ZED-F9R-Integration manual
When a client device makes an AssistNow request, the service responds with the requested data
using standard UBX protocol MGA messages. These messages are ready for direct transmission
from the client to the receiver port without requiring any modification.
3.9.1 Authorization
To use the AssistNow services, customers will need to obtain an authorization token from u-blox. Go
to https://www.u-blox.com/en/solution/services/assistnow or contact your local technical support
to get more information and to request access to the service.
3.9.2 Preserving MGA and operational data during power-off
The time-to-fix after a receiver power interruption is dependent on the amount of operational data
available at startup. Satellite broadcast information plus an estimate of accurate time can be
fetched form the AssistNow service. In addition, the following techniques can restore previously
stored data prior to power down.
• Battery-backed RAM:The receiver operational state stored in this RAM can be maintained
during power outages by connecting the V_BCKP pin to an independent supply, e.g a battery.
This is a recommended method as it will maintain all MGA related information plus any user
configuration, calibration data and an estimate of time via the Real Time Clock. See section
V_BCKP: Backup supply voltage for more information.
• Save-on-shutdown:The receiver can be instructed to dump its current state to flash memory
as part of the shutdown procedure; this data is then automatically retrieved when the receiver
is restarted. For more information, see section Save-on-shutdown feature for more info. For
information on the UBX-UPD-SOS messages consult the applicable interface description [2].
• Advanced calibration handling:The receiver can be instructed to dump its current state (UBX-
MGA-SF and UBX-NAV-PVAT) to host as part of the shutdown procedure or during the drive;
this data is then sent back to the receiver when the receiver is restarted. For more information,
see section Advanced calibration handling for more info.
• Database dump: The receiver can be made to dump the state of its navigation database in the
form of a sequence of UBX messages reported to the host; these messages can be stored by
the host and then sent back to the receiver when it has been restarted. See the description of
the UBX-MGA-DBD messages in the applicable interface description [2] for more information.
3.9.3 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, IMU calibration, 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.
UBX-20039643 - R06
3 Receiver functionality Page 63 of 119
C1-Public
To Next Page
Loading...
Need help?
General
