SARA-G3 series - System Integration Manual
UBX-13000995 - R06
Objective Specification
System description
Page 87 of 218
The accuracy of the position estimated by CellLocate
TM
depends on the availability of historical
observations in the specific area.
1.13.10.2
Hybrid positioning
With u-blox hybrid positioning technology, u-blox wireless modules can be triggered to provide their current
position using either a u-blox GNSS receiver or the position estimated from CellLocate. The choice
depends on which positioning method provides the best and fastest solution according to the user
configuration, exploiting the benefit of having multiple and complementary positioning methods.
Hybrid positioning is implemented through a set of three AT commands that allow GNSS receiver
configuration (AT+ULOCGNSS), CellLocate
TM
service configuration (AT+ULOCCELL), and requesting the
position according to the user configuration (AT+ULOC). The answer is provided in the form of an
unsolicited AT command including latitude, longitude and estimated accuracy (if the position has been
estimated by CellLocate
TM
), and additional parameters if the position has been computed by the GNSS
receiver.
The configuration of mobile network cells does not remain static (e.g. new cells are continuously added or
existing cells are reconfigured by the network operators). For this reason, when a hybrid positioning
method has been triggered and the GNSS receiver calculates the position, a database self-learning
mechanism has been implemented so that these positions are sent to the server to update the database
and maintain its accuracy.
The use of hybrid positioning requires a connection via the DDC (I
2
C) bus between the SARA-G350
wireless module and the u-blox GNSS receiver (refer to section 2.5.3).
Refer to
GNSS Implementation Application Note [21] for the complete description of the feature.
u-blox is extremely mindful of user privacy. When a position is sent to the CellLocate server u-blox
is unable to track the SIM used or the specific device.
1.13.11
Firmware upgrade Over AT (FOAT)
1.13.11.1
Overview
This feature allows upgrading the module Firmware over the UART interface, using AT Commands.
AT Command AT+UFWUPD triggers a reboot followed by the upgrade procedure at specified a baud
rate (refer to
u-blox AT Commands Manual [2] for more details)
Both Xmodem-1k protocol (1024 bytes packets) and Xmodem protocol (128 bytes packets) can be
used for downloading the new firmware image via a terminal application
A special boot loader on the module performs firmware installation, security verifications and module
reboot
Firmware authenticity verification is performed via a security signature during the download. The
firmware is then installed, overwriting the current version. In case of power loss during this phase, the
boot loader detects a fault at the next wake-up, and restarts the firmware download from the
Xmodem-1k handshake. After completing the upgrade, the module is reset again and wakes-up in
normal boot
