SAM-M10Q - Integration manual
Requirements
AssistNow Online
AssistNow Offline
AssistNow Autonomous
Requires external flash memory
No
Optional
Optional
Requires internet connection
Permanently
Sporadically
No
Amount of internet data
Medium
High
None
Ephemeris in data
Yes
No
No
Almanac in data
Yes
Yes
Yes
Table 16: AssistNow service overview
2.12.1 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.
2.12.2 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 and an estimate of accurate time can be
fetched form the AssistNow service. In addition, the following techniques can restore the data that
was stored prior to powering 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, any user
configuration, calibration data, and an estimate of time via the real-time clock. See
for
more information.
•
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 SAM-M10Q interface description [
] for more information.
2.12.3 AssistNow offline
AssistNow Offline is a feature that combines special firmware in u-blox receivers and a proprietary
service run by u-blox. It is targeted at receivers that only have occasional internet access and so
cannot use AssistNow Online. AssistNow Offline speeds up time to first fix (TTFF), typically to
considerably less than 10 s.
AssistNow Offline currently supports GPS and GLONASS. u-blox intends to expand the
AssistNow Offline Service to support other GNSS (such as BeiDou and Galileo) in due course.
The AssistNow Offline Service uses a simple, stateless, HTTP interface. Therefore, it works on all
standard mobile communication networks that support internet access, including GPRS, UMTS and
Wireless LAN. No special arrangements need to be made with mobile network operators to enable
AssistNow Offline.
Users of AssistNow Offline are expected to download data from the AssistNow Offline Service,
specifying the time period they want covered (1 day to 5 weeks) and the types of GNSS. This data
must be uploaded to a u-blox receiver, so that it can estimate the positions of the satellites when no
better data is available. Using these estimates will not provide as accurate a position fix as if current
ephemeris data is used, but it will allow a much faster TTFF in nearly all cases.
The data obtained from the AssistNow Offline Service is organized by date, normally a day at a time.
Consequently, the longer the requested coverage time, the more data there is to handle. Similarly,
each different GNSS requires its own data and in extreme cases, several hundred kilobytes of data
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2 Receiver functionality
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