SAM-M10Q-Integration manual
The longer a receiver observes the sky, the more satellites it will have seen. At the equator, and
with full sky view, approximately ten (GPS) satellites will show up in a one-hour window. After four
hours of observation approx. 16 satellites (i.e. half the constellation), after 10 hours approx. 24
satellites (2/3rd of the constellation), and after approx. 16 hours the full constellation will have been
observed (and AssistNow Autonomous data generated). Lower sky visibility reduces these figures
(i.e. the number of satellites seen). Further away from the equator, the numbers improve because
the satellites can be seen twice a day. For example, at 47 degrees north the full constellation can be
observed in approx. 12 hours with full sky view.
The calculations required for AssistNow Autonomous are carried out on the receiver. This requires
energy and users may therefore occasionally see increased power consumption during short periods
(several seconds, rarely more than 60 seconds) when such calculations are running. Ongoing
calculations will automatically prevent the power save mode from entering the power-off state. The
power-down will be delayed until all calculations are done.
AssistNow Autonomous should be enabled if the system has sporadic access to the
AssistNow Offline service. In this case, the receiver will intelligently choose the more
reliable orbit predictions for each satellite. This way the autonomous prediction can provide
performance improvements if the offline data becomes old or gets outdated.
2.13 CloudLocate
In CloudLocate setup, the host processor of the customer application fetches a set of satellite signal
measurements from the receiver and sends those to the u-blox CloudLocate service for position
calculation. The CloudLocate service uses these measurements and current assistance data to
calculate the receiver position. This data is then provided to the customer enterprise cloud for
further use. Power saving up to 90% is possible compared to a cold start scenario.
The receiver starts to collect measurements as soon as it finds any satellite signals. It does not
need to wait for a position fix for this. Collecting the measurements takes only a short time, so the
application can quickly turn off the receiver or put it into a backup state.
2.13.1 CloudLocate measurements
The satellite signal measurements can be requested from the receiver either as a complete or
compact raw measurement message.
The complete raw measurement message (UBX-RXM-MEASX) provides measurements for all visible
satellites. The customer application can wait until the number of satellites in the message is
sufficient and then send the message to the CloudLocate service. The amount of data in a MEASX
message for five satellites is about 170 bytes. This increases by 24 bytes for each additional
satellite.
Compact raw messages (UBX-RXM-MEAS50, UBX-RXM-MEAS20, UBX-RXM-MEAS12C, and UBX-
RXM-MEAS12D) can be used when the amount of data to be sent to the cloud needs to be
minimized. The data can be reduced to 50, 20, or even 12 Bytes, and the time for the receiver to
stay on shall be limited to the minimum as well. These messages contain the measurement data
in compressed format and use satellites only from a limited set of GNSS constellations. With the
default settings, these messages contain measurement data only for a small number of satellites.
The raw measurement messages are enabled with the configuration keys in the CFG-
MSGOUT configuration group. For example, setting the configuration key CFG-MSGOUT-
UBX_RXM_MEAS50_UART1 to value 1 with UBX-CFG-VALSET message enables output of the UBX-
RXM-MEAS50 message in the UART1 port for each navigation epoch.
UBX-22020019 - R01
2 Receiver functionality Page 51 of 72
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