LISA-U2 series - System Integration Manual
UBX-13001118 - R19
Early Production Information
Features description
Page 146 of 175
3.10.2
Hybrid positioning
With u-blox Hybrid positioning technology, u-blox cellular devices 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 configuration of the GNSS
receiver (AT+ULOCGNSS), configuration of the CellLocate
®
service (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
®
), 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 LISA-U2 cellular module
and the u-blox GNSS receiver (see section 1.10).
See the
GNSS Implementation Application Note
[16] 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.
3.11
Control Plane Aiding / Location Services (LCS)
Not supported by "01", "x2" and "68" product versions
With the Assisted GPS feature, a location server provides the module with the GPS system information that
otherwise has to be downloaded from satellites. The feature allows faster position fixes, increases sensitivity and
reduces module power consumption. The feature is invoked by the module through LCS Supplementary Services
or by the Network during emergency calls.
The assisted GPS Location Services feature is based on the Radio Resources Location Protocol (RRLP), according
to 3GPP TS 44.031 [27], and Radio Resource Control (RRC) according to 3GPP TS 25.331 [28].
For more details, see the
3.12
Firmware (upgrade) Over AT (FOAT)
3.12.1
Overview
This feature allows upgrading the module Firmware over UART, USB and SPI interfaces, using AT Commands.
AT Command AT+UFWUPD triggers a reboot followed by the upgrade procedure at specified a baud rate
(see the
u-blox AT Commands Manual
[2] for more details)
The Xmodem-1k protocol is 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
