AT^WPDOM=4 to minimize the amount of data used, or to set AT^WPDOM=2 to
minimize TTFF.
XTRAOne Mode
XTRAOne Mode is an assisted GPS mode that downloads data from a Qualcomm
server once a week and stores the data on the modem. The modem relies on the stored
data instead of talking to the network to find positioning info. To use XTRAOne mode
you must manually download the data from the Qualcomm XTRAOne servers. This data
is located at:
http://xtra1.gpsonextra.net/xtra.bin
http://xtra2.gpsonextra.net/xtra.bin
http://xtra3.gpsonextra.net/xtra.bin
Once the xtra.bin file is downloaded it must manually be uploaded into the modem. See
the Huawei application guide available at www.zoomtel.com/4575support
.
GPS vs GNSS Positioning
Currently there are 2 navigation systems that provide worldwide coverage. The first,
and most widely used, is the U.S. based Navstar Global Positioning System (GPS).
The second is the Russian based Global Navigation Satellite System (GLONASS).
Your modem can use either the GPS system or both the GPS and GLONASS system
combined. When in standalone mode, using both systems (referred to as GNSS) can
increase the reliability and accuracy of your positioning data. By default your modem is
set up to use GPS only. You can set your modem to use GNSS by entering the
command AT^WGNSS=1. After entering this command you must power cycle the
modem for the command to take affect.
Positioning Data vs NMEA Data
Your modem has the option of providing NMEA (National Marine Electronics
Association) data in addition to the normal positioning data. The normal positioning
data provides you with the longitude, latitude, and altitude of the modem. You can take
this data and plug it into an application such as Google Maps to get your location. NMEA
data is the standard format of GPS data used by most GPS applications. NMEA data
always starts with $ immediately followed by a number. GPS data starts with $GP
and GLONASS data starts with $GN.
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