u-blox ANTARIS 4 - Page 71


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
offonoffon
T_off+
TOW synch
T_off+ T_off+
cTOW synch TOW syn h
on
First Fix
T_aqu
T_reaqu
TOW
alignment
T_reacq_off
First Fix First FixFirst 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