LEON-G100 / LEON-G200 - System Integration Manual
GSM.G1-HW-09002-G3
Preliminary
Feature description
Page 108 of 125
3.10.2
Threshold Definitions
When the application of wireless module operates at extreme temperatures with Smart Temperature Supervisor
activated, the user should note that outside the valid temperature range the device will automatically shut down
as described above.
The input for the algorithm is always the temperature measured within the wireless module (Ti, internal). This
value can be higher than the working ambient temperature (Ta, ambient), since (for example) during
transmission at maximum power a significant fraction of DC input power is dissipated as heat This behavior is
partially compensated by the definition of the upper shutdown threshold (t
+2
) that is slightly higher than the
declared environmental temperature limit.
Table 37 defines the temperature thresholds.
Symbol
Parameter
Temperature
Remarks
t
-2
Low temperature shutdown
–40 °C
Equal to the absolute minimum temperature rating for the wireless
module
t
-1
Low temperature warning
–30 °C
10°C above t
-2
t
+1
High temperature warning
+85 °C
15°C below t
+2
. The higher warning area for upper range ensures
that any countermeasures used to limit the thermal heating will
become effective, even considering some thermal inertia of the
complete assembly.
t
+2
High temperature shutdown
+100 °C
Equal to the internal temperature Ti measured in the worst case
operating condition at typical supply voltage when the ambient
temperature Ta in the setup “A” described below equals the
absolute maximum temperature rating
Table 37: thresholds definition for Smart Temperature Supervisor
3.11
Hybrid positioning and CellLocate
TM
Although GPS is a widespread technology, its reliance on the visibility of extremely weak GPS satellite signals
means that positioning is not always possible. Especially difficult environments for GPS are indoors, in enclosed
or underground parking garages, as well as in urban canyons where GPS signals are blocked or jammed by
multipath interference. The situation can be improved by augmenting GPS receiver data with cellular network
information to provide positioning information even when GPS reception is degraded or absent. This additional
information can benefit numerous applications.
3.11.1
Positioning through cellular information: CellLocate
TM
u-blox CellLocate
TM
enables the estimation of device position based on the parameters of the mobile network
cells visible to the specific device. To estimate its position the u-blox Wireless module sends the CellLocate
TM
server the parameters of network cells visible to it using a UDP connection. In return the server provides the
estimated position based on the CellLocate
TM
database. The u-blox Wireless module can either send the
parameters of the visible home network cells only (normal scan) or the parameters of all surrounding cells of all
mobile operators (deep scan).
The CellLocate
TM
database is compiled from the position of devices which observed, in the past, a specific cell or
set of cells (historical observations) as follows:
1.
Several devices reported their position to the CellLocate
TM
server when observing a specific cell (the As in
the picture represent the position of the devices which observed the same cell A)
