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4.1.1 Microprocessor and memory
CORTEX A8 at 800MHz clock speed with 512 MB of DDR3 and 1GB of non-
volatile NAND FLASH. These provide, in terms of available user space, 468 MB
free RAM and 834 MB free Flash for the default configuration, with a basic
Debian running in the system.
4.1.2 GSM/GPRS System
owa4x provides GSM communication (Quad band GSM 850/900+1800/1900 as
the default configuration). Audio calls, data calls and Short Message Service
are the features supported by GSM.
GPRS is a widely deployed value added service of the cellular infrastructure
that enables direct access to public and private data networks (Internet,
corporate networks, private networks...). Using the owa4x GPRS service
instead of simple GSM service significantly reduces traffic cost since resources
are only allocated when data is to be sent/received.
GPRS service is class B and class 12. Four time-slots for the downlink and one
for the uplink are available.
HSPA is also available as option with HSDPA Cat.8 / HSUPA Cat.6 data rates:
DL 7.2Mbps and UL 5.7Mbps.
4.1.3 GNSS
GNSS (Global Navigation Satellite System) includes most of the available
regional systems composed of a constellation of satellites orbiting the Earth,
such as GPS, GLONASS, Galileo and Beidou, transmitting signals that allow
the GNSS receivers to determine the receiver position (longitude, latitude and
height) and time (Universal Time Coordinated, UTC).
With the GNSS module included in owa4x, accurate position and time
information is provided for Location Based Applications. The default datum
used by the GNSS is WGS-84.
The GNSS can work in 2D navigation (viewing 3 satellites) or 3D navigation
(viewing at least 4 satellites). When the GNSS starts up, it gives a valid position
as soon as it sees 3 satellites, but it can only know the altitude once it sees 4
satellites. This is the reason why in the starting process, there is the possibility
of a position jump. This position jump is more likely to happen the greater the
altitude is.
The GNSS outputs the altitude as HAE (“Height Above Ellipsoid”) ( i.e. WGS-
84). But since an ellipsoid cannot model the shape of the earth perfectly, one
can see some deviation from the so-called “Mean Sea Level” altitude. MSL
refers to the actual sea level. The difference between these two altitudes can
exceed 100m.
The supported GNSS receiver is Ublox NEO-M8N.
4.1.4 Hardware Interfaces
Owa4X is able to interface with many different devices through an extensive
range of hardware signals, grouped into several connectors. Here every
connector pin-out is depicted together with a brief description of every signal
and electrical specifications and advice of use.
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General