SAM-M10Q - Integration manual
periods (in the range of minutes or longer), only use on/off operation. See section
and
for more information on the two modes of operation.
POSUPDATEPERIOD, ACQPERIOD
The update period POSUPDATEPERIOD specifies the time
between successive position fixes. If no position fix can be obtained within the acquisition timeout,
the receiver will retry after the time specified by the search period ACQPERIOD. Update and search
periods are fixed with respect to an absolute time grid based on reference time standard (i.e., GPS
time or UTC). They do not refer to the time of the last valid position fix or last position fix attempt.
Where multiple GNSS can operate simultaneously, UTC time is used as the reference time standard.
The update period setting is ignored if the receiver is set into cyclic tracking mode. It only has an
impact if the receiver is set to on/off mode. New settings are ignored if the update period or the
search period exceeds the maximum number of milliseconds in a week. In that case the previously
stored values remain effective.
GRIDOFFSET
Once the receiver has a valid time, the update grid is aligned to the start of the week of
the reference time standard (midnight between Saturday and Sunday). Before having a valid time,
the update grid is unaligned. A grid offset shifts the update grid with respect to the start of the week
of the reference time standard. The grid offset is not used in cyclic tracking operation.
ONTIME
This specifies how long the receiver stays in the "Tracking" state before switching to the
"POT" state in PSMCT or the "Inactive for update" state in PSMOO.
MINACQTIME
The receiver tries to obtain a position fix for at least the time given by MINACQTIME.
If the receiver determines that it needs more time for the given starting conditions then it will
automatically prolong this time. If MINACQTIME is set to zero, the receiver determines the time.
Once the MINACQTIME has expired, the receiver will terminate the acquisition state if either a fix is
achieved or if the receiver estimates that any signals received are insufficient (too weak or too few)
for a fix to be possible.
MAXACQTIME
This defines the maximum time that the receiver will spend in the "Acquisition"
state. If the receiver is unable to acquire a valid position fix within this maximum time, it will
transition to the "Inactive for search" state (if DONOTENTEROFF is disabled). Subsequently, the
receiver will attempt to acquire another position fix according to the search period ACQPERIOD. If
MAXACQTIME is set to zero, the receiver will autonomously determine the maximum time to spend
in the "Acquisition" state. Note that shorter settings (below about 45 s) will degrade an unaided
receiver's ability to collect new Ephemeris data at low signal levels.
DONOTENTEROFF
If this option is enabled, then when the receiver cannot get a fix it keeps
attempting to acquire a position fix instead of entering the "Inactive for search" state. In other
words, the receiver will never be in the "Inactive for search" state and therefore the search period
ACQPERIOD and the minimum acquisition time MINACQTIME will be ignored.
WAITTIMEFIX
A time fix is a fix type in which the receiver will ensure that the time is accurate and
confirmed to within the limits set in CFG-NAVSPG. Enabling the WAITTIMEFIX option will force the
receiver to stay in the "Acquisition" state until the time is known to be within the configured limits,
then it will transition to the "Tracking" state. Take into account that enabling WAITTIMEFIX will delay
the transition from the "Acquisition" state to the "Tracking" state by at least two extra seconds.
The quality of the position fixes can also be configured by setting the limits in the CFG-NAVSPG
group. Setting harder limits in CFG-NAVSPG will typically prolong the time in the "Acquisition" state.
When externally controlled, it is therefore necessary to ensure sufficient time for the receiver at
startup. Refer to
for more information. When internally controlled, the receiver
can make good judgment on the time needed in the "Acquisition" state and no further adjustments
will be needed.
UBX-22020019 - R01
2 Receiver functionality
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