RCB-F9T - Integration manual
GNSS
Signal
gnssId
sigId
numWords
period
GLONASS
L2OF
6
2
3
2s
Table 21: Data message formats reported by UBX-RXM-SFRBX
3.12.2 Save-on-shutdown feature
The save-on-shutdown feature (SOS) enables the u-blox receiver to store the contents of the
battery-backed RAM to an external flash memory and restore it upon startup. This allows the u-
blox receiver to preserve some of the features available only with a battery backup (preserving
configuration and satellite orbit knowledge) without having a battery backup supply present. It does
not, however, preserve any kind of time knowledge. Save-on-shutdown must be commanded by the
host. The restoring of data on startup is automatically done if the corresponding data is present in
the flash. Data expiration is not checked.
The following outlines the suggested shutdown procedure when using the save-on-shutdown
feature:
• With the UBX-CFG-RST message, the host commands the u-blox receiver to stop, specifying
reset mode 0x08 ("Controlled GNSS stop") and a BBR mask of 0 ("Hotstart").
• The host commands the saving of the contents of BBR to the flash memory using the UBX-
UPD-SOS-BACKUP message.
• For a valid request the u-blox receiver reports on the success of the backup operation with a
UBX-UPD-SOS-ACK message.
• The host powers off the u-blox receiver.
The startup procedure is as follows:
• The host powers on the u-blox receiver.
• The u-blox receiver detects the previously stored data in the flash. It restores the corresponding
memory and reports the success of the operation with a UBX-UPD-SOS-RESTORED message
on the port on which it had received the save command message (if the output protocol filter on
that port allows it). It does not report anything if no stored data has been detected.
• Additionally the u-blox receiver outputs a UBX-INF-NOTICE and/or a NMEA-TXT message
with the contents
RESTORED
in the boot screen (depends on the configuration of the port and
information messages) upon success.
• Optionally the host can deliver coarse time assistance using UBX-MGA-INI-TIME_UTC for
better startup performance.
Once the u-blox receiver has started up it is recommended to delete the stored data using a UBX-
UPD-SOS-CLEAR message. The u-blox receiver responds with a UBX-ACK-ACK / UBX-ACK-NAK
message.
3.12.3 Spectrum analyzer
The UBX-MON-SPAN message provides a low-resolution RF spectrum analyzer function sufficient
to identify noise or jammers in the receiver's reception band(s). It can be used for monitoring
potential interferors during customer integration and in normal operation to identify interference,
e.g. when the UBX-MON-RF message detects a possible jamming threat. See
for more details. u-center provides a visualization of the message spectrum output(s) with
features for max-hold and averaging.
This message is intended for comparative analysis of the RF spectrum rather than absolute
and precise measurement.
UBX-22004121 - R01
3 Receiver functionality
Page 49 of 64
C1-Public
Early production information
