SAM-M10Q - Integration manual
UPDATEEPH
To maintain the ability of a fast startup, the receiver needs to update its ephemeris
data on a regular basis. This can be ensured by activating the update Ephemeris option
UPDATEEPH. The ephemeris data is updated approximately every 30 minutes. Refer to
for more information.
2.6.2.7 Satellite data download
The receiver is not able to download satellite data (e.g. the ephemeris) while it is working in on/off
or cyclic tracking operation. Therefore it has to temporarily switch to continuous operation for the
time the satellites transmit the desired data. To save power the receiver schedules the downloads
according to an internal timetable and only switches to continuous operation when data of interest
is being transmitted by the satellites.
Each satellite transmits its own ephemeris data. Ephemeris data download is feasible when the
corresponding satellite has been tracked with a sufficient C/N0 over a certain period of time. The
download is scheduled in a 30-minute grid or immediately when fewer than a certain number of
visible satellites have valid ephemeris data.
Almanac, ionosphere, UTC correction, and satellite health data are transmitted by all satellites
simultaneously. Therefore these parameters can be downloaded when a single satellite is tracked
with a sufficiently high C/N0.
Allowing more ephemerides to be downloaded before going into the "POT" or the "Inactive for update"
state can help improve the quality of the fixes and reduce the number of wake ups needed to
download ephemerides at the cost of extra time in the "Acquisition" state (only when an inadequate
number of ephemerides are downloaded from tracked satellites).
2.6.3 Backup modes
A backup mode is an inactive state where the power consumption is reduced to a fraction of that
in operating modes. The receiver maintains time information and navigation data to speed up the
receiver restart after backup or standby mode.
SAM-M10Q supports two backup modes: hardware backup mode and software standby mode.
2.6.3.1 Hardware backup mode
The hardware backup mode allows entering a backup state and resuming operation by switching the
power supplies on and off. The receiver automatically enters the hardware backup mode if the VCC
and V_IO are removed. The hardware backup mode always requires an independent backup battery.
V_BCKP must be supplied to maintain the backup domain (BBR and RTC) to allow better TTFF,
accuracy, availability, and power consumption at the next startup. As V_IO is not supplied, the PIOs
cannot be driven by an external host processor. If driving of the PIOs cannot be avoided, buffers are
required for isolating the PIOs.
2.6.3.2 Software standby mode
Software standby mode allows control over the backup state with the software command UBX-
RXM-PMREQ. The V_IO and VCC must be supplied, however VCC supply is internally disabled to save
power. The V_IO supply maintains the BBR, RTC, and PIOs.
Entering the software standby mode clears the RAM memory including the receiver configuration.
To maintain the configuration, store it on both RAM and battery-backed RAM (BBR) layers.
The software standby mode can be set for a specific duration, or until the receiver is woken up by
a signal at a wake-up source defined in UBX-RXM-PMREQ. The possible wake-up sources are UART
RX, EXTINT, and/or SPI CS pin. Refer to the interface description [
] for more information on UBX-
UBX-22020019 - R01
2 Receiver functionality
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