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Gemini G3 - User Manual
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4.7.4 GPS
All GeminiG3 radiomodems shipped from the Dataradio factory are fitted with a 12-channel high ef-
ficiency GPS receiver, equipped with WAAS feature for better location precision (<3 meters).
GPS "strings" are collected from embedded GPS receiver in the GeminiG3 mobile radiomodems. The
strings are converted into DCF 2.0 ("Dataradio Compressed Format, version 2.0") reports and pro-
vided to both local and remote delivery services.
Programmers who need to decode the compressed information for their applications may contact Da-
taradio System Engineering for further information.
4.7.4.1
GPS
►
Status
Figure 45 - GPS - Status
Item
Description
Condition
In normal operation, indicates “Differential”. Differential GPS corrects various inaccura-
cies in the GPS system to yield measurements accurate to a couple of meters when the
mobile is moving and even better when stationary.
Other indications are:
Autonomous: GPS values use no additional correction information.
Last known: Indicates GPS data is either old or not enough satellites are present to
achieve a valid location computation.
Invalid: When no GPS signal is present, displays the word “Invalid” and the # of Satellites
indicates “0”.
Number SVs
The field “number of satellites” indicates the number of satellite signals being received
and used to calculate position.
UTC (hhmmss)
Universal time - uses a 24-hour clock format.
Position
Global position in Longitude (East-West) and Latitude (North-South) displayed using in-
formation obtained from a GeminiG3 radiomodem decoding a valid GPS input signal.
If no previous position was obtained, display shows (Unknown).
Positions are reported in degrees plus decimal minutes.
E.g.: Longitude of 73 degrees, 39 minutes and 45 seconds West would appear as:
073 39.7500 W
Altitude (meters)
The field “Altitude” indicates height above the WGS-84 (World Geodetic System) refer-
ence ellipsoid in meters.
True Course
Shows the current GPS-generated true course in degrees.
Ground Speed (km/h)
Shows travel speed (in km/h) from GPS-equipped GeminiG3 mobiles.