your position is our focus
Example
Use on/off time
Enabled
T_on [s]
0
(=
one
valid
fix)
T_off [s]
60
Absolute
align
Disabled
Base
TOW
[s]
Not
used
T_acq [s]
60
T_acq_off [s]
120
T_reacq [s]
5
T_reacq_off [s]
60
Operation
As
long
as
there
is
good
GPS
coverage,
the
receiver
will
perform
PVT
solutions
for
T_on
,
then
switches
to
the
state
If
–
during
the
on
time
-
there
is
loss
of
signal
for
T_reacq
(5
seconds,
before
T_on
expires),
the
receiver
will
shut
down
for
T_reacq_off
(60
seconds).
After
that
off
time,
the
receiver
will
try
to
find
the
signal
for
T_acq
shut
down
for
another
T_acq_off
(2
minutes).
sleep
for
T_off
(60
seconds).
(60
seconds).
If
that
fails
it
will
Table 16: Example settings FXN with On/Off Time
Note
If
T_on
is
set
to
0s,
the
receiver
will
enter
Off
State
as
soon
as
the
Position
Accuracy
is
below
the
P Accuracy Mask
(see
also
Section
4.6.8.1
).
For
an
improved
accuracy,
increase
T_on
by
a
few
seconds.
4.2.7.9
FXN with On/Off Time and absolute Alignment
This
mode’s
operation
is
equivalent
to
“
FXN With On/Off Time”
,
but
the
receiver
will
align
on-
and
off
time
to
an
absolute
TOW-based
(GPS
time)
time
grid
after
the
first
successful
fix.
The
parameter
T_off
has
a
slightly
different
meaning
compared
to
the
non-aligned
FixNOW™
mode.
It
is
the
time
grid
unit
rather
than
the
off
time.
T_on
is
still
the
time
the
receiver
operates
in
Full
Power
State
and
output
valid
position
fixes.
Base TOW
is
the
parameter,
which
shifts
the
time
grid
relative
to
TOW
0.
The
TOW
count
begins
with
the
value
0
at
the
beginning
of
the
GPS
week
(transition
period
from
Saturday
23:59:59
hours
to
Sunday
00:00:00
hours).
signal OK
on
GPS
System
state
signal
no signal
signal OK
GPS signal
lost
on
T_aqu
off
T_acq_off
on
Time
off
off
off
on
off
on
T_off+
TOW synch
T_off+
T_off+
c
TOW synch
TOW syn h
on
First Fix
T_aqu
T_reaqu
TOW
alignment
T_reacq_off
First Fix
First Fix
First Fix
T_on
T_on
T_on
T_on
t_on
Figure 59: FXN With On/Off Time and absolute alignment after a first fix
is
caused
by
the
synchronization
of
the
wake
up
time
to
TOW.
Note
If
the
division
of
number
of
seconds
a
week
(604800)
by
T_off
isn’t
an
integer
value,
at
the
end
of
the
week
the
Off
Time
be
shorter
than
T_off
.
This
GPS
Modules
-
System
Integration
Manual
(SIM)
(incl.
Reference
Design)
Receiver
Description
GPS.G4-MS4-05007-A1
Page 71
