivers
have
a
built-in
4.3.2
e
An
a
Active
antennas
have
an
integrated
low-no
correct
voltage
through
pin
V_ANT
or
an
external
inductor.
Usually,
the
supply
voltage
is
fed
to
the
antenna
coaxial
RF
cable.
Active
antennas
require
a
power
supply
that
will
contribute
to
the
total
GPS
system
umption
budget
with
additional
5
to
20
mA
typically.
Inside
the
antenna,
the
DC
component
on
the
Antenna
Low Noise Amplifier LNA
ATR0610
GND
GND
V_ANT
Coaxial Antenna Cable
Active Antenna
RF_IN
17
19
V_ANT
Figure 60: Active antenna biasing
Generally
an
active
antenna
is
easier
to
integrate
into
a
system
design,
as
it
is
less
sensitive
to
jamming
compared
to
a
passive
Antenna.
But
an
active
Antenna
must
also
be
placed
far
from
any
noise
sources
to
have
a
good
performance.
!
Warning
Antennas
should
only
be
connected
to
the
receiver
when
the
receiver
is
not
powered.
Do
not
connect
or
disconnect
the
Antenna
when
the
ANTARIS
®
4
GPS
receiver
is
running
as
the
receiver
calibrates
the
noise
floor
on
power-up.
Connecting
the
antenna
after
power-up
can
result
in
prolonged
acquisition
time.
!
Warning
Never
feed
supply
voltage
into
RF_IN.
ways
feed
via
V_ANT
or
an
external
inductor
.
Note
To
test
GPS
signal
reacquisition,
we
recommend
physically
blocking
the
signal
to
the
antenna,
rather
than
disconnecting
and
reconnecting
the
receiver.
Al
GPS
Modules
-
System
Integration
Manual
(SIM)
(incl.
Reference
Design)
Receiver
Description
GPS.G4-MS4-05007-A1
Page 73