User's Manual

SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R18 Advance Information System description
Page 63 of 206
the position in a shorter time with higher accuracy. When GPS local aiding is enabled, the cellular module
automatically uploads data such as position, time, ephemeris, almanac, health and ionospheric parameter
from the positioning receiver into its local memory, and restores this to the GNSS receiver at the next power
up of the positioning receiver
For more details regarding the handling of the DDC (I
2
C) interface, the GNSS aiding features and the
GNSS related functions over GPIOs, see section 1.11, to the u-blox AT Commands Manual [3] (AT+UGPS,
AT+UGPRF, AT+UGPIOC AT commands) and the GNSS Implementation Application Note [27].
“GNSS data ready” and “GNSS RTC sharing” functions are not supported by all u-blox GNSS receivers
HW or ROM/FW versions. See the GNSS Implementation Application Note [27] or to the Hardware
Integration Manual of the u-blox GNSS receivers for the supported features.
As additional improvement for the GNSS receiver performance, the V_BCKP supply output of SARA-G340,
SARA-G350 and SARA-U2 modules can be connected to the V_BCKP supply input pin of u-blox positioning
chips and modules to provide the supply for the GNSS real time clock and backup RAM when the VCC supply of
the cellular module is within its operating range and the VCC supply of the GNSS receiver is disabled.
This enables the u-blox positioning receiver to recover from a power breakdown with either a hot start or a
warm start (depending on the duration of the GNSS receiver VCC outage) and to maintain the configuration
settings saved in the backup RAM.